Objective: The benefit of adjuvant therapy (AT) remains controversial in stage IB gastric cancer (GC). This study aimed to offer a reference for the rational indications of AT.Methods: We retrospectively included 1216 stage IB GC who experienced curative surgery from the SEER database between 2004 and 2015. These patients were allocated into two groups: Group AT and Group surgery alone (Group SA). We established a nomogram to predict OS and then divided whole cohort into low-risk and high-risk groups based on the OS predicted by the nomogram.Results: Six variables, which were significantly related with OS of entire patients after matched, were incorporated in the nomogram. These variables were age, examined lymph nodes, tumor site, marital, family income and stage IB. The C-index of the model was 0.637 and the calibration curve showed that the anticipated values were in accordance with the actual values. The decision curve demonstrated that the optimal clinical impact was achieved when the threshold possibility was 0-56%. Then, the entire cohort was separated into low-risk (≤159 points) as well as high-risk (>159 points) groups based on the projected 5-year OS of recursive partitioning analysis. Group SA revealed a significantly poorer OS than Group AT for high-risk patients (p < .001); on the other hand, there was a comparable OS for low-risk patients (p = .361).Conclusions: We have developed an effective, intuitional and applied prognostic tool to clinical decision-making. For stage IB GC after surgical resection, AT was only recommended for high-risk patients. However, AT may be dispensable for low-risk patients.
Keywords: Stage IB gastric cancer; adjuvant treatment; decision curve analysis; epidemiology and end results; nomogram; overall survival; surveillance.