Randomised Trial of Volume of Post-operative Radiotherapy Given to Adult Patients With eXtremity Soft Tissue Sarcoma

DISEASE CHARACTERISTICS: * Histologically confirmed soft tissue sarcoma meeting the following criteria: * Lesion originates in extremity * Upper extremity lesions may occur from the medial border of the scapula to tumors as far distal as the finger tips * No lesions of the chest wall arising adjacent to the scapula but not originating in the shoulder bone * Lower extremity regions include hip girdle tumors commencing at the iliac crest, excluding lesions arising from within the pelvis, and extends to include lesions as far distal as the toes * Imaging and pathology from first surgery are required * Has undergone surgical resection of the tumor within the past 12 weeks * No macroscopic tumor in situ after surgery * Microscopically irradical surgical margin allowed * Excisional biopsy with positive margins or other inadequate surgery (macroscopically involved margins) allowed only after further definitive re-excision * Positive margins and no further surgery possible except amputation or major functional loss allowed provided no macroscopic residual disease is present * Local recurrence within 3 months of prior surgery (or other treatment) allowed provided patient undergoes subsequent re-excision * No diagnosis of any of the following: * Rhabdomyosarcoma (alveolar or embryonal) * Primitive neuroectodermal tumor * Soft tissue Ewing's sarcoma * Extraskeletal osteosarcoma * Aggressive fibromatosis (desmoid tumors) * Dermatofibrosarcoma protuberans * Gorlin's syndrome * No regional nodal disease or unequivocal distant metastasis PATIENT CHARACTERISTICS: * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception during and for 3 months after completion of study treatment * No other major medical illness that would preclude study treatment * No other malignancy except adequately treated nonmelanomatous carcinoma of the skin or in situ carcinoma of the cervix PRIOR CONCURRENT THERAPY: * See Disease Characteristics * No prior radiotherapy to the local site * No prior neoadjuvant or adjuvant chemotherapy