Familial renal cell carcinoma from the Swedish Family-Cancer Database

Reliable data on familial risks are important for clinical counselling and cancer genetics.

To evaluate familial risks for renal cell carcinomas (RCC) through parental and sibling probands in the largest available dataset.

This study examined the Swedish Family-Cancer Database on 12.2 million individuals, which contains families with parents and offspring. Cancer data were retrieved from the Swedish Cancer Registry for the years 1961-2008, including 8513 patients with RCC.

Familial risk for offspring was defined through standardised incidence ratios (SIRs) and adjusted for many variables, including a proxy for smoking and obesity.

The familial risk for RCCs was 1.75 when a parent and 2.61 when a sibling was diagnosed with any kidney cancer. Also, RCCs were shown to be associated with prostate cancer (PCa) when parents or parents and siblings were diagnosed with PCa. Among siblings, the associations of RCC with melanoma, non-Hodgkin's lymphoma, and urinary bladder and papillary thyroid tumours were found. None of the results differed significantly after excluding the families with cancer pathognomonic of a von Hippel-Lindau (VHL) disease. Limitations of this study include the small number of familial cases (229 familial cases).

The present analysis showed a high familiarity for RCC, and recessive effects may be important for familial aggregation of RCC. As a novel association, offspring RCC was in excess when parents or parents and siblings were diagnosed with PCa. There is familial clustering beyond VHL and the recent low-risk gene that probably explains a small proportion of the observed familial clustering.