Ipsilateral Breast Cancer Research Articles

Disease recurrence in patients undergoing mastectomy for ductal carcinoma in situ.

With DCIS incidence on the rise, up to 30% of patients undergo mastectomy for Ductal carcinoma in situ (DCIS) (Nash and Hwang, in: Ann Surg Oncol 30(6):3206-3214, 2023). Local recurrence rates after mastectomy for DCIS are reportedly low, but risk factors for recurrence are not known (Kim et al., in: J Cancer Res Ther 16(6):1197-1202, 2020). We aim to define risk factors associated with ipsilateral breast cancer recurrence in patients undergoing mastectomy for DCIS. We aimed to identify risk factors that may contribute to recurrence of breast cancer following mastectomy for pure DCIS. We hypothesized that close or positive mastectomy margins, age at diagnosis, extent of breast disease and mutation carriers would be associated with increased risk of recurrence. We performed a retrospective chart review of patients who underwent unilateral or bilateral mastectomies for pure DCIS at a single academic tertiary referral center from 2013 to 2023. There were 165 patients who met inclusion criteria with an average length of follow-up of 39.9months. On final surgical pathology, the average span of DCIS was 33.7mm (± 24.6mm). Hormone receptor positive disease was identified in 80.6% of the patient cohort. For margin status, 23 patients (14%) had < 1mm margins on final pathology and of those, 1 received adjuvant radiation therapy and 4 returned to the OR for re-excision. Only 1 (0.6%) patient had ipsilateral disease recurrence during the study period. Recurrence after mastectomy for pure DCIS is a rare event and in our study sample, only one recurrence occurred. Risk factors for recurrence appear unrelated to margin status, age, extent of DCIS, or pathogenic mutation (ElSherif et al., in Am J Surg 226(5):646-651, 2023).

Increasing opportunities for breast-conserving therapy in multiple ipsilateral breast cancer: Dutch nationwide study.

An increasing number of breast cancer patients undergo breast-conserving surgery (BCS), but multiple ipsilateral breast cancer (MIBC) is still considered a relative contraindication for breast conservation. This study provides an update on trends in the surgical management for MIBC over a 10-year period. Nationwide data from the Netherlands Cancer Registration of all patients diagnosed with breast cancer between 2011 and 2021 were analysed. The primary outcomes of this study were the incidence of MIBC and the trend in breast surgery type among patients between 2011 and 2021. Secondary outcomes were the positive resection margin rates in patients treated with BCS, the proportion of patients requiring re-excision and overall survival. In total, 114 433 patients (83%) with unifocal breast cancer and 23 932 patients (17%) with MIBC were identified. The incidence of MIBC was stable (17%) over the years. Overall BCS rates, both primary and after neoadjuvant chemotherapy, increased in MIBC from 29% in 2011 to 41% in 2021. Re-excision was performed in 1348 patients (n = 8455, 16%). The 5-year OS estimate for patients with MIBC treated with BCS was 93%. The pathological complete response (pCR) in MIBC patients treated with neoadjuvant chemotherapy followed by mastectomy was 23%. The breast conservation rate in MIBC has increased over the last decade. In addition, 23% of MIBC patients treated with neoadjuvant chemotherapy followed by mastectomy achieved a pCR. This suggests increasing opportunities for even more BCS in MIBC.

Surgical Management and Its Impact on Adjuvant Treatment in Recurrent Ipsilateral Breast Cancer: A Retrospective Cohort Study.

