Role of radiotherapy in the management of desmoid tumors

Purpose: To identify high-risk patients with desmoid tumors who could benefit from postoperative radiotherapy (RT) and to determine the efficacy of postoperative and definitive RT. Materials and Methods: Retrospective analysis of clinical data for all patients with desmoid tumors who underwent definitive local therapy at the University of Michigan from 1984 through 2008. Estimates for local control were calculated using the product-limit method of Kaplan and Meier, and associations with patient, tumor, and RT characteristics were explored using Cox proportional hazard regression. Results: Treatment for 95 patients who qualified for the study included surgery, RT, or both in 54, 13, and 28 cases, respectively. With a median follow-up of 38 months, the actuarial 3-year local control (95% confidence interval [CI]) was not significantly different (p = 0.3) among the three treatment groups: 84.6% (70.2-92.4), 92.3% (56.6-98.9), and 69.0% (43.1-84.9), respectively. Tumor site in the head/neck (p = 0.03) and history of previous surgical therapy (p = 0.01) were associated with increased recurrence risk (HR = 2.8, 95% CI 1.1-7.4, and HR = 3.2, 95% CI = 1.3-7.8), whereas gender, age, use of RT, and positive margins were not (p > 0.2). Conclusions: Our findings suggest equivalent local control rates after surgery, RT, or a combination of both. Although history of previous surgical therapy or site of origin in the head/neck region were found to be associated with increased risk of recurrence after local therapy, there was no clear association between surgical margin status and local control.