Aim: Insufficiency fractures of the pelvis are a well known but rare and frequently misinterpreted radiation sequela. The clinical features and possible risk factors were investigated.
Patients and methods: 71 of living 82 patients, who were treated 1986-1994 for gynecologic tumors were clinically examined. 47 patients underwent also bone scan, CT of the pelvis and 13 patients had osteodensitometry. All patients had been treated with adjuvant (n = 29) or curative intent (n = 18) by d.v. fields with 18-MV photons, with 46 Gy in 23 fractions plus brachytherapy (15-39 Gy). Median follow-up was 36 months.
Results: Seven patients developed pelvic insufficiency fractures 11 months (median, minimum 2 months) after treatment. All patients complained of moderate to severe pelvic pain, which resolved after 5-28 months without specific therapy in five of seven patients. At first examination all but one bone scan showed extremely increased uptake in the os sacrum and/or iliosacral joints, correlating CT scans demonstrated small fractures and bony destruction. Four of the asymptomatic 40 patients with complete radiologic examinations had medium uptake in bone scan (CT normal). Three of four examined patients with insufficiency fractures and seven of nine patients without insufficiency fractures had osteoporosis.
Conclusion: In women who present with pelvic pain after radiotherapy for gynecologic tumors bony destruction and fractures may be indicative of a late radiation effect rather than osseous metastasis, even after early onset of symptoms.