Integration of full-dose adjuvant chemotherapy with definitive radiotherapy for primary breast cancer: four-year update.

Controversy exists over the effect of definitive radiotherapy on the ability to administer full doses of adjuvant chemotherapy in primary breast cancer. Ninety-six consecutive women with clinical stage I and II breast cancer were treated with radiotherapy plus chemotherapy. Three combinations of drugs were used: cyclophosphamide and 5-fluorouracil (CF); cyclophosphamide, methotrexate, and 5-fluorouracil (CMF); or cyclophosphamide, methotrexate, 5-fluorouracil, and prednisone (CMFP). Chemotherapy consisted of two cycles of CF (cyclophosphamide at a dosage of 100 mg/m2 orally on days 1-14+5-fluorouracil at 600 mg/m2 iv on days 1 and 8) during concurrent radiotherapy, followed by six cycles of CMFP (same CF dosages+methotrexate at 40 mg/m2 iv on days 1 and 8+prednisone at 40 mg/m2 orally on days 1-14). The study included 63 premenopausal and 33 postmenopausal patients; 72 had 1-3 positive nodes, had greater than or equal to 4 positive nodes, and 9 had negative nodes and negative estrogen receptors. The mean CF doses delivered during concurrent radiotherapy were 95% of the optimal doses, and the mean CMF doses administered during the six cycles after radiotherapy were 89%. The CMF was delivered at level I (greater than or equal to 85% of optimal doses) to 73% of the patients. With a median follow-up of 36 months, 16 relapses have been observed. Two of these patients had treatment failure only in the breast or axilla and are disease free after mastectomy. Of the 72 patients with 1-3 positive nodes, 10 relapsed in distant sites, while 4 of 15 patients with greater than or equal to 4 positive nodes have had distant failure.(ABSTRACT TRUNCATED AT 250 WORDS)