Late GI and bladder toxicities after radiation for uterine cancer

Objective: To determine the impact of radiation treatment for corpus uteri cancer on the development of late gastrointestinal (GI) and bladder toxicities in older women. Methods: We used a linked database of the Surveillance, Epidemiology and End Results (SEER) program tumor registry records and Medicare claims to estimate the risk of late radiation toxicities in a population based sample of 23,591 women diagnosed with corpus uteri cancer from 1992 to 2005. Gastrointestinal (GI) and bladder diagnoses were included up to 60 months after diagnosis. Cox proportional hazard models were used to estimate risk of any late GI or bladder diagnosis with or without hospitalization, due to radiation. Results: Women treated with radiation had an absolute increase in late GI toxicities of 7.7% and an absolute increase in late bladder toxicities of 3.9%. Most toxicities were not severe. Only 10% of irradiated women with a lower GI diagnosis and less than 1% of irradiated women with a bladder diagnosis, required hospitalization. In the multivariable analysis, advancing age, having chemotherapy, higher comorbidities and prior or early GI and bladder diagnoses were predictive of late toxicities among irradiated women. Conclusions: Late GI toxicities are more common than previously reported. It is important to analyze late toxicities in population based samples of women with uterine cancer. The results of this and future analyses can be used to identify areas where development of "survivorship plans" will remind and encourage women to report symptoms related to potential toxicities.