Contralateral Breast Cancer: Factors Associated with Stage and Size at Presentation

Machine learning on genome-wide association studies to predict the risk of radiation-associated contralateral breast cancer in the WECARE Study

The purpose of this study was to identify germline single nucleotide polymorphisms (SNPs) that optimally predict radiation-associated contralateral breast cancer (RCBC) and to provide new biological insights into the carcinogenic process. Fifty-two women with contralateral breast cancer and 153 women with unilateral breast cancer were identified within the Women’s Environmental Cancer and Radiation Epidemiology (WECARE) Study who were at increased risk of RCBC because they were ≤ 40 years of age at first diagnosis of breast cancer and received a scatter radiation dose > 1 Gy to the contralateral breast. A previously reported algorithm, preconditioned random forest regression, was applied to predict the risk of developing RCBC. The resulting model produced an area under the curve (AUC) of 0.62 (p = 0.04) on hold-out validation data. The biological analysis identified the cyclic AMP-mediated signaling and Ephrin-A as significant biological correlates, which were previously shown to influence cell survival after radiation in an ATM-dependent manner. The key connected genes and proteins that are identified in this analysis were previously identified as relevant to breast cancer, radiation response, or both. In summary, machine learning/bioinformatics methods applied to genome-wide genotyping data have great potential to reveal plausible biological correlates associated with the risk of RCBC.

Concordance of Hormone Receptor Status and BRCA1/2 Mutation Among Women With Synchronous Bilateral Breast Cancer

Goals: BRCA1/2 mutations are associated with bilateral breast cancer. The extent of concordance between synchronous bilateral breast cancer (SBBC) tumors with respect to hormone receptor expression and BRCA1/2 mutations is unknown. We investigated the distribution of BRCA1/2 mutations and bilateral estrogen receptor (ER) status in SBBC. Methods: A retrospective analysis was performed on 15,337 patients with primary breast cancer who underwent surgical treatment at the Fudan University Shanghai Cancer Center between 2007 and 2014. We included 163 patients with synchronous bilateral breast cancer who had germline BRCA1/2 mutations testing. BRCA1/2 pathogenic/likely pathogenic mutations and other clinicopathological characteristics were studied in further analyses. Results: Patients with SBBC developed breast cancer at an older age and had a higher rate of ER positivity than patients with UBC (p < 0.001, separately). In contrast, 14.1% of SBBC patients had carcinomas with a lobular component in either breast based on pathological reports (p < 0.001). Twelve patients had BRCA1 mutations, and 14 patients had BRCA2 mutations, while no patients had mutations in both genes. The BRCA1/2 mutation rate was higher in younger patients (23.4 vs. 11.1%, p = 0.036). SBBC patients with a family history of breast cancer or bilateral ER-negative disease had a higher frequency of BRCA1/2 mutations than the cohort without a history of these conditions. SBBC with a bilateral ER-discordant status had a very low frequency of BRCA1/2 mutations (5.6%). Patients with an ER-positive (concordant or discordant) status had better 3-year disease-free survival than patients with a concordant ER-negative status (HR = 0.324, 95% CI: 0.126-0.837, P = 0.020). However, the outcomes were similar during long-term follow-up. Pathological lymph node stage was the only prognostic factor for SBBC in both univariate and multivariate Cox analyses. Conclusions: Our study shows that Chinese women with SBBC have different characteristics from their UBC counterparts. SBBC patients with a younger age, family history of breast cancer, or bilateral ER-negative disease are more likely to have BRCA1/2 mutations. SBBC patients with a concordant ER-negative status had worse early outcomes. Our results suggest that there may be additional factors underlying the tumor biology and genetics of SBBC.

Prognostic Factors for Metachronous Contralateral Breast Cancer: Implications for Management of the Contralateral Breast

The absolute number of breast cancer survivors who are at risk for metachronous contralateral breast cancer (mCBC) has dramatically increased. The objectives of this study were to identify factors predictive of survival for patients with mCBC and to determine clinicopathological factors predictive of advanced mCBC. Using the Surveillance, Epidemiology, and End Results data base, we identified women, ages 18-80, diagnosed with invasive breast cancer from 1992 to 2010. We excluded patients with bilateral and stage IV primary breast cancer. Patients who developed mCBC ≥12 months from initial diagnosis were identified. Kaplan-Meier methods and Cox proportional hazards modeling were used to determine survival of patients with mCBC. Multivariate logistic regression was utilized to determine factors associated with advanced mCBC. We identified 6,673 patients who developed mCBC during our study period. The median interval between initial breast cancer and mCBC was 5 years. The strongest predictor of overall survival was the nodal status of the mCBC. Other significant prognostic factors included patient age; race; size, nodal status, estrogen receptor status, grade, and type of surgery of the initial breast cancer; grade of the mCBC; and use of radiation therapy for the mCBC. Overall, 25% of mCBCs were node positive. Younger age, black race, and characteristics of the initial breast cancer (increased size, invasive lobular histology, mastectomy treatment, and node-positivity) were significantly associated with node-positive mCBC (all p < 0.0.05). The most powerful predictor of survival for patients with mCBC is the nodal status of mCBC. Patients with advanced initial breast cancers are more likely to develop node-positive mCBC. Adherence to current surveillance and adjuvant therapy guidelines may minimize the risk and mortality of mCBCs.

