Signet Ring Cell Histology Is Not an Independent Predictor of Poor Prognosis After Curative Resection for Gastric Cancer: A Propensity Analysis by the KLASS Group

Whether signet ring cell (SRC) histology carries a worse prognosis than other forms of gastric adenocarcinoma has been questioned. The present study investigated the differences in clinicopathologic features and survival between SRC and non-SRC adenocarcinoma. The prospectively collected data of 2643 patients who had undergone curative gastrectomy between 1998 and 2005 by 10 surgeons were reviewed. Additionally, we employed analysis of covariance, propensity-score risk adjustment, and propensity-based matching to account for possible selection bias. The baseline characteristics of prematched patients with SRC or non-SRC adenocarcinoma histology differed: SRC presented in younger patients and less often in men, was more likely found in the middle stomach, and was more likely to be Stage I. After applying the propensity-score strata and propensity-score matching, there was no difference in the baseline characteristics, and SRC was not an independent risk factor for mortality in the same stage. SRC is not an independent predictor of poor prognosis after curative resection for gastric cancer in Korea.