Background: Breast cancer (BC) recurrence, defined as the reappearance of cancer in the ipsilateral breast after primary treatment, poses significant challenges in clinical management. Despite advances in treatment, recurrence rates persist, ranging from 0.6 to 1.5% annually, reaching 10-15% at 20 years. This study aims to analyze the surgical and oncological characteristics of patients with BC recurrence. Methods: This retrospective study includes 56 patients diagnosed with recurrent BC between October 2018 and April 2022. Data were collected from a prospectively maintained surgical database. A descriptive analysis was performed on the initial BC, and the recurrence, including surgical complications, was classified using the Clavien-Dindo system. The success rates of selective sentinel lymph node (SLN) biopsies and aberrant drainages were assessed based on previous surgeries. Results: The cohort included 55 females and 1 male, with a median age of 65.3 years. The mean time to BC recurrence was 11.5 years. Among them, 26.8% underwent breast-conserving surgery, 41.1% had a mastectomy, 21.4% had a mastectomy with reconstruction, and 10.7% had an excision over a previous mastectomy. An SLN biopsy was performed in 78.6% of cases, with higher success rates in those without a previous axillary lymph node dissection (85.7% vs. 63.2%). Aberrant drainage was more frequent in patients with a previous ALND (44.4% vs. 20%). The median follow-up was 41.3 months, with 10.7% experiencing a second recurrence. Conclusions: Repeat breast-conserving surgery with re-irradiation for ipsilateral recurrence is feasible and does not significantly increase complications. SLN biopsy is valuable for restaging and tailoring adjuvant therapies, with ALND not being necessary if re-SLN biopsy shows no drainage. The management of aberrant drainage remains controversial.

Systematic assessment of HER2 status in ductal carcinoma in situ of the breast: a perspective on the potential clinical relevance

In many countries, hormone receptor status assessment of ductal carcinoma in situ (DCIS) is routinely performed, as hormone receptor-positive DCIS patients are eligible for adjuvant anti-hormonal treatment, aiming to reduce the ipsilateral and contralateral breast cancer risk. Although HER2 gene amplification and its associated HER2 protein overexpression constitute a major prognostic and predictive marker in invasive breast carcinoma, its use in the diagnosis and treatment of DCIS is less straightforward. HER2 immunohistochemistry is not routinely performed yet, as the role of HER2-positivity in DCIS biology is unclear. Nonetheless, recent data challenge this practice. Here, we discuss the value of routine HER2 assessment for DCIS. HER2-positivity correlates strongly with DCIS grade: around four in five HER2-positive DCIS show high grade atypia. As morphological DCIS grading is prone to interobserver variability, HER2 immunohistochemistry could render grading more robust. Several studies showed an association between HER2-positive DCIS and ipsilateral recurrence risk, albeit currently unclear whether this is for overall, in situ or invasive recurrence. HER2-positive DCIS tends to be larger, with a higher risk of involved surgical margins. HER2-positive DCIS patients benefit more from adjuvant radiotherapy: it substantially decreases the local recurrence risk after lumpectomy, without impact on overall survival. HER2-positivity in pure biopsy-diagnosed DCIS is associated with increased upstaging to invasive carcinoma after surgery. HER2 immunohistochemistry on preoperative biopsies might therefore provide useful information to surgeons, favoring wider excisions. The time seems right to consider DCIS subtype-dependent treatment, comprising appropriate local treatment for HER2-positive DCIS patients and de-escalation for hormone receptor-positive, HER2-negative DCIS patients.

109 Ipsilateral breast cancer recurrences by age following electronic brachytherapy (NCT01644669)

109 Ipsilateral breast cancer recurrences by age following electronic brachytherapy (NCT01644669)

Invasive recurrence after breast conserving treatment of ductal carcinoma in situ of the breast in the Netherlands: time trends and the association with tumour grade.

The first aim of this study was to examine trends in the risk of ipsilateral invasive breast cancer (iIBC) after breast-conserving surgery (BCS) of ductal carcinoma in situ (DCIS). A second aim was to analyse the association between DCIS grade and the risk of iIBC following BCS. In this population-based, retrospective cohort study, the Netherlands Cancer Registry collected information on 25,719 women with DCIS diagnosed in the period 1989-2021 who underwent BCS. Of these 19,034 received adjuvant radiotherapy (RT). Kaplan-Meier analyses and Cox regression models were used. A total of 1135 patients experienced iIBC. Ten-year cumulative incidence rates of iIBC for patients diagnosed in the periods 1989-1998, 1999-2008 and 2009-2021 undergoing BCS without RT, were 12.6%, 9.0% and 5.0% (P < 0.001), respectively. For those undergoing BCS with RT these figures were 5.7%, 3.7% and 2.2%, respectively (P < 0.001). In the multivariable analyses, DCIS grade was not associated with the risk of iIBC. Since 1989 the risk of iIBC has decreased substantially and has become even lower than the risk of invasive contralateral breast cancer. No significant association of DCIS grade with iIBC was found, stressing the need for more powerful prognostic factors to guide the treatment of DCIS.

