Clinical Features and Prognosis of Resectable Primary Colorectal Signet-Ring Cell Carcinoma

We attempted to investigate the prognosis of signet-ring cell carcinoma (SRC) patients who underwent curative surgery by comparing them with age-, sex-, and stage-matched non-mucinous adenocarcinoma (NMAC) patients. Between January 2003 and December 2011, 19 patients with primary SRC of the colorectum underwent curative surgery. Four SRC patients under the age of 40 were excluded, and the clinicopathological data of 15 patients (7 men; median age, 56 years) were reviewed and compared with the data of 75 NMAC patients matched by age, sex, and pathologic stage. The median follow-up duration was 30.1 months for the SRC group and 43.7 months for the NMAC group (P=0.141). Involvement of the left side of the colon (73.3% vs. 26.7%, P=0.003) and infiltrative lesions such as Borrmann types 3 and 4 (85.7% vs. 24.0%, P=0.001) were more common in the SRC group than in the NMAC group. The five-year overall survival rate was significantly lower for patients with SRC than for those with NMAC (46.0% vs. 88.7%, hazard ratio, 6.99; 95% confidence interval, 2.33-20.95, P=0.001). Patients with even resectable primary colorectal SRC had a poorer prognosis than age-, sex-, and stage-matched colorectal NMAC patients.