Risk Of Contralateral Breast Cancer Research Articles

Pathogenic variants in cancer susceptibility genes predispose to Ductal Carcinoma In situ of the breast.

To determine the relationship between germline pathogenic variants (PVs) in cancer predisposition genes and the risk of ductal carcinoma in situ (DCIS). Germline PV frequencies in breast cancer predisposition genes (ATM, BARD1, BRCA1, BRCA2, CDH1, CHEK2, PALB2, RAD51C, and RAD51D) were compared between DCIS cases and unaffected controls, and between DCIS and infiltrating ductal carcinoma (IDC) cases from a clinical-testing cohort (n=9,887), a population-based cohort (n=3,876) and the UK Biobank (n=2421). The risk of contralateral breast cancer for DCIS cases with PVs was estimated in the population-based cohort. Germline PVs were observed in 6.5% and 4.6% of women with DCIS in the clinical-testing and population-based cohorts, respectively. BRCA1, BRCA2, and PALB2 PVs frequencies were significantly lower among women with DCIS than IDC (clinical cohort: 2.8% vs. 5.7%; population-based cohort: 1.7% vs. 3.7%), whereas the PV frequencies for ATM and CHEK2 were similar. ATM, BRCA1, BRCA2, CHEK2, and PALB2 PVs were significantly associated with an increased risk of DCIS (OR>2.0), but only BRCA2 PVs were associated with high-risk (OR>4) in both cohorts. The cumulative incidence of contralateral breast cancer among carriers of PVs in high penetrance genes with DCIS was 23% over 15 years. The enrichment of PVs in ATM, BRCA1, BRCA2, CHEK2 and PALB2 among women with DCIS suggests that multigene panel testing may be appropriate for women with DCIS. Elevated risks of contralateral breast cancer in carriers of PVs in high penetrance genes with DCIS confirmed the utility of testing for surgical decision-making.

Adjuvant endocrine therapy and risk of contralateral breast cancer: a systematic review and meta-analysis of observational studies.

Randomized clinical trials support reductions in contralateral breast cancer (CBC) risk with use of adjuvant endocrine therapy, however, real-world treatment effects, particularly for subgroups of breast cancer survivors, remain inconclusive. To address this, population-based observational studies of adjuvant endocrine therapy and CBC were synthesized and meta-analyzed. PubMed and Embase databases were systematically searched for observational studies of endocrine therapy use and CBC risk. Random effects meta-analyses estimated summary relative risks (RRs) and 95% confidence intervals (CIs) for associations between endocrine therapy (ever use of tamoxifen and/or aromatase inhibitors (AIs)) and CBC risk. Heterogeneity across studies was assessed using the I2 test. Subgroup analyses were conducted by study design, menopausal status, and CBC estrogen receptor (ER)-status. Seventeen eligible observational studies (n = 287,576 breast cancer survivors) published between 1995 and 2019 were included. Endocrine therapy use was associated with reduced CBC risk (RR:0.62, 95% CI:0.53, 0.73, I2 = 84.8%, p < 0.0001). No heterogeneity was observed by study design (phet = 0.9). Similar reductions were observed in analyses restricted to tamoxifen use. As only two studies assessed AI use, estimates could not be meta-analyzed. In subgroup analyses, there were no differences in CBC risk reduction by menopausal status (phet = 0.22). Endocrine therapy reduced risk of ER-positive (RR:0.55, 95% CI:0.43, 0.70) but not ER-negative CBC (RR:1.26, 95% CI:0.95, 1.66) (phet < 0.001). This meta-analysis of observational studies supports a reduction in CBC risk with endocrine therapy among breast cancer survivors, in concert with evidence synthesized from randomized clinical trials, and highlights differences in endocrine therapy effectiveness by ER-status of CBC.

Cohort profile: a nationwide study in Dutch CHEK2 c.1100delC families using the infrastructure of the HEreditary Breast and Ovarian cancer study Netherlands – Hebon-CHEK2

PurposeCHEK2 c.1100delC is associated with an increased breast cancer risk in women. While this variant is prevalent in the Netherlands (1% in the general population), knowledge of aetiology and prognosis...

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.

