Cancer Research, Statistics, and Treatment (Sep 2024)
Study of frequency and prognostic significance of HER2 overexpression by immunohistochemistry in high-risk endometrial cancer: A retrospective cohort study
Abstract
Background: The prognostic significance of human epidermal growth factor receptor 2 (HER2) as assessed by immunohistochemistry (IHC) in high-risk endometrial carcinoma (EC) is worth evaluating, owing to limited literature for the Asian population. Objectives: The primary objective of the study was to evaluate the role of HER2 expression as a prognostic indicator of recurrence-free survival in patients with high-risk endometrial cancer. The secondary objectives were to evaluate overall survival and the frequency of HER2 expression, along with other clinicopathological profiles. Materials and Methods: This retrospective cohort study was conducted in Gynecological oncology Department of Amrita Institute of Medical Sciences, Kochi, India, a tertiary care oncology center. The study included high-risk prognostic group of patients with EC from January 2014 to December 2020. HER2 immunohistochemistry was done using EP3 (HER2 neu antibody) clone, with complete basolateral membrane staining of >30% of tumor cells (3+) considered positive. Outcome data were analyzed for both HER2-positive and HER2-negative groups. Results: Thirty-one HER2-positive and 39 HER2-negative patients were eligible for survival analysis. HER2-positive status was significantly associated with non-endometrioid histotype (P, 0.044). HER2 positivity was observed in 42.9% (18/42) of serous carcinomas, and 40% (4/10) of carcinosarcomas. In the HER2-positive group, 22.5% (7/31) experienced recurrence, compared to 43.5% (17/39) in the HER2-negative group. Mortality rates were 38.4% (15/39) in the HER2-negative group and 41.9% (13/31) in the HER2-positive group. Mean recurrence-free survival (RFS) at 4 years and overall survival (OS) at 5 years were not statistically significant between the two groups (P, 0.097, and P, 0.813, respectively). The mean RFS at 4 years was 34.89 months (95% CI, 30.11- 39.66 months) in the HER-2 negative group and 38 months (95% CI, 31.36-44.64 months) in HER2-positive group. Mean OS at 5 years was 41.68 months (95% CI, 34.83-48.52 months) in HER2-negative and 39.58 months (95% CI, 31.08-48.09 months) in HER2-positive group. Conclusion: HER2 overexpression was not found to be an independent prognostic indicator of RFS or OS in high-risk EC in this study.
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