External multicenter validation of the FAMISH score for predicting metachronous gastric lesions after endoscopic submucosal dissection

Background and objectives: Surveillance after gastric endoscopic submucosal dissection (ESD) is crucial due to the high risk of metachronous gastric lesions (MGL), although this risk may differ between patients. We sought to validate the FAMISH score–a prediction score to estimate MGL risk after gastric ESD–within a multicentric framework. Materials and methods: Performance measures of the FAMISH score were assessed in a retrospective analysis of a multicenter cohort, which included consecutive adult patients undergoing ESD for a primary gastric superficial lesion at 15 international centers, with a minimum endoscopic follow-up of at least 3 years. Results: A total of 855 individuals were included, with 20% of them considered low-risk according to the FAMISH score. After a mean follow-up time of 5 years (SD ± 2 years), 168 patients (19.6%) developed MGL. At 3 years of follow-up, the score achieved 90.4% sensitivity and 93.9% NPV. At 5 years follow-up, the score achieved 89.1% sensitivity and 85.3% NPV. The FAMISH risk score achieved a fair diagnostic accuracy with an AUC of 0.618 at 3 years (p < 0.001) and 0.597 (p = 0.006) at 5 years of follow-up. The progression to MGL at 5 years of follow-up was significantly lower for the low-risk group (9.6% vs. 18.2%, p = 0.029). Conclusions: The FAMISH score achieved an acceptable diagnostic accuracy in a multicentric validation cohort from Western countries. This score is a useful tool to identify patients with low risk for MGL allowing to safely extend surveillance intervals and reduce the burden of care.