Occurrence of contralateral breast cancer in a BRCA-positive breast cancer patient who underwent free TRAM flap reconstruction: a case report

This report presents a case of contralateral breast cancer in a BRCA mutation-positive patient who had previously undergone delayed free transverse rectus abdominis myocutaneous flap reconstruction for unilateral breast cancer. Having used up the available abdominal autologous tissue in the first reconstruction, a direct-to-implant procedure was employed for the reconstruction of the second, contralateral breast. Therefore, one breast was reconstructed using autologous tissue from the abdomen, while the other was asymmetrically reconstructed with an implant. If the risk of contralateral breast cancer had been anticipated initially, we might have opted for implant-based reconstruction from the start to facilitate a more symmetrical outcome in the event of subsequent contralateral reconstruction. This case underscores the importance of reviewing the risk of contralateral breast cancer in patients with unilateral breast cancer who also carry mutations in BRCA and other breast cancer susceptibility genes. Furthermore, it encourages consideration of how mutations in breast cancer susceptibility genes, including BRCA, influence the choice of plastic surgery reconstruction techniques. The findings from genetic testing for breast cancer susceptibility are now crucial to achieving aesthetic completeness in breast reconstruction.

Impact of contralateral prophylactic mastectomy on survival outcomes in patients with unilateral breast cancer: A systematic review and meta-analysis.

To synthesize contemporary evidence of the impact of contralateral prophylactic mastectomy (CPM) on survival outcomes in patients with unilateral breast cancer (UBC). PubMed, EMBASE and Scopus databases were searched for observational studies published up to November 15, 2023. Random-effects model was used to obtain pooled effect estimates that were reported as hazards ratio (HR) with 95% confidence intervals (CI). The outcomes of interest were overall survival (OS), breast cancer-specific survival (BCSS), recurrence free survival (RFS) and risk of contralateral breast cancer (CBC). Twenty-one studies were included. Most studies had a retrospective design. CPM was associated with significant improvement of OS (HR 0.80, 95% CI: 0.75, 0.85), BCCS (HR 0.82, 95% CI: 0.74, 0.90), and RFS (HR 0.72, 95% CI: 0.60, 0.86) and significantly reduced risk of CBC (HR 0.05, 95% CI: 0.03, 0.09) in patients with UBC. No evidence of publication bias was detected. Our results provide strong evidence supporting the positive impact of CPM on survival outcomes in patients with UBC. Further research and long-term follow-up studies are warranted to validate these findings.

Bilateral Mastectomy and Breast Cancer Mortality

The benefit of bilateral mastectomy for women with unilateral breast cancer in terms of deaths from breast cancer has not been shown. To estimate the 20-year cumulative risk of breast cancer mortality among women with stage 0 to stage III unilateral breast cancer according to the type of initial surgery performed. This cohort study used the Surveillance, Epidemiology, and End Results (SEER) Program registry database to identify women with unilateral breast cancer (invasive and ductal carcinoma in situ) who were diagnosed from 2000 to 2019. Three closely matched cohorts of equal size were generated using 1:1:1 matching according to surgical approach. The cohorts were followed up for 20 years for contralateral breast cancer and for breast cancer mortality. The analysis compared the 20-year cumulative risk of breast cancer mortality for women treated with lumpectomy vs unilateral mastectomy vs bilateral mastectomy. Data were analyzed from October 2023 to February 2024. Type of breast surgery performed (lumpectomy, unilateral mastectomy, or bilateral mastectomy). Contralateral breast cancer or breast cancer mortality during the 20-year follow-up period among the groups treated with lumpectomy vs unilateral mastectomy vs bilateral mastectomy. The study sample included 661 270 women with unilateral breast cancer (mean [SD] age, 58.7 [11.3] years). After matching, there were 36 028 women in each of the 3 treatment groups. During the 20-year follow-up, there were 766 contralateral breast cancers observed in the lumpectomy group, 728 contralateral breast cancers in the unilateral mastectomy group, and 97 contralateral cancers in the bilateral mastectomy group. The 20-year risk of contralateral breast cancer was 6.9% (95% CI, 6.1%-7.9%) in the lumpectomy-unilateral mastectomy group. The cumulative breast cancer mortality was 32.1% at 15 years after developing a contralateral cancer and was 14.5% for those who did not develop a contralateral cancer (hazard ratio, 4.00; 95% CI, 3.52-4.54, using contralateral breast cancer as a time-dependent covariate). Deaths from breast cancer totaled 3077 women (8.54%) in the lumpectomy group, 3269 women (9.07%) in the unilateral mastectomy group, and 3062 women (8.50%) in the bilateral mastectomy group. This cohort study indicates that the risk of dying of breast cancer increases substantially after experiencing a contralateral breast cancer. Women with breast cancer treated with bilateral mastectomy had a greatly diminished risk of contralateral breast cancer; however, they experienced similar mortality rates as patients treated with lumpectomy or unilateral mastectomy.

