Institutional Outcomes for Patients Receiving Adjuvant Radiotherapy with a Remote History of Augmentation Mammoplasty with Implants

Abstract

<h3>Purpose/Objective(s)</h3> Postmastectomy radiotherapy (RT) in patients with immediate breast reconstruction has well known risks of late complications including delayed wound healing, capsular contracture and poor cosmesis. For patients with a remote history of augmentation mammoplasty with implants (AMI) receiving adjuvant RT for breast cancer, the risk of complications is not well documented. At our institution, due to concerns about cosmesis, patients receiving adjuvant RT with remote AMI receive standard fractionation rather than hypofractionation. The purpose of this quality assurance project is to review outcomes for patients who received RT with remote AMI. <h3>Materials/Methods</h3> Using our radiation treatment planning interface, patients were identified who underwent adjuvant RT to the breast and/or regional nodes in 25 to 28 fractions between January 1, 2013, and December 31, 2019. Chart review was performed to determine demographics, type of reconstruction, complications, subsequent unexpected re-operations due to cosmesis, and dosimetry. EQD2 calculations were generated assuming an α/β=3.4 for normal breast tissue. Patients with and without cosmetic complication were compared for significance using the Mann Whitney U-test (two tailed, p<0.05). <h3>Results</h3> Thirty-two patients underwent RT with remote AMI. Four patients (12.5%) had documented cosmetic complications after adjuvant RT requiring reoperation. Complications included rupture (n=1), contracture (n=2), asymmetry (n=1). The mean time from radiation to reoperation was 697 days (353-1045 days). For patients with cosmetic complications, 75% received chemotherapy prior to RT while 32.1% of patients without complications received chemotherapy prior to RT. Doses ranged from 45-50 Gy in 25 fractions vs 50.4 Gy in 28 fractions. Boost doses ranged 10-16 Gy in 5-8 fractions. In addition to whole breast irradiation (WBI), one patient (25%) with cosmetic complications also received regional nodal RT while 6 patients without complications (21.5%) received adjuvant nodal RT. Of the patients with cosmetic complications, all received boost with electrons and none of the patients had bolus. The total EQD2 for WBI and boost was statistically higher in the group of patients requiring reoperation for cosmesis (57.8 Gy vs 52.3 Gy, p=0.02). <h3>Conclusion</h3> For our cohort of patients receiving RT after remote AMI, the rate of cosmetic complications requiring reoperation was low (12.5%). This rate is significantly lower than institutional and documented rates of cosmetic complications for patients with immediate reconstruction followed by adjuvant RT. While the sample size was small, it is worthwhile to note that patients receiving chemotherapy, boost, and a higher EQD2 were more likely to experience cosmetic complications. Future investigation should include prospective review of a larger cohort of patients with remote AMI and the risk profile of boost.