Randomized trial of adjuvant tamoxifen combined with postoperative radiation therapy or adjuvant chemotherapy in postmenopausal breast cancer

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Abstract
From 1976 to 1984, 427 postmenopausal women with high-risk breast cancer (pN+ or pT > 30 mm) were randomized between postoperative radiation therapy (RT), radiation therapy plus tamoxifen (RT-TAM), adjuvant chemotherapy (CT), or chemotherapy plus tamoxifen (CT-TAM). Surgery was a modified radical mastectomy in all cases. The radiation therapy was given with high-voltage techniques and included the chest wall and regional nodes. The dose was 4600 cGy/4 1/2 weeks. Tamoxifen was given at a dose of 40 mg daily for 2 years. The adjuvant chemotherapy consisted of 12 cycles of cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) (or chlorambucil, methotrexate, and 5-fluorouracil [LMF] for patients entered before 1978). At a median follow-up time of 6 1/2 years the recurrence-free survival was significantly better for patients allocated to radiation therapy compared to chemotherapy and for patients allocated to tamoxifen compared to no adjuvant endocrine treatment (P < 0.01). At 10 years the recurrence-free survival for patients in the RT-TAM, RT, CT-TAM, and CT groups was 63%, 57%, 47%, and 31%, respectively. A significant reduction of treatment failures with tamoxifen was only observed among patients with estrogen receptor-positive tumors. The overall survival difference in favor of patients allocated to radiation therapy or tamoxifen was not significant: the respective survival percentage at 10 years in the RT-TAM, RT, CT-TAM, and CT group was 65%, 62%, 52%, and 50%. The results indicate that postoperative radiation therapy continues to play an important role in the primary management of postmenopausal women with high-risk breast cancer and that the addition of tamoxifen may further improve the results among ER-positive patients.