One hundred forty-seven patients with non-inflammatory, Stage III and IV cancer were treated with irradiation alone (54 patients) or with a combination of irradiation and mastectomy (93 patients). In the T3 category, the local failure rate was 45% (5/11) for the irradiation alone patients vs 12% (3/25 for the irradiation plus surgery patients; in the T4 category these figures were 65% (28/43) vs 13% (9/68), respectively. Corresponding local failure rates by size of primary tumor were 50% (2/4) vs 15% (5/29 for tumors 0-5 cm, 43% (9/21) vs 14% (6/45) for 5-8 cm tumors, and 75% (22/29) vs 5% (1/20 for tumors greater than or equal to 8 cm. The rates of regional failure for the two treatment methods were compared according to N stage; they were 9% (2/23) for irradiation alone vs 11% (8/76) for irradiation plus surgery in the N0-1 category, and 58% (18/31) vs 18% (3/17), respectively, for the N2-3 category. A dose response analysis for patients with tumors greater than 5 cm treated with irradiation alone did not show a decrease in local failure rate with increasing total tumor dose over a range of 4000 to 7000 rad, suggesting that doses in this range are too low for these large tumors. Since a significant late complication rate has been reported with doses higher than this, patients with non-inflammatory, but large (greater than 5 cm) tumors, should be treated with a combination of surgery and irradiation whenever possible to achieve maximum local-regional control with a minimum probability of complications. In 36 patients with inflammatory carcinoma, the rates of local and regional failure were 52% (15/29) and 38% (11/29), respectively, for patients treated with irradiation alone, and 14% (1/7) and 29% (2/7), respectively, for patients receiving irradiation plus surgery. Since none of these differences were statistically significant, one cannot conclude that surgery should necessarily play a role in the treatment of inflammatory carcinoma.