Radiation alone can be used to treat mast cell tumors that are not likely to metastasize (that is, differentiated or localized lymphorecticular tumors). In patients with mast cell tumors that are likely to metastasize (that is, undifferentiated, metastatic mast cell disease or generalized lymphoreticular neoplasms), radiation should not be used as the only treatment agent. In these patients, treatment combinations of hyperthermia/chemotherapy and radiation/hyperthermia/chemotherapy have been shown to have promise, but these treatment combinations need to be evaluated in prospective trials.