First-degree relatives of cancer patients: a target group for primary prevention? A cross-sectional study.

Background: Persons with a first-degree relative (FDR) with cancer are at increased cancer risk. We investigated preventive behaviour, cancer risk perception and readiness to change an unhealthy lifestyle in persons with and without an FDR with cancer.

Methods: Using an online questionnaire, we conducted a cross-sectional study in Germany including persons (≥35 years) with an FDR with colorectal, lung, prostate, breast, stomach or cervical/uterine cancer (n = 621) and persons without cancer in FDRs (n = 303). Quota sampling ensured similar age and sex distributions in both groups.

Results: Unfavourable lifestyle factors were equally common in both groups. The proportion perceiving an increased cancer risk significantly differed (p < 0.0001) with 4% among respondents without cancer in FDRs and 18% (colorectal cancer) to 30% (stomach cancer) among cancer patients' relatives. The proportion of smokers ready to quit smoking was significantly higher among those perceiving an increased vs. a lower cancer risk (64 vs. 46%, p = 0.04). There was a similar association for readiness to increase physical activity and consumption of fruits/vegetables and to reduce alcohol consumption.

Conclusions: Given the increased risk perception and motivation to change an unhealthy lifestyle, our study provides a strong rationale for research on the effectiveness of lifestyle interventions in cancer patients' relatives.