Age-Related Incidence and Peak Occurrence of Contralateral Breast Cancer

Importance

Young patients with breast cancer have higher risk for developing contralateral breast cancer (CBC) and have epidemiologic characteristics different from those of older patients.

Objective

To examine the incidence and peak occurrence of CBC according to age at primary breast cancer (PBC) surgery.

Design, Setting, and Participants

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).

Main Outcomes and Measures

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.

Results

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).

Conclusions and Relevance

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.

Evaluation of Predict, a prognostic risk tool, after diagnosis of a second breast cancer

BACKGROUND

The UK National Health Service's Predict is a clinical tool widely used to estimate the prognosis of early-stage breast cancer. The performance of Predict for a second primary breast cancer is unknown.

METHODS

Women 18 years of age or older diagnosed with a first or second invasive breast cancer between 2000 and 2013 and followed for at least 5 years were identified from the US Surveillance, Epidemiology, and End Results (SEER) database. Model calibration of Predict was evaluated by comparing predicted and observed 5-year breast cancer-specific mortality separately by estrogen receptor status for first vs second breast cancer. Receiver operating characteristic curves and areas under the curve were used to assess model discrimination. Model performance was also evaluated for various races and ethnicities.

RESULTS

The study population included 6729 women diagnosed with a second breast cancer and 357 204 women with a first breast cancer. Overall, Predict demonstrated good discrimination for first and second breast cancers (areas under the curve ranging from 0.73 to 0.82). Predict statistically significantly underestimated 5-year breast cancer mortality for second estrogen receptor-positive breast cancers (predicted-observed = ‒6.24%, 95% CI = ‒6.96% to ‒5.49%). Among women with a first estrogen receptor-positive cancer, model calibration was good (predicted-observed = ‒0.22%, 95% CI = ‒0.29% to ‒0.15%), except in non-Hispanic Black women (predicted-observed = ‒2.33%, 95% CI = ‒2.65% to ‒2.01%) and women 80 years of age or older (predicted-observed = ‒3.75%, 95% CI = ‒4.12% to ‒3.41%). Predict performed well for second estrogen receptor-negative cancers overall (predicted-observed = ‒1.69%, 95% CI = ‒3.99% to 0.16%) but underestimated mortality among those who had previously received chemotherapy or had a first cancer with more aggressive tumor characteristics. In contrast, Predict overestimated mortality for first estrogen receptor-negative cancers (predicted-observed = 4.54%, 95% CI = 4.27% to 4.86%).

CONCLUSION

The Predict tool underestimated 5-year mortality after a second estrogen receptor-positive breast cancer and in certain subgroups of women with a second estrogen receptor-negative breast cancer.

Survival After Development of Contralateral Breast Cancer in Korean Patients With Breast Cancer

Importance

Contralateral breast cancer (CBC) is the most frequently diagnosed primary cancer in patients with breast cancer. Although many studies have reported survival after the development of CBC, results have been inconsistent.

Objective

To investigate whether the development of CBC is associated with survival among patients with breast cancer.

Design, Setting, and Participants

This cohort study was conducted at the Asan Medical Center, Korea, among patients who were diagnosed with primary unilateral, nonmetastatic, stage 0 to III breast cancer between 1999 and 2013 and followed up through 2018. The median (IQR) follow-up was 107 (75-143) months. Patients were categorized into CBC and no-CBC groups by whether they developed CBC during the follow-up period. Data were analyzed from November 2021 to March 2023.

Exposure

Development of CBC.

Main outcomes and measures

Survival rates of CBC and no-CBC groups were compared using a time-dependent Cox proportional hazard model in the entire study population and in subgroup analyses by interval of CBC development and subtype of the primary breast cancer.

Results

Among 16 251 patients with breast cancer (all Asian, specifically Korean; mean [SD] age, 48.61 [10.06] years), 418 patients developed CBC. There was no significant difference in overall survival between CBC and no-CBC groups (hazard ratio, 1.166; 95% CI, 0.820-1.657). Patients who developed CBC within 1.5 years after the surgery of the primary breast cancer had a higher risk for overall death during the study period (hazard ratio, 2.014; 95% CI, 1.044-3.886), and those who developed CBC after 1.5 years showed no significant difference in survival compared with the no-CBC group. Patients with hormone receptor (HR)-positive and human epidermal growth factor receptor 2 (ERBB2, formerly HER2)-negative breast cancer had a higher risk for overall death in the CBC group (hazard ratio, 1.882; 95% CI, 1.143-3.098) compared with the no-CBC group.