Clinical Outcomes for BRCA Pathogenic Variant Carriers With Breast Cancer Undergoing Breast Conservation

Although most women with BRCA-associated breast cancer choose bilateral mastectomy, current guidelines support breast-conserving therapy as an option. As the indications for genetic testing expand and targeted therapies emerge, understanding the outcomes of breast-conserving therapy in the population of patients choosing breast conservation is important. To describe the clinical outcomes of women with BRCA-associated breast cancer who were treated with breast-conserving therapy, including the risks of ipsilateral and contralateral cancer events and bilateral mastectomy-free survival. This cohort study conducted at a single-institution academic national comprehensive cancer center included 172 women identified from a prospectively maintained database who had pathogenic BRCA1/2 variants and were treated with breast-conserving therapy from January 1, 1977, to December 31, 2021. Clinical and pathologic characteristics for patients with BRCA1 and BRCA2 were compared, and estimates of overall survival, bilateral mastectomy-free survival, distant disease-free survival, risk of ipsilateral breast cancer, and risk of contralateral cancer were computed. The cohort included 172 women (mean [SD] age, 47.1 [11.7] years), with 42 (24.4%) receiving a diagnosis of breast cancer prior to 40 years of age. Compared with BRCA2 variant carriers (80 [46.5%]), women with BRCA1 variants (92 [53.5%]) were younger at breast cancer diagnosis and tended to have more advanced tumors, which were more likely to be hormone receptor negative and higher grade. At a median follow-up of 11.8 years (IQR, 5.7-18.2 years), estimates of 10-year survival and risk were: overall survival, 88.5% (95% CI, 83.1%-94.2%); bilateral mastectomy-free survival, 70.7% (95% CI, 63.3%-78.9%); risk of an ipsilateral breast cancer event, 12.2% (95% CI, 5.8%-18.2%); and risk of contralateral cancer, 21.3% (95% CI, 13.3%-28.6%). Risks continued to increase after 10 years of follow-up. In this cohort study, although women with breast cancer and pathogenic BRCA1/2 variants treated with breast-conserving therapy had above-average risks of ipsilateral and contralateral breast cancer events, most did not have another cancer event and remained bilateral mastectomy free. These findings may be useful for informing patients with BRCA variants choosing breast conservation.

Incidence of local breast cancer recurrence with delayed radiation therapy.

The purpose of this research was to examine the probability of ipsilateral breast cancer recurrence in individuals whose RT was delayed after the first chemotherapy and surgery. To analyze the effect of delaying RT for breast cancer patients (by more than 6weeks after treatment). A retrospective analysis comprised 136 female breast cancer patients treated at the Baghdad Centre for Radiation Oncology and Nuclear Medicine from 2021 to May 2022. External beam radiation was started more than 6weeks after chemotherapy was finished for all patients who also had surgery. Clinical examination and ultrasound were part of the follow-up process. Patients' ages varied from 28 to 71, and the majority (83%) had a mastectomy. The majority of cases (95.5%) were diagnosed as invasive ductal carcinoma on histopathology, with 49.6% being at stage 2 and 42.6% being at stage 3. Seventy-six percent of patients tested positive for hormones. Although 10 patients (7.35%) acquired distant metastases within 5years, only 2 (1.47%) had local recurrence because of the delay in RT. Specifically, 91.1% had complete local control with no evidence of disease spread. Delaying RT by more than 6weeks in patients with breast cancer did not substantially affect local control, according to the results of a new research, the first of its type in Iraq.

