Exercise and Prognosis on the Basis of Clinicopathologic and Molecular Features in Early-Stage Breast Cancer: The LACE and Pathways Studies.

To investigate whether the impact of postdiagnosis exercise on breast cancer outcomes in women diagnosed with early-stage breast cancer differs on the basis of tumor clinicopathologic and molecular features. Using a prospective design, 6,211 patients with early-stage breast cancer from two large population-based cohort studies were studied. Age-adjusted and multivariable Cox regression models were performed to determine the relationship between exercise exposure (total MET-hours/week) and recurrence and breast cancer-related death for: (i) all patients ("unselected" cohort), and on the basis of (ii) classic clinicopathologic features, (iii) clinical subtypes, (iv) PAM50-based molecular intrinsic subtypes, and (v) individual PAM50 target genes. After a median follow-up of 7.2 years, in the unselected cohort (n = 6,211) increasing exercise exposure was not associated with a reduction in the risk of recurrence (adjusted Ptrend = 0.60) or breast cancer-related death (adjusted Ptrend = 0.39). On the basis of clinicopathologic features, an exercise-associated reduction in breast cancer-related death was apparent for tumors <2 cm [HR, 0.50; 95% confidence interval (CI), 0.34-0.72], well/moderately differentiated tumors (HR, 0.63; 95% CI, 0.43-0.91), and ER-positive tumors (HR, 0.72; 95% CI, 0.53-0.97). Stratification by clinical subtype indicated that the ER(+)/PR(+)/HER2(-)/low-grade clinical subtype was preferentially responsive to exercise (recurrence: adjusted HR, 0.63; 95% CI, 0.45-0.88; breast cancer-related death: adjusted HR, 0.57; 95% CI, 0.37-0.86). The impact of exercise on cancer outcomes appears to differ as a function of pathologic and molecular features in early-stage breast cancer. Cancer Res; 76(18); 5415-22. ©2016 AACR.

Prevalence and predictors of recent skin examination in a population-based twin cohort.

BACKGROUND: The incidence of melanoma is increasing worldwide. Guidelines for clinical skin exam for improving early diagnosis of melanoma remain inconsistent, and current data on factors associated with regular skin screening on a population basis are limited. METHODS: We used self-reported data from 50,044 members of the California Twin Program, a population-based cohort of twins born in California between 1908 and 1982, to identify prevalence and determinants of recent clinical screening for skin cancer. RESULTS: Prevalence of skin examination was higher than national estimates, with 32% of respondents of all ages reporting ever having skin examination. Sociodemographic and constitutional risk factors including white race, educational attainment, marital status, and number of large moles were strongly associated with recent screening, as were individual and family history of skin cancer. Lower socioeconomic status, racial/ethnic minority status, and paradoxically, frequent UV-related risk behaviors in adulthood were associated with a lower likelihood of recent screening. CONCLUSIONS: As the evidence concerning the efficacy of skin examination continues to evolve, attention should be paid to motivators and barriers of screening, particularly in high-risk subgroups where lack of screening may contribute to disparate rates of thicker melanomas and lower survival. IMPACT: Our results demonstrate the need for prevention strategies targeted to specific at-risk groups to increase earlier detection leading to improved outcomes.

Breastfeeding, PAM50 tumor subtype, and breast cancer prognosis and survival.

BACKGROUND: Breastfeeding is associated with decreased breast cancer risk, yet associations with prognosis and survival by tumor subtype are largely unknown. METHODS: We conducted a cohort study of 1636 women from two prospective breast cancer cohorts. Intrinsic tumor subtype (luminal A, luminal B, human epidermal growth factor receptor 2 [HER2]-enriched, basal-like) was determined by the PAM50 gene expression assay. Breastfeeding history was obtained from participant questionnaires. Questionnaires and medical record reviews documented 383 recurrences and 290 breast cancer deaths during a median follow-up of nine years. Multinomial logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) between breastfeeding and tumor subtype. Cox regression was used to estimate hazard ratios (HRs) for breast cancer recurrence or death. Statistical significance tests were two-sided. RESULTS: Breast cancer patients with basal-like tumors were less likely to have previously breastfed than those with luminal A tumors (OR = 0.56, 95% CI = 0.39 to 0.80). Among all patients, ever breastfeeding was associated with decreased risk of recurrence (HR = 0.70, 95% CI = 0.53 to 0.93), especially breastfeeding for six months or more (HR = 0.63, 95% CI = 0.46 to 0.87, P trend = .01). Similar associations were observed for breast cancer death. Among women with luminal A subtype, ever breastfeeding was associated with decreased risks of recurrence (HR = 0.52, 95% CI = 0.31 to 0.89) and breast cancer death (HR = 0.52, 95% CI = 0.29 to 0.93), yet no statistically significant associations were observed among the other subtypes. Effects appeared to be limited to tumors with lower expression of proliferation genes. CONCLUSIONS: History of breastfeeding might affect prognosis and survival by establishing a luminal tumor environment with lower proliferative activity.

