Adjuvant Letrozole Research Articles

The role of Letrozole in IVF treatment: new remedy or old mirage?

Aromatase inhibitors, particularly letrozole, are now established as first-line ovulation induction agents, offering an effective ovarian stimulation strategy to enhance outcomes of intrauterine insemination. In recent years, they have also emerged as potentially valuable adjuvants to gonadotropin ovarian stimulation for IVF, particularly in fertility preservation in women with estrogen-responsive cancers. Their primary mechanism of action is to reduce circulating estrogen levels by inhibiting androgen aromatization. Recent studies have provided evidence that this property may confer therapeutic advantages in other patients undergoing IVF. In this article, evidence supporting the role of adjuvant letrozole in poor responders, as a moderator of OHSS symptoms, and an agent for improving the luteal phase after ovarian stimulation is reviewed. The use of letrozole for endometrial preparation in the frozen-thawed embryo transfer cycle is also considered.

Identification of non-adherence to adjuvant letrozole using a population pharmacokinetics approach in hormone receptor-positive breast cancer patients

BackgroundLetrozole, an aromatase inhibitor metabolised via CYP2A6 and CYP3A4/5 enzymes, is used as adjuvant therapy for women with hormone receptor (HR)-positive early breast cancer. The objective of this study was to quantify the impact of CYP2A6 genotype on letrozole pharmacokinetics (PK), to identify non-adherent patients using a population approach and explore the possibility of a relationship between non-adherence and early relapse. MethodsBreast cancer patients enrolled in the prospective PHACS study (ClinicalTrials.gov NCT01127295) and treated with adjuvant letrozole 2.5 mg/day were included. Trough letrozole concentrations (Css,trough) were measured every 6 months for 3 years by a validated LC-MS/MS method. Concentration-time data were analysed using non-linear mixed effects modelling. Three methods were evaluated for identification of non-adherent subjects using the base PK model. Results617 patients contributing 2534 plasma concentrations were included and led to a one-compartment PK model with linear absorption and elimination. Model-based methods identified 28 % of patients as non-adherent based on high fluctuations of their Css,trough compared to 3 % based on patient declarations. The covariate analysis performed in adherent subjects revealed that CYP2A6 intermediate (IM) and slow metabolisers (SM) had 21 % (CI95 % = 12 – 30 %) and 46 % (CI95 % = 41 – 51 %) lower apparent clearance, respectively, compared to normal and ultrarapid metabolisers (NM+UM). Early relapse (19 patients) was not associated with model-estimated, concentration-based or declared adherence in the total population (p = 0.41, p = 0.37 and p = 0.45, respectively). ConclusionsThese findings will help future investigations focusing on the exposure-efficacy relationship for letrozole in adjuvant setting.

Abstract PO4-20-11: Excellent Response to Trastuzumab Deruxtecan in “HER-2 Low” Leptomeningeal Breast Cancer and Diagnostic and Monitoring Utility of CNSide Assay

Abstract A 72-year-old female presented to the emergency department with sudden onset of imbalance and cognitive decline. Two years ago, she was diagnosed with stage III estrogen receptor (ER) positive, progesterone receptor (PR) negative and human epidermal growth factor receptor 2 (HER2) negative (immunohistochemistry score: 0) invasive breast cancer. She subsequently underwent lumpectomy, adjuvant radiation and chemotherapy. She had been taking adjuvant letrozole at the time of presentation. Magnetic resonance imaging (MRI) of the brain showed obstructive hydrocephalus without any parenchymal lesion or leptomeningeal enhancement. MRI of spine, computerized tomography of chest/abdomen/pelvis and bone scan were unrevealing except a left adrenal mass which was equivocal for metastasis. Cerebrospinal fluid (CSF) analysis showed rare malignant cells. Based on the morphology of malignant cells and the patient’s prior history of breast cancer, the diagnosis of leptomeningeal disease with breast primary was made. There were insufficient cells for additional studies. CNSide, a microfluidic platform that uses antibody capture method to detect CSF tumor cells, showed 4678 tumor cells per milliliter (ml) of CSF. Immunocytochemistry of these cells showed that the cells were ER negative (criterion: < 2.6% ER positive cells) and programmed cell death ligand 1 (PD-L1) negative (criterion: < 3.4% PD-L1 positive cells). Fluorescence in situ hybridization (FISH) testing showed 22% of tumor cells with HER2 amplification (either HER2 to CEP17 ratio >/= 2.0 or HER2 copy number >/= 6). She underwent ventriculoperitoneal (VP) shunt placement with complete recovery of her neurological symptoms. Five weeks later, she was started on trastuzumab deruxtecan (T-DXd) mainly because of the HER2 FISH results from CNSide. She did not receive central nervous system(CNS) irradiation due to complete resolution of neurological symptoms with VP shunt placement. After two cycles of T-DXd, MRI brain showed mild leptomeningeal enhancement along bilateral superior cerebellar sulci. Positron emission tomography/computed tomography(PET/CT) scan showed a new sclerotic rib focus, thought to represent treatment response. It also showed decrease in size of the adrenal mass. The adrenal mass was hypermetabolic on PET, consistent with malignancy. CSF cytology was negative, while CSF tumor cell count significantly reduced to 6.72 cells/ml using CNSide. There were no new neurological symptoms. Despite MRI brain findings, she was continued on T-DXd given overall favorable clinical, radiological and CSF data. After 7th cycle of T-DXd, repeat CSF cytology continued to remain negative, CNSide CSF tumor cell count decreased further to 6.27 cells/ml, MRI brain showed interval resolution of prior leptomeningeal enhancement, CT scan showed further decrease in size of the adrenal mass (baseline 5.4cm to 3cm), stable rib sclerotic lesion and no additional metastatic lesion. To date, she has undergone eight cycles of T-DXd which has effectively controlled her disease for a period of seven months. She has not needed VP shunt revision and continues to do well. To our knowledge, this is the first case demonstrating the activity of T-DXd against CSF tumor cells where a small subset exhibited HER2 amplification. This case also highlights the benefits of using advanced and highly sensitive CSF assays to diagnose and surveil leptomeningeal disease and to assess HER2 signaling. This case is well-timed especially in the era of next-generation, CNS penetrating, potent HER2-directed antibody-drug conjugate like T-DXd which can mount antitumor activity even with minimal HER2 expression in tumors. Citation Format: Sarah Stanford, Zeni Kharel, Lauryn Hemminger, Tyler Schmidt, Sara Hardy, Jason Zittel, Nimish Mohile, Ajay Dhakal. Excellent Response to Trastuzumab Deruxtecan in “HER-2 Low” Leptomeningeal Breast Cancer and Diagnostic and Monitoring Utility of CNSide Assay [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-20-11.

