Neoadjuvant chemotherapy and radiotherapy for locally advanced breast cancer: Safety and efficacy of reverse sequence compared to standard technique?

Background: The reverse sequence of neoadjuvant chemotherapy, preoperative radiotherapy, mastectomy then immediate breast reconstruction is currently proposed for selected patients with locally advanced breast cancer. Few studies have compared it to the standard sequence of neoadjuvant chemotherapy, mastectomy and radiotherapy with or without differed reconstruction. Our study compares overall (OS) and recurrence-free (RFS) survivals of breast cancer patients treated with reverse sequence compared to the standard technique.

Methods: In this retrospective, single center study at a Comprehensive Cancer Center in France, patients were included if: female, age <65y, had received neoadjuvant chemotherapy, mastectomy and radiotherapy, and were M0. Outcomes for patients treated by reverse sequence (RS) are compared to those for patients treated by standard sequence (ST). Data was collected from medical records.

Results: From January 2009 to April 2018, 222 eligible patients were treated, 46 by RS and 176 by ST. Mean follow-up was 61.7 months. Five-year OS and RFS did not differ between groups. 5-yr OS: 88.4% 95%CI [74.1-95.0] for RS and 81.5% 95%CI [74.0-87.0] for ST (P = 0.4412); 5-yr RFS: 78.3% 95%CI [61.9-88.3] for RS and 70.1% 95%CI [62.2-76.7] for ST (P = 0.3003). Overall treatment time was significantly shorter in the RS group, and the rate of severe surgical complications did not differ between groups.

Conclusions: For locally advanced breast cancer patients with an indication for radiation therapy the reverse sequence offers similar safety and efficacy results as the standard treatment while allowing immediate breast reconstruction. However, careful patient selection is necessary, particularly with regard to preoperative lymph node invasion.