Adjuvant systemic therapy for breast cancer in BRCA1/BRCA2 mutation carriers in a population-based study of risk of contralateral breast cancer.

Given the greatly elevated risks of contralateral breast cancer (CBC) observed in breast cancer patients who carry mutations in BRCA1 and BRCA2, it is critical to determine the effectiveness of standard adjuvant therapies in preventing CBC in mutation carriers. The WECARE study is a matched, case-control study of 708 women with CBC as cases and 1,399 women with unilateral breast cancer (UBC) as controls, including 181 BRCA1/BRCA2 mutation carriers. Interviews and medical record reviews provided detailed information on risk factors and breast cancer therapy. All study participants were screened for BRCA1 and BRCA2 mutations using denaturing high-performance liquid chromatography (DHPLC) to detect genetic variants in the coding and flanking regions of the genes. Conditional logistic regression was used to compare the risk of CBC associated with chemotherapy and tamoxifen in BRCA1/BRCA2 mutation carriers and non-carriers. Chemotherapy was associated with lower CBC risk both in non-carriers (RR = 0.6 [95% CI: 0.5-0.7]) and carriers (RR = 0.5 [95% CI: 0.2-1.0]; P value = 0.04). Tamoxifen was associated with a reduced CBC risk in non-carriers (RR = 0.7 [95% CI: 0.6-1.0]; P value = 0.03). We observed a similar but non-significant reduction associated with tamoxifen in mutation carriers (RR = 0.7 [95% CI: 0.3-1.8]). The tests of heterogeneity comparing carriers to non-carriers did not provide evidence for a difference in the associations with chemotherapy (P value = 0.51) nor with tamoxifen (P value = 0.15). Overall, we did not observe a difference in the relative risk reduction associated with adjuvant treatment between BRCA1/BRCA2 mutation carriers and non-carriers. However, given the higher absolute CBC risk in mutation carriers, the potentially greater impact of adjuvant therapy in reducing CBC risk among mutation carriers should be considered when developing treatment plans for these patients.

Dose to the contralateral breast from radiotherapy and risk of second primary breast cancer in the WECARE study.

PURPOSE: To quantify the risk of second primary breast cancer in the contralateral breast (CB) after radiotherapy (RT) for first breast cancer. METHODS AND MATERIALS: The study population included participants in the Women's Environmental, Cancer, and Radiation Epidemiology study: 708 cases (women with asynchronous bilateral breast cancer) and 1399 controls (women with unilateral breast cancer) counter-matched on radiation treatment. Participants were <55 years of age at first breast cancer. Absorbed doses to quadrants of the CB were estimated. Rate ratios (RR) and 95% confidence intervals (CI) were calculated using multivariable-adjusted conditional logistic regression models. RESULTS: Across all patients, the mean radiation dose to the specific quadrant of the CB tumor was 1.1 Gy. Women <40 years of age who received >1.0 Gy of absorbed dose to the specific quadrant of the CB had a 2.5-fold greater risk for CB cancer than unexposed women (RR = 2.5, 95% CI 1.4-4.5). No excess risk was observed in women >40 years of age. Women <40 years of age with follow-up periods >5 years had a RR of 3.0 (95% CI 1.1-8.1), and the dose response was significant (excess RR per Gy of 1.0, 95% CI 0.1-3.0). CONCLUSIONS: Women <40 years of age who received a radiation dose >1.0 Gy to the CB had an elevated, long-term risk of developing a second primary CB cancer. The risk is inversely related to age at exposure and is dose dependent.