PATIENT CHARACTERISTICS: Age: 18 to 65 Performance status: WHO 0 or 1 Life expectancy: Not specified Hematopoietic: Not specified Hepatic: Not specified Renal: Not specified Other: Able to tolerate full course of conventional radiotherapy No prior or concurrent medical condition that would preclude study therapy No prior malignancies within 5 years except nonmelanomatous skin cancer or carcinoma in situ of the cervix