Complications of Implant-Based Reconstruction and Postmastectomy Radiation in the Era of Adjuvant CDK4/6 Inhibitors.

Objectives: Abemaciclib is approved for adjuvant use in hormone receptor-positive, human epidermal growth factor receptor 2-negative breast cancer. Its toxicity profile is derived from studies favoring patients undergoing breast conservation therapy. This study investigates the impact of abemaciclib on wound complications in the setting of postmastectomy radiation therapy (PMRT) and implant-based reconstruction.

Methods: A single-center, retrospective chart review was conducted. Patients who underwent mastectomy, implant-based reconstruction, and PMRT between January 2020 and December 2022 were included. Descriptive statistics characterized the study population and determined rates of any complication, major complications requiring reoperation, and complications by subtype (contracture, extrusion, tissue expander changes, infection, seroma, dermatitis, and pain). χ2 and the Fisher Exact tests assessed associations between abemaciclib use, complications, and potential risk factors.

Results: Seventy-five patients were included. Fifteen underwent adjuvant abemaciclib therapy. Thirty-four patients (45.3%) were obese (BMI ≥30), 24 (32.0%) had a smoking history, and 4 (5.3%) had diabetes. The incidences of any complication and major complications were 33.3% and 17.5%, respectively. There was no significant association between abemaciclib use and any complication (P=1.000), major complications (P=0.729), or any complication subtype (P=0.865). There was a significant association between BMI and any complication (P=0.014).

Conclusions: The study suggests that the use of adjuvant abemaciclib is not associated with an increased risk of postradiation reconstructive complications in patients undergoing implant-based reconstruction. Continued surveillance of complications associated with abemaciclib is warranted with a larger sample size.