Suppression Of Ovarian Function Trial Research Articles

Adjuvant Ovarian Function Suppression in Premenopausal Hormone Receptor–Positive Breast Cancer

Few oncology studies have assessed the effectiveness of adjuvant ovarian function suppression (OFS) in observational settings for premenopausal hormone receptor-positive breast cancer. Target trial emulation is increasingly used for estimating treatment outcomes in observational cohorts. To describe hormone therapy and OFS treatment patterns (aim 1), examine the association between adding OFS to tamoxifen (TAM) or aromatase inhibitor (AI) and survival (aim 2), and examine the association between duration of hormone treatment (TAM or AI) plus OFS (H-OFS) and survival (aim 3). This population-based cohort study included all premenopausal, early-stage breast cancer diagnoses between 2010 and 2020 in Alberta, Canada. Target trial emulation was conducted. Eligibility criteria were directly modeled after the Suppression of Ovarian Function Trial (SOFT) and Tamoxifen and Exemestane Trial (TEXT). Participants were followed up for a maximum of 5 years. Data were analyzed from July 2022 through March 2023. For aim 2, exposures were receiving the following baseline treatments for 2 years: AI + OFS (AI-OFS), TAM + OFS (T-OFS), and TAM alone. For aim 3, exposures were a 2-year or greater and a less than 2-year duration of H-OFS. Recurrence-free survival was the primary outcome of interest. Marginal structural Cox models with inverse probability treatment and censoring weights were used to estimate hazard ratios (HRs), adjusted for baseline and time-varying confounding variables. Among 3434 female patients with premenopausal, early-stage breast cancer diagnoses (median [IQR] age, 45 [40-48] years), 2647 individuals satisfied SOFT and TEXT eligibility criteria. There were 2260 patients who initiated TAM, 232 patients who initiated T-OFS, and 155 patients who initiated AI-OFS; 192 patients received H-OFS for 2 or more years, and 195 patients received H-OFS for less than 2 years. The 5-year recurrence risks were not significantly lower in AI-OFS vs TAM (HR, 0.76; 95% CI, 0.38-1.33) or T-OFS vs TAM (HR, 0.87; 95% CI, 0.50-1.45) groups. Patients receiving H-OFS for 2 or more years had significantly better 5-year recurrence-free survival compared with those receiving H-OFS for less than 2 years (HR, 0.69; 95% CI, 0.54-0.90). This study found no significant reductions in recurrence risk for AI-OFS and T-OFS compared with TAM alone. H-OFS duration for at least 2 years was associated with significantly improved recurrence-free survival.

Cost-Effectiveness Analysis of Adjuvant Endocrine Therapy With Ovarian Suppression in Premenopausal Patients With Hormone Receptor-Positive Early Breast Cancer in China

PurposeEndocrine therapy combined with ovarian function suppression (OFS) is recommended in intermediate- or high-risk patients among premenopausal women with hormone receptor-positive early breast cancer. However, in China, the cost-effectiveness of this strategy compared with endocrine therapy alone is unclear. This study aimed to evaluate the long-term cost-effectiveness of tamoxifen (TAM), TAM+OFS, and exemestane plus OFS (EXE+OFS). MethodsOn the basis of prognostic data from the Suppression of Ovarian Function Trial (SOFT), cost data from the Hospital Information System of the West China Hospital of Sichuan University, and health utility values from the published literature, a Markov model was established. The incremental cost-effectiveness ratio (ICER) was used to compare the treatment strategies. ResultsIn a 25-year simulation of adjuvant therapy in Chinese women with early breast cancer, the total costs of TAM, TAM+OFS, and EXE+OFS were $7821, $9318, and $9445, respectively. The quality-adjusted life-years (QALYs) were 11.615, 11.896, and 11.734 years, respectively. Compared with TAM, the ICERs of TAM+OFS and EXE+OFS were $5,327.4021/QALY and $13,647.0588/QALY, respectively. The ICERs of TAM+OFS and EXE+OFS were below the threshold of $32,517/QALY. The reliability and stability of the simulation results were verified using Monte Carlo simulation and sensitivity analysis. ConclusionIn the context of limited resources in China, TAM+OFS and EXE+OFS are cost-effective options compared with TAM.

Efficacy of ovarian function suppression of 3-monthly versus monthly GnRH agonist as endocrine therapy for premenopausal breast cancer patients.

527 Background: The combined analysis of the Suppression of Ovarian Function Trial (SOFT) and Tamoxifen and Exemestane Trial (TEXT) trials have shown significant survival benefit of adding ovarian function suppression (OFS) with GnRH agonists (GnRHa) to aromatase inhibitors (AI) versus tamoxifen in high-risk premenopausal patients (pts) with estrogen receptor (ER)-positive breast cancer (BC). In both studies, GnRHa was administered every 4 weeks. However, the efficacy of 3-monthly GnRHa plus AI has not been well studied. We conducted a retrospective study designed to assess the efficacy of OFS with 3-montlhy compared with monthly goserelin, associated with AI, in premenopausal pts with ER-positive BC. Methods: Medical records of premenopausal pts with ER-positive BC who received OFS with 10.8mg 3-montlhy goserelin plus AI or 3.6mg monthly goserelin plus AI, between June/2013 and January/2023 were reviewed. Patient characteristics, such as age, body mass index (BMI) and prior chemotherapy were analyzed. Estradiol (E2) levels were measured by gas chromatography tandem mass spectrometry. Pts with at least one E2 level above 2.72 pg/ml were considered to have ineffective OFS. Analysis of E2 measurements was divided into periods: < 3, 3 to 6, 6 to 9, 9 to 12, 12 to 18, 18 to 24 and > 24 months. E2 levels greater than 2.72 pg/ml were evaluated at each timepoint. Results: A total of 88 pts were included. 27 (30.7%) received monthly goserelin and 61 (69.3%) 3-monthly goserelin. Patient characteristics were well balanced between the groups. Relevant demographic data are shown in table. For E2 analysis, 20 (22.7%) pts had at least one measurement greater than 2.72 pg/ml, 11 (40.7%) in the monthly group and 9 (14.8%) in the 3-monthly group (p = 0.007). The percentages of E2 measurements ≥ 2.72 pg/ml, in each time period, were 0%, 40%, 12.5%, 16.7%, 33.3%, 50% and 50% in monthly group versus 8%, 4.2%, 10%, 14.3%, 4.8%, 8.3% and 5.6%, in 3-monthly group, respectively. Conclusions: Our study demonstrated that more pts who underwent 3-monthly goserelin had E2 levels below the defined threshold of 2.72 pg/ml compared with monthly goserelin, when associated with AI, with statistical significance. These findings suggest that 3-monthly goserelin may result in better efficacy in OFS when comparing with monthly and provide greater convenience for pts. [Table: see text]

