Alcohol consumption, smoking, and invasive breast cancer risk after ductal carcinoma in situ.

PURPOSE: Alcohol is an established risk factor for invasive breast cancer, and women with a prior ductal carcinoma in situ diagnosis are at higher risk of invasive breast cancer than the general population. However, for women with a prior ductal carcinoma in situ diagnosis, few studies have evaluated the association between alcohol and smoking and risk of subsequent invasive breast cancer. METHODS: Utilizing a population-based case-control design nested among women diagnosed with a ductal carcinoma in situ between 1995 and 2013, we compared 243 cases diagnosed with a subsequent invasive breast cancer and 423 individually matched controls never diagnosed with a subsequent breast cancer. RESULTS: Compared with never to occasional drinkers, drinkers consuming at least 7 alcoholic drinks per week on average at ductal carcinoma in situ diagnosis had a higher risk of invasive breast cancer that was borderline significant (OR 1.79, 95% CI 1.01-3.17, P value = 0.04). Smoking was not significantly associated with risk of developing an invasive breast cancer after adjustment for alcohol consumption. CONCLUSIONS: These findings suggest that consuming at least one alcoholic drink per day on average is positively associated with invasive breast cancer for women with a prior ductal carcinoma in situ diagnosis. If confirmed, modulating alcohol consumption could be one strategy for women with a history of ductal carcinoma in situ to impact their risk of invasive breast cancer.

Association between antidepressant use and second breast cancer event after ductal carcinoma in situ diagnosis: a nested case-control study.

PURPOSE: Controversy exists regarding the potential relationship between antidepressant use and risk of breast cancer. No previous studies have evaluated the relationship between antidepressant use after diagnosis of ductal carcinoma in situ (DCIS) and risk of a subsequent breast cancer restricted to women with a history of DCIS. METHODS: We conducted a population-based, nested case-control study in western Washington State. Cases included 337 women diagnosed with DCIS and a subsequent breast cancer and they were compared to 592 individually matched controls (on age, year of DCIS diagnosis, primary treatment, histology, grade, and disease-free survival time) who were diagnosed with DCIS but not a subsequent breast cancer. Information on antidepressant use after DCIS diagnosis was obtained from comprehensive medical records reviews. Antidepressant use was defined as greater or equal to 3 months of duration. RESULTS: Antidepressant use after initial DCIS was associated with a 1.4-fold increased risk of a subsequent breast cancer event (adjusted OR 1.41, 95% CI 1.02, 1.95). Similar risks were observed when assessing individual antidepressant classes, however, there was no sufficient power across specific classes of antidepressants. CONCLUSIONS: Antidepressant use after DCIS diagnosis was associated with an increased risk of subsequent breast cancer in women. Further studies are needed to confirm the associations observed.

Antihypertensive medications and risks of recurrence and mortality in luminal, triple-negative, and HER2-overexpressing breast cancer.

PURPOSE: Antihypertensives are commonly prescribed medications and their effect on breast cancer recurrence and mortality is not clear, particularly among specific molecular subtypes of breast cancer: luminal, triple-negative (TN), and HER2-overexpressing (H2E). METHODS: A population-based prospective cohort study of women aged 20-69 diagnosed with a first primary invasive breast cancer between 2004 and 2015 was conducted in the Seattle, Washington and Albuquerque, New Mexico greater metropolitan areas. Multivariable-adjusted Cox proportional hazards regression was used to estimate hazard ratios (HR) and 95% confidence intervals (CI) for risks of breast cancer recurrence, breast cancer-specific mortality, and all-cause mortality associated with hypertension and antihypertensives. RESULTS: In this sample of 2,383 luminal, 1,559 TN, and 615 H2E breast cancer patients, overall median age was 52 (interquartile range, 44-60). Hypertension and current use of antihypertensives were associated with increased risks of all-cause mortality in each subtype. Current use of angiotensin-converting enzyme inhibitors was associated with increased risks of both recurrence and breast cancer-specific mortality among luminal patients (HR: 2.5; 95% CI: 1.5, 4.3 and HR: 1.9; 95% CI: 1.2, 3.0, respectively). Among H2E patients, current use of calcium channel blockers was associated with an increased risk of breast cancer-specific mortality (HR: 1.8; 95% CI: 0.6, 5.4). CONCLUSION: Our findings suggest that some antihypertensive medications may be associated with adverse breast cancer outcomes among women with certain molecular subtypes. Additional studies are needed to confirm these findings.

