Hypothesized role of pregnancy hormones on HER2+ breast tumor development.

Breast cancer incidence rates have declined among older but not younger women; the latter are more likely to be diagnosed with breast cancers carrying a poor prognosis. Epidemiological evidence supports an increase in breast cancer incidence following pregnancy with risk elevated as much as 10 years post-partum. We investigated the association between years since last full-term pregnancy at the time of diagnosis (≤10 or >10 years) and breast tumor subtype in a case series of premenopausal Hispanic women (n = 627). Participants were recruited in the United States, Mexico, and Spain. Cases with known estrogen receptor (ER), progesterone receptor (PR), and HER2 status, with one or more full-term pregnancies ≥1 year prior to diagnosis were eligible for this analysis. Cases were classified into three tumor subtypes according to hormone receptor (HR+ = ER+ and/or PR+; HR- = ER- and PR-) expression and HER2 status: HR+/HER2-, HER2+ (regardless of HR), and triple negative breast cancer. Case-only odds ratios (ORs) and 95 % confidence intervals (CIs) were calculated for HER2+ tumors in reference to HR+/HER2- tumors. Participants were pooled in a mixed-effects logistic regression model with years since pregnancy as a fixed effect and study site as a random effect. When compared to HR+/HER2- cases, women with HER2+ tumors were more likely be diagnosed in the post-partum period of ≤10 years (OR = 1.68; 95 % CI, 1.12-2.52). The effect was present across all source populations and independent of the HR status of the HER2+ tumor. Adjusting for age at diagnosis (≤45 or >45 years) did not materially alter our results (OR = 1.78; 95 % CI, 1.08-2.93). These findings support the novel hypothesis that factors associated with the post-partum breast, possibly hormonal, are involved in the development of HER2+ tumors.

Factors that influence mammography use and breast cancer detection among Mexican-American and African-American women.

OBJECTIVE: This study examined factors that influence mammography use and breast cancer detection, including education, health insurance, and acculturation, among Mexican-American (MA) and African-American (AA) women. METHODS: The study included 670 breast cancer cases (388 MAs and 282 AAs), aged 40-86 years at diagnosis. Data on mammography use, detection, and delay in seeking care were collected via questionnaires and medical records. Using a language-based bidimensional acculturation measure, MAs were classified as English-dominant (n = 67), bilingual (n = 173), and Spanish-dominant (n = 148). Mammography prior to diagnosis was assessed by racial/ethnic acculturation subgroup using logistic regression. RESULTS: In age-adjusted models, mammography use was non-significantly lower among English-dominant (OR = 0.84; 95% CI: 0.45-1.59) and bilingual (OR = 0.86; 95% CI: 0.55-1.35) MAs and significantly lower among Spanish-dominant MAs (OR = 0.53; 95% CI: 0.34-0.83) than among AA women. After adjustment for education or insurance, there was no difference in mammography use by race/ethnicity and acculturation subgroup. Despite high self-reported mammography use (75%), a large proportion of cases reported self-detection (59%) and delay in seeking care >90 days (17%). CONCLUSIONS: These findings favor promoting culturally appropriate messaging about the benefits and limitations of mammography, education about breast awareness, and prompt reporting of findings to a health professional.