Purpose: To review the induction of pelvic fractures as a result of radiation therapy and to assess their management.
Materials and methods: The charts of patients with endometrial and vaginal cancers irradiated between 1991 and 1995 were reviewed. All patients were treated with megavoltage machines, energy ranging from cobalt to 25 MV photons.
Results: We treated 336 patients, with a median follow-up duration of 28.9 months (range 0-73.3). Sixteen patients had symptomatic pelvic fractures. The 5-year actuarial incidence of symptomatic pelvic fracture was 2.1%. All patients had pain as the first symptom. The median time of onset was 11 months (range 4-46). Imaging studies of 37.5% (6/16) were initially interpreted to be recurrent malignancy. All patients were managed conservatively and nine patients showed radiological evidence of healing over a median time of 13 months (range 2-34). Six patients had specific drug treatment including provera, premarin, calcium supplements, or pamidronate. Of these, five healed. For the ten patients who did not have any specific treatment, only four showed signs of healing at the time of last follow-up. There was a trend toward earlier healing with specific drug treatment (P=0.11).
Conclusions: Fractures can easily be mistaken for metastatic lesions (37.5% in this series) which might be treated with further irradiation. Although not statistically significant, there was a trend towards early healing with drug therapy. More studies are required to generate quantitative data for dose-response relationships and to evaluate the effect of drug therapy on the healing of such fractures.