Hypertensive diseases in pregnancy and subsequent lower risk of breast cancer: the common immune and antiangiogenic profile

Abstract

I read with great interest the study by Opdahl et al (2012) who reported from the links between two national registries including almost one million women having giving their first birth in Norway between 1967 and 2008, that women with hypertension or preeclampsia in their first pregnancy, as well as in any pregnancy, had a reduced breast cancer risk (hazard ratio (HR) 0.83, 95% confidence interval (CI) 0.77, 0.90 and HR 0.84, 95% CI 0.79, O.89, respectively). During follow-up, 15 856 women were diagnosed with invasive breast cancer in the registry, and these population-based data confirmed those of previous large case–control studies in reporting a reduced risk of breast cancer after hypertensive disorders of pregnancy in diverse states of America (Troisi et al, 1998; Innes and Byers, 2004; Terry et al, 2007). The Italian study by Talamini et al, (1997) and the Jerusalem Perinatal Study (Calderon-Margalit et al, 2009) were not specifically designed to address this particular link and were based on the inclusion of only 28 and 63 breast cancer cases, respectively, their conflicting conclusions possibly reflecting a particular genetic susceptibility or misclassification of patients with pregnancy-induced hypertension without diagnosis of preeclampsia.