Ipsilateral recurrence and breast cancer outcomes in carriers of BRCA1/2 pathogenic variants according to locoregional treatments.

e12584 Background: Our previous study of 255 breast cancer (BC) patients, carriers of BRCA1/2 pathogenic variants (PV), showed that patients who underwent mastectomy without post-mastectomy radiotherapy (PMRT) had higher rates of local recurrence (LR) than those who underwent PMRT or breast-conserving therapy (BCT). Our aim was to verify our previous findings in a larger cohort. Methods: Clinical data was extracted from the medical records of BRCA1/2 mutation carriers with BC, treated at a single institution between 1/2006-12/2022. Data extracted included demographics, tumor characteristics, disease stage, surgical and oncological treatment, use of RT and disease outcomes. Results: Overall, 481 BC patients with BRCA1/2 germline mutations were identified, 20 of them presented with synchronous bilateral disease. Median follow-up time was 75.3 months (range 12.5-211). After excluding 16 patients with metastatic de novo disease and 1 patient not operated for medical reasons, 464 patients with 484 primary tumors were analyzed. Of these, 234 (48.3%) mastectomies (84% were skin- or nipple-sparing, SSM/NSM, 16% total mastectomy) and 250 (51.7%) BCT were performed. In the non-PMRT group (n=153) there was earlier disease stage at diagnosis (77.6% of tumors were Tis and T1N0) compared to the PMRT group (n=81) and BCT group (4.9% and 45%, respectively, p&lt;0.001). All had free surgical margins. LR rate in the study cohorts was 20/153 breasts (13.1%) in the non-PMRT group compared with 1/81 breasts (1.2%) in the PMRT group (p=0.003), and 16/250 (6.4%) in the BCS group (p=0.024). All but one recurrence were invasive. Cumulative incidence of LR at 5 and 10 years was 14.1% and 15.9% in the non-PMRT, compared to 4.4% and 9.4% in BCT group, respectively (p=0.034). No significant difference in overall survival was observed (p=0.39). Conclusions: BRCA1/2 PV carriers treated with mastectomy without PMRT had higher rates of LR than those who underwent mastectomy and PMRT or BCT, despite earlier stage disease. Further studies are needed to compare these outcomes to non- BRCA1/2 carriers and find means to improve local control in these patients.

Is breast conservation surgery feasible in ipsilateral cancer recurrence with previous radiotherapy?

Introduction: Breast-conserving surgery (BCS) is the preferred modalityfor early breast cancer, yet there is a significant research gap in understandingthe feasibility of BCS in ipsilateral recurrent breast cancer(IRBC) post-radiotherapy. This systematic review aims to investigate theoutcomes of repeat BCS (rBCS) in managing IRBC, providing crucialinsights for clinicians and patients in evaluating treatment options.Methods: The PRISMA framework guided data collection from PubMedand Embase. A qualitative systematic approach involved descriptive andthematic analysis, examining patterns and consistencies in outcome findingsacross identified studies. Due to the nature of the research, no statisticalanalysis was conducted.Results: Four papers, employing a 95% confidence level, were included.Studies revealed a 2.103 risk ratio for second local recurrence (SLR) afterrBCS compared to mastectomy. Pooled data indicated SLR rates of15.7% for BCS and 10.3% for mastectomy, with a 5-year overall survival(OS) rate of 86.8 and 79.8%, respectively. Repeat radiotherapy showed aprotective effect for SLR and a small OS benefit favoured rBCS. However,this came with overall evidence certainty. Other studies found a 5-year OSof 77 and 87% after rBCS, with oncological advantages for adjunctiveradiotherapy. Post-IBTR, 84% had a 5-year survival rate, while multivariateanalysis highlighted factors influencing SLR.Conclusion: This systematic review suggests that rBCS may be consideredin a subset of patients with IBCR after BCS and RT. Individual assessmentencompassing tumour-size and duration prior to relapse showsimportance approach feasibility. However, further research wouldimprove subject knowledge and aid in optimal patient selection.

