Risk factors for complications among breast cancer patients treated with post-mastectomy radiotherapy and immediate tissue-expander/permanent implant reconstruction: a retrospective cohort study

The use of post-mastectomy radiotherapy (PMRT) following immediate breast reconstruction has increased recently, and its safety is becoming a major concern. We aimed to evaluate the complication rates of PMRT to immediate tissue-expander/permanent implant (TE/PI)-based reconstructions for breast cancer and its association with radiotherapy timing (irradiation to TE or PI). We retrospectively reviewed the cases of breast cancer patients who underwent mastectomy, immediate TE/PI reconstruction, and PMRT between January 2003 and December 2014. The rates of complications including reconstruction failure, re-operation, and infection were estimated by Kaplan-Meier analysis. The risk factors including radiotherapy timing were analyzed by log-rank test and multivariate Cox proportional hazard model. A total of 81 patients were included. Median follow-up was 32 months (range 2-120 months). Radiotherapy consisted of 50 Gy to the reconstructed breast and supraclavicular region in most cases. Total reconstruction failure, re-operation, and infection rates were 12.3, 13.6, and 11.1%, and 5-year cumulative reconstruction failure, re-operation, and infection rates were 16.7, 16.6, and 12.2%, respectively. No significant differences were observed in complication rates with respect to radiotherapy timing. In multivariate analysis, age 55 years and older was a significant risk factor for complications (P < 0.05). There were no significant differences in rates of reconstruction failure, re-operation, or infection with regard to radiotherapy timing. PMRT to reconstructed breasts of older patients aged 55 years or over can be expected to result in more complications than in younger patients.