Prognostic factors and the role of chemotherapy in patients with pT3N0M0 gastric cancer: a propensity score matching analysis based on the SEER database

The benefit of chemotherapy for pT3N0M0 gastric cancer after curative gastrectomy remains controversial. This study aimed to identify prognostic factors and evaluate the influence of chemotherapy on pT3N0M0 GC. The pT3N0M0 GC patients diagnosed between 2004 and 2021 were identified in the Surveillance, Epidemiology, and End Results database. They were divided into the chemotherapy group and the non-chemotherapy group. Cox proportional hazard regression analyses, Kaplan-Meier survival analyses, competing risk analyses, and propensity score matching were employed. A total of 1468 pT3N0M0 GC patients were included in the original cohort and 618 patients (309 in each group) were selected to construct the matched cohort. Age, location, tumor grade, Lauren type, chemotherapy, and number of examined lymph nodes(eLN) were observed to affect the prognosis of patients. Chemotherapy was an independent prognostic factor for pT3N0M0 GC. Survival analyses identified that patients with chemotherapy had a better prognosis than those without chemotherapy in the two cohorts. Competing risk analyses demonstrated that the cumulative incidence of cancer-specific death was significantly lower among patients with chemotherapy than those without chemotherapy. Survival analyses based on subgroups presented that chemotherapy could significantly improve the prognosis of those patients with high-risk prognostic factors, such as age > 65 years, location up, grade low, and diffuse type. Age, tumor location, tumor grade, Lauren type, chemotherapy, and number of eLN were associated with the prognosis of pT3N0M0 GC. Patients with pT3N0M0 GC could benefit from chemotherapy. Adjuvant chemotherapy might be recommended for these patients after curative gastrectomy.