Radiation therapy in the management of desmoid tumors

Purpose: To evaluate the outcome of patients with extra-mesenteric desmoid tumors treated with radiation therapy, with or without surgery. Methods and Materials: The outcome for 75 patients receiving radiation for desmoid tumor with or without complete gross resection between 1965 and 199 4 was retrospectively reviewed utilizing univariate and multivariate statis tical methods. Results: With a median follow-up of 7.5 years, the overall freedom from rel apse was 78% and 75% at 5 and 10 years, respectively. Of the total, 23 pati ents received radiation for gross disease because it was not resectable. Of these 23 patients, 7 sustained local recurrence, yielding a 31% actuarial relapse rate at 5 years, Radiation dose was the only significant determinan t of disease control in this group. A dose of 50 Gy was associated with a 6 0% relapse rate, whereas higher doses yielded a 23% relapse rate (p < 0.05) , The other 52 patients received radiation in conjunction with gross total resection of tumor. The 5- and 10-year relapse rates were 18% and 23%, resp ectively. No factor correlated significantly with disease outcome. There wa s no evidence that radiation doses exceeding 50 Gy improved outcome. Positi ve resection margins were not significantly deleterious in this group of ir radiated patients. For all 75 patients, there was no evidence that radiatio n margins exceeding 5 cm beyond the tumor or surgical field improved local- regional control. Ultimately, 72 of the 75 patients were rendered disease-f ree, but 3 required extensive surgery (amputation, hemipelvectomy) to achie ve this status. Significant radiation complications were seen in 13 patient s. Radiation dose correlated with the incidence of complications. Doses of 56 Gy or less produced a 5% 15-year complication rate, compared to a 30% in cidence with higher doses (p < 0.05), Conclusions: Radiation is an effective modality for desmoid tumors,either a lone or as an adjuvant to resection, For patients with negative resection m argins, postoperative radiation is not recommended. Patients with positive margins should almost always receive 50 Gy of postoperative radiation. Unre sectable tumors should be irradiated to a dose of approximately 56 Gy, with a 75% expectation of local control. (C) 1998 Elsevier Science Inc.