Conclusions and Relevance

This study found that development of CBC in patients with breast cancer was not associated with survival but that early development of CBC after diagnosis of the primary breast cancer or development of CBC in patients with HR-positive/ERBB2-negative breast cancer was associated with survival. These results may provide valuable information for patients seeking advice on opting for contralateral prophylactic mastectomy.

The impact of coding germline variants on contralateral breast cancer risk and survival

Evidence linking coding germline variants in breast cancer (BC)-susceptibility genes other than BRCA1, BRCA2, and CHEK2 with contralateral breast cancer (CBC) risk and breast cancer-specific survival (BCSS) is scarce. The aim of this study was to assess the association of protein-truncating variants (PTVs) and rare missense variants (MSVs) in nine known (ATM, BARD1, BRCA1, BRCA2, CHEK2, PALB2, RAD51C, RAD51D, and TP53) and 25 suspected BC-susceptibility genes with CBC risk and BCSS. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated with Cox regression models. Analyses included 34,401 women of European ancestry diagnosed with BC, including 676 CBCs and 3,449 BC deaths; the median follow-up was 10.9 years. Subtype analyses were based on estrogen receptor (ER) status of the first BC. Combined PTVs and pathogenic/likely pathogenic MSVs in BRCA1, BRCA2, and TP53 and PTVs in CHEK2 and PALB2 were associated with increased CBC risk [HRs (95% CIs): 2.88 (1.70-4.87), 2.31 (1.39-3.85), 8.29 (2.53-27.21), 2.25 (1.55-3.27), and 2.67 (1.33-5.35), respectively]. The strongest evidence of association with BCSS was for PTVs and pathogenic/likely pathogenic MSVs in BRCA2 (ER-positive BC) and TP53 and PTVs in CHEK2 [HRs (95% CIs): 1.53 (1.13-2.07), 2.08 (0.95-4.57), and 1.39 (1.13-1.72), respectively, after adjusting for tumor characteristics and treatment]. HRs were essentially unchanged when censoring for CBC, suggesting that these associations are not completely explained by increased CBC risk, tumor characteristics, or treatment. There was limited evidence of associations of PTVs and/or rare MSVs with CBC risk or BCSS for the 25 suspected BC genes. The CBC findings are relevant to treatment decisions, follow-up, and screening after BC diagnosis.

Contralateral prophylactic mastectomy: A narrative review of the evidence and acceptability

The uptake of contralateral prophylactic mastectomy (CPM) has increased steadily over the last twenty years in women of all age groups and breast cancer stages. Since contralateral breast cancer is relatively rare and the breast cancer guidelines only recommend CPM in a small subset of patients with breast cancer, the drivers of this trend are unknown. This review aims to evaluate the evidence for and acceptability of CPM, data on patient rationales for choosing CPM, and some of the factors that might impact patient preferences. Based on the evidence, future recommendations will be provided. First, data on contralateral breast cancer risk and CPM rates and trends are addressed. After that, the evidence is structured around four main patient rationales for CPM formulated as questions that patients might ask their surgeon: Will CPM reduce mortality risk? Will CPM reduce the risk of contralateral breast cancer? Can I avoid future screening with CPM? Will I have better breast symmetry after CPM? Also, three different guidelines regarding CPM will be reviewed. Studies indicate a large gap between patient preferences for radical risk reduction with CPM and the current approaches recommended by important guidelines. We suggest a strategy including shared decision-making to enhance surgeons’ communication with patients about contralateral breast cancer and treatment options, to empower patients in order to optimize the use of CPM incorporating accurate risk assessment and individual patient preferences.

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Contralateral prophylactic mastectomy rates have increased over the last 20 years.

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Patients may want CPM to reduce risk of contralateral breast cancer and mortality.

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Patients do not always have the tools available to make a well-informed decision.

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Patient and surgeon’s shared decision-making could optimize the use of CPM.