Evaluation of the Impact of Letrozole in Combination with the GnRH Antagonist Ovarian Stimulation Protocol in Patients Expected to Have a Poor Ovarian Response (POSEIDON Groups 3 and 4).

Background and Objectives: The objective of this study was to evaluate the impact of adjuvant letrozole administration during ovarian stimulation using the gonadotropin-releasing hormone (GnRH) antagonist protocol on treatment outcomes in women categorized into POSEIDON groups 3 and 4. Materials and Methods: This retrospective cohort study analyzed data from patients classified into POSEIDON groups 3 and 4 who underwent fresh embryo transfer subsequent to intracytoplasmic sperm injection following a GnRH antagonist stimulation protocol between January 2017 and December 2021. Patients were divided into two groups: the GnRH-LZ group, who received letrozole at a dosage of 5 mg/day for five consecutive days, and the GnRH-ant group, who did not receive adjuvant letrozole. The primary outcome measure of the study was a comparative analysis of live birth rates between the two groups. Results: A total of 449 patients were deemed suitable for final analysis and were allocated into two groups: 281 patients in the GnRH-ant group and 168 patients in the GnRH-LZ group. Live birth rates were found to be comparable in both groups (11% vs. 9%, p = 0.497). Letrozole administration significantly reduced the total amount of gonadotropins required (2606.2 ± 1284.5 vs. 3097.8 ± 1073.3, p < 0.001), the duration of ovarian stimulation (11.2 ± 3.9 vs. 10.2 ± 3, p = 0.005), and the serum peak estradiol concentration (901.4 ± 599.6 vs. 463.8 ± 312.3, p < 0.001). Conclusions: Adjuvant letrozole administration did not demonstrate a significant impact on live birth rates among women categorized into POSEIDON groups 3 and 4. However, this approach may offer potential cost reductions by diminishing the necessity for exogenous gonadotropins and shortening the duration of ovarian stimulation.

Epiretinal membrane formation associated with letrozole therapy – Two case reports

Letrozole, an aromatase inhibitor, is being increasingly used for adjuvant endocrine therapy in hormone-positive postmenopausal breast cancer. Although aromatase inhibitors are thought to increase vitreoretinal traction by causing estrogen reduction, posterior segment complications of letrozole are sparsely reported. We report two cases of presumed epiretinal membrane formation in postmenopausal, hormone receptor–positive breast cancer patients on adjuvant letrozole therapy.

Adjuvant letrozole administration in gonadotropin releasing hormone antagonist cycles do not affect ploidy status of embryos

ObjectiveTo evaluate the effects of adjuvant letrozole administration on euploid embryo rates in gonadotropin releasing hormone (GnRH) antagonist cycles. MethodsThis retrospective study was conducted by analyzing data of patients that underwent GnRH antagonist cycles with intra-cytoplasmic sperm injection (ICSI) and pre-implantation genetic testing for aneuploidy between 2013 and 2021. Study included a total of 713 patients which 84 of them were received adjuvant letrozole and 629 patients underwent ovulation induction without any adjuvant therapy. ResultsIn patients with letrozole administration, total dose of consumed gonadotropins were significantly lower (2166.80 ± 738.82 IU vs. 2541.96 ± 755.76 IU; p < 0.001, respectively), and duration of stimulation was slightly longer (9.80 ± 1.23 days vs. 9.53 ± 1.38 days; p = 0.037) in comparison to patients without letrozole administration. Overall euploidy rates were found similar among letrozole group and control group (28.02 % ± 31.08 % vs. 23.02 % ± 30.87 %; p = 0.109). Similar rate of euploidy remained even after stratification of patients in accordance with female age. There was no significant difference in terms of live birth rates between letrozole administered group and control group (66.7 % vs 62.2 %, respectively). ConclusionCo-treatment with 5 mg/day letrozole for 5 days does not appear to affect euploidy rates of obtained embryos in GnRH antagonist cycles with ICSI.

SNP of Aromatase Predict Long-term Survival and Aromatase Inhibitor Toxicity in Patients with Early Breast Cancer: A Biomarker Analysis of the GIM4 and GIM5 Trials.

