Comparison of Four Different Treatment Regimens in Treating Women With Stage I Breast Cancer

RATIONALE: Radiation therapy uses high-energy x-rays to damage tumor cells. Estrogen can stimulate the growth of breast cancer cells. Hormone therapy using tamoxifen may fight breast cancer by blocking the uptake of estrogen by the tumor cells. Combining radiation therapy and tamoxifen with surgery may kill more tumor cells. It is not yet known which treatment regimen is most effective for stage I breast cancer. PURPOSE: Randomized phase III trial to compare the effectiveness of four different treatment regimens in treating women who have stage I breast cancer.