Reproductive and menopausal factors and risk of second primary breast cancer after in situ breast carcinoma.

PURPOSE: In situ breast cancer patients have a higher risk of developing a second primary breast cancer than women in the general population have of developing breast cancer. We have limited understanding of why some women with a previous in situ breast cancer develop second primary breast cancers while others do not. METHODS: In this population-based nested case-control study, we evaluated the association between reproductive and menopausal factors and risk of developing a second primary breast cancer among women with a previous in situ breast cancer. Using conditional logistic regression, these associations were evaluated in 552 cases and 1032 individually matched controls. RESULTS: Older age at menarche was associated with risk of second primary breast cancer among women with a previous in situ breast cancer (compared to age < 12, age 13: OR 0.60 (0.42, 0.85); age ≥ 14: OR 0.69 (0.47, 1.00); Ptrend = 0.07). Breastfeeding for > 12 months was associated with a decreased risk of developing a second primary breast cancer (OR 0.62 (0.39, 0.98)). No associations were observed for other reproductive or menopausal factors evaluated. CONCLUSIONS: Results from this study suggest that reproductive factors may play a role in development of a second primary breast cancer after diagnosis of in situ breast carcinoma.

Body mass index and risk of luminal, HER2-overexpressing, and triple negative breast cancer.

Triple negative (TN, tumors that do not express estrogen receptor (ER), progesterone receptor (PR), or human epidermal growth factor receptor 2 (HER2)) and HER2-overexpressing (H2E, ER-/HER2+) tumors are two particularly aggressive subtypes of breast cancer. There is a lack of knowledge regarding the etiologies of these cancers and in particular how anthropometric factors are related to risk. We conducted a population-based case-case study consisting of 2659 women aged 20-69 years diagnosed with invasive breast cancer from 2004 to 2012. Four case groups defined based on joint ER/PR/HER2 status were included: TN, H2E, luminal A (ER+/HER2-), and luminal B (ER+/HER2+). Polytomous logistic regression was used to estimate odds ratios (ORs) and associated 95 % confidence intervals (CIs) where luminal A patients served as the reference group. Obese premenopausal women [body mass index (BMI) ≥30 kg/m(2)] had an 82 % (95 % CI 1.32-2.51) increased risk of TN breast cancer compared to women whose BMI <25 kg/m(2), and those in the highest weight quartile (quartiles were categorized based on the distribution among luminal A patients) had a 79 % (95 % CI 1.23-2.64) increased risk of TN disease compared to those in the lowest quartile. Among postmenopausal women obesity was associated with reduced risks of both TN (OR = 0.74, 95 % CI 0.54-1.00) and H2E (OR = 0.47, 95 % CI 0.32-0.69) cancers. Our results suggest obesity has divergent impacts on risk of aggressive subtypes of breast cancer in premenopausal versus postmenopausal women, which may contribute to the higher incidence rates of TN cancers observed among younger African American and Hispanic women.

Height, body mass index (BMI), BMI change, and the risk of estrogen receptor-positive, HER2-positive, and triple-negative breast cancer among women ages 20 to 44 years.

