BackgroundWomen with pathogenic BRCA germline mutations have an increased risk for breast and ovarian cancer that seems to be modified by life-style factors. Though, randomized trials investigating the impact of lifestyle interventions on cancer prevention and prognosis in BRCA carriers are still missing.MethodsWe implemented a multicenter, prospective randomized controlled trial in BRCA1/2 patients, comparing a lifestyle intervention group (IG) with a control group (CG) with the primary aim to prove feasibility. Intervention comprised a structured, individualized endurance training alongside nutrition education based on the Mediterranean diet (MD) for 3 months, plus monthly group training and regular telephone contact during the subsequent 9 months. The CG attended one session on healthy nutrition and the benefits of physical activity. Primary endpoints were feasibility, acceptance and satisfaction over 12 months. Furthermore, effects on physical fitness, diet profile, body mass index (BMI), quality of life and perceived stress were investigated.ResultsSixty-eight participants (mean age 41, mean BMI 23.2 kg/m2) were enrolled, of whom 55 (81%, 26 IG, 29 CG) completed 12 months. 73% (n = 26) participated in at least 70% of all intervention sessions. Predictors for drop-outs (19%; n = 13) or non-adherence (27%; n = 7) were not found. 73% rated the program highly and 80% would participate again. Severe adverse events did not occur. Positive effects in the IG compared to the CG were observed for secondary endpoints: BMI, MD eating pattern and stress levels.ConclusionsThis lifestyle intervention was feasible, safe and well accepted. Positive results on eating habits, physical fitness and stress levels warrant a larger randomized trial.Trial registrationThe study has been retrospectively registered at ClinicalTrials.gov (reference: NCT02087592) on March 12, 2014. The first patient was included on February 24, 2014.

Increasing rates of obesity, lack of physical activity, sedentary behavior, and frequent alcohol consumption are major lifestyle-related risk factors for breast cancer. In fact, it has been estimated that about one-third of breast cancer cases are attributable to factors women can change. Most research has focused on examining the impact of one single exposure on breast cancer risk while adjusting for other risk modifiers. Capitalizing on big data, major efforts have been made to evaluate the combined impact of well-established lifestyle factors on overall breast cancer risk. At the individual level, data indicate that even simple behavior modifications could have a considerable impact on breast cancer prevention. Moreover, there is emerging new evidence that adopting a healthy lifestyle may be particularly relevant for women with hereditary susceptibility to breast cancer. On the absolute risk scale, studies suggest that the presence of certain risk factors, such as excessive body weight, had a substantially higher impact on breast cancer risk if women had a hereditary predisposition to cancer. The existing body of knowledge gives the medical professionals guidance as to which factors to focus on when counseling patients. However, well-designed randomized controlled trials utilizing objective methods are crucial to providing concrete recommendations.

The present data in this small cohort of 68 mutation carriers suggest that smoking and low physical activity during adolescence are risk factors for developing breast cancer in women with BRCA1 or BRCA2 mutation. Further data of the ongoing LIBRE 2 study are necessary to confirm these findings in a larger cohort of 600 mutation carriers.