Contralateral prophylactic mastectomy (CPM): A systematic review of patient reported factors and psychological predictors influencing choice and satisfaction

OBJECTIVE

Conduct a systematic review of quantitative and qualitative studies exploring patient reported factors and psychological variables influencing the decision to have contralateral prophylactic mastectomy (CPM), and satisfaction with CPM, in women with early stage breast cancer.

METHODS

Studies were identified via databases: Medline, CINAHL, Embase and PsycINFO. Data were extracted by one author and crosschecked by two additional authors for accuracy. The quality of included articles was assessed using standardised criteria by three authors.

RESULTS

Of the 1346 unique citations identified, 17 were studies that met the inclusion criteria. Studies included were primarily cross-sectional and retrospective. No study utilised a theoretical framework to guide research and few studies considered psychological predictors of CPM. Fear of breast cancer was the most commonly cited reason for CPM, followed by cosmetic reasons such as desire for symmetry. Overall, women appeared satisfied with CPM, however, adverse/diminished body image, poor cosmetic result, complications, diminished sense of sexuality, emotional issues and perceived lack of education regarding alternative surveillance/CPM efficacy were cited as reasons for dissatisfaction.

CONCLUSION

Current literature has begun to identify patient-reported reasons for CPM; however, the relative importance of different factors and how these factors relate to the process underlying the decision to have CPM are unknown. Of women who considered CPM, limited information is available regarding differences between those who proceed with or ultimately decline CPM.

A population perspective to mitigating risk for second primary breast cancer

SUMMARY There are more than 2 million breast cancer survivors in the USA. Approximately 5–10% of survivors will develop a second, metachronous breast cancer within 10 years’ time; a risk two- to six-times higher than that in the general population. Women who develop metachronous cancer are more likely to die from the disease compared with women with unilateral cancer. Risk factors for metachronous cancer include BRCA mutation status, young age, family history and tumor phenotype, while adjuvant chemotherapy and endocrine therapy may attenuate the risk. Surveillance guidelines recommend annual mammography, but MRI is not currently indicated for most women. An increasing number of women are choosing prophylactic contralateral mastectomy, although it is not likely to be beneficial for most women. Improved strategies are needed for identifying survivors at an increased risk in order to help guide clinical decisions regarding follow-up care. This review presents an overview of the burden and risk factors for metachronous breast cancer and discusses challenges and opportunities for a population approach to mitigating risk and adverse outcomes from these cancers.

Patient and tumor characteristics of bilateral breast cancer at screening mammography in the Netherlands, a population-based study

Few data are available on bilateral breast cancer in the screening population. The aim of this study was to determine patient and tumor characteristics of women with bilateral breast cancer at screening mammography. We included all 350,637 screening mammography examinations of women participating in a biennial screening program in a southern screening region of the Netherlands between May 1998 and January 2010. For referred women, all breast imaging reports, biopsy results, and surgery reports during one year after referral were collected. We compared patient and tumor characteristics of referred women with a diagnosis of bilateral breast cancer or unilateral breast cancer at workup. Bilateral or unilateral breast cancer had been diagnosed in respectively 40 (2.2%) and 1766 (97.8%) of 1806 referred women. Women with bilateral or unilateral breast cancer did not differ significantly in mean age, mammographic breast density, family history of breast cancer, or use of hormone replacement therapy. Compared with index cancers, contralateral cancers comprised significantly more lobular cancers (P = 0.02). Tumor size, mitotic activity, and estrogen receptor status were comparable for both groups, but contralateral cancers had a significantly lower risk of lymph node metastases (P = 0.03). Compared to unilateral breast cancer, contralateral malignancies in women with bilateral breast cancer comprised significantly more lobular cancers (P = 0.004) and lymph node negative cancers (P = 0.01). Contralateral breast cancers detected at screening comprise more lobular cancers and show less nodal involvement than index cancers or unilateral cancers. No differences are observed with respect to other patient and tumor characteristics.

Survival after bilateral breast cancer: results from a population-based study

BACKGROUND

Controversy exists on the impact of bilaterality of breast cancer on survival. We used population-based data to compare survival of women with unilateral versus bilateral breast cancer.

PATIENTS AND METHODS

At the Geneva cancer registry, we identified all 7,912 women diagnosed with invasive breast cancer between 1970 and 2002. Breast cancers were categorized as unilateral, synchronous bilateral (contralateral tumour diagnosed within six months after the first tumour) and metachronous bilateral (contralateral tumour diagnosed over six months after the first tumour). With multivariate modelling we compared characteristics and survival between women with unilateral and bilateral disease.

