FRACTURES FOLLOWING RADIATION THERAPY AND LIMB SALVAGE SURGERY FOR LOWER EXTREMITY SOFT TISSUE SARCOMAS: HIGH DOSE VERSUS LOW DOSE RADIOTHERAPY

Abstract

As patients live longer following treatment for soft tissue sarcomas, complications from treatment will continue to emerge. Predicting which patients are at risk allows for improved preoperative planning, treatment, and surveillance. The data presented here suggests that females greater than fifty-five years of age treated with high dose, postoperative radiotherapy in combination with limb salvage surgery for soft tissue sarcomas are at an increased risk of post irradiation fractures. Unlike previous reports, a significantly higher rate of fracture occurred in patients who received higher doses (60 or 66Gy) of radiation versus lower doses (50 Gy).

This retrospective study was performed to determine if the timing and dosage of radiotherapy are related to the risk of post radiation pathologic fracture following combined therapy for lower extremity soft tissue sarcomas. Three hundred sixty-four patients with sarcomas treated with external beam radiation therapy and limb salvage surgery were evaluated. High dose radiation was defined as 60 Gy or 66 Gy; low dose as 50Gy. Radiation timing schedules were preoperative, postoperative, or preoperative with a postoperative boost. Univariate and multivariate analysis was used to determine which factors were associated with fracture risk. Twenty- seven pathologic fractures occurred in twenty-three patients. Twenty- four fractures occurred in twenty patients who were treated with high dose radiation. Sixteen of these patients had postoperative radiation (fourteen patients received 66Gy, two received 60Gy), and four had pre-operative radiation with a postoperative boost (total dose = 66Gy). Three fractures occurred in three patients who received low dose preoperative radiation (50Gy). Both high dose radiation (versus low dose) (p=.001) and preoperative radiation (versus postoperative) (p =0.002) were associated with a risk of fracture. Findings in this study were consistent with previous reports in that females over fifty-five years of age who undergo removal of a thigh sarcoma combined with radiation therapy are at a higher risk of a pathologic fracture, and differs in that there was a significantly higher rate of fracture in patients who received higher doses (60 or 66Gy) of radiation versus lower doses (50 Gy), and when radiation therapy was given postoperatively versus preoperatively.