Abstract PO2-22-04: Median Five-Year Follow-Up Results from the Multi-Institution Trial for the Treatment of Early-Stage Breast Cancer Using Intra-Operative Electronic Brachytherapy

Abstract Background: An IRB-approved single arm prospective multi-institution trial was designed to determine the efficacy and outcome of single fraction 20 Gy intra-operative radiation therapy (IORT) using disposable balloon electronic brachytherapy at the time of breast conserving surgery for early-stage breast cancer (women at least 40 years old, infiltrating ductal carcinoma [IDC] or ductal carcinoma in situ [DCIS], single lesion no larger than 3 cm, pN0). Ipsilateral breast tumor recurrences (IBTR) at median 5-year follow-up, the primary protocol endpoint of the trial, would be analyzed with outcomes compared to reported whole breast radiation therapy (WBRT) results. Methods: Between May 2012–July 2018,1199 enrolled breast cancer patients at twenty-six national and international institutions were successfully treated per protocol with lumpectomy plus single 20 Gy fraction IORT using disposable balloon electronic brachytherapy. Data collection and retrospective chart review included demographics, treatment, histopathology, toxicity, IBTR (defined as recurrence in the lumpectomy cavity/index quadrant), and survival. Results: All subjects were successfully treated with a single 20 Gy fraction of IORT. IORT cohort characteristics of the treated subjects are summarized in Table 1. Sixty-six (5.5%) patients received subsequent unplanned risk-adjusted WBRT. At median 5.0-year follow-up (range 0.5 – 9 years), there were 42 (3.50%) IBTR. The original mean tumor size of patients with IBTR was 13.6mm (range 0.03 - 30mm). The mean time to IBTR was 47.6 months (range 12 – 98 months). There were 30 IBTR in patients originally diagnosed with IDC, and 12 IBTR among patients originally diagnosed with DCIS. Three patients originally diagnosed with IDC recurred as DCIS, while 4 patients with DCIS recurred as IDC. The remainder recurred with the same pathology as their original diagnoses. Sorting by 2017 ASTRO accelerated partial breast irradiation (APBI) criteria, there were 25 IBTR in patients categorized immediately following lumpectomy plus IORT as Suitable, 12 IBTR among patients categorized immediately following lumpectomy plus IORT as Cautionary, and 5 IBTR in patients categorized immediately following lumpectomy plus IORT as Unsuitable. Nine (0.75%) patients experienced new ipsilateral primary breast cancers, with 8 classified as Suitable and one as Cautionary using post-lumpectomy plus IORT ASTRO APBI criteria. Seventeen (1.4%) patients experienced acute serious adverse events (SAEs). These included 5 wound infections, 4 hematomas, 2 skin ulcerations, 2 cellulitis, 2 seromas, 1 skin necrosis, and 1 wound dehiscence. All SAEs resolved within 6 months of IORT. One patient died of breast cancer metastases at 3-year follow-up. One patient who was diagnosed with IBTR at 3-year follow-up died 3 years later from dementia. There were 45 unrelated patient deaths. Conclusions: At median 5.0-year follow-up, the 1199 early-stage breast cancer patients successfully treated in this multi-institution trial with a single 20 Gy fraction of IORT to the lumpectomy cavity at the time of partial mastectomy experienced an IBTR of 3.50%. This recurrence rate is acceptable when compared to the 0.9% - 2.5% IBTR reported for WBRT, given the benefits of IORT (convenience, decreased exposure to XRT, better cosmetic outcome, patient preference). Table 1. IORT cohort characteristics Citation Format: Barbara Schwartzberg, AM Nisar Syed, Ajay Bhatnagar, Sophia Rahman, Veronica Jones, Albert Chang, Todd Cockerham, Virginia Osborn, Robert Cohen, Charles Hodge, Christina Lopez-Penalver, Bapsi Chakravarthy, William Dooley, Chika Madu, Atsuko Okabe, Maen Farha, Andrea Madrigrano, Christopher Morrison, Geoffrey Neuner, Craig Wengler, Steven David, Katayoon Toosie, Bryon Stephens. Median Five-Year Follow-Up Results from the Multi-Institution Trial for the Treatment of Early-Stage Breast Cancer Using Intra-Operative Electronic Brachytherapy [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 PO2-22-04.