Evaluation of PAM50 intrinsic subtypes and risk of recurrence (ROR) scores in premenopausal women with early-stage HR+ breast cancer: A secondary analysis of the SOFT trial.

504 Background: The landmark Suppression of Ovarian Function Trial (SOFT) in premenopausal breast cancer patients revealed that the addition of ovarian function suppression (OFS) to adjuvant endocrine therapy with either tamoxifen (T+OFS) or exemestane (E+OFS) reduces the risk of recurrence compared with adjuvant tamoxifen alone. There are no biomarkers to aid decision-making about intensification of endocrine therapy with OFS. The purpose of this study is to assess the prognostic and predictive ability of PAM50 intrinsic subtypes and ROR scores in premenopausal women with HR+/HER2- breast cancer in the SOFT trial. Methods: Gene expression analyses were performed via the NanoString Breast Cancer 360 assay on RNA isolated from FFPE tumor samples from the SOFT trial that were HR+/HER2- (n=1245/3047). PAM50 subtype and ROR score were determined centrally by NanoString Technologies (Seattle, WA, USA), blinded to clinical characteristics, treatment and outcome. Median follow-up was 12 years. Primary endpoint in this study was distant recurrence-free interval (DRFI). Secondary endpoints were breast cancer-free interval (BCFI) and disease-free survival (DFS). Kaplan-Meier analysis and Cox proportional hazards regression models, stratified by prior chemotherapy and lymph node status, were used to evaluate the predictive performance of PAM50 intrinsic subtypes and ROR categories (low vs intermediate vs high), and secondarily ROR score as a continuous variable. We also investigated differences between very young (<40yrs) vs young (>40yrs) women. Results: Tumor samples from 1084/1245 (87%) patients successfully completed PAM50 testing and are included in this analysis. Patient characteristics in this cohort were similar to the entire SOFT trial population. Intrinsic subtype and ROR category distribution is described below. Subtype distribution significantly differed between very young vs young premenopausal women, with fewer luminal A and more luminal B and non-luminal tumors seen in the very young (p<0.001). The ROR score distribution also differed significantly: in node-negative patients there were significantly more ROR-high scores amongst very young compared to young women (36% vs 14%, p<0.001). Conclusion: Breast cancer diagnosed in very young women has aggressive disease biology. Prognostic and predictive analyses of both intrinsic subtypes and the ROR score are ongoing and will be presented at the meeting. Clinical trial information: NCT00066690 . [Table: see text]

Abstract GS1-06: Evaluation of the Breast Cancer Index in premenopausal women with early-stage HR+ breast cancer in the SOFT trial

Abstract Background: The landmark Suppression of Ovarian Function Trial (SOFT) in premenopausal breast cancer patients revealed that the addition of ovarian function suppression (OFS) to adjuvant endocrine therapy with either tamoxifen (T+OFS) or exemestane (E+OFS) reduces the risk of recurrence compared with adjuvant tamoxifen alone. The benefit from the addition of OFS was most clinically meaningful for patients at higher clinico-pathologic risk of recurrence. There are no biomarkers to aid decision-making about intensification of endocrine therapy with OFS and its resultant toxicities. The Breast Cancer Index (BCI) is a gene expression–based signature that stratifies patients based on the risk of overall (0-10 years) and late (post-5 years) distant recurrence (DR) and predicts the likelihood of benefit from extended endocrine therapy in early stage HR+ breast cancer. The purpose of this study is to assess BCI’s prognostic and predictive ability in premenopausal women randomly assigned to 5-years treatment with E+OFS or T+OFS vs T alone in the SOFT trial. Methods: All available FFPE tumor samples from the SOFT trial (n=1718 of 3047) were included in the study. BCI testing was performed blinded to clinical characteristics, treatment and outcome. Median follow-up was 13 years. Primary endpoint was breast cancer-free interval (BCFI). Secondary endpoints were distant recurrence-free interval (DRFI) and disease-free survival (DFS). Kaplan-Meier analysis and Cox proportional hazards regression models, stratified by prior chemotherapy and lymph node status, were used to evaluate the predictive performance of BCI (H/I) status (High vs Low), and secondarily H/I as a continuous score. Hypothesis testing for interaction was performed by stratified log-rank tests. Results: Tumor samples from 1687 (98%) patients (30.4% < 40 years, 64.1% T1, 50.1% G2, 65.8% N0, 85.5%% HER2-, 53.3% received prior chemotherapy) were successful in BCI testing and included in the final analysis. Patient characteristics in the translational cohort are representative of the parent SOFT trial. 42.4% of patients’ tumors had H/I-High status. Prognostic and predictive analyses are ongoing and will be presented at the meeting. Citation Format: Ruth O’Regan, Yi Zhang, Gini F. Fleming, Prudence Francis, Roswitha Kammler, Giuseppe Viale, István Láng, Meritxell Bellet Ezquerra, Hervé R. Bonnefoi, Sherene Loi, Marco Colleoni, Catherine A. Schnabel, Kai Treuner, Meredith Regan. Evaluation of the Breast Cancer Index in premenopausal women with early-stage HR+ breast cancer in the SOFT trial [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr GS1-06.

