What is the Optimum Timing of Post-mastectomy Radiotherapy in Two-stage Prosthetic Reconstruction: Radiation to the Tissue Expander or Permanent Implant?

Background: Postmastectomy radiotherapy is increasingly common for patients with advanced breast cancer. The optimal timing and sequence of mastectomy, reconstruction, and radiotherapy remains unresolved for patients choosing immediate two-stage prosthetic reconstruction. Methods: Long-term outcomes were compared for all patients with prosthetic-based reconstruction without radiation, radiation to the tissue expander, or to the permanent implant from 2003 to 2012 performed by the senior author (P.G.C.). Surgeon-evaluated outcomes included reconstructive failure, aesthetic results, and capsular contracture. Odds of failure with radiotherapy at different times were evaluated with logistic regression and Kaplan-Meier analysis. Patient-reported outcomes were assessed using the BREAST-Q. Results: A total of 1486 reconstructions without radiation, 94 reconstructions with tissue expander radiation, and 210 reconstructions with permanent implant radiation were included. Six-year predicted failure rates were greater for patients with tissue expander radiation than for patients with permanent implant radiation (32 percent versus 16.4 percent; p < 0.01). Patients undergoing radiation to the tissue expander had a greater proportion of very good to excellent aesthetic results compared to patients with permanent implant radiation (75.0 percent versus 67.6 percent; p < 0.01) and lower rates of grade IV capsular contracture (p < 0.01). BREAST-Q scores were similar for patients with the different radiation timings. Conclusions: Although the risk of reconstructive failure is significantly higher for patients with tissue expander radiation compared to patients with permanent implant radiation, the aesthetic results and capsular contracture rates are slightly better. Patient reported outcomes do not differ between patients with tissue expander or permanent implant radiation.