Prognosis of poorly cohesive gastric carcinoma depending on the depth of tumor invasion and the amount of signet ring cells in tumor

Current data of the prognosis of signet ring cell gastric carcinoma (SRC) are contradictory, and our knowledge of other subtypes of poorly cohesive carcinoma is poor. Objective. To study the prognosis of poorly cohesive gastric carcinoma depending on the amount of the signet ring cells and depth of tumor invasion in comparison with other types of gastric cancer (GC) according to the classification of P. Lauren. Material and methods. In 315 patients with GC after surgical treatment, pathological tissue samples were reviewed by using a semi-quantitative assessment of the proportion of diffuse and intestinal components of the tumor to clarify the type of GC according to the P. Lauren classification, as well as the proportion of signet ring cells. Results. In pT1-T2 tumors, 5-year overall survival (5-OS) in patients with diffuse and intestinal types of gastric cancer has demonstated no differences. In cases of serous membrane invasion (pT4a—T4b), the 5-OS rates in patients with poorly cohesive gastric carcinoma worsens sharply compared to the intestinal type (28.6% versus 49.7%, p=0.006) and becomes comparable with 5-OS in mixed type of gastric cancer (15.2%, p=0.644). As the depth of invasion increases, the amount of signet-ring cells in poorly cohesive cancer decreases. The highest percentage of signet ring cells was found when the tumor was localized within the mucous and submucous layers (27.5% for pT1a, 43.0% for pT1b). For pT2, the proportion of signet ring cells was 12.0%, for pT3 — 11.2%, pT4 — 8.3%. This feature explains the high percentage of early cancer in patients with signet ring cell (SRC) GC. No significant differences in 5-OV was found with poorly cohesive carcinoma depending on the amount of signet ring cells (≥1%, ≥10%, ≥50%, ≥90%). Conclusion. Invasion of the serous membrane of the stomach contributes to the rapid implementation of the tendency of poorly cohesive gastric carcinoma to peritoneal dissemination of the tumor. The proportion of signet ring cells in poorly cohesive gastric carcinoma does not affect to aggressive properties of the tumor.