Prostate cancer and family links

Clinical bottom line

The risk of prostate cancer is about doubled in a man with any affected relative. It may be increased by about three times in men with a brother with prostate cancer.

Reference

DW Bruner et al. Relative risk of prostate cancer for men with affected relatives: systematic review and meta-analysis. International Journal of Cancer 2003 107: 797-803.

Background

While there is no single gene that is known to be responsible for even a minority of prostate cancers, basic research suggests that some form of genetic predisposition is likely. For instance, the BRCA 1 and 2 genes associated with higher risk of breast cancer are also associated with higher rates or prostate cancer. This systematic review and meta-analysis sought evidence about any increased risk of prostate cancer in men with an affected relative.

Systematic review

Published studies were sought using MEDLINE up to November 2000. There were a large number of exclusion criteria, including those involving other primary cancer sites, or pathology studies, or molecular genetic studies.

Results

There were 23 studies, 14 case-control studies and nine cohort studies. Participants were usually white. Table 1 shows the results, with the risk of prostate cancer about doubled in a man with any affected relative. It may be increased by about three times in men with a brother with prostate cancer.

Table 1: Family history of prostate cancer and relative risk of prostate cancer

History of prostate cancer	Relative risk (95% CI)
Any relative with prostate cancer	2.0 (1.6 to 2.6)
First-degree relative with prostate cancer	2.2 (2.1 to 2.4)
Second-degree relative with prostate cancer	1.9 (1.5 to 2.3)
Father with prostate cancer	2.1 (1.8 to 2.5)
Brother with prostate cancer	2.9 (2.2 to 3.7)

Comment

This is a useful study which showed pretty consistent findings in all its analyses, except for one small study with few events.