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.

Abstract GS02-04: Surgical Treatment of Women with Breast Cancer and a BRCA1 Mutation: An International Analysis of the Impact of Bilateral Mastectomy on Survival

Abstract Background: Women with breast cancer and a BRCA1 mutation face a high risk of contralateral breast cancer. For this reason, many women with a unilateral breast cancer opt for bilateral mastectomies. Some will have a contralateral prophylactic mastectomy as a second surgery. However, it is not clear to what extent this operation impacts breast cancer mortality. The objective of the current study was to evaluate the differences in survival by surgical treatment in an international cohort of women with a BRCA1 mutation and unilateral breast cancer. Methods: Eligible participants were identified from a large international cohort of women with breast cancer and a BRCA1 mutation, from 26 collaborating centres. Patients with DCIS and stage IV breast cancer were excluded. Patients with synchronous bilateral cancer were excluded. Demographic data were patient reported and clinical and treatment data were collected from medical records. Women were followed from date of breast cancer diagnosis to either date of last follow-up or date of death. Results: There were 2482 eligible participants from 26 centres from 11 countries. The mean age of breast cancer diagnosis was 43.1 years (range 18-70 years). Among those who had a unilateral mastectomy or lumpectomy, the risk of contralateral breast cancer at 20 years was 27.5%. After experiencing a contralateral cancer the hazard ratio for breast cancer death was 2.14 (95%CI 1.43-3.18), P=0.0002. The fifteen-year breast cancer specific survival in the entire cohort was 82.9%. The survival was 78.7% for those who had a unilateral mastectomy, 86.2% for those who had a lumpectomy, and 88.7% for those who had bilateral mastectomies. 529 of the women who initially underwent a unilateral surgery subsequently had a contralateral or bilateral preventive mastectomy in the follow up period. 529 of the women with unilateral surgery had a contralateral or bilateral preventive mastectomy in the follow up period. After adjusting for age of diagnosis, tumor size, nodal status, chemotherapy (yes/no) and preventive mastectomy (time dependent) the hazard ratio for breast cancer mortality for bilateral surgery versus unilateral surgery was 0.78 (95% CI 0.55-1.13), p = 0.19. Discussion: Women with a BRCA1 mutation and breast cancer who develop a contralateral breast cancer have double the risk of mortality compared to women who do not develop contralateral breast cancer. We observed a small non-significant reduction in mortality for those who had bilateral mastectomies as initial treatment, but the cohort will require longer follow up for definitive results. Women with a BRCA1 mutation should be counselled on the risks of contralateral breast cancer and make surgical decisions with this knowledge. Citation Format: Kelly Metcalfe, Jan Lubinski, Jana Soukupová, Rinat Bernstein-Molho, Mina Lee, Evans Gareth, Arvids Irmejs, Robert Fruscio, Cynthia Villareal Garza, Joanne Ngeow, Jennifer Plichta, Rinat Yerushalmi, Steven Narod. Surgical Treatment of Women with Breast Cancer and a BRCA1 Mutation: An International Analysis of the Impact of Bilateral Mastectomy on Survival [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 GS02-04.

TP53-associated early breast cancer: new observations from a large cohort.

A recent large, well-annotated international cohort of patients with Li-Fraumeni syndrome and early-stage breast cancer was examined for shared features. This multicenter cohort study included women with a germline TP53 pathogenic or likely pathogenic variant and nonmetastatic breast cancer diagnosed between 2002 and 2022. Clinical and genetic data were obtained from institutional registries and clinical charts. Descriptive statistics were used to summarize proportions, and differences were assessed using χ2 or Wilcoxon rank sum tests. Metachronous contralateral breast cancer risk, radiation-induced sarcoma risk, and recurrence-free survival were analyzed using the Kaplan-Meier methodology. Among 227 women who met study criteria, the median age of first breast cancer diagnosis was 37 years (range = 21-71), 11.9% presented with bilateral synchronous breast cancer, and 18.1% had ductal carcinoma in situ only. In total, 166 (73.1%) patients underwent mastectomies, including 67 bilateral mastectomies as first breast cancer surgery. Among those patients with retained breast tissue, the contralateral breast cancer rate was 25.3% at 5 years. Among 186 invasive tumors, 72.1% were stages I to II, 48.9% were node negative, and the most common subtypes were hormone receptor-positive/HER2-negative (40.9%) and hormone receptor positive/HER2 positive (34.4%). At a median follow-up of 69.9 months (interquartile range = 32.6-125.9), invasive hormone receptor-positive/HER2-negative disease had the highest recurrence risk among the subtypes (5-year recurrence-free survival = 61.1%, P = .001). Among those who received radiation therapy (n = 79), the 5-year radiation-induced sarcoma rate was 4.8%. We observed high rates of ductal carcinoma in situ, hormone receptor-positive, and HER2-positive breast cancers, with a worse outcome in the hormone receptor-positive/HER2-negative luminal tumors, despite appropriate treatment. Confirmation of these findings in further studies could have implications for breast cancer care in those with Li-Fraumeni syndrome.