Abstract P4-07-05: Real world data of adjuvant endocrine therapy for breast cancer in very young women. A Chilean 20-year experience

Abstract BACKGROUND: Breast cancer (BC) is the most common cancer diagnosed in premenopausal women with an increasing incidence for age 35 or less. Although proportionally less frequent, hormone receptor (HR)–positive BC still remains the main subtype for this group, but given tumor characteristics and suboptimal adjuvant endocrine therapy (ET), present inferior long-term outcomes when compared to HR-positive BC in older women. Both Tamoxifen and Exemestane Trial (TEXT) and Suppression of Ovarian Function Trial (SOFT) have helped to optimize ET strategies for premenopausal women, identifying which patients benefit from ovarian function suppression (OFS). In Chile, we have scarce data on very young BC patients and limited access to proper OFS treatment specially in our public health system. Thus we aim to characterize a cohort of very young women regarding treatment strategies and survival, plus as an exploratory analysis evaluate Regan Score in our cohort. METHODS We conducted a retrospective population-cohort study involving women under 36 years of age, with early HR-positive/human epidermal growth factor receptor 2 (HER2)–negative BC, treated both at a community hospital and at an academic private hospital between 2001 and 2021. We did a descriptive analysis including stage distribution and treatment strategies (chemotherapy (CT), ET of choice and OFS use). We evaluated prognosis for the entire population. Survival analysis was carried out using the Kaplan-Meier method. RESULTS A total of 143 patients were included. Median age at diagnosis was 33 (19 - 36); 15.4% percent of patients were diagnosed in stage I, 51.4% stage II and 30.1% stage III. Eighty six percent received CT, 35.0% neoadjuvant. Ninety three percent received endocrine adjuvant treatment: 81.2% TAM alone, 6.8% TAM/OFS and 10.5% IA/OFS. Regarding OFS strategies only 38.5% received gonadotropin-releasing hormone (GnRH) agonists while the rest were oophorectomized. Regan median composite score was 2.77 (2.61 - 2.93) for the entire cohort. Rising to 2.95 (2.79 - 3.11) for patients treated with CT plus ET compared to 1.91 (1.55 - 2.27) for those treated with ET exclusively (p=0.0001). Patients that received TAM alone had a median Regan Score of 2.72 (0.77-4) compared to 3.14 (2.07-4.0) for patients that had OFS added (p=0.04). With a median follow-up of 59 months, 5-year Disease Free Survival (DFS), Distant DFS and Overall Survival (OS) for the entire cohort were 63.5%, 66.9% and 88.7%, respectively. CONCLUSION. To our knowledge this is one of the largest cohorts considering very young women BC in Latinamerica. We confirm their elevated overall risk with markedly higher Regan scores compared to SOFT and TEXT populations for both CT and ET exclusively treated patients. Due to access difficulties very few patients received OFS and when used, surgical oophorectomy was the main strategy of choice, with all the potential long term consequences it conveys. Thus OFS use was restricted to very high risk women, meaning that a large group of only TAM users were undertreated according to nowadays standards. This could explain the elevated recurrence risk observed in our population when compared to other under 35 years of age cohorts. Table 1. Cohort characteristics Table 2. Regan risk score Citation Format: Ana Heredia, Benjamin Walbaum, Francisco Acevedo, Cesar Sánchez. Real world data of adjuvant endocrine therapy for breast cancer in very young women. A Chilean 20-year experience [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-07-05.

Genomic characterisation of hormone receptor-positive breast cancer arising in very young women

Very young premenopausal women diagnosed with hormone receptor-positive, human epidermal growth factor receptor 2-negative (HR+HER2-) early breast cancer (EBC) have higher rates of recurrence and death for reasons that remain largely unexplained. Genomic sequencing was applied to HR+HER2- tumours from patients enrolled in the Suppression of Ovarian Function Trial (SOFT) to determine genomic drivers that are enriched in young premenopausal women. Genomic alterations were characterised using next-generation sequencing from a subset of 1276 patients (deep targeted sequencing, n= 1258; whole-exome sequencing in a young-age, case-control subsample, n= 82). We defined copy number (CN) subgroups and assessed for features suggestive of homologous recombination deficiency (HRD). Genomic alteration frequencies were compared between young premenopausal women (<40 years) and older premenopausal women (≥40 years), and assessed for associations with distant recurrence-free interval (DRFI) and overall survival (OS). Younger women (<40 years, n= 359) compared with older women (≥40 years, n= 917) had significantly higher frequencies of mutations in GATA3 (19% versus 16%) and CN amplifications (CNAs) (47% versus 26%), but significantly lower frequencies of mutations in PIK3CA (32% versus 47%), CDH1 (3% versus 9%), and MAP3K1 (7% versus 12%). Additionally, they had significantly higher frequencies of features suggestive of HRD (27% versus 21%) and a higher proportion of PIK3CA mutations with concurrent CNAs (23% versus 11%). Genomic features suggestive of HRD, PIK3CA mutations with CNAs, and CNAs were associated with significantly worse DRFI and OS compared with those without these features. These poor prognostic features were enriched in younger patients: present in 72% of patients aged <35 years, 54% aged 35-39 years, and 40% aged ≥40 years. Poor prognostic features [n= 584 (46%)] versus none [n= 692 (54%)] had an 8-year DRFI of 84% versus 94% and OS of 88% versus 96%. Younger women (<40 years) had the poorest outcomes: 8-year DRFI 74% versus 85% and OS 80% versus 93%, respectively. These results provide insights into genomic alterations that are enriched in young women with HR+HER2- EBC, provide rationale for genomic subgrouping, and highlight priority molecular targets for future clinical trials.