BACKGROUND: The evidence regarding correlations between various anthropometric characteristics and breast cancer risk among young women is mixed, and few studies have assessed these associations by subtype. METHODS: This was a population-based, case-control study of 779 women with estrogen receptor (ER)-positive breast cancer; 182 women with ER-negative/human epidermal growth factor-2 (HER2)-negative/progesterone receptor-negative (triple-negative [TN]) breast cancer; and 60 women with ER-negative/HER2-overexpressing, invasive breast cancer ages 20 to 44 years who were diagnosed from 2004 to 2010 in the Seattle-Puget Sound metropolitan area; as well as 939 cancer-free controls. Associations between height and body mass index (BMI) at different time points in relation to breast cancer risk were assessed using polytomous logistic regression. RESULTS: Height, BMI at age 18 years, and BMI at the reference date were not related to the risks of ER-positive, TN, or HER2-overexpressing breast cancer. Changes in BMI from age 18 years to the reference date were not related to the risk of either ER-positive or HER2-overexpressing breast cancer. However, compared with women who had a BMI change from 0 to 4.9 kg/m(2) from age 18 years to the reference date, those who experienced a BMI increase ≥10 kg/m(2) during the same interval had a 2.0-fold (95% confidence interval, 1.2-fold to 3.3-fold increase) increased risk of TN breast cancer. For women with ER-positive disease, there was some evidence that parity modified the effect of BMI change (Pinteraction = .002), because a BMI increase of ≥10 kg/m(2) was associated with a reduced risk of ER-positive disease only among nulliparous women (odds ratio, 0.3; 95% confidence interval, 0.2-0.6). CONCLUSIONS: The correlations appear to differ substantially between BMI change and the risks of TN breast cancer and ER-positive breast cancer.

Active smoking and the risk of estrogen receptor-positive and triple-negative breast cancer among women ages 20 to 44 years.

BACKGROUND: Evidence regarding the correlation between smoking and breast cancer among young women is mixed, and previous studies have not assessed whether smoking is associated differentially with risks of the major breast cancer subtypes. METHODS: This was a population-based, case-control study of 778 women with estrogen receptor (ER)-positive breast cancers and 182 women with ER-negative, progesterone receptor-negative, and human epidermal growth factor receptor 2-negative (triple-negative [TN]), invasive breast cancers ages 20 to 44 years who were diagnosed from 2004 to 2010 in the Seattle-Puget Sound metropolitan area. A control group of 938 cancer-free women also was included. Associations between various aspects of smoking history and the risks of ER-positive and TN breast cancer were assessed using polytomous logistic regression. RESULTS: Ever-smokers had a 1.3-fold increased risk (95% confidence interval [CI], 1.1-fold to 1.7-fold increased risk) of breast cancer overall; and, when stratified by cancer subtype, they had a 1.4-fold increased risk (95% CI, 1.1-fold to 1.8-fold increased risk) of ER-positive breast cancer, but there was no elevation in their risk of TN disease (odds ratio, 1.1; 95% CI, 0.7-1.6). Current/recent smokers with a ≥10 pack-year history of smoking had a 1.6-fold increased risk (95% CI, 1.1-fold to 2.4-fold increased risk) of ER-positive breast cancer but had no increase in their risk of TN breast cancer (odds ratio, 1.0; 95% CI, 0.5-1.9). CONCLUSIONS: The current results suggested that young women who are current/recent smokers with high pack-year histories may have an increased risk of ER-positive breast cancer but not TN breast cancer. Although this association was modest, the findings suggest that an increased risk of ER-positive breast cancer may be another health risk incurred by young women who smoke.

Use of menopausal hormone therapy and risk of ductal and lobular breast cancer among women 55-74 years of age.

The Women's Health Initiative (WHI) randomized trials found that use of combined estrogen and progestin menopausal hormone therapy (CHT) increases breast cancer risk, but use of unopposed estrogen hormone therapy (EHT) does not. However, several questions regarding the impact of hormone use on risk of different types of breast cancer and what thresholds of use confer elevations in risk remain. We conducted a population-based case-control study among women 55-74 years of age to assess the association between menopausal hormone use and risk of invasive ductal and invasive lobular breast carcinomas. Associations were evaluated using polytomous logistic regression and analyses included 880 ductal cases, 1,027 lobular cases, and 856 controls. Current EHT and CHT use were associated with 1.6-fold [95 % confidence interval (CI): 1.1-2.2] and 2.3-fold (95 % CI: 1.7-3.2) increased risks of lobular breast cancer, respectively, but neither was associated with risk of ductal cancer. Lobular cancer risk was increased after 9 years of EHT use, but after only 3 years of CHT use. Evidence across more than a dozen studies indicates that lobular carcinoma is the type of breast cancer most strongly influenced by menopausal hormones. Here, we characterize what thresholds of duration of use of both EHT and CHT that confer elevations in risk. Despite the rapid decline in hormone therapy use the WHI results were published, study of the hazards associated with these medications remains relevant given the estimated 38 million hormone therapy prescriptions that are still filled in the United States annually.

