OUTLINE: This is a multicenter study. Beginning within 5 weeks after surgery, patients undergo radiotherapy to the brain 5 days a week for 6 weeks. Patients receive high-dose oral tamoxifen every 6 hours beginning on day 1 of radiotherapy and continuing in the absence of disease progression. Patients are followed every 3 months through year 1, every 4 months for 1 year, every 6 months for 2 years, and then annually thereafter.