95 (PB-095) Poster - The INFLUENCE 3.0 model: time-dependent risks of locoregional recurrence and contralateral breast cancer, now also including patients treated with neoadjuvant systemic therapy

95 (PB-095) Poster - The INFLUENCE 3.0 model: time-dependent risks of locoregional recurrence and contralateral breast cancer, now also including patients treated with neoadjuvant systemic therapy

Society of Surgical Oncology Breast Disease Site Working Group Statement on Contralateral Mastectomy: Indications, Outcomes, and Risks.

Rates of contralateral mastectomy (CM) among patients with unilateral breast cancer have been increasing in the United States. In this Society of Surgical Oncology position statement, we review the literature addressing the indications, risks, and benefits of CM since the society's 2017 statement. We held a virtual meeting to outline key topics and then conducted a literature search using PubMed to identify relevant articles. We reviewed the articles and made recommendations based on group consensus. Patients consider CM for many reasons, including concerns regarding the risk of contralateral breast cancer (CBC), desire for improved cosmesis and symmetry, and preferences to avoid ongoing screening, whereas surgeons primarily consider CBC risk when making a recommendation for CM. For patients with a high risk of CBC, CM reduces the risk of new breast cancer, however it is not known to convey an overall survival benefit. Studies evaluating patient satisfaction with CM and reconstruction have yielded mixed results. Imaging with mammography within 12 months before CM is recommended, but routine preoperative breast magnetic resonance imaging is not; there is also no evidence to support routine postmastectomy imaging surveillance. Because the likelihood of identifying an occult malignancy during CM is low, routine sentinel lymph node surgery is not recommended. Data on the rates of postoperative complications are conflicting, and such complications may not be directly related to CM. Adjuvant therapy delays due to complications have not been reported. Surgeons can reduce CM rates by encouraging shared decision making and informed discussions incorporating patient preferences.

Increased risk of contralateral breast cancer for BRCA1/2 wild-type, high-risk Korean breast cancer patients: a retrospective cohort study

BackgroundThis study aimed to investigate the contralateral breast cancer (CBC) recurrence rate in Korean breast cancer patients according to their BRCA1/2 germline mutation status, focusing particularly on the CBC recurrence risk in BRCA1/2 negative (BRCAx) patients.MethodsWe conducted a retrospective study on 13,107 primary breast cancer patients. The patients were divided into high-risk and low-risk groups for hereditary breast cancer based on the Korean National Health Insurance Service’s eligibility criteria for BRCA1/2 germline mutation testing. The high-risk group was further categorized into the BRCAmutation group, the BRCAxgroup, and the not tested group. We evaluated the overall survival and cumulative risk of developing CBC in these patients.ResultsAmong 4494 high-risk patients, 973 (21.7%) underwent genetic testing for BRCA1/2 germline mutation, revealing mutations in 158 patients (16.2%). We observed significant overall survival differences across all four groups, with the high-risk, not-tested group demonstrating notably worse overall survival (p < 0.001). However, when adjusted for other prognostic factors, there was no significant differences in hazard ratio of death between the four groups. The cumulative risk of CBC also varied among the groups. Patients with BRCA1/2 mutations showed a 7.3-fold increased risk of CBC compared to the low-risk group (95% CI 4.11–13.0, p < 0.001). Interestingly, BRCAx patients also demonstrated a significantly higher risk of CBC (HR 2.77, 95% CI 1.76–4.35, p < 0.001). The prognostic importance of the BRCAx for CBC recurrence persisted after adjusting for the age and subtype, but became insignificant when the family history of breast cancer was adjusted.ConclusionBreast cancer patients who are at high risk of hereditary breast cancer but with wild-type BRCA 1/2 genes (BRCAx) have increased risk of developing contralateral breast cancer when compared to the low-risk patients. More careful surveillance and follow-up can be offered to these patients especially when they have family history of breast cancer.

