Familial renal cell carcinoma: hereditary or coincidental?

The familial clustering of some cancers may be related to genetic factors, shared carcinogenic exposure among relatives or chance association. In cases of familial renal cell carcinoma identifying those persons at risk for renal tumors is difficult. There have been 28 family aggregates of renal carcinoma reported since 1961 but an abnormality in the constitutional karyotype has been demonstrated in the members of only 1 of these families. Since 1980 we have identified 5 more families in which a total of 12 relatives had renal cell carcinoma. However, peripheral blood karyotypes obtained from the 7 patients and 5 unaffected relatives whom we studied showed no significant abnormalities. With current laboratory techniques it is not possible to differentiate reliably familial renal tumors occurring by chance from those hereditary tumors posing a threat to remaining relatives. Therefore, in families with multiple cases of renal cell carcinoma we recommend that screening be conducted as has been suggested for families with von Hippel-Lindau's disease, with an initial renal ultrasound for family members at age 30 years and repeat examinations every 2 to 3 years.