Abstract PD2-09: The role of CYP2D6 mediated tamoxifen metabolism in the suppression of ovarian function trial (SOFT)

Abstract Tamoxifen (T) is a pro-drug that undergoes CYP2D6-mediated metabolic activation to metabolites that more potently inhibit estrogen stimulated growth compared to the parent drug. While many studies have examined the role of CYP2D6 genotype in T-treated postmenopausal women, the role of CYP2D6 metabolism in premenopausal women (pre-MW) receiving T, with or without ovarian function suppression (OFS) or exemestane (E) and OFS is unknown. Methods: SOFT randomized 3066 (pre-MW) from 2003-2011 in 27 countries, stratified according to prior receipt or nonreceipt of chemotherapy and nodal status, to receive 5 years of T, T+OFS, or E+OFS. We designed a pharmacogenetics substudy (activated October 2010) to collect blood DNA from North American (NA) patients (pts) or to extract non-tumor DNA from available formalin fixed paraffin embedded (FFPE) tissue blocks. For pts with a blood sample, CYP2D6 was genotyped beginning with the Luminex Tag-It Mutation Detection Kit and when needed, with a copy number variation assay and/or sequencing assays. For pts with FFPE-derived DNA, CYP2D6 genotyping for *3, *4, *6, *9, *10, *17 and *41 was performed using a Taqman Allelic Discrimination Assay. CYP2D6 phenotypes were called by classifying pts on the basis of a combination of poor (PM: *3, *4, *5, *6, *7, *8), slow (SM: *10), intermediate (IM: *9, *17, *29, *41) and extensive metabolizer alleles (EM; all others). Activity scores (AS) from phenotypes assigned for each allele: 0 if PM, 0.25 if SM, 0.5 if IM and 1 if EM allele, and multiplied x2 or x3 if duplicate or triplicate. With concomitant use of potent CYP2D6 inhibitor, AS=0; use of weak inhibitor subtracted 0.5. Metabolizer status was defined by CYP2D6 genotype alone or in combination with CYP2D6 inhibitor use at randomization from the AS: extensive (AS 1.25 to 3), intermediate (AS &amp;gt;0.5 to &amp;lt;1.25), slow/poor (AS 0 to 0.5) metabolizer status. The laboratory was blinded to all clinical data. The substudy primary objective was to assess the association between disease-free survival (DFS) and CYP2D6 metabolizer status in the T arm, and secondarily in the T + OFS, and E + OFS arms. A Cox model estimated hazard ratios comparing status according to treatment assignment, with prespecified prognostic factors. Results: 1200/3047 (39%) randomized pts in the intention-to-treat (ITT) population had successful CYP2D6 genotyping and 50% received prior chemotherapy. Following randomization, 435/1023 (42%) NA pts provided a blood sample and CYP2D6 genotypes were derived in 435/435. Non-tumor tissue was macrodissected from 1277 available FFPE blocks, resulting in DNA concentrations of &amp;gt; 0.3 ng/ml in 1053, and successfully derived CYP2D6 genotypes for 765/3047 pts (25%). 182 (15%) pts had DFS events after 8 yrs median follow-up. Metabolizer status from genotype was 57% extensive, 29% intermediate, 15% slow/poor. Metabolizer status was not associated with DFS in pts assigned T alone (P=0.60; Table), nor in pts assigned T+OFS (P=0.41) or E+OFS (P=0.30). 11% of pts used CYP2D6 inhibitors concomitantly at randomization; for 8% it changed the metabolizer status. The results using this definition were consistent. Conclusion: This retrospective-prospective SOFT pharmacogenetics substudy found no relation of CYP2D6 metabolizer status with DFS in premenopausal pts receiving T, T + OFS, or E + OFS. Given that 50% were pretreated with chemotherapy, further study is needed regarding the role of CYP2D6 metabolism in patients treated with T monotherapy. TableTreatment GroupN pts (N events)Comparison (N pts)Hazard Ratio95% CITamoxifen324 (56)Intermediate (114) vs Extensive (210)0.780.43-1.39Tamoxifen265 (52)Slow/Poor (55) vs Extensive (210)1.110.58-2.13Tamoxifen + OFS357 (46)Intermediate (122) vs Extensive (235)0.730.38-1.40Tamoxifen + OFS299 (45)Slow/Poor (64) vs Extensive (235)1.250.64-2.43Exemestane + OFS344 (46)Intermediate (107) vs Extensive (237)0.590.28-1.22Exemestane + OFS293 (47)Slow/Poor (56) vs Extensive (237)1.130.56-2.27 Citation Format: Matthew P. Goetz, Gini F. Fleming, Mary Kuffel, John R. Hawse, John L. Black, Richard Weinshilboum, James N. Ingle, Patrizia dell’Orto, Olivia Biasi, Roswitha Kammler, Sherene Loi, Marco Colleoni, Giuseppe Viale, Prudence A Francis, Meredith M Regan. The role of CYP2D6 mediated tamoxifen metabolism in the suppression of ovarian function trial (SOFT) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PD2-09.

Adjuvant endocrine treatment for estrogen receptor (ER)-positive/HER2-negative breast cancer.