Evaluation of the impact of breast-conserving surgery on cancer outcomes of multiple (multifocal or multicentric) ipsilateral breast cancer

Background Breast conservative therapy (BCT) includes conservative breast surgery (CBS) with adjuvant radiotherapy and is now considered a standard treatment for early-stage breast cancer to achieve survival with acceptable aesthetic outcomes. Management of multiple ipsilateral breast cancer (MIBC) is a challenge, since the choice of optimal surgical procedures is controversial. Recently, many breast surgeons have advocated CBS is technically feasible to safely excise MIBC in selected cases. Aim This study aimed to evaluate the outcome of MIBC patients who received CBS with special attention on local control and recurrence. Patient and method This retrospective study was carried out on 90 patients at Al Azhar University Hospital and Ain Shams University Hospitals between January 2021 and January 2023. Results The majority of patients 85 (94.4%) had two foci of disease while five (5.5%) patients had three foci. The distance between the lesions ranges between 0.5 and 6.5 cm. The most common type of CBS was wide local excision en bloc resection of all lesions with normal tissue in between was done in 85 (94.4%) patients and five (5.5%) patients had two separate incisions leaving normal tissue in between. Clear margins were reported in 79 (87.7%) patients. 15 (5.5%) patients had different pathological lesion types (heterogeneous). One patient had a recurrence and another had distant metastases. Conclusion With good patient selection, there is no difference between CBS and mastectomy in the management of MIBC. CBS is oncological safe provided that an adequate excision with clear margins followed by whole-breast radiation therapy and adjuvant systemic therapy.

Oncologic safety of breast conserving surgery after neoadjuvant chemotherapy in patients with multiple ipsilateral breast cancer: A retrospective multi-institutional cohort study

IntroductionThe recent ACOSOG Z11102 trial demonstrated low recurrence rates with breast conserving surgery (BCS) in women with multiple ipsilateral breast cancers (MIBC). Questions remain regarding the oncologic safety of BCS in women with MIBC receiving neoadjuvant chemotherapy (NAC). MethodsWe conducted a retrospective cohort study of adult patients who underwent BCS following NAC for stage I-III breast cancer from 2012 to 2021 at two academic centers. Descriptive statistics were used to summarize the data and the Kaplan-Meier method was used to provide estimates for recurrence and survival outcomes. MIBC was defined as ≥2 foci of malignancy. ResultsA total of 544 patients were included; 29.4% (n = 160) ER+/HER2-, 17.7% (n = 96) ER+/HER2+, 18.2% (n = 99) ER-/HER2+, and 34.7% (n = 189) with ER-/HER2-disease. Overall, 80.5% (n = 438) had unifocal breast cancer while 19.5% (n = 106) had MIBC. Of patients with MIBC, 90.6% (n = 96) had multifocal and 9.4% (n = 10) had multicentric disease. Pathologic complete response was achieved in 41.1% of patients with MIBC versus 41.5% of patients with unifocal disease (p = 0.94). At a median follow-up of 55 months (IQR 32-83); 4.8% of patients in the unifocal group and 4.7% of patients in the MIBC group had had a local recurrence (p = 0.97). There was no difference in 5-year local recurrence-free survival (p = 0.92), recurrence-free survival (p = 0.06), or overall survival (p = 0.07) between the groups. ConclusionIn this large cohort of women undergoing BCS post-NAC, there was no significant difference in in breast tumor recurrence or survival outcomes between patients with unifocal disease and those with MIBC.

Immediate and delayed risk of breast cancer associated with classic lobular carcinoma in situ and its variants.

