Radiotherapy in the management of desmoid tumors in children and adolescents

Background: In about one third of patients suffering from a desmoid tumor p rimary complete resection is not feasible. Furthermore in locally relapsing tumors reoperation alone does not result in cure in many cases. Radiothera py can be applied in both groups of patients with curative intention. But t he indication of radiotherapy is challenging particularly in children and a dolescents due to the impending late radiation sequelae such as growth dela y, fibrosis and radiation induced secondary malignancy. Patients and method: The follow up and outcome of five irradiated children/ adolescents with desmoid tumors, registered in the German-Cooperative-Soft- Tissue-Sarcoma Study (CWS) was looked at, and the corresponding literature was reviewed. Results: Radiotherapy of gross residual or relapsing tumors resulted in lon g lasting event free survival in two cases (3/ 8 years), but in one patient local progression occurred despite irradiation. Postoperative radiotherapy in patients with microscopic residual disease resulted in both, long lasti ng event free survival (14 years, 1 patient) and in early local relapse (1. 5 years, 1 patient). The role of radiotherapy could not be evaluated clearl y by the CWS-experience due to the fact that the irradiated patients were t reated individually also by chemotherapy and/ or tamoxifen. But despite spa rse and retrospective data there is evidence in the literature, that radiot herapy is able to control 65-90% of the unresectable desmoid tumors and tha t the local relapse rate can be reduced by radiotherapy by 10-20% in patien ts with microscopic residual disease following resection. Conclusions: Radiotherapy as primary treatment should be given if complete tumor resection is not feasible without mutilation. Radiotherapy can be app lied postoperatively if the risk of local relapse seems to be highly life- or function threatening.