In estrogen receptor-positive (ER+) breast cancer, single-nucleotide polymorphisms (SNP) in the aromatase gene might affect aromatase inhibitors (AI) metabolism and efficacy. Here, we assessed the impact of SNP on prognosis and toxicity of patients receiving adjuvant letrozole. We enrolled 886 postmenopausal patients in the study. They were treated with letrozole for 2 to 5 years after taking tamoxifen for 2 to 6 years, continuing until they completed 5 to 10 years of therapy. Germline DNA was genotyped for SNP rs4646, rs10046, rs749292, and rs727479. Log-rank test and Cox model were used for disease-free survival (DFS) and overall survival (OS). Cumulative incidence (CI) of breast cancer metastasis was assessed through competing risk analysis, with contralateral breast cancer, second malignancies and non-breast cancer death as competing events. CI of skeletal and cardiovascular events were assessed using DFS events as competing events. Subdistribution HR (sHR) with 95% confidence intervals were calculated through Fine-Gray method. No SNP was associated with DFS. Variants rs10046 [sHR 2.03, (1.04-2.94)], rs749292 [sHR 2.11, (1.12-3.94)], and rs727479 [sHR 2.62, (1.17-5.83)] were associated with breast cancer metastasis. Three groups were identified on the basis of the number of these variants (0, 1, >1). Variant-based groups were associated with breast cancer metastasis (10-year CI 2.5%, 7.6%, 10.7%, P = 0.035) and OS (10-year estimates 96.5%, 93.0%, 89.6%, P = 0.030). Co-occurrence of rs10046 and rs749292 was negatively associated with 10-year CI of skeletal events (3.2% vs. 10%, P = 0.033). A similar association emerged between rs727479 and cardiovascular events (0.3% vs. 2.1%, P = 0.026). SNP of aromatase gene predict risk of metastasis and AI-related toxicity in ER+ early breast cancer, opening an opportunity for better treatment individualization.

Delayed versus immediate use of zoledronic acid for postmenopausal patients with ER/PR positive early breast cancer who are using adjuvant letrozole.

8 Background: Aromatase inhibitors are the standard adjuvant therapy for postmenopausal women with hormone receptor (HR) positive early breast cancer (EBC). In such patients, a significant reduction in bone density was observed. To stop bone loss, bisphosphonates have a powerful effect on reducing bone resorption and improving the survival of patients with EBC. This study compared potential bone-protection of immediate versus delayed administration of zoledronic acid (ZOL) in patients with EBC receiving adjuvant letrozole. Methods: In a prospective two-arm comparative study, 65 postmenopausal patients with HR+ EBC in whom adjuvant letrozole treatment was initiated (2.5 mg/day for 5 years), we included either (45) immediate ZOL treatment or (20) delayed ZOL treatment (both at 4 mg every 6 months). Patients in the delayed ZOL group received ZOL only for fracture or increased bone pain or developed bone mineral density (BMD)T score = or &lt; -2.0. We aimed to assess the change in lumber spine BMD every 3 months for 24 months for both immediate and delayed arm patients, in addition to evaluating bone pain deterioration and the disease-free survival (DFS). Results: Analysis of data showed significant differences between immediate and delayed arms in the first three BMD measurements with mean values were -1.55± 0.4 vs. -1.9± 0.2, -1.56± 0.3 vs. -2.5± 0.3, and -1.4±0.3 vs. -3.5± 0.3 with p&lt;0.002, 0.001, 0.0001 respectively. Despite ZOL administration in delayed arm patients was initiated 6 months later than immediate arm patients, improvement of BMD was detected in delayed arm later on. The median DFS for immediate and delayed arms were 39± 0.6 months and 21± 0.4 months respectively with p&lt;0.001 in both. Although, in pre-ZOL bone pain scoring, most patients of delayed arm (75%) were found to have a score of 3 compared to 51.1% of immediate arm, significant improvement in bone pain scores in both arms separately after ZOL administration was noted with p-values 0.031, and 0.025 respectively. Conclusions: Immediate ZOL administration prevented bone loss, improved bone pain, and ameliorate DFS in postmenopausal women with HR+ EBC receiving adjuvant letrozole. Clinical trial information: PACTR202112813934276.

Effects of letrozole on serum estradiol and estrone in postmenopausal breast cancer patients and tolerability of treatment: a prospective trial using a highly sensitive LC–MS/MS (liquid chromatography–tandem mass spectrometry) method for estrogen measurement

PurposeTo analyze serum estradiol (E2) and estrone (E1) during letrozole treatment and their association to Quality of Life (QoL) and side-effects.MethodsPostmenopausal breast cancer patients starting adjuvant letrozole were eligible. Serum samples were taken at baseline, three, and 12 months. E2 and FSH were measured with routine chemiluminescent immunoassays. E2 and E1 were analyzed after trial completion with a highly sensitive liquid chromatography-tandem mass spectrometry method (LC–MS/MS) with lower limits of quantification (LLOQ) of 5 pmol/L. QoL was measured at baseline and at 12 months with the EORTC QLQ-C30 and QLQ-BR23 and the Women’s Health questionnaires, and menopause-related symptoms with the modified Kupperman Index.ResultsOf 100 screened patients 90 completed the trial. Baseline mean LC–MS/MS E2 and E1 were 12 pmol/L (range < 5–57) and 66 pmol/L (< 5–226), respectively. E2 levels measured by immunoassay and LC–MS/MS showed no correlation. E2 and E1 were completely suppressed by letrozole except for one occasion (E1 11 pmol/L at 3 months). Pain, side effects of systemic therapy, vasomotor symptoms, joint and muscle aches, and vaginal dryness increased during letrozole treatment. A high baseline E2 was significantly associated with increased aching joints and muscles, but not with the other side effects.ConclusionsLetrozole supresses E2 and E1 completely below the LLOQ of the LC–MS/MS in postmenopausal women. High pre-treatment E2 levels were associated with more joint and muscle pain during letrozole. Automated immunoassays are unsuitable for E2 monitoring during letrozole therapy due to poor sensitivity.

Effects of letrozole co-treatment on outcomes of gonadotropin-releasing hormone antagonist cycles in POSEIDON groups 3 and 4 expected poor responders.