RESULTS

Patients with synchronous bilateral tumours (n = 155, 2.0%) had more often lobular histology and less frequently stage I disease than women with unilateral disease. Women with metachronous breast cancer (n = 219, 2.8%) received less often chemotherapy or hormone therapy for their first tumours. Ten-year disease-specific survival was similar (66%) after unilateral and metachronous bilateral breast cancer, but worse after synchronous bilateral cancer (51%). After adjustment, breast cancer mortality risks were not significantly increased for women with either synchronous or metachronous bilateral disease (Hazard ratios 1.1 (0.8-1.5) and 0.8 (0.5-1.4), respectively).

CONCLUSION

This large population-based study indicates that bilaterality of breast cancer is not associated with impaired survival.

Twenty-year incidence and patterns of contralateral breast cancer after breast conservation treatment with radiation

PURPOSE

This study was undertaken to determine the incidence of contralateral breast cancer (CLB) after treatment for early-stage breast cancer with breast-conserving treatment (BCT), and to observe patterns of CLB presentation.

METHODS

Medical records of 1,801 women treated for unilateral AJCC Stage 0-II breast cancer with BCT between 1977 and 2000 were analyzed as a retrospective cohort.

RESULTS

The incidence of any CLB at 20 years was 15.4%. The annual risk of developing any CLB remained constant at approximately 0.75% per year after treatment. The median time to any CLB was 8.2 years (range, 0.5-26.5 years). No difference in incidence of CLB was demonstrated in patients with primary invasive carcinoma vs. DCIS (p = 0.84). The majority of patients (83%) developing CLB tumors developed invasive disease. The risk of developing an invasive CLB did not differ significantly for patients with DCIS vs. those with primary invasive carcinoma (p = 0.20). The method of detection of the primary tumor (mammography vs. physical examination) was not predictive of detection of the CLB (p = 0.20). Finally, the location of CLB tumors was not affected by that of prior tumors (p = 0.82).

CONCLUSIONS

The risk of development of CLB persists for at least 20 years after treatment for early-stage breast cancer. CLB tumors are frequently invasive, and their location is not influenced by location of prior tumors. Mammography and physical examination remain essential after BCT for detection of a contralateral breast cancer, regardless of the method of detection of the primary tumor.

Addressing the soy and breast cancer relationship: review, commentary, and workshop proceedings

The impact of soyfood intake on breast cancer risk has been investigated extensively. Much of this focus can be attributed to the soybean being a dietary source that is uniquely rich in isoflavones. The chemical structure of isoflavones is similar to that of estrogen, and isoflavones bind to both estrogen receptors (ER alpha and ER beta) (although they preferentially bind to and activate ER beta) and exert estrogen-like effects under some experimental conditions. Isoflavones also possess nonhormonal properties that are associated with the inhibition of cancer cell growth. Thus, there are several possible mechanisms by which soy may reduce the risk of breast cancer. However, the role of isoflavones in breast cancer has become controversial because, in contrast to the possible beneficial effects, some data from in vitro and animal studies suggest that isoflavones, especially genistein, the aglycone of the main soybean isoflavone genistin, may stimulate the growth of estrogen-sensitive tumors. Limited human data directly address the tumor-promoting effects of isoflavones and soy. Because the use of soyfoods and isoflavone supplements is increasing, it is important from a public health perspective to understand the impact of these products on breast cancer risk in women at high risk of the disease and on the survival of breast cancer patients. To this end, a workshop was held in November 2005 to review the existing literature and to make research recommendations. This paper summarizes the workshop findings and recommendations. The primary research recommendation is that the impact of isoflavones on breast tissue needs to be evaluated at the cellular level in women at high risk for breast cancer.

Prognosis of metachronous contralateral breast cancer according to stage at diagnosis: The importance of early detection

Detection of metachronous contralateral breast cancer (MCBC) is an important aspect of follow-up among the many women previously diagnosed with first primary breast cancer (FPBC). While randomized studies have demonstrated the efficacy of early detection of FPBC, such findings cannot be generalized to women previously diagnosed with breast cancer since they were specifically excluded from participation. In this study, we determined if detection of MCBC at stage 0-I improves prognosis among women diagnosed with stage 0-III FPBC. Using data from the 1990-2000 Surveillance, Epidemiology, and End Results program, we defined MCBC as contralateral breast cancer that occurred at least 6 months after stage 0-III FPBC diagnosis. Women who developed a MCBC were categorized as having stage 0-I versus stage II-IV. To avoid lead-time bias, survival of MCBC was measured from the date of FPBC. Among 170,453 women who had been diagnosed with stage 0-III FPBC, 2904 were subsequently diagnosed with MCBC. Of these 2904 women, 329 died from breast cancer and 194 died from other causes. Seventy percent of women were diagnosed with stage 0-I MCBC. An 81% survival benefit existed for stage 0-I MCBC relative to those with stage II-IV MCBC in multivariable analysis (adjusted hazard ratio: 0.19; 95% confidence interval: 0.15-0.25). The findings are robust for various subpopulations. Unmeasured confounding was unlikely to explain the observed results in sensitivity analysis. For women with stage 0-III FPBC, diagnosis of stage 0-I MCBC is associated with an 81% reduction in risk of breast cancer death.