Impact of radiation on immediate breast reconstruction: a retrospective single institution cohort study.

[BACKGROUND] While the trend towards immediate breast reconstruction is growing, data on the long-term outcomes of patients receiving irradiation afterwards are scarce. We retrospectively reviewed the long-term complication rates in patients who received adjuvant radiation therapy after immediate breast reconstruction in our institution.

[METHODS] We included 134 patients with breast cancer who underwent single-stage immediate breast reconstruction between January 2008 and December 2018. Sixty-eight patients received adjuvant irradiation and 66 patients did not. Autologous tissue, implant-based, and combined (implant and flap) reconstruction were performed in 40, 55, and 39 patients, respectively. Flap and implant complications data were collected. Baker's classification was used to assess capsular contracture.

[RESULTS] The average follow-up was 47 months. Both groups had similar baseline clinical characteristics and treatments received. The irradiated-group had a higher incidence of adjuvant chemotherapy (P<0.01) and a significantly higher rate of grade III/IV capsular contracture (42.1% 26.9%; P=0.004) than that of the non-irradiated group. The median time to the development of capsular contracture was 37 41 months in the irradiated the non-irradiated group, respectively. There were no differences in the incidence of flap complications between both groups. The only significant risk factor associated with grade III/IV capsular contracture was adjuvant post-mastectomy irradiation. The irradiated group had a higher risk of developing grade III/IV capsular contracture [odds ratio (OR), 4.35; 95% confidence interval (CI): 1.55-12.27].

[CONCLUSIONS] Postmastectomy radiotherapy adversely affects implant-based immediate one-stage reconstruction by increasing the rate of moderate to severe capsular contracture but is not associated with flap complications.