To evaluate the effects of adjuvant letrozole administration on outcomes of gonadotropin-releasing hormone (GnRH) antagonist cycles with intra-cytoplasmic sperm injection in POSEIDON groups 3 and 4 expected poor responder women. This study was conducted by retrospective analysis of patients with expected poor ovarian response (POSEIDON groups 3 and 4) that underwent GnRH antagonist cycles with intra-cytoplasmic sperm injection between 2010 and 2020. A total of 488 patients with letrozole co-administration and 2564 patients without any adjuvant treatment that underwent GnRH antagonist cycles within the selected period of time were included in the study. Implantation rates, clinical pregnancy rates and live birth delivery rates were significantly higher in letrozole administered patients in comparison to controls among POSEIDON group 3 women (0.39 ± 0.46 vs 0.27 ± 0.40, p = 0.01; 46.1% vs 33%, p = 0.014; 42.7% vs 31.5%, p = 0.034, respectively). Mean total doses of gonadotropins required per cycle were significantly lower in letrozole administered patients among both POSEIDON groups 3 and 4 women (2864.65 ± 878.47IU vs 3757.27 ± 1088.89IU, p < 0.001; 3286.06 ± 770.16IU vs 3666.48 ± 959.66IU, p < 0.001, respectively). Adjuvant letrozole co-administration in intra-cytoplasmic sperm injection cycles following GnRH antagonist protocol appears to improve implantation, clinical pregnancy and live birth delivery rates in women with POSEIDON group 3 expected poor ovarian response.

The Impact of Suppressing Estradiol During Ovarian Stimulation on the Unsupported Luteal Phase: A Randomized Controlled Trial.

Supraphysiological sex steroid levels at the follicular-luteal phase transition are implicated as the primary cause of luteal insufficiency after ovarian stimulation (OS) for in vitro fertilization. We aimed to determine the impact of suppressing estradiol levels during OS of multiple dominant follicles on the unsupported luteal phase and markers of endometrial maturation. At 2 university hospitals, 25 eligible egg donors were randomized to undergo OS using exogenous gonadotropins with or without adjuvant letrozole 5 mg/day. Final oocyte maturation was triggered with a GnRH agonist. No luteal support was provided. The primary outcome was the duration of the luteal phase. Secondary outcomes were luteal phase hormone profiles and the endometrial transcriptomic signature 5 days after oocyte pick up (OPU + 5). The median (interquartile range [IQR]) luteal phase duration was 8.0 (6.8-11.5) days compared with 5.0 (5.0-6.8) days in the intervention and control group, respectively (P < 0.001). Estradiol levels were effectively suppressed in the letrozole group with a median of 0.86 (0.23-1.24) nmol/L at OPU compared to 2.82 (1.34-3.44) nmol/L in the control group. Median (IQR) progesterone levels at OPU + 5 were 67.05 (15.67-101.75) nmol/L in the letrozole group vs 2.27 (1.05-10.70) nmol/L in the control group (P < 0.001). In the letrozole group, 75% of participants revealed endometrial transcriptomic signatures interpreted as post-receptive. In the control group, 40% were post-receptive and 50% noninformative. Suppressing estradiol levels in the follicular phase with adjuvant letrozole significantly reduces the disruption of the unsupported luteal phase after OS.

Does adjuvant letrozole reduce uterine peristalsis prior to fresh embryo transfer?

STUDY QUESTIONDoes adjuvant letrozole in ovarian stimulation for IVF decrease the uterine peristalsis frequency (UPF) prior to fresh embryo transfer (ET)?SUMMARY ANSWERAdjuvant letrozole in ovarian stimulation for IVF does not reduce the UPF significantly prior to fresh ET.WHAT IS KNOWN ALREADYThroughout the cycle, uterine peristalsis aids spermatozoa transport to the fallopian tube and may affect implantation. At fresh ET, UPF is negatively correlated with implantation and clinical pregnancy rates and is believed to be modulated by oestradiol and progesterone. High levels of oestradiol, from multiple follicular development, in ovarian stimulation have been reported to increase UPF, whereas progesterone is considered to be an utero-relaxant. The influence of androgens is unclear. Co-treatment with letrozole during gonadotropin ovarian stimulation limits the supra-physiological oestradiol rise and may therefore reduce UPF prior to fresh ET.STUDY DESIGN, SIZE, DURATIONThis study was carried out on subjects participating in a single-centre double-blinded randomized controlled trial of the impact of letrozole on follicle development and endocrine profiles, and investigated the impact of adjuvant letrozole in ovarian stimulation for IVF on UPF prior to fresh ET and the correlations of UPF with endocrine markers. Between 2016 and 2017, 39 women expected to be normal responders were randomized to co-treatment with letrozole or placebo. Of these, 33 women completed this element of the study. The study was carried out according to the Helsinki Declaration and the ICH-Good-Clinical-Practice.PARTICIPANTS/MATERIALS, SETTING, METHODSEligible women were randomized 1:1 to adjuvant treatment with letrozole 5 mg/day or placebo in an antagonist protocol using a fixed dose of recombinant (r) FSH 150 IU/day. Final maturation was triggered with hCG 6500 IU and luteal support with vaginal progesterone was administered from the day following oocyte aspiration. Less than 1 h prior to fresh ET, 6-min duration transvaginal ultrasound recordings of the uterus in sagittal section were performed and blood samples were drawn.MAIN RESULTS AND THE ROLE OF CHANCEA total of 33 women completed the study (letrozole n = 17; placebo n = 16). Age, BMI and ovarian reserve markers were similar between the groups. On the day of ET, serum oestradiol levels were significantly suppressed in the letrozole group to a mean of 867 ± 827 pmol/l compared to 3110 ± 1528 pmol/l in the placebo group (P < 0.001). Mean UPF prior to fresh ET did not differ between the intervention and placebo group (3.3 ± 0.36 versus 3.5 ± 0.51 per minute respectively, P = 0.108). UPF was assessed and agreed by two observers who were blinded to adjuvant treatment. Two patients were excluded due to poor quality of the ultrasound recordings. Supra-physiological serum oestradiol in the placebo group were negatively correlated with UPF (P = 0.014; R = –0.62), but the more physiological serum oestradiol levels in the letrozole group showed no correlation with UPF (P = 0.567; R = 0.15). Serum progesterone levels were similar in both groups and did not show any significant correlation with UPF. Testosterone levels were significantly higher in the letrozole group (P = 0.005) and showed a non-significant trend that negatively correlated with UPF in the placebo group (P-value = 0.071, R = –0.48).LIMITATIONS, REASONS FOR CAUTIONLimitations of the study included the limited sample size and the lack of a power calculation specifically determined for this endpoint.WIDER IMPLICATIONS OF THE FINDINGSThe supra-physiological levels of oestradiol generated during ovarian stimulation were significantly suppressed in the intervention group. However, UPF prior to fresh ET was similar in both groups. Modulating the luteal phase sex steroids with adjuvant letrozole had little measured impact on UPF. Any beneficial effect of adjuvant letrozole during ovarian stimulation is unlikely to be due to significant modulation of UPF.STUDY FUNDING/COMPETING INTEREST(S)M.D.H.’s salary was funded by an unrestricted research grant from Gedeon Richter. The expenses of the study were funded by a scientific collaboration: ReproUnion, co-financed by the European Union, Interreg Öresund-Kattegat-Skagerrak and Ferring Pharmaceuticals. The assays for the analyses were funded by Roche Diagnostics and an unrestricted research grant from Merck Life Science AS, Denmark. The authors have no competing interests to declare regarding this study.TRIAL REGISTRATION NUMBERClinicaltrials.gov: NCT02939898, EudraCT no.: 2015-005683-41.

