Radiotherapy in implant-based immediate breast reconstruction: risk factors, surgical outcomes, and patient-reported outcome measures in a large Swedish multicenter cohort.

The purpose of this large cohort study was to analyze the effects of prior and postoperative radiotherapy (RT) on surgical outcomes and patient-reported outcome measures (PROMs) in implant-based immediate breast reconstruction (IBR). All breast cancer patients (n = 725, of whom 29 had bilateral IBR) operated with implant-based IBR at four Stockholm hospitals from 2007 to 2011 were included. The median follow-up was 43 months. Three groups were compared: no RT (n = 386), prior RT (n = 64), and postoperative RT (n = 304). Outcomes were IBR failure (implant loss with or without secondary autologous reconstruction), unplanned reoperations, and PROMs, as measured by the BreastQ(®) questionnaire. IBR failure occurred in 22/386 (6 %) of non-irradiated cases, 16/64 (25 %) after prior and 45/304 (15 %) after postoperative RT (p < 0.001). Failure risk was higher after prior than postoperative RT (HR 9.28 vs. 3.08). Further risk factors were high BMI, less surgeon reconstructive experience, and postoperative infection, while the use of permanent implants lowered the risk of IBR failure. The estimated 5 years IBR failure rate was 10.4 % for non-irradiated, 28.2 % for previously and 25.2 % for postoperatively irradiated patients (p < 0.001). At least one unplanned reoperation occurred in 169/384 of non-irradiated (44 %), 42/64 (66 %) of previously, and 180/303 (59 %) of postoperatively irradiated breasts (p < 0.001). Further contributing factors were the use of one-stage expander and permanent implants, less surgeon reconstructive experience, and smoking. RT significantly impaired scores on all scales of the BreastQ(®). However, a clear majority of women in all groups would choose IBR again. Implant-based IBR remains a feasible option for women undergoing mastectomy as patient satisfaction levels are high. After prior RT, however, autologous alternatives should be considered.