The results of a new study indicate that older women who undergo radiation to treat cervical, anal, or rectal cancer have an increased risk of pelvic fracture. Researchers suggest that "these women could be targeted for preventive strategies," such as bone mineral density screening, drug therapy to prevent osteoporosis, and fall prevention. The findings were published in the Journal of the American Medical Association (November 23/30, 2005).
Researchers at the University of Minnesota in Minneapolis linked data from the Surveillance, Epidemiology, and End Results cancer registry to Medicare claims data. The study included 6428 women aged 65 years and older who were treated for pelvic malignancies between 1986 and 1999. Of these women, 2855 underwent radiation therapy as part of their treatment. Within the first 5 years of the study, those who received radiation therapy for anal cancer had the highest rate of pelvic fractures14%compared with 7.5% who did not receive radiation. Similar patterns were observed in patients with cervical cancer (8.2% vs 5.9%) and rectal cancer (11.2% vs 8.7%).
The investigators attribute the higher risk in the anal cancer group to the need to treat cancerous lymph nodes in the groin area, which are hard to treat without also exposing the thighbone to radiation. They hope that better targeting of radiation therapy could someday reduce the volume of healthy tissue exposed to radiation, thus decreasing such adverse side effects.