Parental cancer as a risk factor for brain tumors (Sweden)

Objective: We used the nationwide Swedish Family-Cancer Database to analyze the risk for adult (15-61 years) brain tumors in offspring through parenta l cancer probands. Additionally, cancer risks were assessed among siblings of brain tumor probands. Methods: In offspring and parents, respectively, 5425 and 20,938 cases of b rain tumors were diagnosed between the years 1958 and 1996. Groups of offsp ring were compared by calculating standardized incidence ratios (SIRs) for brain tumors. Results: Of brain tumor patients, 2.1% had a parent with nervous system can cer; SIRs were 1.7, 2.4, and 2.5 for all brain tumors, astrocytomas, and me ningiomas, respectively. Parental endometrial cancer and melanoma were asso ciated with offspring astrocytoma, and parental breast and thyroid cancers with offspring ependymoma and neurinoma, respectively. SIR for sibling nerv ous system tumors from brain tumor probands was not increased overall but w as 2.5 in those diagnosed at ages 15-34 years. Conclusion: These data show a familial risk for brain tumors among adults.