Clustering of place of birth for women with breast cancer: differences by tumor characteristics

Breast Cancer Outcomes in a Racially and Ethnically Diverse Cohort of Insured Women

Background

It is unknown how subsequent breast cancer outcomes vary by biologic subtype and race/ethnicity in a diverse cohort of breast cancer survivors.

Methods

We conducted a prospective cohort study of 6,154 insured breast cancer survivors (AJCC TNM stages 0-IV) diagnosed between 1996-2007 and followed them through 1/1/2010 for subsequent breast cancer events (recurrence, contralateral breast cancer, metastasis, mortality). We compared subsequent breast cancer rates by race/ethnicity groups and biologic subtype (luminal A, luminal B, HER2-enriched, and triple negative). We calculated hazard ratios (HRs) with 95% CIs using multivariable Cox proportional hazards models, adjusted for sociodemographics, cancer treatments, and tumor characteristics.

Results

The cohort was diverse: 62.4% non-Hispanic White, 13.2% Hispanic, 14.9% African American, and 9.5% Asian. We identified 1,456 subsequent breast cancer events over 22,830 person-years. Although certain Asian women had higher crude subsequent breast cancer rates compared with Whites, within each biologic subtype category, these disparities disappeared in the multivariable analyses. After accounting for race/ethnicity, compared with women with luminal A tumors (reference), women with luminal B (adjusted HR=3.65, 95% CI: 3.08-4.32), HER2-enriched (adjusted HR=2.81, 95% CI: 2.25-3.51) and triple negative (adjusted HR=1.25, 95% CI: 1.01-1.54) tumors had statistically increased risks of subsequent breast cancer. Factors that were statistically significantly associated with increased risk included higher stage, larger tumor size, positive lymph nodes, and no adjuvant endocrine or chemotherapy (all P<.025).

Discussion

Our data suggest that disparities in subsequent breast cancer outcomes were more strongly associated with tumor characteristics and non-use of adjuvant treatments than race/ethnicity.

Sleep and Breast Cancer in the Western New York Exposures and Breast Cancer (WEB) Study

STUDY OBJECTIVES

Night shift work is associated with increased breast cancer risk, possibly from altered sleep. Epidemiologic evidence is sparse regarding sleep disturbances and breast cancer tumor markers. We examined sleep disturbance in association with breast tumor aggressiveness and mortality following diagnosis.

METHODS

We analyzed associations of measures of sleep disturbance in a sample of 1,122 incident breast cancer cases from the Western New York Exposures and Breast Cancer (WEB) Study. Sleep disturbance was assessed using self-administered questionnaires; responses about difficulty falling asleep, waking up frequently, having trouble staying asleep, and waking up feeling tired and worn out were used to create a summary sleep disturbance score. We used general linear models to examine associations of sleep disturbance with markers of tumor aggressiveness among cases: estrogen receptor (ER) status, progesterone receptor (PR) status, and human epidermal growth factor receptor-2 (HER2) status; tumor size, stage, grade, lymph node involvement, and presence of metastasis. In addition, we examined the association between sleep disturbance and survival using Cox regression.

RESULTS

Among breast cancer cases, sleep disturbance was higher for women with ER- / PR- tumors compared to women with ER+ / PR+ tumors, even after adjusting for potential covariates (P for trend = .02). Results suggest that the association of sleep quality differs by menopausal status, where mild sleep disturbance is associated with higher breast cancer mortality in premenopausal women; however, we had a relatively small sample size.

CONCLUSIONS

Sleep disturbance may be associated with aggressive subtypes of breast cancer; however, further studies are needed.

Exposure to traffic-related air pollution and the risk of developing breast cancer among women in eight Canadian provinces: a case-control study

A few recent studies have reported positive associations between long-term exposure to traffic-related air pollution and the incidence of breast cancer. We capitalized on an existing Canadian multi-site population-based case-control study to further investigate this association. We used the National Enhanced Cancer Surveillance System, a population-based case-control study conducted in eight of 10 Canadian provinces from 1994 to 1997. A total of 1569 breast cancer cases and 1872 population controls who reported at least 90% complete self-reported addresses over the 1975-1994 exposure period were examined. Mean exposure levels to nitrogen dioxide (NO2) (an indicator of traffic-related air pollution) were estimated for this period using three different measures: (1) satellite-derived observations; (2) satellite-derived observations scaled with historical fixed-site measurements of NO2; and (3) a national land-use regression (LUR) model. Proximity to major roads was also examined. Using unconditional logistic regression, stratified by menopausal status, we estimated odds ratios (ORs) adjusted for many individual-level and contextual breast cancer risk factors. We observed positive associations between incident breast cancer and all three measures of NO2 exposure from 1975 to 1994. In fully adjusted models for premenopausal breast cancer, a 10ppb increase in NO2 exposure estimated from the satellite-derived observations, the scaled satellite-derived observations, and the national LUR model produced ORs of 1.26 (95% confidence intervals (CIs): 0.92-1.74), 1.32 (95% CI: 1.05-1.67) and 1.28 (95% CI: 0.92-1.79). For postmenopausal breast cancer, we found corresponding ORs of 1.10 (95% CI: 0.88-1.36), 1.10 (95% CI: 0.94-1.28) and 1.07 (95% CI: 0.86-1.32). Substantial heterogeneity in the ORs was observed across the eight Canadian provinces and reduced ORs were observed when models were restricted to women who had received routine mammography examinations. No associations were found for road proximity measures. This study provides some support for the hypothesis that traffic-related air pollution may be associated with the development of breast cancer, especially in premenopausal women. With the few studies available, further research is clearly needed.

Social correlates of total cancer in adults and the very old: UK Understanding Society Cohort, 2009-2010

OBJECTIVE

Understanding of the social determinants of cancer in adults and the very old is still limited. The aim of this study was to provide recent evidence on the social correlates of adult total cancer in a national and population-based setting.

STUDY DESIGN

A cross-sectional study in the recent years between 2009 and 2010.

METHOD

Data was retrieved and analysed from the UK Longitudinal Household Survey. Information on demographics, living and work conditions, self-reported cancer and age of onset was obtained by household interview. Analyses included Chi-squared test, t-test, and multilevel logistic regression modelling.

RESULTS

Of 50,994 people included in the cohort, 1623 (3.5%) had ever cancer. Of these, 1592 (98.0%) occurred in adulthood (16y+) and only 109 people had their first cancer (incident cancer) at the age when they were interviewed. In the middle-aged and young adults, being female (OR 1.57, 95%CI 1.20-2.06, P = 0.001 and OR 2.04, 95%CI 1.07-3.87, P = 0.03, respectively), not born in the UK (OR 0.54, 95%CI 0.34-0.88, P = 0.01 and OR 0.31, 95%CI 0.09-1.02, P = 0.05, respectively), and being obese/overweight (OR 1.49, 95%CI 1.07-2.07, P = 0.02 and OR 2.34, 95%CI 1.17-4.66, P = 0.02, respectively) were associated with total cancer. However, no associated social factors of cancer in the very old were found. Moreover, prevalence was higher in East Midlands (OR 1.73, 95%CI 1.00-3.00, P = 0.05) but not other regions, compared to London region.

CONCLUSION

Social environment seems to continue playing a role in the aetiology of cancer in adults, although novel and/or pooled investigation for the very old would be warranted.