Abstract P3-12-31: A 10 year retrospective study of male breast cancer patients within central Scotland

Abstract Background. This study is a retrospective review of all of the male breast cancer patients treated within NHS Tayside, Scotland, over a 10 year period. The trust’s catchment area covers a population of 550,000 people. It evaluates several different important factors including epidemiology, patient presentation, pathology results, and treatment interventions. It also explores how choice of hormonal therapy influences patients’ overall outcomes. Materials And Methods. 33 patients in total were identified from the NHS breast cancer database. These results were then statistically analysed in order to determine overall trends within the data. Results. Patients’ ages ranged from 48 to 87 years old, with a mean age at 71 years. 94% of these patients had a palpable lump at presentation, with 42% having at least one palpable axillary node. 18% of patients experienced nipple discharge and 33% experienced some form of nipple distortion, confirming the fact that involvement of the nipple-areolar complex in males occurs early on and in a significant number of cases. 42% of patients experienced associated breast pain, a significantly higher rate than female breast cancer patients. The most common tumour grade was stage T2, highlighting the fact that males tend to be diagnosed on average 6-9 months later than females, who most commonly present at stage T1. The most common histological type was invasive ductal carcinoma (76% of cases). 66% of patients were ER+, PR+, HER2-. 61% of patients received surgical intervention. 33% underwent a sentinel lymph node biopsy (SLNB) and of these, 46% had node involvement. 27% of patients had axillary node clearance as part of their surgical intervention. 21% of patients had a synchronous malignancy at the time of diagnosis. This highlights that the majority of patients were elderly and as a result had other diseases of old age. The overall survival rate for our patient cohort was 55%, with a cancer specific survival rate of 88%. 33% of patients have completed 5 or more years of follow up. 30% are still within their 5 years of follow up, and 36% died within their 5 years of follow up, either as a result of their malignancy or for unrelated causes. Only 30% of patients were referred for genetic testing, with zero BRCA mutations identified, supporting the fact that contrary to popular belief, BRCA mutations occur in male breast cancer no more commonly than in female patients. The recurrence rate of the 11 patients receiving adjuvant Tamoxifen was 0, as was the recurrence rate of the 15 patients receiving adjuvant Letrozole. The similarities here can likely be attributed to the small sample size of this study, however it is now recognised that Tamoxifen should be the drug of choice. Letrozole has no effect on aromatase within the testes, which is responsible for 20% of oestrogen production. Conclusions. Male breast cancer is an important but often overlooked topic. Cases occur sporadically and are associated with old age, however there are a number of recognised risk factors including lifestyle and hormonal influences. A high proportion of patients will experience associated pain and early involvement of the nipple-areolar complex. A delay in diagnosis also means that many patients present at a higher stage of the disease, with more nodal involvement. Tamoxifen is the hormonal therapy of choice in these patients. Citation Format: Rachel EL Morris, Vasileios Pitsinis. A 10 year retrospective study of male breast cancer patients within central Scotland [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-12-31.

Abstract P3-09-03: Single nucletotide polymorphisms of aromatase gene (CYP19A1) and toxicity of adjuvant aromatase inhibitors: A translational, prospective study

