Long-term results after 12-year follow-up of patients treated with whole-breast and boost irradiation after breast-conserving surgery

The long-term outcomes of whole-breast and boost irradiation after breast-conserving surgery (BCS) for patients with breast cancer were retrospectively analyzed. Patients who received whole-breast and boost irradiation after BCS from 1990 to 2002 were included. Boost irradiation was administered to each tumor bed, regardless of the surgical margin status. The median doses of whole-breast and boost irradiation were 45 Gy in 25 fractions (range 36-45 Gy), and 14 Gy in 7 fractions (range 0-14 Gy), respectively. Data for 306 patients were analyzed. With a median follow-up time of 144 months, the 10-year overall survival, disease-free survival, ipsilateral breast tumor recurrence (IBTR), and metachronous contralateral breast cancer (MCBC) occurrence rates were 93.0, 84.1, 2.1, and 4.1 %, respectively. In the multivariate analysis, pT2 was a significant risk factor for IBTR (p = 0.041), while age aecurrency sign 50 years and pT2 were significant risk factors for MCBC occurrence (p = 0.003 and 0.043, respectively). One patient (0.3 %) developed angiosarcoma in the irradiated region 120 months after the completion of radiation therapy. The 12-year outcome of breast-conserving therapy using whole-breast and boost irradiation with doses of 45 and 14 Gy, respectively, was favorable.