Alcohol, Smoking, and Risks of Breast Cancer Recurrence and Mortality among Women with Luminal, Triple-Negative, and HER2-Overexpressing Breast Cancer.

BACKGROUND: This study evaluates the relationship between smoking, alcohol, and breast cancer outcomes according to molecular subtype. METHODS: This population-based prospective cohort consisted of 3,876 women ages 20 to 69 diagnosed with a first primary invasive breast cancer from 2004 to 2015 in the Seattle-Puget Sound region. Breast cancer was categorized into three subtypes based on estrogen receptor (ER), progesterone receptor (PR), and HER2 expressions: luminal (ER+), triple-negative (TN; ER-/PR-/HER2-), and HER2-overexpressing (H2E; ER-/HER2+). We fit Cox proportional hazards models to assess the association between alcohol consumption and smoking status at diagnosis and risks of recurrence, breast cancer-specific mortality, and all-cause mortality. RESULTS: Histories of ever smoking [HR, 1.33; 95% confidence interval (CI), 1.01-1.74] and current smoking (HR, 1.59; 95% CI, 1.07-2.35) were associated with greater risk of breast cancer recurrence among TN cases. Smoking was also associated with greater risk of recurrence to bone among all cases and among luminal cases. Elevated risks of breast cancer-specific and all-cause mortality were observed among current smokers across all subtypes. Alcohol use was not positively associated with risk of recurrence or mortality overall; however, TN patients who drank four or more drinks per week had a decreased risk of recurrence (HR, 0.71; 95% CI, 0.51-0.98) and breast cancer-specific mortality (HR, 0.73; 95% CI, 0.55-0.97) compared with non-current drinkers. CONCLUSIONS: Patients with breast cancer with a history of smoking at diagnosis have elevated risks of recurrence and mortality. IMPACT: These findings underscore the need to prioritize smoking cessation among women diagnosed with breast cancer.

Metabolic syndrome and risks of breast cancer outcomes for luminal, triple-negative, and HER2-overexpressing subtypes.

BACKGROUND: We evaluated the association between metabolic syndrome (obesity plus two metabolic risk factors) and breast cancer outcomes according to molecular subtype. METHODS: This population-based prospective cohort consisted of 3,267 women aged 20-69 diagnosed with a first primary invasive breast cancer from 2004-2015 in the Seattle-Puget Sound region. Breast cancer was categorized into three subtypes based on estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression: luminal (ER+), triple-negative (ER-/PR-/HER2-), and HER2-overexpressing (H2E) (ER-/HER2+). We used time-varying Cox models to assess the association between prevalent and incident metabolic syndrome and risks of recurrence, breast cancer-specific mortality, and all-cause mortality. RESULTS: Metabolic syndrome was associated with a greater risk of recurrence (HR:3.24; 95% CI:1.13-9.33) and breast cancer-specific mortality (HR:5.34; 95% CI:2.32-12.31) only for the H2E subtype, and greater risks of all-cause mortality for luminal (HR:1.92; 95% CI:1.37-2.68), H2E (HR:5.09; 95% CI:2.51-10.32), and all cases combined (HR:1.90; 95% CI:1.42,2.53). We also observed heterogeneity in recurrence and mortality outcomes across specific components of metabolic syndrome and molecular subtypes. CONCLUSIONS: Metabolic syndrome is associated with all-cause mortality among women with breast cancer and with breast cancer-specific mortality among women with the H2E subtype. IMPACT: These results highlight the importance of managing comorbidities to decrease the risk for adverse outcomes among breast cancer survivors.

Reproductive factors and risk of estrogen receptor positive, triple-negative, and HER2-neu overexpressing breast cancer among women 20-44 years of age.

