Whole breast irradiation (WBI) after breast conserving surgery (BCS) is the standard treatment modality for controlling ipsilateral local recurrence of breast cancer. However, the WBI needs 5 to 6 weeks of the treatment period. Partial breast irradiation (PBI) has recently appeared as an alternative treatment to WBI in selected early breast cancer patients. This study was performed to evaluate the feasibility of PBI alone after BCS.

The brachy-catheters were inserted at the lumpectomy site after BCS. Six to nine days after the operation, the patients underwent fractionated PBI twice in a day with median dose of 3 Gy. The median value of the total dose was 3,120 cGy (28 to 34 Gy) given over 5 days. Forty-one patients who were proven as having a tumor-free margin by pathologic report were included in this study. Thirty-five patients had axillary lymph node-negative disease and thirty-six patients underwent concurrent adjuvant CMF chemotherapy. Follow-up ultrasono graphy was performed one month after the completion of PBI.

The median post-operative hospital stay was 15 days (range: 12-17 days). Twenty-eight patients had seromas smaller than 1 cm in size and the 13 patients appeared to have 1~3 cm sized seromas on the follow-up ultrasonography. Long lasting (> 3 months) seromas were ob-served in 7 patients. None of the patients complained of tenderness or discomfort of the operation site and complications such as skin desquamation, pigmentation and wound contracture were not observed. Fat necrosis was observed in 1 patient. There was no case of local recurrence at the median follow-up period of 19 months (range: 15-41 months).

PBI for early breast cancer using interstitial brachytherapy was a safe and effective alternative to WBI with excellent cosmetic results after BCS. The results of the current study prompts a multi-center clinical trial of PBI as an alternative to the WBI in early breast cancer to validate its feasibility in a selected patient population.