[Safety and efficacy of whole breast irradiation with a concomitant boost: analysis of 121 cases treated at the Institute of Cancerology of Lorraine].

PURPOSE

To evaluate the safety and efficacy of whole breast irradiation with a concomitant boost.

PATIENTS AND MATERIALS

This is a retrospective study of 121 patients with node negative T1-T2 breast tumors inferior to 3 cm in diameter, previously treated by conservative surgery without chemotherapy. A dose of 50 Gy was delivered to the whole breast in 2 Gy daily fractions with 5 weekly treatments. A concomitant boost to the lumpectomy site delivered a total of 10 Gy in 1 Gy fractions twice a week. This would result in an equivalent tumour bed dose (assuming an α/β of 4) of approximately 65 Gy in 2 Gy fractions.

RESULTS

Over 7 years, 121 patients were treated. The median age was 67 years (range, 46-86 years). Stage distribution was: 115 T1, 6 T2; 116 tumors had positive hormonal receptors, 6 grade SBR3. With a median follow-up of 6 years (range, 1.4-11.4 years), 5-year overall survival was 98.2% (95% confidence interval [CI] 0.95-1), disease-free survival was 100% and local recurrence-free survival 100%. The maximum acute skin toxicity by the end of treatment was grade 2. Cosmetic outcomes were good on the long term. One spontaneous rib fracture was observed 1 year after radiotherapy among 76 patients.

CONCLUSIONS

The study shows that whole breast radiation therapy with a concomitant boost is safe and effective for selected patients with low risk of relapse, and gives excellent long term results. This protocol represents a good alternative to longer standard whole breast radiation therapy with sequential boost to the lumpectomy bed.