To determine the risk of breast cancer due to lobular carcinoma in situ (LCIS). This retrospective IRB-approved study identified cases of LCIS after percutaneous breast biopsy from 7/2005 to 7/2022. Excluded were cases with less than 2years of imaging surveillance or a concurrent ipsilateral breast cancer diagnosis within 6months of the LCIS diagnosis. Final outcomes of cancer versus no cancer were determined by pathology at surgical excision or the absence of cancer on imaging surveillance. A total of 116 LCIS lesions were identified. The primary imaging findings targeted for percutaneous biopsy included calcifications (50.0%, 58/116), MR enhancing lesions (25.0%, 29/116), noncalcified mammographic architectural distortions (10.3%, 12/116), or masses (14.7%, 17/116). Surgical excision was performed in 49.1% (57/116) and imaging surveillance was performed in 50.9% (59/116) of LCIS cases. There were 22 cancers of which 11 cancers were discovered at immediate excision [19.3% (11/57) immediate upgrade] and 11 cancers developed later while on imaging surveillance [18.6% (11/59) delayed risk for cancer]. Among all 22 cancers, 63.6% (14/22) occurred at the site of LCIS (11 at immediate excision and 3 at surveillance) and 36.4% (8/22) occurred at a location away from the site of LCIS (6 in a different quadrant and 2 in the contralateral breast). LCIS has both an immediate risk (19.3%) and a delayed risk (18.6%) for cancer with 90.9% occurring in the ipsilateral breast (63.6% at and 27.3% away from the site of LCIS) and 9.1% occurring in the contralateral breast.

208 (PB-115) Poster - Breast conserving therapy in patients with multiple ipsilateral breast cancer in the era of neoadjuvant therapy – a nationwide population based study

208 (PB-115) Poster - Breast conserving therapy in patients with multiple ipsilateral breast cancer in the era of neoadjuvant therapy – a nationwide population based study

Invasive breast cancer and breast cancer death after non-screen detected ductal carcinoma in situ from 1990 to 2018 in England: population based cohort study

ObjectivesTo evaluate the long term risks of invasive breast cancer and death related to breast cancer after non-screen detected ductal carcinoma in situ. Risks for women in the general population...

Imaging Changes and Outcomes of Patients Undergoing Active Monitoring for Ductal Carcinoma In Situ: Seven-Year Follow-up Study

Rationale and ObjectiveTo determine the imaging changes and their associated positive predictive value (PPV) for invasive breast cancer in women undergoing active monitoring for DCIS. Materials and MethodsIn this seven-year follow-up retrospective IRB-exempted cohort study, we reviewed patients diagnosed with DCIS who elected active monitoring between 2003 to 2022 at a single academic institution. Imaging characteristics, histopathology at initial diagnosis, and subsequent follow-up were recorded. Low-risk DCIS was defined as low or intermediate grade and hormone receptor (HR) positive (estrogen and/or progesterone receptor positive) disease diagnosed in women at least 40 years of age. Progression was defined as subsequent ipsilateral invasive breast cancer diagnosis. ResultsThere were 39 patients with a median age of 58.4 years (IQR: 51.1 – 69.6 years) and a median follow-up of 4.3 years (range: 0.6-16.4 years). Nearly two thirds of patients (64%, 25/39) had stable imaging (range: 0.6-16.4 years) and remained progression-free during active monitoring. Among the remaining 14 patients (36%) there were 24 imaging findings which prompted 22 subsequent core needle biopsies (range: 1-3 biopsies per patient) and two surgical biopsies. The positive predictive value (PPV) of invasive cancer was 29% (7/24) overall and 38% (3/8) for masses, 33% (3/9) for calcifications, 17% (1/6) for non-mass enhancement, and 0% (0/1) for architectural distortion. ConclusionsOf the radiographic changes prompting an additional biopsy, development of a new mass (38%) and new calcifications (33%) had the highest PPV for invasive progression. Close imaging follow-up should be a critical component for patients undergoing monitoring for DCIS.