Postlumpectomy imaging: is there a role for the study of the contralateral breast?-a retrospective cohort.

Some patients with breast cancer submitted to breast-conserving surgery might benefit from a postlumpectomy imaging examination previously to radiation therapy. This aims to document the complete removal of cancer and might be accomplished using mammogram with breast and axillary ultrasonography. These modalities study not only the affected side but also the contralateral side. In fact, it is well-documented that women with breast cancer have an increased risk for contralateral breast cancer. Thus, we intended to evaluate the value of postlumpectomy imaging undertaken before adjuvant radiotherapy regarding the evaluation of the contralateral breast and axilla. In this retrospective study, medical records for patients with breast cancer submitted to breast-conserving surgery and referred to our radiotherapy unit between 2018 and 2019 were reviewed. All patients had to be submitted to bilateral mammogram with breast and axillary ultrasonography previously to radiotherapy. Patients with bilateral disease or with a history of breast cancer were excluded. One thousand two hundred forty patients were analyzed. 19 (1.5%) had suspicious findings for contralateral breast disease, and 8 (0.6%) had a re-excision positive for residual malignancy. Higher age, invasive lobular carcinoma associated or not with lobular carcinoma in situ, and presence of lobular carcinoma in situ were associated with an increased risk for residual disease. Contralateral evaluation as part of postlumpectomy imaging revealed itself useful at detecting contralateral cancer, with some demographic and clinical features being associated with an increased risk for residual disease.

Age-Related Incidence and Peak Occurrence of Contralateral Breast Cancer

Young patients with breast cancer have higher risk for developing contralateral breast cancer (CBC) and have epidemiologic characteristics different from those of older patients. To examine the incidence and peak occurrence of CBC according to age at primary breast cancer (PBC) surgery. This cohort study included patients who were diagnosed with and underwent surgery for unilateral nonmetastatic breast cancer at Asan Medical Center, Korea, between January 1, 1999, and December 31, 2013, with follow-up through December 31, 2018. Data were analyzed from December 1, 2021, through April 30, 2023. Patients were divided into 2 groups according to their age at surgery for PBC: younger (≤35 years) vs older (>35 years). The main outcomes were cumulative incidence and hazard rate of CBC in the entire study population and in subgroups divided by cancer subtype, categorized according to hormone receptor (HR) and ERBB2 status. A total of 16 251 female patients with stage 0 to III breast cancer were analyzed; all patients were Korean. The mean (SD) age was 48.61 (10.06) years; 1318 patients (8.11%) were in the younger group, and 14 933 (91.89%) were in the older group. Median follow-up was 107 months (IQR, 79-145 months). Compared with the older group, the younger group had significantly higher incidence of CBC (10-year cumulative incidence, 7.1% vs 2.9%; P < .001) and higher risk (hazard ratio, 2.10; 95% CI, 1.62-2.74) of developing CBC. The hazard rate, which indicates risk for developing CBC at a certain time frame, differed according to the subtype of primary cancer. In patients with the HR+/ERBB2- subtype, the risk increased continuously in both age groups. In patients with the triple negative subtype, the risk increased until approximately 10 years and then decreased in both age groups. Meanwhile, in the HR-/ERBB2+ subtype, risk peaked earlier, especially in the younger group (1.7 years since first surgery in the younger group and 4.8 years in the older group). In this cohort study, patients aged 35 years or younger with breast cancer had a higher risk of developing CBC than older patients. Moreover, young patients with the HR-/ERBB2+ subtype tended to have a shorter interval for developing CBC. These findings might be useful in guiding treatment decisions, such as contralateral prophylactic mastectomy.

Risk factors of developing contralateral breast cancer after first primary breast cancer treatment.

