Early-stage Breast Cancer Treated with 3-week Accelerated Whole-breast Radiation Therapy and Concomitant Boost

Purpose: To report early outcomes of accelerated whole-breast radiation therapy with concomitant boost.

Methods And Materials: This is a prospective, institutional review board-approved study. Eligibility included stage TisN0, T1N0, and T2N0 breast cancer. Patients receiving adjuvant chemotherapy were ineligible. The whole breast received 40.5 Gy in 2.7-Gy fractions with a concomitant lumpectomy boost of 4.5 Gy in 0.3-Gy fractions. Total dose to the lumpectomy site was 45 Gy in 15 fractions over 19 days.

Results: Between October 2004 and December 2010, 160 patients were treated; stage distribution was as follows: TisN0, n = 63; T1N0, n = 88; and T2N0, n = 9. With a median follow-up of 3.5 years (range, 1.5-7.8 years) the 5-year overall survival and disease-free survival rates were 90% (95% confidence interval [CI] 0.84-0.94) and 97% (95% CI 0.93-0.99), respectively. Five-year local relapse-free survival was 99% (95% CI 0.96-0.99). Acute National Cancer Institute/Common Toxicity Criteria grade 1 and 2 skin toxicity was observed in 70% and 5%, respectively. Among the patients with ≥ 2-year follow-up no toxicity higher than grade 2 on the Late Effects in Normal Tissues-Subjective, Objective, Management, and Analytic scale was observed. Review of the radiation therapy dose-volume histogram noted that ≥ 95% of the prescribed dose encompassed the lumpectomy target volume in >95% of plans. The median dose received by the heart D05 was 215 cGy, and median lung V20 was 7.6%.

Conclusions: The prescribed accelerated schedule of whole-breast radiation therapy with concomitant boost can be administered, achieving acceptable dose distribution. With follow-up to date, the results are encouraging and suggest minimal side effects and excellent local control.