Approximately 70% of women with breast cancer worldwide receive a diagnosis of ER-positive/ HER2-negative disease. Recurrence-free survival of the node-negative population of these women is approximately 85%, and most are treated with endocrine chemotherapy. Endocrine treatment for ERpositive/HER2-negative early breast cancer is a major treatment strategy. Breast cancer clinicians have gained much experience with this issue, but new data regarding adjuvant endocrine therapy have recently been accumulated. In the integrated analyses of the Suppression of Ovarian Function Trial (SOFT) and Tamoxifen and Exemestane Trial (TEXT) trials, the addition of ovarian function suppression (OFS) to tamoxifen showed a significant improvement in both 8-year disease-free survival [hazard ratio (HR) 0.76, 95% confidence interval (CI): 0.62-0.93] and overall survival (HR 0.67, 95% CI: 0.48-0.92) compared with tamoxifen alone for premenopausal patients with breast cancer, with the assumption of 5 years as an appropriate duration for OFS. The ATLAS trial showed that, compared with 5 years of tamoxifen, 10 years of tamoxifen provided further benefit to women with HR-positive early breast cancer in recurrence [5-9 years: rate ratio (RR) 0.90, 95% CI: 0.79-1.07; ≥10 years: RR 0.75, 95% CI: 0.62-0.90; and all years: log-rank P=0.002] and breast cancer mortality (5-9 years: RR 0.97, 95% CI: 0.79-1.18; ≥10 years: RR 0.71, 95% CI: 0.58-0.88; and all years: log-rank P=0.01), particularly after reaching 10 years, which is considered a "carry over" benefit. In this review, adjuvant endocrine treatment for ER-positive/HER2-negative early breast cancer is discussed. Particular areas of focus are premenopausal patients, especially regarding the addition of OFS, postmenopausal patients, the duration of adjuvant endocrine therapy, the treatment implications of multigene expression assays, and adjuvant endocrine therapy for ductal carcinoma in situ. Some of this evidence supports the clinical management of breast cancer patients as well as clinical studies in the future.

Adjuvant endocrine therapy for premenopausal women: risk stratification, type and duration

Updated results from the Suppression of Ovarian Function Trial (SOFT) and Tamoxifen and Exemestane Trial (TEXT) have helped to identify differential value of various adjuvant endocrine therapy strategies in high-risk and low-risk premenopausal early breast cancer. With a median follow-up of 8 years in SOFT, there is now a significant improvement in disease-free survival (DFS) for those assigned to receive 5 years of tamoxifen plus ovarian function suppression (T + OFS) as compared with tamoxifen (T). Further improvement in DFS was observed for those assigned exemestane plus OFS (E + OFS). While the relative treatment effect from the addition of OFS to tamoxifen in the no chemotherapy and prior chemotherapy cohorts in SOFT was similar, larger absolute improvement in DFS was observed with endocrine therapy escalation in the premenopausal cohort who had received chemotherapy. Despite some improvement in DFS in the lower risk no-chemotherapy cohort, the 8-year results for that cohort continue to show a low risk of distant metastases with the use of adjuvant tamoxifen as sole systemic therapy. A small overall survival advantage from the addition of OFS to tamoxifen has now emerged in SOFT, which appears more clinically meaningful in the prior chemotherapy cohort.In the joint analysis of SOFT and TEXT, there is currently no overall survival improvement at 8 years for those assigned E + OFS versus T + OFS, despite a significant reduction in distance recurrences with E + OFS. Assessing absolute improvements in freedom from distant recurrence observed with the different endocrine strategies across the risk spectrum of patients with HER2-negative tumours in SOFT and TEXT, may assist decision-making for premenopausal patients.

Absolute Improvements in Freedom From Distant Recurrence to Tailor Adjuvant Endocrine Therapies for Premenopausal Women: Results From TEXT and SOFT.

PURPOSEThe Tamoxifen and Exemestane Trial (TEXT)/Suppression of Ovarian Function Trial (SOFT) showed superior outcomes for premenopausal women with hormone receptor (HR)–positive breast cancer treated with adjuvant exemestane plus ovarian function suppression (OFS) or tamoxifen plus OFS versus tamoxifen alone. We previously reported the magnitude of absolute improvements in freedom from any recurrence across a continuous, composite measure of recurrence risk to tailor decision making. With longer follow-up, we now focus on distant recurrence.METHODSThe TEXT/SOFT HR-positive/human epidermal growth factor receptor 2 (HER2)–negative analysis population included 4,891 women stratified by predetermined chemotherapy use. Kaplan-Meier estimates of 8-year freedom from distant recurrence were analyzed using subpopulation treatment effect pattern plot (STEPP) methodology across subpopulations defined by the continuous composite measure of recurrence risk. For each patient, the composite risk value was obtained from a Cox model that incorporated age; nodal status; tumor size; grade; and estrogen receptor, progesterone receptor, and Ki-67 labeling index expression levels.RESULTSThe overall rate of 8-year freedom from distant recurrence was 91.1% and ranged from approximately 100% to 63% across lowest to highest composite risks. TEXT patients who received chemotherapy had an average absolute improvement with exemestane plus OFS versus tamoxifen plus OFS of 5.1%, and STEPP analysis showed improvements from less than 1% to more than 15% from lowest to highest composite risks. SOFT patients who remained premenopausal after chemotherapy had an average 5.2% absolute improvement with exemestane plus OFS versus tamoxifen and reached 10% across composite risks; for tamoxifen plus OFS versus tamoxifen, the maximum improvement was approximately 3.5%. Women who did not receive chemotherapy had a more than 97% rate of 8-year freedom from distant recurrence, and improvements with exemestane plus OFS ranged from 1% to 4%.CONCLUSIONPremenopausal women with HR-positive/HER2-negative breast cancer and high recurrence risk, as defined by clinicopathologic characteristics, may experience a 10% to 15% absolute improvement in 8-year freedom from distant recurrence with exemestane plus OFS versus tamoxifen plus OFS or tamoxifen alone. The potential benefit of escalating endocrine therapy versus tamoxifen alone is minimal for those at low recurrence risk.

