The relationship of HER2 on survival in postoperative gastric cancer patients treated with adjuvant chemoradiotherapy: A single-center experience, retrospective study

Objective: We performed a retrospective study to evaluate whether it has prognostic or predictive significance in terms of both local control and survival in gastric cancer treated with adjuvant chemoradiotherapy after surgery, according to human epidermal growth factor receptor 2 (HER2) status, and to compare it with literature data. Materials and Methods: From 2012 to 2022, we retrospectively analyzed 128 gastric cancer patients who underwent surgery with curative intent and then received adjuvant chemoradiotherapy and grouped them based on their HER2 status. Results: The mean age of all patients was 60.31 ± 11.43 (range: 29–94 years). According to gender distribution, 89 (70%) were male and 39 (30%) were female. In general, 34 (27%) of patients were HER2 positive, while 94 (73%) was negative. Mean survival times were 44.95 ± 4.15 (95% CI: 36.8–53.1) months and 41.19 ± 7.07 (95% CI: 27.32–55.06) months for HER2-negative and positive patients, respectively. Median survival time was 28 ± 5.96 (95% CI: 16.31–39.68) months for HER2-negative patients, whereas it was 22 ± 5.9 (95% CI: 10.43–33.56) months for positive patients. One-, 2-, and 3-year survival rates were 72.9%, 48.6%, and 38.2% for HER2 positive and 74.6%, 53.2%, and 43.4% for HER2-negative patients, respectively. There was no significant difference between the two groups (P = 0.819). The mean DFS were 16.71 ± 2.48 (95% CI: 11.85–21.57) months and 17.1 ± 3.47 (95% CI: 10.29–21.91) months for HER2-negative and positive patients, respectively. Median survival time was 11 ± 2.24 (95% CI: 6.6–15.39) months for HER2-negative patients, whereas it was 16 ± 5.85 (95% CI: 4.51–27.47) months for positive patients. One-, 2-, and 3-year survival rates were 47.1%, 22.3%, and 8.9% for HER2 positive and 59.8%, 34.2%, and 17.1% for HER2-negative patients, respectively. There was no significant difference between the two groups (P = 0.492). Considering the logistic regression analysis of the factors affecting survival in patients with GC, there was a statistical difference in survival in N2 (P < 0.042) and N3 (P < 0.005) disease and in HER2 positive (P < 0.041) patients. Conclusion: Although our study did not demonstrate any statistically significance of HER2 status in gastric cancer patients treated with chemoradiotherapy after surgery, the median OS of 22 months in HER2-positive patients and 28 months in negative patients, have shown us that larger randomized trials are in need.