Identifying chemotherapy benefits in high-risk patients with stage IB gastric cancer based on recurrence prediction value: A multicenter retrospective study.

[BACKGROUND] This study aimed to identify high-risk patients with stage IB gastric cancer who were likely to benefit from adjuvant chemotherapy (AC) through a precise assessment of recurrence risk.

[METHODS] This multicenter, retrospective study analyzed patients with stage IB gastric cancer who underwent surgery between January 2010 and December 2021. High-risk factors (HR+) included poorly differentiated tumors, lymphovascular invasion, perineural invasion, or age <50 years, while those without were classified as negative (HR-). The Recurrence Prediction Value (RPV) was developed by weighting these factors.

[RESULTS] Totally, 555 and 409 patients were included in the training and validation datasets, respectively. Using RPV, patients were stratified into three groups. The 3-year recurrence-free survival (RFS) rate for the HR+ with high RPV subgroup was lower than both the HR+ with low RPV and HR-with low RPV subgroups (training set: 86.7 % vs. 95.6 % vs. 98.4 %; all P < 0.001; validation set: 84.5 % vs. 94.0 % vs. 98.4 %; all P < 0.05). Subgroup analysis revealed that only the HR+ with high RPV subgroup benefited from AC, with significant RFS improvements (training set: AC vs. non-AC: 88.9 % vs. 83.9 %, P = 0.043; validation set: 92.2 % vs. 75.2 %, P = 0.003). A nomogram based on RPV for predicting recurrence demonstrated good calibration and discrimination, with C-index values of 0.748 and 0.711 for training and validation sets, respectively.

[CONCLUSIONS] This study presents a method for identifying the benefit of chemotherapy in patients with stage IB gastric cancer based on RPV, which could assist surgeons in providing personalized treatment strategies for these patients.