Gestational hypertensive disorders and maternal breast cancer risk in a nationwide cohort of 40,720 parous women

Menée à partir de données 2003-2009 de la cohorte "Sister Study" portant sur 50 884 femmes ayant des antécédents familiaux de cancer du sein (âge : 35-74 ans ; durée moyenne de suivi : 10,9 ans), cette étude analyse l'association entre des troubles hypertensifs de la grossesse (hypertension gestationnelle, prééclampsie, éclampsie) et le risque de cancer du sein (3 198 cas)

Résumé en anglais

Background: Pre-eclampsia and gestational hypertension are hypothesized to be associated with reduced maternal breast cancer risk, but the epidemiologic evidence is inconclusive. Our objective was to examine associations between gestational hypertensive disorders and breast cancer in a nationwide cohort of women with a family history of breast cancer.

Methods: Women ages 35-74 years who had a sister previously diagnosed with breast cancer, but had never had breast cancer themselves, were enrolled in the Sister Study from 2003-2009 (N=50,884). At enrollment, participants reported diagnoses of eclampsia, pre-eclampsia, or gestational hypertension in each pregnancy. We used Cox proportional hazards models to estimate HRs and 95% CIs for the association between history of a gestational hypertensive disorder and incident invasive breast cancer or ductal carcinoma in situ among 40,720 parous women. We used age as the time scale and adjusted for birth cohort, race–ethnicity, and reproductive, socioeconomic, and behavioral factors. We examined effect measure modification by risk factors for gestational hypertensive disease and breast cancer and assessed possible etiologic heterogeneity across tumor characteristics.

Results: The prevalence of gestational hypertensive disease was 12%. During follow-up (mean=10.9 years), 3198 eligible women self-reported a breast cancer diagnosis. History of a gestational hypertensive disorder was not associated with breast cancer risk (HR=1.0, 95% CI 0.90, 1.1). We did not observe clear evidence of effect measure modification or etiologic heterogeneity.

Conclusions: History of a gestational hypertensive disorder was not associated with breast cancer risk in a cohort of women with a first-degree family history of breast cancer.