Abstract Background: Extending adjuvant endocrine treatment (ET) with aromatase inhibitors (AI) to 7-10 years decreases the risk of relapse in hormone receptor-positive (HR+) breast cancer (BC). However, such benefit comes at the price of higher incidence of skeletal and cardiovascular (CV) events. Biomarkers predicting such toxicities might help clinicians in tailoring adjuvant ET to patient’s needs. We conducted a prospective study to assess whether SNPs in the gene encoding for the aromatase enzyme (CYP19A1) affect the risk of skeletal and CV events in HR+ early BC patients enrolled in the GIM4 trial. Methods: The GIM4 trial randomized HR+ BC postmenopausal patients who had been already treated with 2-3 years of adjuvant tamoxifen to either 3-2 years or 5 years of adjuvant letrozole. Four SNPs of CYP19A1 were evaluated: rs10046, rs4646, rs479292 and rs727479. SNPs were genotyped through PCR on DNA obtained from patients’ peripheral blood samples. Skeletal and CV events were assessed from randomization in the GIM4 trial to last follow-up, disease recurrence or death. Skeletal events were defined as the onset of osteoporosis or bone fractures. CV events were defined as the onset of thrombosis, embolism, stroke, myocardial infarction, hearth failure, or arrythmia. Univariate and multivariate logistic regressions were performed to evaluate the association between SNPs and skeletal and CV events. Bonferroni correction for multiplicity was used for univariate SNPs association tests, with a corrected alpha of 0.012. Only associations with an alpha level &amp;lt;0.012 were considered significant and included in multivariate models.Multivariate models’ covariates included: treatment arm (5 vs 3-2 years letrozole), (neo)adjuvant chemotherapy, previous hormone replacement therapy, age, BMI, previous biphosphonates, hypercholesterolemia and hypertension at baseline. SNPs were tested for Hardy–Weinberg equilibrium (HWE) and linkage disequilibrium (LD). Interaction between SNPs of interest and treatment arm was also investigated. Results: Of 2,056 patients enrolled in the GIM4 trial, 647 entered this translational study. All SNPs were in HWE. The CT and TT variants of rs10046 were less associated to skeletal events compared to variant CC, suggesting a dominant effect of the minor T allele (odds ratio [OR]: 0.47,. 95% confidence interval [CI]: 0.28-0.79, p=0.005). The association was independent from the other covariates (adjusted OR [aOR]: 0.43, p=0.002). Patients with rs10046-TT had no significant differences in the odd of skeletal events according to treatment arm. Conversely, in patients with rs10046-CC, skeletal events were more likely with 5-year letrozole (interaction p=0.043). Compared to rs10046-CC, rs10046-TT/CT was also less associated with CV events at both univariate (OR: 0.46 95% CI: 0.27-077, p=0.003) and multivariate analysis (aOR: 0.41, p&amp;lt;0.001).The rs727479—GG variant was associated with more CV events compared to the GT and TT variants (OR: 2.30, 95%CI: 1.27-4.15, p=0.009), suggesting a recessive effect of the minor G allele. The association remained significant at multivariate analysis (aOR: 2.30, p=0.010). No significant interaction was observed among treatment arms, rs10046 or rs272479 variants (interaction p=0.070 and 0.061). Rs10046-CC and rs727479-GG variants were in high LD (D’=0.92, haplotype-CG frequency: 39%). Hence, the association between genotype rs10046-CC/rs727479-GG and CV events was investigated. The association was significant at the multivariate analysis (aOR: 2.79, p=0.002). With such genotype, the odd of CV events was significantly increased with the 5-year letrozole (interaction p=0.046). Conclusions: SNPs of CYP19A1 could be useful biomarkers of long-term toxicity in HR+ BC patients who are candidates for adjuvant AI. Citation Format: Benedetta Conte, Chiara Molinelli, Giancarlo Bisagni, Antonio Durando, Giovanni Sanna, Stefania Gori, Ornella Garrone, Stefano Tamberi, Sabino De Placido, Francesco Schettini, Antonio Pazzola, Riccardo Ponzone, Filippo Montemurro, Gianluigi Lunardi, Rosario Notaro, Anna Turletti, Claudia Bighin, Francesca Poggio, Giulia Buzzatti, Matteo Lambertini, Luca Boni, Lucia Del Mastro. Single nucletotide polymorphisms of aromatase gene (CYP19A1) and toxicity of adjuvant aromatase inhibitors: A translational, prospective study [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P3-09-03.

Continuous versus intermittent extended adjuvant letrozole for breast cancer: final results of randomized phase III SOLE (Study of Letrozole Extension) and SOLE Estrogen Substudy

Late recurrences in postmenopausal women with hormone receptor-positive breast cancers remain an important challenge. Avoidance or delayed development of resistance represents the main objective in extended endocrine therapy (ET). In animal models, resistance was reversed with restoration of circulating estrogen levels during interruption of letrozole treatment. This phase III, randomized, open-label Study of Letrozole Extension (SOLE) studied the effect of extended intermittent letrozole treatment in comparison with continuous letrozole. In parallel, the SOLE estrogen substudy (SOLE-EST) analyzed the levels of estrogen during the interruption of treatment. SOLE enrolled 4884 postmenopausal women with hormone receptor-positive, lymph node-positive, operable breast cancer between December 2007 and October 2012 and among them, 104 patients were enrolled in SOLE-EST. They must have undergone local treatment and have completed 4-6 years of adjuvant ET. Patients were randomized between continuous letrozole (2.5 mg/day orally for 5 years) and intermittent letrozole treatment (2.5 mg/day for 9 months followed by a 3-month interruption in years 1-4 and then 2.5 mg/day during all of year 5). Intention-to-treat population included 4851 women in SOLE (n= 2425 in the intermittent and n= 2426 in the continuous letrozole groups) and 103 women in SOLE-EST (n= 78 in the intermittent and n= 25 in the continuous letrozole groups). After a median follow-up of 84 months, 7-year disease-free survival (DFS) was 81.4% in the intermittent group and 81.5% in the continuous group (hazard ratio: 1.03, 95% confidence interval: 0.91-1.17). Reported adverse events were similar in both groups. Circulating estrogen recovery was demonstrated within 6 weeks after the stop of letrozole treatment. Extended adjuvant ET by intermittent administration of letrozole did not improve DFS compared with continuous use, despite the recovery of circulating estrogen levels. The similar DFS coupled with previously reported quality-of-life advantages suggest intermittent extended treatment is a valid option for patients who require or prefer a treatment interruption.

