Signet ring cell histology is associated with unique clinical features but does not affect gastric cancer survival

Signet ring cell histology is found in 3 to 39 per cent of gastric cancer cases and has been reported to be a feature of poor prognosis, although this issue has not been rigorously examined. The objective of this study was to determine those demographic and clinical variables associated with signet ring cell histology and to determine the effect of signet ring cell histology on survival using multivariate analyses. We studied a historical cohort of consecutive cases of gastric cancer reported to the population-based California Cancer Registries of Orange, San Diego, and Imperial Counties from 1984 through 1994. Factors associated with signet ring cell histology were assessed using chi2 and logistic regression. Life tables were constructed to assess unadjusted survival and survival differences in patient subgroups. Multivariate survival was determined using a Cox proportional hazards model. Of 3020 patients, 464 (15%) had signet ring cell histology. Patients with signet ring cell histology were more likely to be younger than 50 years (odds ratio (OR) = 2.4; 95% confidence interval (CI) = 1.6-3.5), less likely to be male (OR = 0.49; 95% CI = 0.37-0.66), and more likely to have tumors of the distal stomach (OR = 2.0; 95% CI = 1.4-3.0). Signet ring cell histology did not adversely affect unadjusted overall survival, race-stratified survival, or stage-stratified survival. Multivariate analysis indicated that patients with signet ring cell histology had an insignificant increased risk of dying (relative risk = 1.027; P>0.10) in comparison with patients without signet ring cell histology. Patients with signet ring cell histology were more likely to be young women and to have tumors of the distal stomach. Signet ring cell histology did not impact survival in our group of largely advanced gastric cancer cases.