The effects of contemporary treatment of DCIS on the risk of developing an ipsilateral invasive Breast cancer (iIBC) in the Dutch population

PurposeTo assess the effects of contemporary treatment of ductal carcinoma in situ (DCIS) on the risk of developing an ipsilateral invasive breast cancer (iIBC) in the Dutch female population.MethodsClinical data was obtained from the Netherlands Cancer Registry (NCR), a nationwide registry of all primary malignancies in the Netherlands integrated with the data from PALGA, the Dutch nationwide network and registry of histo- and cytopathology in the Netherlands, on all women in the Netherlands treated for primary DCIS from 2005 to 2015, resulting in a population-based cohort of 14.419 women. Cumulative iIBC incidence was assessed and associations of DCIS treatment type with subsequent iIBC risk were evaluated by multivariable Cox regression analyses.ResultsTen years after DCIS diagnosis, the cumulative incidence of iIBC was 3.1% (95% CI: 2.6–3.5%) in patients treated by breast conserving surgery (BCS) plus radiotherapy (RT), 7.1% (95% CI: 5.5–9.1) in patients treated by BCS alone, and 1.6% (95% CI: 1.3–2.1) in patients treated by mastectomy. BCS was associated with a significantly higher risk for iIBC compared to BCS + RT during the first 5 years after treatment (HR 2.80, 95% CI: 1.91–4.10%). After 5 years of follow-up, the iIBC risk declined in the BCS alone group but remained higher than the iIBC risk in the BCS + RT group (HR 1.73, 95% CI: 1.15–2.61).ConclusionsAlthough absolute risks of iIBC were low in patients treated for DCIS with either BCS or BCS + RT, risks remained higher in the BCS alone group compared to patients treated with BCS + RT for at least 10 years after DCIS diagnosis.

Association of DCIS size and margin status with risk of developing breast cancer post-treatment: multinational, pooled cohort study

ObjectiveTo examine the association between size and margin status of ductal carcinoma in situ (DCIS) and risk of developing ipsilateral invasive breast cancer and ipsilateral DCIS after treatment, and stage...

Evaluation of the association of area-level socioeconomic deprivation and breast cancer recurrence by oestrogen receptor subtypes in Scotland

BackgroundWomen from socioeconomically deprived areas have lower breast cancer (BC) incidence rates for screen-detected oestrogen receptor (ER) + tumours and higher mortality for select tumour subtypes. We aimed to determine if ipsilateral breast cancer recurrence (IBR) differs by Scottish Index of Multiple Deprivation (SIMD) quintile and tumour subtype in Scotland.MethodsPatient data for primary invasive BC diagnosed in 2007–2008 in Scotland was analysed. Manual case-note review for 3495 patients from 10 years post-diagnosis was used. To determine the probability of IBR while accounting for the competing risk of death from any cause, cumulative incidence functions stratified by ER subtype and surgery were plotted. Multivariable Cox Proportional Hazards models were used to estimate the association of SIMD accounting for other predictors of IBR.ResultsAmong 2819 ER + tumours, 423 patients had a recurrence and 438 died. SIMD was related to death (p = 0.018) with the most deprived more likely to have died in the 10-year period (17.7% vs. 12.9%). We found no significant differences by SIMD in prognostic tumour characteristics (grade, TNM stage, treatment, screen-detection) or risk of IBR. Among 676 patients diagnosed with ER- tumours, 105 died and 185 had a recurrence. We found no significant differences in prognostic tumour characteristics by SIMD except screen detection with the most deprived more likely than the least to have their tumours detected from screening (46.9% vs. 28%, p = 0.03). Among patients with ER- tumours, 50% had mastectomy and the most deprived had increased 5-year IBR risk compared to the least deprived (HR 3.03 [1.41–6.53]).ConclusionsIBR is not a major contributor to mortality differences by SIMD for the majority of BC patients in our study. The lack of inequities in IBR are likely due to standardised treatment protocols and access to healthcare. The association with socioeconomic deprivation and recurrence for ER- tumours requires further study.