Preliminary result of accelerated partial breast irradiation after breast-conserving surgery

Purpose To investigate the feasibility of accelerated partial breast irradiation (APBI) for Japanese patients, we started high-dose-rate interstitial brachytherapy (HDR-ISBT) as monotherapy after breast-conserving surgery (BCS). Methods We implanted 45 Tis-2 breast cancer patients at National Hospital Organization Osaka National Hospital between June 2002 and June 2006. Our eligibility criteria were broader than the ones used previously in western countries. We included margin-positive cases and younger patients (median age: 44; range: 26-68) to adapt the criteria for Japanese women. Total prescribed doses were 36-42 Gy in six to seven fractions, and the volumes encompassed by 100% prescribed dose (V100) were 38.5-315.1 cc. Fifteen patients received chemotherapy. Results Treatment could be completed for all patients. Two local failures (4%) and two distant metastases were observed, while one patient died of liver metastasis. Seven wound complications, four with and three without infection, and two rib fractures occurred. The significant risk factors for wound complications were non-administration of prophylactic antibiotics during ISBT (P < 0.01), open cavity implant (P < 0.05), large V100 (P < 0.01), V150 (P < 0.05), and V200 (P < 0.05). Conclusion APBI after BCS for Japanese women with relatively small breasts was well tolerated, but special care should be taken with treatment technique.