BACKGROUND While several modalities have been proposed for the treatment of desmoid tumour/aggressive fibromatosis, high local recurrence rates have been reported. We present a retrospective study of including patients treated with radiation therapy, some of them in combination with surgical resection. PATIENTS AND METHODS Thirty-four consecutive patients were included (mean age 40+/-16 years, 9 male). Complete follow-up was available in 31 patients (51+/-36 months). Seventeen patients (50%) were treated with radiation therapy alone, 17 patients with radiation therapy and surgery. Radiation therapy (external beam) was applied in most cases to a total dose of 50.4 Gy in 28 fractions. The lesion was located in the upper extremity in 11 patients, in the lower extremity in 14 cases and on the trunk in 9 cases. RESULTS Overall recurrence/progression free survival was 88.5% at 5 years and 77.5% at 10 years. Recurrence free survival of the subset of patients undergoing combined treatment with radiation therapy and surgical resection was 83.6% at 5 years and 10 years. In patients who did not receive surgery but only radiation therapy, MRI showed a complete response in 20%, a partial response in 20%, and stable disease in 53% of cases. In this subset, two-third of patient had a metabolic response to radiotherapy (i.e. decrease uptake on the thallium-210 scan after radiotherapy compared to pre-therapy levels). CONCLUSION Low recurrence rates can be achieved with the use of radiation therapy alone in selected cases. Patients with a metabolic response (decrease) to radiotherapy may be treated with a non-surgical approach. Surgery might be considered in patients with a poor metabolic response to radiotherapy.