Jansson F, et al. - Researchers determined the impact of genetic relation on the concordance of non–low-risk prostate cancer among brothers. A heritable pattern of non–low-risk prostate cancer was noted that was indicative of shared genetic factors. Monozygotic twins showed the highest concordance. As per findings, a clinically relevant increased risk of developing an aggressive prostate cancer exists in a man whose brother has been diagnosed with a non–low-risk prostate cancer.

Methods

• Using the Prostate Cancer Database Sweden, a total of 4,262 pairs of brothers with prostate cancer were identified.
• Categorization of their cancers as low risk (Gleason score ≤ 6; clinical stage T1-2, Nx/N0, Mx/M0; and prostate-specific antigen ≤ 10 ng/mL) or non–low risk was done.
• Researchers calculated the odds ratio (OR) for concordance of non–low-risk cancer using logistic regression for the different types of fraternity (monozygotic twins, dizygotic twins, full brothers, and half-brothers).

Results

• After adjusting for age and year of diagnosis, they found that among monozygotic twins who both were diagnosed with prostate cancer, the OR for both brothers being in the non–low-risk category was 3.82 (95% CI, 0.99 to 16.72).
• The corresponding adjusted OR was noted to be 1.21 (95% CI, 1.04 to 1.39) among full brothers.
• Similar results were obtained when the analysis was restricted to brothers who both were diagnosed within 4 years.