Does Epigallocatechin Gallate as a Radiation Protective Agent Reduce the Anti-Tumor Effect of Radiotherapy in Postoperative Breast Cancer Radiotherapy?

Abstract

Based on the previous encouraging results, we further explored whether EGCG would have a protective effect on potential tumor lesions, that is, reduce the efficacy of radiotherapy. We selected patients with stage III breast cancer with or without EGCG. The local control rate, distant metastasis rate, DFS and OS were compared between the two groups. Patients with stage III breast cancer who were treated with EGCG and radiotherapy was selected from a phase II clinical study (ClinicalTrials.gov, No. NCT02580279). Each patient was matched with one control patient without EGCG From the medical database of our hospital matching for age and stage. The control group of stage-and age-matched patients was selected at random from the medical database of our hospital RESULTS: We identified 43 EGCG patients and 43 matched controls. The median age was 45 years (range: 26-67). Between the two groups, there were no obvious differences in the baseline demographic or clinical features. When compared to the placebo group, the mean radiation-induced dermatitis index (RIDI) in the EGCG group was substantially lower (2.56±1.14 vs 3.36±1.16 T = -3.232, P = 0.002). Repeated measures ANOVA indicated the significant differences in the RTOG score during the course of radiotherapy between the two groups (F = 9.611 P = 0.003). The patients mostly experienced RID two or three weeks after starting radiotherapy, although in the EGCG group, it appeared later (3.19±0.91 weeks) than it did in the placebo group (2.67±0.84 weeks), P = 0.008. The median follow-up for patients in the EGCG group at the time of data collection was 50.6 months with 95% confidence interval (CI) from 43.9 to 57.3. While it was 48.6 months (95% CI: 43.4-53.9) for patients in the control group. There was no significant difference in overall survival (OS), disease free-survival (DFS) and freedom from locoregional (LRF) and distant failure (DMF) (P > 0.05). At the data cut-off (December 2021), the 4-year DFS with EGCG was 71.4% compared to 65.4% with conventional therapy, and the 4-year OS was 77.0% compared to 80.3%. The prophylactic use of EGCG solution reduced the RID score of stage III breast cancer patients without negatively impacting the therapeutic effect of radiotherapy on the tumor. EGCG is safe and feasible choice for RID for breast cancer during radiotherapy.