Aspects of reproductive history are among the most well-established breast cancer risk factors. However, relatively little is known about how they influence risk of different molecular subtypes of breast cancer, particularly among younger women. Using data from a population-based case-control study of women 20-44 years of age, we assessed the relationships between various reproductive factors and risk of estrogen receptor positive (ER+), triple-negative, and HER2-overexpressing breast cancers. Detailed reproductive histories were obtained through structured interviewer administered in-person questionnaires. Reproductive histories among control women (n = 941) were compared to those of ER+ cases (n = 781), triple-negative cases (n = 180), and HER2-overexpressing cases (n = 60) using polytomous logistic regression. Age at menarche, parity, and number of full-term pregnancies were similarly associated with risk of all three breast cancer subtypes. In contrast, age at first live birth, the interval between age at menarche and age at first birth, and breastfeeding were inversely associated with risk of triple-negative breast cancer (P values for trend 0.002, 0.006 and 0.018, respectively), but were not associated with risk of ER+ or HER2-overexpressing cancers. A strong inverse association between breastfeeding and risk of triple-negative breast cancer has now been consistently observed across numerous studies, and at present it is the most well-established protective factor for this aggressive and lethal form of breast cancer. Further studies clarifying the biological mechanisms underlying this relationship and confirming our results with respect to age at first birth and the interval between age at menarche and age at first birth are needed.

Disparities in Risk of Advanced-Stage Liver Cancer and Mortality by Race and Ethnicity.

BACKGROUND: In the United States, liver cancer is the fifth and seventh most common cause of cancer-related death among men and women, respectively. Compared with other racial or ethnic groups in the United States, Asian and Pacific Islander populations experience the highest incidence rates of liver cancer, but little is known about disparities in risk of advanced-stage disease or risk of liver cancer mortality across these heterogenous populations. METHODS: In a population-based cohort of 60 146 patients aged 20-79 years diagnosed with liver cancer from 2004 to 2018 identified through the Surveillance, Epidemiology, and End Results Program, we examined associations between race or ethnicity, including specific Asian and Pacific Islander subgroups, and risk of advanced-stage liver cancer and liver cancer-specific mortality. RESULTS: Compared with non-Hispanic White patients, non-Hispanic Black, Filipino, and Laotian patients had 30%-85% elevated odds of being diagnosed with stage IV liver cancer, whereas Hispanic, Vietnamese, and Chinese patients had 7%-33% lower odds of being diagnosed with stage IV liver cancer (all P <.05). Additionally, non-Hispanic Black, Kampuchean, and Laotian patients had 6%-22% elevated hazards of liver cancer-specific mortality, and Hispanic, Vietnamese, Chinese, and Korean patients had 3%-27% lower hazards of liver cancer-specific mortality (all P <.05). All statistical tests were 2-sided. CONCLUSIONS: Substantial variations in risk of advanced-stage liver cancer and risk of liver cancer mortality were observed by race and ethnicity, including considerable heterogeneity across individuals broadly defined as Asians and Pacific Islanders. Further efforts to understand the contributors to these disparities are needed to inform potential targeted screening and treatment interventions.

Relationship between diabetes and risk of second primary contralateral breast cancer.

Breast cancer survivors have a substantially higher risk of developing a second primary contralateral breast cancer (CBC) compared to the risk of breast cancer among women in the general population. While data regarding the relationship between diabetes and breast cancer incidence are inconsistent, diabetes is more clearly linked to an elevated risk of all-cause mortality among breast cancer survivors. However, no prior studies have assessed its impact on CBC risk. We assessed the relationship between diabetes, and CBC risk in a population-based nested case-control study consisting of women 40-79 years of age diagnosed with a first primary ER-positive invasive breast cancer. It included 322 women who developed a second primary CBC and 616-matched control women diagnosed only with a first breast cancer. We used conditional logistic regression to quantify associations between diabetes and CBC risk. Compared to women without a history of diabetes, diabetics had a 2.2-fold [95% confidence interval (CI) 1.3-3.6] increased risk of CBC. This risk was more pronounced among women diagnosed with their first breast cancer before age 60 years (odds ratio, OR = 11.5, 95% CI 2.4-54.5), compared to those diagnosed at age 60 years or older (OR = 1.5, 95% CI 0.8-2.7, P for interaction = 0.011). Diabetics diagnosed with breast cancer appear to have an elevated risk of CBC. This is the first study to report this relationship, but if confirmed efforts to insure that diabetic breast cancer survivors are carefully screened for second breast cancers may be warranted.

Bisphosphonate Use and Breast Cancer Risk among Women with Ductal Carcinoma In Situ.

