Complications from post-mastectomy radiotherapy in patients undergoing immediate breast reconstruction: a population-based study

Background — Previous studies have shown an increase in the number of women electing immediate breast reconstruction at the time of mastectomy. Although often not known at the time, some of these women will require postoperative radiotherapy. The purpose of this study is to investigate if exposure to radiotherapy after mastectomy with immediate breast reconstruction is associated with an increased risk of further surgery to manage complications arising from radiation.

Methods — This retrospective, population-based cohort study included all patients who underwent mastectomy with immediate reconstruction from 2007 to 2014 in the province of Ontario, Canada. Exposure to adjuvant radiotherapy was captured using data from Cancer Care Ontario. The study outcome was reoperation for breast reconstruction performed during the follow-up window. Cox proportional hazard models were used to assess the impact of radiotherapy exposure on risk of breast reconstruction reoperation.

Results — We identified 2,342 patients who underwent mastectomy with immediate reconstruction over an eight-year period in Ontario, of which 378 (16.1%) underwent adjuvant radiotherapy. Patients who received radiation were significantly more likely to undergo reoperation during follow-up (Hazard Ratio 1.76, 95% CI 1.49-2.08; p<0.0001). Patients with implant-based reconstructions (n= 1629, 69.6%) were not more likely to undergo reoperation than those with flap-based procedures (n=713, 30.4%) after (Hazard Ratio 1.01, 95% CI 0.85-1.21; p=0.885).

Conclusions — Adjuvant radiotherapy initiated after mastectomy with immediate breast reconstruction is associated with an increased risk of additional breast reconstruction surgery, regardless of the type of reconstruction used. Patients with breast cancer who choose to undergo immediate reconstruction after mastectomy should be advised that additional reconstruction procedures may be required.