Primary signet ring cell carcinoma of colorectum: an age- and sex-matched controlled study.

OBJECTIVE: To evaluate the differences of clinicopathological features between colorectal signet ring cell carcinoma and ordinary adenocarcinoma.
METHODS: The clinicopathological data of 28 cases with primary colorectal signet ring cell carcinoma was reviewed and compared with the data from 56 age- and sex-matched patients with ordinary adenocarcinoma.
RESULTS: Fifteen cases (53.5%) with primary signet ring cell carcinoma were younger than 40 yr of age. Compared with 985 ordinary adenocarcinoma cases, signet ring cell carcinoma is present in excess in younger patients (p < 0.005). Further comparison with 56 age- and sex-matched ordinary adenocarcinomas showed that signet ring cell carcinomas could affect any sites of colon, presented as scirrhous appearance more frequently, had a higher percentage of stage III or IV tumors (78.6 vs 48.2%, 14.3 vs 7.2%, p < 0.005), had a higher rate of peritoneal seeding (35.7 vs 12.5%, p < 0.005) but a lower rate of liver metastasis (14.3 vs 32.1%, p < 0.005), and had a lower curative resection rate (64.2 vs 80.4%, p < 0.005) and a higher local or distant metastasis rate (61.1 vs 17.8%, p < 0.05). Survival with signet ring cell carcinoma is lower than that of ordinary adenocarcinoma. "Stage-on-diagnosis" and "presence of subsequent distant metastasis" were the major factors influencing survival of signet ring cell carcinoma patients.
CONCLUSION: The delay in diagnosis reduces the chance of curative resection, increases the possibility of local or distant metastasis postoperatively, and, thus, shortens the survival chances. To improve outcome, recognition of the factors responsible for this delay should be stressed so that this tumor may be found at a stage when cure is possible.