Pelvic insufficiency fractures after radiation therapy for pelvic cancer in female patients: an updated meta-analysis of 11,272 patients

Pelvic insufficiency fractures (PIFs) are a debilitating complication of pelvic radiotherapy (RT) for pelvic cancer in female patients, which could lead to a sharp decline in patients’ quality of life. A 2019 meta-analysis by Lucas Gomes Sapienza reported a PIF rate of 14%, but advancements in RT techniques (IMRT, VMAT, C-ion RT) and new published studies necessitate an updated analysis. This study aimed to re-evaluate PIF incidence, fracture location, and associated factors using recent high-quality evidence. A systematic search of PubMed, Web of Science and Cochrane Library (1980–April 2025) with cohort studies for gynecologic/anal/rectal cancers, pelvic insufficiency fractures. Data on PIF incidence, location, and RT methods were extracted. Random-effects models were used to address expected high heterogeneity. Subgroup analyses were explored in detail. The pooled PIF incidence was 17% (95% CI: 15–20%), higher than the prior 14% estimate. Sacral bone/sacroiliac joint involvement dominated (71%), followed by pubic bone (11.6%). Subgroup analyses revealed higher PIF rates with definitive RT (25%) vs. adjuvant RT (6%). Modern RT techniques (IMRT: 8%, 3D-CRT: 11%) reduced PIF risk vs. historical methods (AP/PA: 22%, 4-field: 18%). However, VMAT and C-ion RT showed elevated rates (30%), likely due to higher doses (≥ 55 Gy). Regional difference indicates Europe (23%) > Asia (20%) > USA (9%). MRI detected more PIFs (19%) than other modalities (14%). Low BMI (16%) and menopause (18%) correlated with higher PIF risk. The incidence of PIF after pelvic RT has risen in recent years. Sacral regions are highly likely to develop PIF. Modern RT techniques like IMRT are required, along with routine MRI surveillance.