Relatives of Crohn's disease patients and breast cancer: an overlooked condition

Recent data suggest that patients suffering from Crohn's disease (CD) may be at higher risk of developing extra-intestinal malignancies. This is attributed to inflammation and immunodepression due to medications. However, a genetic predisposition cannot ruled out. In the present study we investigated the prevalence of breast cancer in first-degree female relatives of CD patients compared with relatives of patients without evidence of gastrointestinal diseases. A total of 1302 female first-degree relatives of CD patients and 1294 relatives of controls were included. We found that CD was an independent risk factor for breast cancer development (OR = 2.76, 95% CI = 1.2-6.2; p = 0.017), and this is particularly evident in mothers (3.6% vs 1%, p = 0.009 - OR = 3.7, 95% CI 1.4-10). Among CD group, smoking habit of CD patients was associated with increased risk of cancer compared with relatives of non-smokers (7.7% vs 2.9%, p = 0.01 - OR = 2.8 95% CI 1.2-6.6). Intriguingly, stage at diagnosis was significantly higher in CD relatives (p = 0.04). Our findings suggest that first-degree female relatives of CD patients are at higher risk of developing breast cancer but receive diagnosis at more advanced stages, therefore advocating the need of more active screening protocol in this population.