Postmastectomy Radiotherapy Using 5040 cGy in 28 Fractions for Patients with Immediate Breast Reconstruction: Institutional Outcomes

Abstract

For patients planned to undergo adjuvant postmastectomy radiotherapy (PMRT) for breast cancer, immediate breast reconstruction (IBR) has been considered a relative contraindication. Delayed wound healing, increased risk of capsular contracture, fat necrosis, poor cosmesis, and rates of reoperation are of concern. Patients who have undergone IBR at our institution with an indication for PMRT are prescribed extended fractionation as per institutional policy. The aim of this quality assurance project is to review rates of reoperation for patients who received PMRT after IBR with autologous tissue (AT), tissue expanders (TE), or permanent implants (PI). Using a patient information system, patients were identified who underwent adjuvant PMRT to the chest wall and regional nodes to a total dose of 5040 cGy in 28 fractions between January 1, 2013 and January 31, 2019. Radiotherapy plans were reviewed. Medical records were reviewed for patient and treatment characteristics, and unexpected reoperation rate. Seventy-three patients underwent IBR and PMRT. Eleven (15.1%) patients had AT, 24 (32.9%) had TE, and 38 (52.1%) had PI. Twenty-four patients (32.9%) had documented cosmetic complications (including capsular contracture and asymmetry) after PMRT requiring reoperation. Cosmetic complications (CC) leading to reoperation were documented in 45.5% of patients with AT, 37.5% of patients with TE, and 26.3% of patients with PI. The mean elapsed time from PMRT completion to reoperation for cosmetic complications was 12.3 months (range = 2.3-33.1 months). Most patients received either adjuvant or neoadjuvant chemotherapy (97.3%). Of the patients having CC leading to reoperation compared to those without complication, a higher proportion received neoadjuvant chemotherapy, but this difference was not statistically significant (39.1% vs 19.4%, p = 0.135). For patients with CC leading to reoperation, there was a significantly higher volume of chest wall receiving ≥5040 cGy (851cc vs 680 cc, p = 0.023). Bolus was slightly more common in patients with CC but this difference was not statistically significant (91.7% vs 81.5, p = 0.461). For our cohort of patients receiving PMRT after IBR, the rate of CC is comparable to those quoted elsewhere. Interestingly, for our cohort, patients having PI had the lowest rate of CC leading to reoperation compared those with AT and TE. Patients with CC had a higher volume of chest wall receiving ≥ 5040 cGy. Further dosimetric analysis is needed to determine if there is a correlation with capsule dose and cosmetic outcomes.