Pelvic fractures after definitive and postoperative radiotherapy for cervical cancer: A retrospective analysis of risk factors

Objectives This study clarified the incidence of and identified the risk factors for post-radiation pelvic insufficiency fractures (PIFs) in women who received postoperative definitive or adjuvant radiotherapy (RT) for cervical cancer. Patients and methods The medical records and data of imaging studies, including computed tomography scan and magnetic resonance imaging, of women with cervical cancer who received external-beam RT for the entire pelvic area between January 2003 and December 2012 at our institution were reviewed. Results A total of 533 patients with histologically diagnosed cervical cancer who received RT (298: definitive RT, 235: adjuvant RT) were included in this study. Eighty-four patients (15.8%) developed PIF in the irradiated field. Median age at onset of PIF was 72.5 years (range: 54–95 years), and 82 of them (98%) were postmenopausal women. Sixty-nine patients (80%) developed PIF within 3 years from the completion of RT. The median time for the development of PIF was 14 months (range: 1–81 months). The most commonly involved fracture site was the sacral bone. Postmenopausal state, coexistence of rheumatoid arthritis, and high-dose-rate intracavitary brachytherapy (HDR-ICBT) use were significant predisposing factors for the development of PIF, according to multivariate analysis. Conclusions The incidence rate of PIF among patients who received RT for locally advanced cervical cancer was 15.8%. The principal predisposing factors for post-radiation PIF were postmenopausal state, rheumatoid arthritis, and HDR-ICBT use. Active interventions, including bone density screening followed by medication, should be considered during the early stage of RT for women with high-risk factors of PIF.