Revisiting adjuvant ovarian suppression in premenopausal breast cancer patients.

Adjuvant ovarian suppression, on addition to chemotherapy, reduces the risk of breast cancer in pre-menopausal women after surgery and adjuvant hormonal therapy. Suppression of Ovarian Function Trial (SOFT) and Tamoxifen and Exemestane Trial (TEXT) showed greater benefit with exemestane in high risk females in comparison to Tamoxifen. Ovarian Function Suppression (OFS) and exemestane became the standard of care, with 30% patients experiencing grade 3 and more side effects. Much higher benefit was seen in high risk group. But there are concerns about incomplete OFS (estrogen escape) with exemestane plus OFS. Updated analysis of TEXT AND SOFT showed better survival benefit with OFS plus Tamoxifen as compared to OFS plus exemestane. Overall survival is a better end point. Should preference be given to Tamoxifen over exemestane? Further research is required to get the final answer.

Tailoring Adjuvant Endocrine Therapy for Premenopausal Breast Cancer

BackgroundIn the Suppression of Ovarian Function Trial (SOFT) and the Tamoxifen and Exemestane Trial (TEXT), the 5-year rates of recurrence of breast cancer were significantly lower among premenopausal women who received the aromatase inhibitor exemestane plus ovarian suppression than among those who received tamoxifen plus ovarian suppression. The addition of ovarian suppression to tamoxifen did not result in significantly lower recurrence rates than those with tamoxifen alone. Here, we report the updated results from the two trials.MethodsPremenopausal women were randomly assigned to receive 5 years of tamoxifen, tamoxifen plus ovarian suppression, or exemestane plus ovarian suppression in SOFT and to receive tamoxifen plus ovarian suppression or exemestane plus ovarian suppression in TEXT. Randomization was stratified according to the receipt of chemotherapy.ResultsIn SOFT, the 8-year disease-free survival rate was 78.9% with tamoxifen alone, 83.2% with tamoxifen plus ovarian suppression, and 85.9% with exemestane plus ovarian suppression (P=0.009 for tamoxifen alone vs. tamoxifen plus ovarian suppression). The 8-year rate of overall survival was 91.5% with tamoxifen alone, 93.3% with tamoxifen plus ovarian suppression, and 92.1% with exemestane plus ovarian suppression (P=0.01 for tamoxifen alone vs. tamoxifen plus ovarian suppression); among the women who remained premenopausal after chemotherapy, the rates were 85.1%, 89.4%, and 87.2%, respectively. Among the women with cancers that were negative for HER2 who received chemotherapy, the 8-year rate of distant recurrence with exemestane plus ovarian suppression was lower than the rate with tamoxifen plus ovarian suppression (by 7.0 percentage points in SOFT and by 5.0 percentage points in TEXT). Grade 3 or higher adverse events were reported in 24.6% of the tamoxifen-alone group, 31.0% of the tamoxifen–ovarian suppression group, and 32.3% of the exemestane–ovarian suppression group.ConclusionsAmong premenopausal women with breast cancer, the addition of ovarian suppression to tamoxifen resulted in significantly higher 8-year rates of both disease-free and overall survival than tamoxifen alone. The use of exemestane plus ovarian suppression resulted in even higher rates of freedom from recurrence. The frequency of adverse events was higher in the two groups that received ovarian suppression than in the tamoxifen-alone group. (Funded by Pfizer and others; SOFT and TEXT ClinicalTrials.gov numbers, NCT00066690 and NCT00066703, respectively.)

184 - Surgical Findings and Pathology in Women Undergoing Bilateral Oophorectomy for Treatment of Premenopasual Breast Cancer: a Study of the Fellows Pelvic Research Research Network in Minimally Invasive Gynecologic Surgery

Study Objective: Since publication of the Suppression of Ovarian Function Trial (SOFT) data, some women with premenopausal breast cancer have been recommended to undergo bilateral oophorectomy to facilitate breast cancer treatment with aromatase inhibitors. Our objective is to describe the procedures performed, intra-abdominal findings, and surgical pathology of this population.

Adjuvant endocrine therapy for premenopausal women: Type and duration

The Early Breast Cancer Trialists' Collaborative Group (EBCTCG) meta-analysis of randomized tamoxifen trials, found that women age <45 years with estrogen receptor-positive (ER+ve) breast cancer, allocated 5 years of adjuvant tamoxifen, have substantial long-term reduction of breast cancer recurrence. Breast cancer mortality was reduced by about one-third through the first 15 years. Increasing the duration of tamoxifen to 10 years can further reduce the risk of recurrence. For women age <45 years allocated 5 years of tamoxifen, the risk of contralateral breast cancer is halved over 15 years.The initial results from the Suppression of Ovarian Function Trial (SOFT) indicate tamoxifen is a suitable therapy for premenopausal women with low risk clinical-pathologic features. For women at sufficient risk to receive chemotherapy who have premenopausal E2 levels within 8 months of completion, the addition of ovarian suppression to tamoxifen for 5 years resulted in some reduction of recurrence. The use of ovarian suppression combined with an aromatase inhibitor exemestane for 5 years, resulted in further reduction of recurrence.The joint analysis of SOFT and Tamoxifen and Exemestane Trial (TEXT) found the combination of ovarian suppression plus exemestane significantly reduced recurrence, compared with ovarian suppression plus tamoxifen. Premenopausal women with ER+ve HER2-negative breast cancer with high-risk features can derive a meaningful improvement in 5-year invasive breast cancer-free interval with exemestane plus ovarian suppression, as an alternative to tamoxifen. Very young women under age 35 with ER+ve breast cancer have higher risks of recurrence, and the use of ovarian suppression with oral endocrine therapy should be considered.