Breast cancer (BC) is the most common cancer among women worldwide. Increased survival of primary BC (PBC) has increased contralateral breast cancer (CBC) and become a health problem. This study aimed to determine the effect of disease-free interval (DFI), risk factors and PBC characteristics on the progression of CBC within primary BC survivors. This retrospective study identified 5003 women diagnosed with breast cancer between 2000 and 2020 in the cancer research center. The study included 145 CBC and 4858 PBC survivors, with CBC diagnosed at least 6 months after the detection of primary BC. ER+, PR+, and HER2+ were reported in 72.13%, 66.67%, and 30% of CBC patients. Invasive ductal carcinoma (IDC) BC was reported in 69.57% of patients, and 81.90% and 83.64% of the patients were treated with adjuvant chemotherapy and external radiotherapy. The Kaplan-Meier method indicated that the median time interval between PBC and CBC was 3.92 years, and the 5-year DFI was 97%. The Cox proportional hazard regression model indicated that although more than half of the participants had no family history of BC (69.57%), women 60 years and older were negatively associated with CBC. This study provides the first investigation of CBC and DFI risk factors among PBC survivors in Iran. Age was found to be negatively associated with CBC development particularly after the age of 60, indicating the necessity of tracking CBC survivors carefully in this age group.

Endocrine therapy initiation among women diagnosed with ductal carcinoma in situ breast cancer from 2001-2016.

487 Background: Endocrine therapy (ET) initiation in people within 1 year of diagnosis of estrogen-receptor-positive (ER+) ductal carcinoma in situ (DCIS) has ranged from 21-45% in prior studies; however, these studies did not evaluate initiation post-2011 and may not reflect current patterns of use. ET use following ER+ DCIS diagnosis can reduce the relative risks of recurrence and contralateral breast cancer by 30-50%. We evaluated ET initiation over time and by demographic, tumor, and treatment characteristics in the Kaiser Permanente Breast Cancer Survivors Study between 2001-2016. Methods: We included people aged 20+ years diagnosed with unilateral DCIS with at least 1 year of cancer-free follow-up from three U.S. integrated health systems. We excluded people with ER-negative disease, no surgery, and those who received chemotherapy or unknown radiation therapy. ET dispensings (tamoxifen and aromatase inhibitors) were extracted from electronic pharmacy records within 1 year of a person’s initial DCIS breast cancer diagnosis. Using generalized linear models with a log link and Poisson distribution, we estimated relative rates (RRs) of ET use (vs none) over time and by demographic, tumor, and other treatment characteristics. Results: Among 1,782 pre- and postmenopausal people, 577 (32%) initiated ET within 1 year of diagnosis. From 2001-2016, ET use did not change over time (34% vs 36%), tamoxifen use declined slightly (34% vs 29%), and aromatase inhibitor use increased slightly (0% vs 7%). People were less likely to initiate ET if they were ≥65 years, Black, had borderline or unknown ER status, were not tested for ER, had breast conserving surgery (BCS) without radiation, or had a unilateral mastectomy. Conclusions: Only one-third of people with DCIS diagnosed in a community healthcare setting and potentially eligible for ET, initiated treatment within 1 year of their diagnosis. Previous studies have shown long-term benefits of ET use in people with DCIS; however, we saw no increase in use over time. Concerns about side-effects, overdiagnosis and overtreatment of DCIS, and confusion about treatment guidelines may explain relatively low ET initiation.[Table: see text]

Risk of contralateral breast cancer among Asian/Pacific Islander women in the United States.

While breast cancer studies often aggregate Asian/Pacific Islander (API) women, as a single group or exclude them, this population is heterogeneous in terms of genetic background, environmental exposures, and health-related behaviors, potentially resulting in different cancer outcomes. Our purpose was to evaluate risks of contralateral breast cancer (CBC) among subgroups of API women with breast cancer. We conducted a retrospective cohort study of women ages 18 + years diagnosed with stage I-III breast cancer between 2000 and 2016 in the Surveillance, Epidemiology and End Results registries. API subgroups included Chinese, Japanese, Filipina, Native Hawaiian, Korean, Vietnamese, Indian/Pakistani, and other API women. Asynchronous CBC was defined as breast cancer diagnosed in the opposite breast 12 + months after first primary unilateral breast cancer. Multivariable-adjusted subdistribution hazard ratios (SHR) and 95% confidence intervals (CI) were estimated and stratified by API subgroups. From a cohort of 44,362 API women with breast cancer, 25% were Filipina, 18% were Chinese, 14% were Japanese, and 8% were Indian/Pakistani. API women as an aggregate group had increased risk of CBC (SHR 1.15, 95% CI 1.08-1.22) compared to NHW women, among whom Chinese (SHR 1.23, 95% CI 1.08-1.40), Filipina (SHR 1.37, 95% CI 1.23-1.52), and Native Hawaiian (SHR 1.69, 95% CI 1.37-2.08) women had greater risks. Aggregating or excluding API patients from breast cancer studies ignores their heterogeneous health outcomes. To advance cancer healthequity among API women, future research should examine inequities within the API population to design interventions that can adequately address their unique differences.