Women with a history of ductal carcinoma in situ (DCIS) have an elevated risk of a subsequent invasive breast cancer, but there are few established potentially modifiable factors known to lower this risk. Bisphosphonates are a commonly used treatment for patients with osteoporosis and have been shown to lower risks of recurrence and mortality in patients with invasive breast cancer; however, their use has not previously been investigated within the context of DCIS. Utilizing a population-based nested case-control design, we compared 301 cases of women diagnosed with DCIS and a subsequent breast cancer and 587 individually matched controls (on age, DCIS diagnosis year, primary treatment, histology, grade, and disease-free survival time) who were diagnosed with DCIS but never a subsequent breast cancer. Information on recency and duration of bisphosphonate use was ascertained from patient interviews and medical record reviews. Current users of bisphosphonates had a reduced risk of developing an invasive breast cancer compared with never users [OR = 0.50; 95% confidence interval (CI): 0.26-0.99]. Users of bisphosphonates for ≥48 months had a similar reduction in risk (OR = 0.45; 95% CI, 0.24-1.06). This is the first study to document that bisphosphonate use is associated with a lower risk of subsequent invasive breast cancer among women with a history of DCIS. This finding is consistent with the protective effect of bisphosphonates observed in other breast cancer settings. If validated by others, bisphosphonates may be an effective risk-reducing approach with the potential added benefits of its positive impacts on bone health and fracture risk. SIGNIFICANCE: This study finds that bisphosphonate use among women with a history of DCIS is associated with lower risk of subsequent invasive breast cancer, providing a potential preventative approach for this high-risk population.

Determinants of Guideline-Discordant Breast Cancer Care.

BACKGROUND: Evidence-based breast cancer treatment guidelines recommend the most appropriate course of therapy based on tumor characteristics and extent of disease. Evaluating the multilevel factors associated with guideline discordance is critical to identifying strategies to eliminate breast cancer survival disparities. METHODS: We identified females diagnosed with a first primary, stage I-III breast cancer between the ages of 20-69 years of age from the population-based Seattle-Puget Sound Surveillance, Epidemiology, and End Results registry. Participants completed a survey about social support, utilization of patient support services, hypothesized barriers to care, and initiation of breast cancer treatment. We used logistic regression to estimate odds ratios and 95% confidence intervals (CI). RESULTS: Among 1,390 participants, 10% reported guideline-discordant care. In analyses adjusted for patient-level sociodemographic factors, individuals who did not have someone to go with them to appointments or drive them home (OR 1.96; 95% CI, 1.09-3.59) and those who had problems talking to their doctors or their staff (OR 2.03; 95% CI, 1.13-3.64) were more likely to be guideline discordant than those with social support or without such problems, respectively. Use of patient support services was associated with a 43% lower odds of guideline discordance (OR 0.57; 95% CI, 0.36-0.88). CONCLUSIONS: Although guideline discordance in this cohort of early-stage breast cancer survivors diagnosed <70 years of age was low, instrumental social support, patient support services, and communication with doctors and their staff emerged as potential multilevel intervention targets for improving breast cancer care delivery. IMPACT: This study supports extending the reach of interventions designed to improve guideline concordance.

Cancer Cell Intrinsic and Immunologic Phenotypes Determine Clinical Outcomes in Basal-like Breast Cancer.