P–613 Adjuvant letrozole in ovarian stimulation for in vitro fertilization does not reduce uterine peristalsis frequency prior to fresh embryo transfer

Abstract Study question Does adjuvant letrozole in ovarian stimulation (OS) for in vitro fertilization (IVF) decrease the uterine peristalsis frequency (UPF) prior to fresh embryo transfer (ET)? Summary answer Adjuvant letrozole in (OS) for IVF does not reduce the UPF significantly prior to fresh ET. What is known already Throughout the cycle UPF aids spermatozoa transport to the fallopian tube and may affect implantation. At fresh, ET UPF is negatively correlated with implantation- and clinical pregnancy rates and is believed to be modulated by estradiol and progesterone. High levels of estradiol, from multiple follicular development, in OS have been reported to increase UPF, whereas progesterone is considered to be utero-relaxant. The influence of androgens is unclear. Co-treatment with letrozole during gonadotropin OS limits the estradiol rise the supra-physiological estradiol and may therefore reduce UPF prior to fresh ET. Study design, size, duration: This single centre study was nested within a multicentre double blinded RCT investigating the impact of letrozole co-treatment during gonadotropin OS for IVF on late follicular and luteal estradiol, progesterone and testosterone levels. Between 2016 and 2017, 39 women expected normal responders were randomised to co-treatment with letrozole or placebo. Of these, 33 women completed this element of the study. The study was carried out according to the Helsinki Declaration and the ICH-Good-Clinical-Practice. Participants/materials, setting, methods Eligible women were randomised 1:1 to adjuvant treatment with letrozole 5 mg/day or placebo in an antagonist protocol using a fixed dose of recFSH 150 IU/day. Final maturation was triggered with rhCG 6,500 IU and luteal support with vaginal progesterone was administered from the day following oocyte aspiration. Less than one hour prior to fresh ET, six minute duration transvaginal ultrasound recordings of the uterus in sagittal section were performed and blood samples were drawn. Main results and the role of chance A total of 33 women completed the study (letrozole n = 17; placebo n = 16). Age, BMI, and ovarian reserve markers were similar between the groups. On day of ET, serum estradiol levels were significantly suppressed in the letrozole group to mean 867 ± 827 pmol/L compared to 3,110 ± 1,528 pmol/L in the placebo group (P &amp;lt; 0.0001). Mean UPF prior to fresh ET did not differ between the intervention and control group (3.3 ± 0.36 versus 3.5 ± 0.51 per minute respectively, P = 0.108). UPF was assessed and agreed by two observers who were blind to adjuvant treatment. Two patients were excluded due to poor quality of the ultra sound recording. Supra-physiological serum estradiol in the placebo group was negatively correlated with UPF (P = 0.014; R = –0.62), but the more physiological serum estradiol levels in the letrozole group showed no correlation with UPF (P = 0.567; R = 0.15). Serum progesterone levels were similar in both groups and did not show any significant correlation with UPF. Testosterone levels were significantly higher in the letrozole group (P = 0.005) and showed a non-significant trend negatively correlated with UPF in the placebo group (P-value=0.07, R= –0.48). Limitations, reasons for caution The limited sample size risks masking minor effects. Wider implications of the findings: The supra-physiological levels of estradiol were significantly supressed in the intervention group, but UPF prior to fresh ET was similar in both groups. UPF is not strongly correlated to luteal phase sex steroid levels. Any beneficial effect of adjuvant letrozole during OS is not through an impact of UPF. Trial registration number NCT02939898

P–446 Controlled ovarian stimulation protocols for oocyte vitrification induce differential gene expression profiles in primary tumours of breast cancer

Abstract Study question Could controlled ovarian stimulation (COS) protocols used in fertility preservation (FP) impact on malignant cell proliferation and tumour molecular profiling of breast cancer (BC) patients? Summary answer Letrozole supplementation during ovarian stimulation for oocyte vitrification could be considered as a safe procedure in estrogen-dependent BC patients undergoing FP. What is known already High estradiol levels associated to COS could promote changes in gene expression in estrogen-positive BC tumors. Estradiol levels reached during the ovarian stimulation could aggressively promote malignant cell proliferation and cell migration to adjacent organs. Aromatase inhibitors such as letrozole, are added to standard stimulation protocols to avoid this undesirable potential side effect. Despite the reassuring clinical results achieved by using letrozole for FP in BC patients, there is still a lack of evidence regarding its impact on malignant cell behaviour. For this reason, specific molecular studies to properly evaluate safety of letrozole in this specific population are still required. Study design, size, duration Experimental in vivo study. Thirty 5-week-old Nude-nu female mice were divided into three different groups: BC (n = 10), BC and FSH stimulation (BC-FSH, n = 10), or BC and letrozole stimulation (BC-LTZ, n = 10). BC was considered the control group, whereas BC-FSH and BC-LTZ represented distinct COS protocols. Hormone-dependent BC was induced in all mice. Animals were followed-up for 5 months and then euthanized to collect kidney, ovary, spleen, and liver tissues for gene expression and immunohistochemistry (IHC) analysis. Participants/materials, setting, methods One million of human MCF–7 BC cells were injected into the mouse left kidney capsule. Two days after xenograft, COS was induced by 10IU FSH or 1mg/ml letrozole + 10IU FSH, followed by ovarian triggering with 10IU hCG at 48h. Human BC RT2 Profiler PCR Arrays were performed to evaluate the impact of COS on tumour behaviour. BC biomarkers (Ki67, Erα, PR and HER–2) were also analyzed by IHC to validate gene expression results. Main results and the role of chance The differential gene expression was firstly assessed in kidney samples, as they represent the xenograft site, and different expression profiles were obtained depending on the COS protocol used. The BC-FSH group showed a global over-expression pattern of all genes of the array when compared to BC and BC-LTZ. Further gene ontology analysis revealed that cellular process, biological regulation, metabolic process, and proteases were the most over-represented biological terms, with a 20.5-fold over-expression for MMP2 compared to the other groups. On the other hand, BC-LTZ mice presented gene expression profiles similar to that of controls. When other tissues were analysed to detect malignant cell presence, our results revealed a significant up-regulation of matrix-proteases, cell cycle and proliferation related-genes, in liver samples from the BC-FSH group, but no amplification of any of the studied genes was detected in ovarian tissue or spleen. IHC findings confirmed the presence of human BC cells in 100% of samples from kidney tissue and in 30% of samples from liver tissue in the BC-FSH group. No human cells were detected by IHC in the BC and BC-LTZ groups. Limitations, reasons for caution Since this is an animal model of estrogen-dependent BC induced through a cell line, further validation with human tumour breast cancer samples would be required. Wider implications of the findings: Adjuvant letrozole in COS protocols prevents BC cell migration. The present study suggests that this protective effect could be mediated by interfering ER-pathway downstream genes involved in cell proliferation and matrix digestion. Altogether, letrozole could safely be used as a supplement during COS procedures for oocyte vitrification in BC women. Trial registration number Not applicable

