Abstract
BACKGROUND: Implant-based breast reconstruction (IBBR) is a widely adopted technique following mastectomy in breast cancer patients. However, the impact of chemotherapy type and duration on the development of capsular contracture remains unclear. METHODS: This nationwide, retrospective, cohort study used Health Insurance Review and Assessment Service data to identify breast cancer patients who received chemotherapy and underwent immediate IBBR between January 2015 and December 2018. Follow-up continued until January 2024, with a median follow-up of 5.2 years. A total of 4303 patients (direct-to-implant [DTI], n = 2083; tissue expander insertion [TEI], n = 2220) were included. RESULTS: Chemotherapy type and duration were not significantly associated with capsular contracture risk in either the DTI or TEI groups. In the DTI cohort, no significant difference in contracture incidence was found between neoadjuvant and adjuvant chemotherapy before or after matching (p = 0.056 and p = 0.121, respectively). In the TEI cohort, an initially significant difference (p = 0.019) was no longer observed after matching (p = 0.213). Similarly, chemotherapy duration (≤12 weeks vs. >12 weeks) did not impact contracture risk in either cohort. Multivariate analysis identified age, radiotherapy, lymphedema, and axillary lymph node dissection (ALND) as independent risk factors for contracture (p < 0.005). Comorbidities, such as diabetes and autoimmune diseases, also showed no significant association with contracture risk. CONCLUSIONS: These findings suggest that chemotherapy decisions should not be guided by contracture concerns. Instead, optimizing reconstruction outcomes should focus on modifiable factors, such as radiotherapy, lymphedema, and ALND.