Treatment Efficacy, Adherence, and Quality of Life Among Women Younger Than 35 Years in the International Breast Cancer Study Group TEXT and SOFT Adjuvant Endocrine Therapy Trials.

Purpose To describe benefits and toxicities of adjuvant endocrine therapies in women younger than 35 years with breast cancer (n = 582) enrolled in the Suppression of Ovarian Function Trial (SOFT) and Tamoxifen and Exemestane Trial (TEXT). Methods In SOFT, women still premenopausal after surgery with or without chemotherapy were randomly assigned to tamoxifen alone, tamoxifen plus ovarian function suppression (OFS), or exemestane plus OFS. In TEXT, all received OFS with or without concomitant chemotherapy and were randomly assigned to exemestane plus OFS or tamoxifen plus OFS. We summarize treatment efficacy, quality of life, and adherence of the cohort of women younger than 35 years in SOFT and TEXT, alongside data from the cohort of older premenopausal women. Results For 240 human epidermal growth factor receptor 2-negative patients younger than 35 years enrolled in SOFT after receiving chemotherapy, the 5-year breast cancer-free interval (BCFI) was 67.1% (95% CI, 54.6% to 76.9%) with tamoxifen alone, 75.9% with tamoxifen plus OFS (95% CI, 64.0% to 84.4%), and 83.2% with exemestane plus OFS (95% CI, 72.7% to 90.0%). For 145 human epidermal growth factor receptor 2-negative patients younger than 35 years in TEXT, 5-year BCFI was 79.2% (95% CI, 66.2% to 87.7%) with tamoxifen plus OFS and 81.6% (95% CI, 69.8% to 89.2%) with exemestane plus OFS. The most prominent quality of life symptom for patients younger than 35 years receiving OFS was vasomotor symptoms, with the greatest worsening from baseline at 6 months (on the order of 30 to 40 points), but loss of sexual interest and difficulties in becoming aroused were also clinically meaningful (≥ 8-point change). The level of symptom burden was similar in older premenopausal women. A total of 19.8% of women younger than 35 years stopped all protocol-assigned endocrine therapy early. Conclusion In women younger than 35 years with hormone receptor-positive breast cancer, adjuvant OFS combined with tamoxifen or exemestane produces large improvements in BCFI compared with tamoxifen alone. Menopausal symptoms are significant but are not worse than those seen in older premenopausal women.

Abstract P2-09-06: Addition of ovarian function suppression to endocrine therapy in premenopausal women with early breast cancer: A meta-analysis

Abstract Introduction The Suppression of Ovarian Function Trial (SOFT) and the Tamoxifen and EXemestane Trial (TEXT), together with the Austrian Breast Cancer Study Group (ABCSG-12)and the Eastern Cooperative Oncology Group 3193 (E-3193 trials, have examined adding ovarian function suppression (OFS) using gonadotropin–releasing hormone (GnRH) agonists to endocrine therapy in premenopausal women with early stage breast cancer. However, OFS with GnRH agonist plus aromatase inhibitor has subsequently been found to not consistently reduce estradiol levels to optimal target in the SOFT-EST study (JCO 2016; 34:1584) and implications of these study findings for clinical practice are controversial. Therefore, to further examine this issue, we conducted a systematic literature review and meta-analysis of available evidence. Methods We updated a recently published literature review of randomized clinical trials (JCO 2016; 34:1689) through June 1, 2016 using the keywords “breast cancer,” “ovarian function suppression,” “tamoxifen,” and “aromatase inhibitor”. Of 683 of records identified through database searching, the 4 studies named above met inclusion criteria and were included in the quantitative synthesis. Information on disease-free survival (DFS) and overall survival was examined using hazard ratio (HR) and 95% confidence interval (CI). Because of significant heterogeneity in one performed meta-analyses, the random-effects (DerSimonian and Laird) method was used to estimate the combined RR for studies (Open MetaAnalyst). Results Combining ABCSG-12, SOFT and TEXT trial findings, OFS addition to aromatase inhibitor resulted in 65 fewer DFS events across the 3 trials compared to OFS addition to tamoxifen (350 DFS events vs. 415 DFS events, respectively, HR 0.89, 95% CI 0.57-1.39, P=0.62, Tau2 =0.09, heterogeneity P&amp;lt;0.01). In contrast, 30 more deaths were seen with OFS plus aromatase inhibitor use (155 deaths vs. 125 deaths, respectively, HR 1.31, 95% CI 0.93 -1.84, P=0.12, Tau2 =0.03, heterogeneity P=0.18). Combining SOFT and E-3193 trials to compare OFS addition to tamoxifen to tamoxifen alone use, more concordance between DFS events and overall survival is seen. There were 24 fewer DFS events across the 2 trials with OFS addition to tamoxifen compared to tamoxifen alone (160 DFS events vs. 184 DFS events, respectively, HR 0.83, 95% CI 0.67-1.03, P=0.09, Tau2 =0, heterogeneity P=0.94) and there were 14 fewer deaths in the OFS plus tamoxifen compared to tamoxifen alone group (58 deaths vs. 72 deaths, respectively, HR 0.76 95% CI 0.53 -1.07, P=0.12, Tau2 =0, heterogeneity P=0.78). Conclusion In conclusion, the apparent discordance between DFS and overall survival in the aromatase inhibitor and OFS trials and the results suggesting incomplete and/or intermittent estrogen suppression with GNRH analogs in the SOFT-EST trial suggest that adoption of OFS plus aromatase inhibitor use as adjuvant therapy in premenopausal women with early stage breast cancer may be premature. Longer term survival analyses of the endocrine therapy trials are needed before reliable risks and benefits of aromatase inhibitor plus OFS and tamoxifen plus OFS use as adjuvant therapy can be determined. Citation Format: Chlebowski R, Pan K, Col NF. Addition of ovarian function suppression to endocrine therapy in premenopausal women with early breast cancer: A meta-analysis [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P2-09-06.