Mortality after contralateral breast cancer in Denmark

PURPOSE

How a second breast cancer diagnosis affects survival in comparison with unilateral breast cancer (UBC) is unclear. Prognostic factors for contralateral breast cancer (CBC) are also not well established. We aimed to investigate the survival pattern after CBC with particular focus on time between first and second breast cancer diagnosis and age at CBC diagnosis.

METHODS

Within the nationwide Danish Breast Cancer Cooperative Group database, we identified 68,466 breast cancer patients diagnosed during 1978-2012. Patients who subsequently developed CBC were identified in a previously established database (N = 3004). Patients were followed for breast cancer-specific death in the Danish Register of Causes of Death until 2015. Hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated using Cox proportional hazard regression models. Cumulative breast cancer mortality from date of CBC was estimated using the Aalen-Johansen method.

RESULTS

Compared with UBC patients, the rate of dying from breast cancer was more than twofold higher following a CBC diagnosis, after adjustment for age, period, tumor characteristics, and treatment of the first breast cancer (HR 2.48; 95% CI 2.31-2.66). Short time interval (< 5 years) was associated with higher breast cancer-specific mortality after CBC among patients < 70 years at CBC diagnosis compared with longer time intervals, but not among patients ≥ 70 years at CBC diagnosis.

CONCLUSION

Breast cancer-specific mortality rates were markedly higher after compared with before a CBC diagnosis. We found higher breast cancer-specific mortality after CBC associated with a short interval between diagnoses among patients diagnosed with CBC before age 70 years.

Patterns of Occurrence and Outcomes of Contralateral Breast Cancer: Analysis of SEER Data

Population-based estimates are lacking for the temporal trends in the contralateral breast cancer (CBC) risk for patients with breast cancer (BC). Data for BC patients diagnosed with CBC were collected from the Surveillance, Epidemiology, and End Results database. CBC incidence was calculated using the Kaplan-Meier method and the temporal trend in CBC incidence was assessed using joinpoint regression. Survival analysis was calculated using propensity scoring (PS) and multivariate Cox regression with a competing risk model. We found that 10,944 of 212,630 patients with early-stage BC were subsequently diagnosed with secondary BC in the contralateral breast. The 5-, 10-, 15-, and 20-year cumulative CBC incidences were 1.9, 4.6, 7.6, and 10.5%, respectively. Being younger (<40 years), black, hormone receptor-negative, and having undergone radiotherapy were correlated with a high risk of CBC occurrence. CBC incidence increased continuously in the first 11 years after the initial cancer diagnosis, and the upward trend slowed from years 11 to 21, and tended to decline from years 21 to 24. CBC diagnosis was significantly and negatively associated with survival. We reported population-based estimates of the CBC occurrence pattern and risk factors. Patients are at high risk of developing CBC in the first 21 years after the initial BC diagnosis.

Incidence of isolated local breast cancer recurrence and contralateral breast cancer: A systematic review

An increasing number of women is surviving breast cancer and due to that at risk of developing an isolated ipsilateral breast tumor recurrence (IBTR) or a contralateral breast cancer (CBC). Patients' main concern is cancer recurrence. Patient counseling on breast cancer recurrence is challenging. In order to provide healthcare professionals and patients more guidance, a systematic literature review of the incidence of isolated IBTR and CBC in women diagnosed with early invasive breast cancer was performed. Medline, EMBASE and the Cochrane Library were searched from 2000 until October 2015. Multicenter studies reporting an IBTR or CBC rate in curatively treated adult females diagnosed with invasive breast cancer were included. The initial search yielded 6998 potentially relevant articles. Twenty were eligible for inclusion, representing 25 recurrence incidence rates. Both isolated IBTR and CBC incidence rates steadily increased with the length of follow-up, indicating that IBTR and CBC occur even more than 15 years after diagnosis. The annual incidence rate of isolated IBTR and CBC in women diagnosed with an early invasive breast cancer was 0.6% (range: 0.4-1.1%) and 0.5% (range: 0.2-0.7%), respectively. Analyzed data were lacking information about important risk factors and given treatment with regard to the incidence of recurrence, which hampers the prediction of patient tailored recurrence risks. The presented rates are therefore the best available estimates of isolated IBTR and CBC annual incidence rates based on the current literature. Healthcare professionals could use these rates in their communication with patients diagnosed with early invasive breast cancer.