Tumors after radiotherapy for skin hemangioma in childhood. A case-control study

A case-control study was conducted to investigate the possible association between absorbed dose and cancer risk in a cohort of 14,647 individuals (33% males and 67% females) less than 18 months old and irradiated for skin hemangioma between 1920 and 1959. The cases consisted of 56 breast cancers (in 55 patients), 14 thyroid cancers, 16 brain tumors and 8 tumors of bone and soft tissues. Four controls were matched to each case. They were matched for sex, age at treatment, treatment modality and treatment year. Absorbed doses were categorized in three exposure groups, less than 0.1 Gy, 0.1-0.4 Gy, and greater than or equal to 0.5 Gy, and odds ratios (OR) were estimated with the lowest exposure group as reference. A statistically significant positive dose-response relationship was found for thyroid cancer (OR: 1.0; 4.8; 4.3) and for tumors of bone and soft tissues (OR: 1.0; 1.6; 19.5). For breast cancer and brain tumors no significant dose-response relationship could be found. The median absorbed dose in the tumor sites among the cases of thyroid cancer, tumors of bone and soft tissues, breast cancer and brain tumors was 0.2 Gy, 0.3 Gy, 0.03 Gy and 0.04 Gy respectively. The dose was probably too low to detect any dose-response relationship for breast cancer and brain tumors.