Abstract 4864: Epidemiological characteristics and treatment strategies of gastric cancer with neuroendocrine differentiation (NED)

Abstract

Abstract Background: Gastric cancer with neuroendocrine differentiation (NED) occurs in 10% to 40% of cases, a significant proportion that is under-researched. The lack of clinical guidelines for this subgroup necessitates the development of effective treatment protocols. Methods: This study enrolled 149 gastric cancer patients, analyzing retained surgical wax blocks via immunohistochemistry for syn, CgA, and CD56 expressions. Patients were categorized into NED-positive and NED-negative groups for analysis, employing continuous variable analysis, categorical variable analysis, clustering, principal component analysis (PCA), feature importance analysis, heatmap analysis, and survival prognosis. Moreover, the clinical efficacy and safety of first-line (surufatinib + SOX + anti PD-1 antibody, n=3) and second-line (surufatinib + anti PD-1 antibody, n=3) treatments were observed in six advanced gastric cancer with NED patients, exploring the epidemiological characteristics, feasibility, and importance of clinical treatments for NED. Results: The study revealed a 10.1% incidence of NED positivity in gastric cancer patients. NED-positive patients exhibited a rapid decline in early survival probability, with a median relapse-free survival of 32.4 months compared to 41.5 months in NED-negative patients, indicating a poorer prognosis for NED-positive patients. In-depth analysis suggested significant correlations between NED status and factors such as gender, tumor location, pathological type, and AJCC staging, with the most significant associations observed in males, stage IIIA, and gastric angle location. In the six advanced gastric cancer with NED cases, effective tumor reduction was observed in both first-line (100% tumor shrinkage rate, ORR 66.7%, DCR 100%) and second-line treatments (66.7% tumor shrinkage rate, ORR 33.3%, DCR 100%), showing sustained partial responses (PR) exceeding 10 months in two patients and 7 months in one patient, respectively. The major grade 3 or higher TEAEs being neutropenia and thrombocytopenia in the first-line, and hypertension and proteinuria in the second-line therapy. Conclusion: This study provides pivotal epidemiological and clinical treatment evidence for gastric cancer with NED, underscoring the necessity of personalized treatment strategies for this subgroup. Future research should focus on refining treatment protocols to enhance the quality of life and overall prognosis for these patients. Citation Format: Zhen Huang, Jinlai Wei, Yifan Shen, Jun Zhang. Epidemiological characteristics and treatment strategies of gastric cancer with neuroendocrine differentiation (NED) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4864.