Radiotherapy benefited the survival of patients with intestinal-type gastric adenocarcinoma: a SEER population-based study

Currently, the role of adjuvant radiotherapy (RT) in the treatment of patients with intestinal-type gastric adenocarcinoma (IGA) has not been well established. This study aimed to elucidate the survival impact of RT on such patients.

The Surveillance, Epidemiology, and End Results (SEER) database was utilized to select eligible patients. The recruited patients were dichotomized into those not received RT versus those received RT. The 1:1 propensity score matching (PSM) analysis was conducted to balance the confounding factors between the two comparison groups. The categorical variables were assessed by Chi-square test. Cancer-specific survival (CSS) and overall survival (OS) of the patients were compared by Kaplan–Meier (KM) methods. Cox proportional hazard models were used to identify prognostic factors associated with CSS.

A total of 3572 eligible patients were enrolled for our analysis, of which, 2896(81.1%) patients did not receive RT and 676(18.9%) patients received RT. Before PSM, except race and tumor size, significant differences in patients’ baseline characteristics were observed in no RT versus RT group. The KM plots before PSM indicated that RT exerted significant survival benefits for the recruited patients (p < 0.001). After PSM, most confounders were well balanced between the two comparison groups. The KM plots showed significantly superior CSS and OS in the RT group (p < 0.05). Grade IV, stage II–IV, and N3 were identified as independent risk factors, while LN examined > 15 and RT were independent protective factors for favorable prognosis. Subgroup survival analysis revealed that RT brought a significant CSS advantage for the stage IV patients.

Based on PSM analysis of the cohort from SEER database, RT showed significant survival benefits for patients with IGA. Our study supports adjuvant RT for this specific cohort.