Absolute Benefit of Adjuvant Endocrine Therapies for Premenopausal Women With Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative Early Breast Cancer: TEXT and SOFT Trials.

Risk of recurrence is the primary consideration in breast cancer adjuvant therapy recommendations. The TEXT (Tamoxifen and Exemestane Trial) and SOFT (Suppression of Ovarian Function Trial) trials investigated adjuvant endocrine therapies for premenopausal women with hormone receptor-positive breast cancer, testing exemestane plus ovarian function suppression (OFS), tamoxifen plus OFS, and tamoxifen alone. We examined absolute treatment effect across a continuum of recurrence risk to individualize endocrine therapy decision making for premenopausal women with human epidermal growth factor receptor 2 (HER2) -negative disease. The TEXT and SOFT hormone receptor-positive, HER2-negative analysis population included 4,891 women. The end point was breast cancer-free interval (BCFI), defined as time from random assignment to first occurrence of invasive locoregional, distant, or contralateral breast cancer. A continuous, composite measure of recurrence risk for each patient was determined from a Cox model incorporating age, nodal status, tumor size and grade, and estrogen receptor, progesterone receptor, and Ki-67 expression levels. Subpopulation treatment effect pattern plot methodology revealed differential treatment effects on 5-year BCFI according to composite risk. SOFT patients who remained premenopausal after chemotherapy experienced absolute improvement of 5% or more in 5-year BCFI with exemestane plus OFS versus tamoxifen plus OFS or tamoxifen alone, reaching 10% to 15% at intermediate to high composite risk; the benefit of tamoxifen plus OFS versus tamoxifen alone was apparent at the highest composite risk. The SOFT no-chemotherapy cohort-for whom composite risk was lowest on average-did well with all endocrine therapies. For TEXT patients, the benefit of exemestane plus OFS versus tamoxifen plus OFS in 5-year BCFI ranged from 5% to 15%; patients not receiving chemotherapy and with lowest composite risk did well with both treatments. Premenopausal women with hormone receptor-positive, HER2-negative disease and high recurrence risk, as defined by clinicopathologic characteristics, may experience improvement of 10% to 15% in 5-year BCFI with exemestane plus OFS versus tamoxifen alone. An improvement of at least 5% may be achieved for women at intermediate risk, and improvement is minimal for those at lowest risk.

Twelve-Month Estrogen Levels in Premenopausal Women With Hormone Receptor-Positive Breast Cancer Receiving Adjuvant Triptorelin Plus Exemestane or Tamoxifen in the Suppression of Ovarian Function Trial (SOFT): The SOFT-EST Substudy.

To describe estradiol (E2), estrone (E1), and estrone sulfate (E1S) levels during the first year of monthly triptorelin plus exemestane or tamoxifen and to assess possible suboptimal suppression while receiving exemestane plus triptorelin. Premenopausal patients with early breast cancer on the Suppression of Ovarian Function Trial who selected triptorelin as the ovarian suppression method and were randomly assigned to exemestane plus triptorelin or tamoxifen plus triptorelin were enrolled until the target population of 120 patients was reached. Blood sampling time points were 0, 3, 6, 12, 18, 24, 36, and 48 months. Serum estrogens were measured with a highly sensitive and specific assay. This preplanned 12-month analysis evaluated E2, E1, E1S, follicle-stimulating hormone, and luteinizing hormone levels in all patients and the proportion of patients with E2 levels greater than 2.72 pg/mL at any time point during treatment with exemestane plus triptorelin. One hundred sixteen patients (exemestane, n = 86; tamoxifen, n = 30; median age, 44 years; median E2, 51 pg/mL; 55% prior chemotherapy) started triptorelin and had one or more samples drawn. With exemestane plus triptorelin, median reductions from baseline E2, E1, and E1S levels were consistently ≥ 95%, resulting in significantly lower levels than with tamoxifen plus triptorelin at all time points. Among patients on exemestane plus triptorelin, 25%, 24%, and 17% had an E2 level greater than 2.72 pg/mL at 3, 6, and 12 months, respectively. Baseline factors related to on-treatment E2 level greater than 2.72 pg/mL were no prior chemotherapy (P = .06), higher body mass index (P = .05), and lower follicle-stimulating hormone and luteinizing hormone (each P < .01). During the first year, most patients on exemestane plus triptorelin had E2 levels below the defined threshold of 2.72 pg/mL, consistent with levels reported in postmenopausal patients on aromatase inhibitors, but at each time point, at least 17% of patients had levels greater than the threshold.

Are SOFT and TEXT results practice changing and how?

Optimal adjuvant endocrine therapy for premenopausal women with hormone-receptor positive breast cancer has long been debated. In particular, the role of ovarian function suppression in addition to standard tamoxifen divided oncologists worldwide, and more recently, the role of aromatase inhibitors as an alternative to tamoxifen in the setting of ovarian suppression became a key question.In 2014, the long awaited results of the International Breast Cancer Study Group (IBCSG) led randomized, phase 3 trials, Suppression of Ovarian Function Trial (SOFT) and Tamoxifen and Exemestane Trial (TEXT), provided additional evidence to inform the discussion.The interpretation of the SOFT and TEXT trial data can facilitate better selection of appropriate endocrine therapy according to individual disease characteristics, recognizing the complexity of the puzzle, which is still not complete.