# Comprehensive Evaluation of Hepatotoxicity Following Radiation Therapy in Breast Cancer Patients

## TL;DR

Modern breast cancer treatments with radiation and chemotherapy rarely cause serious liver damage, but some patients may need closer monitoring.

## Contribution

This study provides a comprehensive evaluation of hepatotoxicity in breast cancer patients undergoing radiation and systemic therapy.

## Key findings

- Only a small percentage of patients showed mild and temporary liver function changes.
- Three patients met criteria for radiation-induced liver disease.
- Neoadjuvant therapy was associated with liver enzyme elevation.

## Abstract

Breast cancer treatments often include radiation and chemotherapy that may affect the liver. Because the liver is close to the breast and processes many drugs, there has been concern about possible damage. In our study of over 500 patients, only a small number showed mild and temporary changes in liver function tests, and very few developed serious liver problems. These results suggest that modern breast cancer treatments are generally safe for the liver. Still, patients who receive chemotherapy before surgery may need closer monitoring to keep their liver healthy during treatment.

Purpose: The liver is susceptible to adverse effects from radiation therapy (RT) and systemic therapy (ST) for breast cancer, given its anatomical proximity. Thus, we evaluated hepatotoxicity after RT and ST for breast cancer. Methods: This multicenter retrospective study included breast cancer patients treated with RT in 2021 and underwent a liver function test (LFT) before and after RT. Patients with bilateral breast cancer or a history of thoracic or abdominal RT and liver disease were excluded. Changes in Common Terminology Criteria for Adverse Events (CTCAE) grading of liver enzyme elevation (LEE) of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) and its associations with Dose-volume histogram (DVH) parameters and other clinical factors were analyzed. Results: In total, 529 patients were included in the analysis. Median values of mean liver dose, V5Gy, V10Gy, and V20Gy dose to the liver were 1.37 Gy, 4.3%, 2.1%, and 0.9%, respectively. In the post-RT LFT, 6 (1.1%), 9 (1.7%), and 25 (4.7%) patients showed CTCAE grade elevation of AST, ALT and ALP, respectively, with most cases being grade 1. Three patients (0.6%) met the diagnostic criteria for radiation-induced liver disease (RILD). In multivariate logistic regressions including various DVH parameters, neoadjuvant therapy was associated with LEE. Conclusions: The incidences of LEE and RILD after multimodal therapy for breast cancer were limited, suggesting that RT and ST can be considered safe in terms of hepatotoxicity. Nevertheless, caution in treating patients who underwent neoadjuvant therapy, especially to those with underlying liver disease, might help minimize LEE.