Familial bladder cancer in an oncology clinic.

We have evaluated family history and cigarette smoking history on 49 consecutively ascertained patients with urinary bladder carcinoma and compared them with 956 consecutively ascertained patients with histologically verified cancer (all sites), all of whom were being treated in the same oncology clinics. Data was collected through interviews, questionnaires, and primary medical and pathology documents. Cancer risks were compared on the basis of anatomic sites involved and with cumulative risk estimated from data in the Third National Cancer Survey. A permutation test was also employed. Significant heterogeneity of risk (z = 4.85, p less than or equal to 0.02) for bladder cancer was found in relatives of probands with bladder cancer. Significant heterogeneity or increase in risk of bladder cancer was not observed when families with lung, other smoking related cancer, and nonsmoking related cancer were analyzed. Though based on a limited number of verified bladder cancer patients, we have provided statistical evidence in support of our hypothesis that bladder cancer may have a stronger familial etiologic component than heretofore recognized.