# Impact of Chemotherapy on Implant-Based Breast Reconstruction in Breast Cancer Patients: A Nationwide, Retrospective, Cohort Study

## TL;DR

A study of over 4000 breast cancer patients found that chemotherapy does not increase the risk of capsular contracture after implant-based breast reconstruction.

## Contribution

This nationwide study is the first to show that chemotherapy type and duration do not affect capsular contracture risk in implant-based breast reconstruction.

## Key findings

- Chemotherapy type and duration were not associated with increased capsular contracture risk in either direct-to-implant or tissue expander insertion groups.
- Radiotherapy, lymphedema, and axillary lymph node dissection were identified as significant risk factors for capsular contracture.
- Comorbidities like diabetes and autoimmune diseases did not significantly affect contracture risk.

## Abstract

Breast reconstruction using implants is commonly performed after mastectomy in breast cancer patients. Some patients worry that chemotherapy might increase the risk of complications, such as capsular contracture, a condition where scar tissue tightens around the implant. To address this concern, we studied over 4000 Korean breast cancer patients who had implant-based reconstruction and received chemotherapy. We found that neither the type nor duration of chemotherapy increased the risk of capsular contracture. However, other factors, like radiation therapy, lymphedema, and extensive lymph node surgery, were linked to a higher risk. These results suggest that chemotherapy should not be avoided due to fears about contracture. Instead, reconstruction should focus on improving outcomes and reducing other risks, such as managing lymphedema and carefully planning radiation and lymph node surgery.

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.