Comparison of outcomes following postmastectomy radiation therapy in patients with autologous free flap reconstruction depending on the radiation therapy protocol: Systematic review and meta-analysis.

[BACKGROUND] Changes in the standard postmastectomy radiation therapy (PMRT) dosage schedule have led to the development of the hypofractionated radian therapy technique (HRT) that allows patients to receive fewer radian therapy sessions with higher doses in each session. Additionally, advancements in technology introduced the intensity-modulated radiation therapy (IMRT) technique to the widely used three-dimensional conformal radiation therapy. This review aimed to investigate the influence of radiation therapy protocols that may alter the postoperative outcomes of autologous free flap reconstruction.

[METHODS] We reviewed the literature using MEDLINE and Embase databases for articles investigating outcomes of free flap autologous breast reconstruction in patients who underwent PMRT. The main search terms were synonyms of "radiation," "autologous," and either "immediate" and/or "delayed." Exclusion criteria included articles without a radiation protocol and dose. Cochrane risk of bias tool was used for bias assessment.

[RESULTS] Studies were identified and analyzed using the preferred reporting items for systematic reviews and meta-analyses guidelines. Overall, 238 papers underwent abstract screening and 112 underwent full-text screening, and 19 studies were extracted. The HRT group had significantly fewer postoperative complications than the conventional radian therapy (CRT) group (12.6% and 36.6%, respectively, P < 0.001). Further subgroup analyses were performed by including immediate and delayed breast reconstruction and radiation techniques including IMRT.

[DISCUSSION] A remarkable decrease in postoperative complication rate in HRT was noted. HRT is considered a superior option for free flap reconstructive outcomes over CRT in patients with breast cancer after immediate and delayed breast reconstructions. Flap fibrosis was more prevalent in immediate breast reconstructions. However, aesthetic revision rates were comparable.