Lifestyle and environmental factors in women carrying BRCA pathogenic variants with and without cancer

In the development of breast cancer and ovarian cancer there may be an influence of lifestyle and environmental factors. This influence could be relevant also in patients with genetic predisposition such as in carriers of germline pathogenic variants in the BRCA genes. However, this issue has been addressed in only a few studies so far.

In this retrospective, multicenter case-control study, we enrolled participants with a pathogenic variant BRCA gene and divided into 2 groups: group 1, patients with breast cancer and/or ovarian cancer, and group 2, subjects without cancer. We compared these groups regarding demographic data as age, body mass index, smoking habits, estroprogestinic use, Mediterranean diet, and physical activity. Multivariable analyses were used to identify predisposing factors. All evaluations were 2-tailed and considered statistically significant if the P value was less than .05.

We enrolled 281 participants, 135 (79.4%) with breast cancer, 32 (18.8%) with ovarian cancer, 3 (1.8%) with both, and 111 unaffected (39.5%) women. Independent risk factors associated with cancer were age (P < .0001); body mass index (P = .007); family history (P = .002); occupation (P = .003); smoking habits (P = .012), number of cigarettes smoked (P = .016), and pack-year index (P = .022); and estroprogestinic use (P = .032) and years of estroprogestinic use (P = .029). At multivariate analysis, age (odds ratio [OR] = 1.062; P < .0001), family history (OR = 0.129; P = .001), number of cigarettes smoked (P = .014), and estroprogestinic use (OR = 2.009; P = .025) were statistically significant risk factors associated with cancer development.

In the development of breast cancer and ovarian cancer, lifestyle and environmental factors seem to play a statistically significant role in the presence of genetic predisposition associated with BRCA1 and BRCA2 gene mutations.