Baxter NN et al. (2005) Risk of pelvic fractures in older women following pelvic irradiation. JAMA 294: 2587–2593

Pelvic fractures are a major cause of mortality and morbidity among the aging female population. Radiation therapy for pelvic cancers can cause bone damage, which might increase the risk of bone fracture in elderly patients.

In a retrospective study using SEER PROGRAM data from 1986–1999, Baxter and colleagues investigated whether women with pelvic malignancies had increased risk of pelvic fracture following radiation therapy (n = 2,855) compared with those who did not receive this treatment (n = 3,575). The cumulative 5-year fracture rate was higher in women receiving radiation therapy than in those who did not undergo treatment. Using a proportional hazards model, the authors adjusted for confounding factors and showed that the risk of fracture following radiotherapy was associated with the site of cancer. Anal cancer patients had a higher risk of fracture than rectal or cervical cancer patients probably because of the close proximity of the femoral heads to the target nodes for radiotherapy.

No data were available on the radiation dosage or fields used in these patients, but modern techniques might reduce the exposure of bones to radiation relative to these earlier cases. Nevertheless, the study shows that radiation therapy is a considerable risk factor for fractures in elderly women with pelvic malignancies, and methods to minimize irradiation dose to the bone should be investigated. Targeted prevention strategies for reducing the risk of bone fracture in these patients need to be assessed in trials.