Menstrual and reproductive factors and risk of soft tissue sarcomas

BACKGROUND. Soft tissue sarcomas (STS) are a heterogeneous group of neoplasms whose etiology remains largely undefined. A role for female hormones in the development of STS has been suggested. To investigate this possibility, the authors analyzed data from a hospital-based case-control study conducted in Northern Italy between 1983 and 1998. METHODS. Cases were 104 women aged < 79 years with incident STS who were admitted to the cancer institutes and major teaching and general hospitals. Controls were 505 women admitted to the same network of hospitals for acute, nonneoplastic, nongynecologic, and nonimmune-related conditions. RESULTS. The multivariate odds ratio (OR) for women aged greater than or equal to 15 years compared with those aged < 12 years at menarche was 1.94 (95% confidence intervals [95% CI], 0.80-4.74). No association with STS risk was observed for menstrual cycle pattern, age at menopause, parity, and abortions. Late age at first pregnancy and birth were found to be related to an increased risk of STS, with an OR of 3.16 (95% CI, 0.96-10.44) and 2.79 (95%% CI, 0.79-9.90) for women aged greater than or equal to 30 years at first pregnancy and birth compared with those aged < 20 years. The trend in risk was significant for age at first pregnancy. No relation with the risk of STS emerged for age at last birth and time since first or last birth. CONCLUSIONS. The risk of STS was found to be weakly related to late age at first pregnancy or birth, but not to other menstrual and reproductive factors. (C) 2000 American Cancer Society.