PURPOSE: Basal-like breast cancer (BLBC) is a particularly aggressive intrinsic molecular subtype of breast cancer that lacks targeted therapies. There is also no clinically useful test to risk stratify patients with BLBC. We hypothesized that a transcriptome-based phenotypic characterization of BLBC tumors and their microenvironments may overcome these challenges. EXPERIMENTAL DESIGN: We conducted a retrospective correlative genomic sequencing study using a matched pairs design with validation in five independent cohorts. The study was conducted on a large population-based prospective cohort of the major molecular subtypes of breast cancer conducted in the greater Seattle-Puget Sound metropolitan area. Cases consisted of women 20-69 years of age first diagnosed with invasive breast cancer identified through the population-based Surveillance Epidemiology and End Results program. Patients for this analysis (n = 949) were identified from the 1,408 patients with stage I-III triple-negative breast cancer [estrogen receptor-negative (ER-), progesterone receptor-negative (PR-), HER2-]. Of the 949 women, 248 developed a recurrence after their initial diagnosis. A matched set of 67 recurrent and nonrecurrent BLBC tumors was subjected to transcriptome sequencing. Through RNA sequencing of the matched sets of recurrent and nonrecurrent BLBC tumors, we aimed to identify prognostic phenotypes.To identify nonredundant and uncorrelated prognostic genes, we used an ensemble of variable selection algorithms, which resulted in a ranking of genes on the basis of their expected utility in classification. Using leave-one-out cross-validation, we trained a random forest classifier on the basis of the top 21 genes (BRAVO-DX). Validations were performed in five independent triple-negative or BLBC cohorts, and biomarker robustness and transferability were demonstrated by employing real-time PCR. RESULTS: We found that cancer cell intrinsic and immunologic phenotypes are independent predictors of recurrence. By simultaneously interrogating the tumor and its microenvironment, we developed a compound risk model that stratified patients into low-, medium-, and high-risk groups, with a 14%/56%/74% chance of recurrence, respectively. Biologically, the primary tumors of patients who developed a recurrence had increased growth factor signaling and stem-like features, while nonrecurrent tumors showed high lymphocyte infiltration with clonal expansion of T and B cells, as well as antitumor polarization of macrophages. We validated our model in five independent cohorts, including three large cohorts, where BRAVO-DX was highly informative in identifying patients with disease recurrence [HR, 6.79 (95% confidence interval (CI), 1.89-24.37); HR, 3.45 (95% CI, 2.41-4.93); and HR, 1.69 (95% CI, 1.17-2.46)]. A smaller gene set focused on the tumor immunophenotype, BRAVO-IMMUNE, was highly prognostic in all five cohorts. CONCLUSIONS: Together, these results indicate that phenotypic characteristics of BLBCs and their microenvironment are associated with recurrence-free survival and demonstrate the utility of intrinsic and extrinsic phenotypes as independent prognostic biomarkers in BLBC. Pending further evaluation and validation, our prognostic model has the potential to inform clinical decision-making for patients with BLBC as it identifies those at high risk of rapidly progressing on standard chemotherapy, as well as those who may benefit from alternative first-line therapies.

Recent Use of Oral Contraceptives and Risk of Luminal B, Triple-Negative, and HER2-Overexpressing Breast Cancer.

Oral contraceptive use is a well-established risk factor for breast cancer and is common among reproductive-aged women in the USA. Its relationship with less common, more aggressive, molecular subtypes is less clear. A population-based case-case analysis was conducted comparing three less common molecular subtypes to luminal A breast cancer among 1701 premenopausal cases aged 21-49 diagnosed with a first primary invasive breast cancer between 2004 and 2015. Medical record reviews and structured interviewer-administered questionnaires were used to collect data on oral contraceptive use. Multinomial logistic regression was used to estimate odds ratios (OR) and corresponding 95% confidence intervals (95% CI) for recency of oral contraceptive use for each subtype of breast cancer. Current use of oral contraceptives and use within 5 years before diagnosis was associated with lower odds of H2E tumors compared with luminal A tumors [OR = 0.5, 95% CI: 0.3, 0.9 and OR = 0.5, 95% CI: 0.4, 0.8, respectively] with increasing duration associated with decreasing odds (p for trend < 0.05). Oral contraceptive use was not associated with risks of TN or luminal B breast cancer. Oral contraceptive use may be more strongly positively associated with risks of luminal A, luminal B, and TN breast cancer than with risk of H2E tumors. These findings contribute to the etiological understanding of different molecular subtypes of breast cancer.

Relationship between Diabetes and Diabetes Medications and Risk of Different Molecular Subtypes of Breast Cancer.

