Abstract PO3-23-05: Capsular contracture after post-mastectomy radiotherapy in the patients undergoing implant-based breast reconstruction: impact of implant positioning and two-stage surgery

Abstract Background Capsular contracture is a significant concern in patients undergoing post-mastectomy radiotherapy (PMRT) following implant-based breast reconstruction. It negatively impacts cosmetic outcomes and can have a profound effect on the individual's quality of life. Our study aimed to explore whether the degree of capsular contracture varies based on the placement of the inserted implant and the type of operation (one- or two-staged). Patients and Methods This retrospective study was conducted at a single center, Ganganm Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea. Our study included patients who underwent PMRT following total mastectomy and implant-based breast reconstruction surgery between January 2017 and September 2022. To assess the degree of capsular contracture, we evaluated the presence of capsular contracture, particularly severe capsular contracture classified as Baker grade 3 or higher, as well as implant migration. The implants were placed either in the pre-or sub-pectoral position, and the surgical approach employed was either direct-to-implant (DTI) or two-staged operation. Results A total of 195 patients were included in the study, with 83 (42.6%) patients in the pre-pectoral group and 112 (57.4%) patients in the sub-pectoral group. In addition, 116 underwent a two-stage operation, while 79 underwent DTI surgery. There was a significant difference in the occurrence of capsular contracture based on the implant placement, with 16 patients (19.3%) in the pre-pectoral group and 46 patients (41.1%) in the sub-pectoral group experiencing this complication (OR 4.142 [1.973-8.698]). Furthermore, the severity of capsular contracture differed significantly between the two groups, with 5 patients (6.0%) in the pre-pectoral group and 16 patients (14.3%) in the sub-pectoral group affected (OR 3.434 [1.153-10.227]). The incidence of capsular contracture was lower in the two-stage operation group compared to the DTI group (28 [23.9%] vs 34 [38.6%]; OR 3.064 [1.528-6.141]), and the severity of capsular contracture was also reduced (9 [7.7%] vs 12 [14.5%]; OR 2.854 [1.092-7.455]). There were no significant differences in other complications such as seroma and infection. In addition, sub-pectoral placement was identified as a significant risk factor for implant upward migration (OR 2.531 [95% CI, 1.263-5.071]). Conclusions Our findings suggest that pre-pectoral reconstruction and the two-stage operation are beneficial for patients who may undergo PMRT based on their initial nodal stage. These approaches can help reduce the incidence of capsular contracture and abnormal implant migration following radiation, leading to improved aesthetic outcomes and greater patient satisfaction. Citation Format: Sohyun Moon, Kyunghyun Min, Jung Hwan Eom, Yoonwon Kook, Seung Ho Baek, Junghyun Kim, Min Ji Kim, Seung Eun Lee, In Sik Yun, Tai Suk Roh, Soong June Bae, Joon Jeong, Young Seok Kim, Sung Gwe Ahn. Capsular contracture after post-mastectomy radiotherapy in the patients undergoing implant-based breast reconstruction: impact of implant positioning and two-stage surgery [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-23-05.