Prophylactic Salpingo-Oophorectomy and Survival After BRCA1/2 Breast Cancer Resection

Few studies have investigated whether prophylactic salpingo-oophorectomy (PSO) for patients with previously resected breast cancer who carry pathogenic germline BRCA1 or BRCA2 variants is associated with a reduced risk of cancer-specific death. To assess the association of PSO and prophylactic mastectomy (PM) with prognosis after quadrantectomy or mastectomy as primary treatment for patients with BRCA1 or BRCA2 breast cancer. This retrospective cohort study was performed in a single-institution, tertiary referral center. Consecutive patients with invasive breast cancer treated surgically between 1972 and 2019 were recruited and followed up prospectively after they were found to carry the BRCA1 or BRCA2 gene variant. The data analysis was performed between April 2022 and July 2023. Following breast surgery, some patients underwent PSO, PM, or both, whereas others did not. The primary study end point was overall survival as measured by the Kaplan-Meier method. Secondary end points were crude cumulative incidence of breast cancer-specific mortality, ipsilateral breast tumor recurrence (IBTR), contralateral breast cancer, ovarian cancer, and ovarian cancer-specific mortality. Of 480 patients included in the cohort (median age at initial surgery, 40.0 years; IQR, 34.0-46.0 years), PSO was associated with a significantly reduced risk of death (hazard ratio [HR], 0.40; 95% CI, 0.25-0.64; P < .001). This reduction was most evident for patients carrying the BRCA1 variant (HR, 0.35; 95% CI, 0.20-0.63; P = .001), those with triple-negative disease (HR, 0.21; 95% CI, 0.09-0.46; P = .002), and those with invasive ductal carcinoma (HR, 0.51; 95% CI, 0.31-0.84; P = .008). Prophylactic salpingo-oophorectomy was not associated with risk of contralateral breast cancer or IBTR. Initial or delayed PM was associated with a reduced risk of IBTR but not with overall survival or breast cancer-specific mortality. The study findings suggest that PSO should be offered to all patients with BRCA1/2 breast cancer who undergo surgery with curative intent to reduce risk of death. In particular, PSO should be offered to patients with the BRCA1 variant at the time of breast surgery.

Adherence to hormonal therapy after surgery among older women with ductal carcinoma in situ: Implications for breast cancer-related adverse health events.

Evidence from randomized clinical trials (RCTs) shows that receipt of hormonal therapy after surgery for estrogen receptor-positive ductal carcinoma in situ (DCIS) reduces the risk of DCIS and contralateral invasive breast cancer (IBC) but not death from breast cancer. RCTs examined homogeneous samples, and therefore whether this evidence can be generalized to diverse populations is unclear. Population-based data from four state cancer registries (California, New Jersey, New York, and Texas) were analyzed on women aged 65 years and older newly diagnosed with DCIS who underwent surgery with or without radiation during the years 2006-2013. Registry records were merged with Medicare enrollment in Parts A and/or B and D (prescription drugs) and associated claims. Whether adherence to hormonal therapy was associated with adverse breast cancer-related health events was analyzed. Achieving excellent adherence did not affect death from breast cancer. In contrast, the risk of developing a subsequent breast tumor was 6.24 percentage points (breast-conserving surgery [BCS] with radiation therapy [RT]) and 10.54 percentage points (BCS alone) lower for women with excellent versus low adherence (p<.00001). For excellent versus good adherence, the reduced risk among women who had BCS with and without RT was approximately 3 and 5 percentage points, respectively. A similar pattern emerged for the risk of IBC among women who achieved excellent versus good or low adherence, whereas good versus low adherence comparisons were not significant. This analysis of a diverse population-based cohort of women with DCIS demonstrates that achieving excellent adherence to hormonal therapy is critical to minimizing the occurrence of developing subsequent breast tumors. Our analysis of a diverse population-based cohort of women with ductal carcinoma in situ demonstrates that achieving excellent adherence to hormonal therapy is critical to minimizing the occurrence of developing subsequent breast tumors.