Polymorphisms of T- cell leukemia 1A gene loci are not related to the development of adjuvant letrozole-induced adverse events in breast cancer

Letrozole, an aromatase inhibitor (AI), is the first-line adjuvant drug for treating hormone receptor-positive (HR+) breast cancer in postmenopausal women. However, harmful adverse events (AEs) and significant differences in drug response among individuals remain a significant problem in clinical application. Current evidence suggests that the observed individual variation in the treatment outcomes of AI is conferred by genetic variants. Hence, in this study, we examined the association of TCL1A gene polymorphisms with letrozole-induced AEs. The study subjects were postmenopausal HR+ breast cancer patients who were receiving adjuvant letrozole. Genomic DNA was isolated by a routine standard phenol-chloroform method. In total, 198 South Indian patients were genotyped for four single nucleotide polymorphisms (SNPs) in the TCL1A gene loci by the TaqMan allelic discrimination assay using the RT-PCR system. We used the odds ratio and 95% confidence interval to assess the genetic association. Musculoskeletal (MS) AEs and vasomotor symptoms (VMSs) are the most common side effects observed in the study cohort. Among 198 patients, 81 experienced musculoskeletal toxicity, reporting MS-AEs, 57 had VMSs, and 33 of them had both. The most frequently identified polymorphic variants in the patient series were rs11849538 (G), with an allele frequency of about 27.3%, followed by rs7158782-G (27.3%), rs7159713-G (25.8%), and rs2369049-G (22.5%). The genetic association analysis indicated no significant difference in the proportion of TCL1A gene variants between patients with and without AEs on either MS-AEs or VMSs. Though we observed high LD in all patient groups, the inferred haplotypes displayed a non-significant association with letrozole-induced specific AEs. However, the SNP functionality analysis by RegulomeDB provided a 2b rank score for rs7158782, suggesting a potential biological function. Our findings suggest that TCL1A gene polymorphisms may not play any role in the prediction of letrozole-induced AEs in South Indian HR+ breast cancer patients.

Clinical Outcomes Following Letrozole Treatment according to Estrogen Receptor Expression in Postmenopausal Women: LETTER Study (KBCSG-006)

PurposeIn this trial, we investigated the efficacy and safety of adjuvant letrozole for hormone receptor (HR)-positive breast cancer. Here, we report the clinical outcome in postmenopausal women with HR-positive breast cancer treated with adjuvant letrozole according to estrogen receptor (ER) expression levels.MethodsIn this multi-institutional, open-label, observational study, postmenopausal patients with HR-positive breast cancer received adjuvant letrozole (2.5 mg/daily) for 5 years unless they experienced disease progression or unacceptable toxicity or withdrew their consent. The patients were stratified into the following 3 groups according to ER expression levels using a modified Allred score (AS): low, intermediate, and high (AS 3–4, 5–6, and 7–8, respectively). ER expression was centrally reviewed. The primary objective was the 5-year disease-free survival (DFS) rate.ResultsBetween April 25, 2010, and February 5, 2014, 440 patients were enrolled. With a median follow-up of 62.0 months, the 5-year DFS rate in all patients was 94.2% (95% confidence interval [CI], 91.8–96.6). The 5-year DFS and recurrence-free survival (RFS) rates did not differ according to ER expression; the 5-year DFS rates were 94.3% and 94.1%in the low-to-intermediate and high expression groups, respectively (p = 0.6), and the corresponding 5-year RFS rates were 95.7% and 95.4%, respectively (p = 0.7). Furthermore, 25 patients discontinued letrozole because of drug toxicity.ConclusionTreatment with adjuvant letrozole showed very favorable treatment outcomes and good tolerability among Korean postmenopausal women with ER-positive breast cancer, independent of ER expression.Trial RegistrationClinicalTrials.gov Identifier: NCT01069211

Association between BMI, vitamin D, and estrogen levels in postmenopausal women using adjuvant letrozole: a prospective study

Studies have suggested that women with elevated BMI or 25-OH vitamin D levels may derive less benefit from AIs versus tamoxifen. We prospectively investigated whether high BMI or 25-OH vitamin D levels were associated with higher estrogen levels in post-menopausal women receiving standard adjuvant letrozole (2.5 mg/day). Furthermore, we evaluated whether an increased dose of letrozole resulted in lower serum estrogens in women with BMI > 25 kg/m2. Correlation between entry BMI and day 29 serum biomarkers (estrogens, 25-OH vitamin D, insulin, CRP, leptin) was assessed in all patients. On day 29, participants with BMI > 25 kg/m2 switched to letrozole 5 mg/day for 4-weeks and blood was drawn upon completion of the study. The change in serum estrogen levels was assessed in these patients (BMI > 25 kg/m2). 112 patients completed days 1–28. The Pearson correlations of estradiol and estrone with BMI or serum 25-OH vitamin D levels were near zero (−0.04 to 0.07, p = 0.48–0.69). Similar results were obtained for correlation with markers of obesity (insulin, CRP, and leptin) with estradiol and estrone (−0.15 to 0.12; p = 0.11–0.82). Thirty-one patients (BMI > 25 kg/m2) completed the interventional component; Increasing the dose of letrozole did not further reduce estradiol or estrone levels (change 0.1 and 0.4 pmol/L respectively; p = 0.74 and 0.36). There was no observed association between markers of obesity (BMI, insulin, leptin, and CRP), serum 25-OH vitamin D levels and estradiol or estrone levels. Additionally, an increased dose of letrozole did not further reduce estradiol or estrone levels compared to the standard dose.