Incidence of pelvic fractures after definitive radiotherapy for cervical cancer: A retrospective multi-center cohort study: IPFAR study

Background This multicenter study aimed to identify risk factors for pelvic insufficiency fractures (PIFs) in women who received definitive radiotherapy (RT) as initial treatment for cervical cancer and to were examine differences in the incidence of PIFs across institutions. Methods Medical records of 208 women who received definitive RT as the initial treatment for cervical cancer at four institutions between January 2016 and December 2018 reviewed. Results The median age was 61.5 years (range: 29–93 years). Overall, 59 patients (28.4%) developed PIF, 48 (81.4%) of them within two years from completion of RT. Multivariate analysis identified menopausal status, as well as the institution where RT was performed, as independent risk factors for PIF. The incidences of PIF were 19.8%, 33.9%, 18.9%, and 50% in Institution A, B, C, and D, respectively. The hazard ratio for Institution D (based on Institution A) was 1.214 (95% confident interval: 1.015–1.412). However, no statistically significant differences in patient backgrounds or RT details were observed among institutions. Conclusions Despite targeting the same population and implementing similar RT treatment protocols, significant differences in PIF rates were observed among institutions. Caution should be exercised when making direct comparisons between institutions.