Partial breast re-irradiation for local recurrence of breast carcinoma: Benefit and long term side effects.

INTRODUCTION AND AIMS: To evaluate the outcome after partial breast re-irradiation for in-breast tumor recurrence (IBTR) following second breast conserving surgery (BCS) as alternative to salvage mastectomy.

METHODS AND RESULTS: A survey of the literature was performed including publications between 2002 and 2012 (PubMed). Strategies comprised partial breast radiotherapy by external beam radiotherapy (EBRT), interstitial brachytherapy (BT) in low-, high- and pulse-dose rate technique, combined EBRT/BT, and intraoperative radiotherapy (IORT). Published evidence is scarce, with altogether ten articles identified, in sum reporting about 310 patients. The vast majority (82%) was treated by brachytherapy. Selection criteria for a second breast conservation attempt were comparable within all reports: all women presented with T0-2 recurrent lesions, late onset after primary treatment (70 months, mean of means) and no evidence of metastatic disease before undergoing gross tumor resection with free surgical margins. Treatment doses were in a similar range for brachytherapy (LDR 30-55 Gy, HDR 30-34 Gy; PDR 40-50 Gy), biologically comparable to the only series exclusively using EBRT (50 Gy). Follow-up times amounted 49 months (mean of the means, range 21-89). Oncologic results were similar among the different methods with local control rates ranging between 76% and 100%, and disease free and overall survival rates comparable to mastectomy series. Acute toxicity was low in all cohorts. All authors reported cosmetic outcome, scoring results from excellent to good in 60-80% of patients, mostly without using standardized evaluation schemes. Major late effects were fibrosis in re-irradiated parenchyma as a function of dose and volume, asymmetry (primarily due to double surgery), and breast pain. There were hardly any G3 and no G4 late reactions noted.

DISCUSSION AND CONCLUSION: In a highly selected group of patients with IBTR, partial breast irradiation after second BCS is a viable alternative to mastectomy, yielding high breast preservation rates without compromising oncologic safety. Whereas the evidence for brachytherapy is more solid, there is still little information about the effectiveness of PBI via EBRT or novel strategies like IORT, which therefore should preferably be investigated within trials.