BACKGROUND: Type II diabetes and certain diabetes treatments have been observed to impact breast cancer risk. However, their associations with different breast cancer molecular subtype defined by estrogen receptor (ER)/progesterone receptor (PR)/HER2 status are unclear. METHODS: We conducted a retrospective multi-center population-based case-case study consisting of 4,557 breast cancer cases to evaluate the impact of type II diabetes and diabetes medications on the risk of different breast cancer molecular subtypes [ER+/HER2-, ER+/HER2+, triple negative (ER-/PR-/HER2-), and HER2 overexpressing (H2E, ER-/PR-/HER2+)]. Using ER+/HER2- cases as the reference group, we estimated ORs and corresponding 95% confidence intervals (CI) for each subtype using polytomous logistic regression. RESULTS: Compared with those without a diabetes history, women with type II diabetes had a 38% (95% CI, 1.01-1.89) increased odds of triple-negative breast cancer (TNBC). Current and longer term recent metformin use (13-24 months of treatment within the 24-month period prior to breast cancer diagnosis) was associated with elevated odds of TNBC (OR = 1.54; 95% CI, 1.07-2.22 and OR = 1.80; 95% CI, 1.13-2.85, respectively). CONCLUSIONS: The odds of having a triple-negative rather than ER+/HER2- breast cancer is greater for women with type II diabetes, and particularly for those who were users of metformin. This finding is supported by some preclinical data suggesting that diabetes may be more strongly associated with risk of triple-negative disease. IMPACT: Our study provides novel evidence regarding potential differential effects of type II diabetes and metformin use on risk of different molecular subtypes of breast cancer.

Relationship Between Anthropometric Factors and Risk of Second Breast Cancer Among Women With a History of Ductal Carcinoma In Situ.

BACKGROUND: Women with ductal carcinoma in situ (DCIS) have an elevated risk of a second breast cancer, but few data are available regarding the impact of modifiable lifestyle factors on this risk. METHODS: In a population-based case-control patient study of women with a history of DCIS in western Washington diagnosed between 1996 and 2013, 497 patients diagnosed with DCIS and a second ipsilateral or contralateral invasive or in situ breast cancer were enrolled. There were 965 matched control patients with one DCIS diagnosis. Associations between anthropometric factors and risk of an invasive or in situ second breast cancer event were evaluated using conditional logistic regression. Statistical tests were two-sided. RESULTS: Obesity (body mass index [BMI] ≥ 30 kg/m2) at initial DCIS diagnosis was associated with a 1.6-fold (95% confidence interval [CI] = 1.2 to 2.2) increased risk of any second breast cancer and a 2.2-fold increased risk of a contralateral second breast cancer (95% CI = 1.4 to 3.3) compared with normal weight women (BMI < 25 kg/m2). BMI and weight, both at initial DCIS diagnosis and at the time of the second breast cancer diagnosis, were positively associated with risk of any second and second invasive breast cancers (odds ratio = 1.01-1.04, all P ≤ .03). CONCLUSIONS: Although additional confirmatory studies are needed, obesity appears to be an important contributor to the risk of second breast cancers within the growing population of women with DCIS. This has potential clinical relevance with respect to identifying which women with a history of DCIS may require more careful monitoring and who may benefit from lifestyle modifications.

Family History and Risk of Second Primary Breast Cancer after In Situ Breast Carcinoma.

Background: Incidence rates of in situ breast carcinomas have increased due to widespread adoption of mammography. Very little is known about why some women with in situ breast cancer later develop second primary breast cancers.Methods: In this population-based nested case-control study among in situ breast cancer survivors, including 539 cases with a second primary breast cancer and 994 matched controls, we evaluated the association between first-degree family history of breast cancer and risk of developing a second primary breast cancer.Results: First-degree family history of breast cancer was associated with an increased risk of developing a second primary breast cancer among women with a previous in situ breast cancer [odds ratio (OR) = 1.33, 95% confidence interval (CI), 1.05-1.69] and those with two or more affected first-degree relatives had an even higher risk (OR = 1.94; 95% CI, 1.15-3.28). Those whose relative was diagnosed at less than 50 years old were more likely to develop a second primary breast cancer (OR = 1.78; 95% CI, 1.24-2.57). No difference in risks associated with number or age of affected relatives was observed by menopausal status.Conclusions: Results from this study suggest that first-degree family history of breast cancer may be an important risk factor for development of a second primary breast cancer among women with a previous in situ breast cancer.Impact: Given the growing population of in situ breast cancer survivors, a better understanding of risk factors associated with development of a second primary breast cancer is needed to further understand risk. Cancer Epidemiol Biomarkers Prev; 27(3); 315-20. ©2018 AACR.