Colorectal Signet-ring Cell Carcinoma: Clinicopathological Features And Prognostic Factors

Objective: To analyze the difference of clinicopathological features between colorectal signet-ring cell carcinomas(SRCC), mucinous adenocarcinomas(MAC), classical adenocarcinomas(AC). To explore prognostic factors of colorectal signetring cell carcinomas.Methods: A total of 2128 patients underwent surgery for colorectal adenocarcinomas at our hospital between Jan 2009 and Sep 2015. All patients were classified into was SRCC(37 cases), MAC(153 cases), AC(1938 cases) according to histological subtype. The clinicopathological data, including age, sex, length-diameter of tumor, presence or absence of intestinal obstruction, location of tumor, staging, tumor markers, and surgical procedure were compared with three groups. Prognostic factors of SRCC were analyzed. Counting data was processed by chi-square test, measurement data was processed by variance analysis or non-parametric test. Survival analysis was calculated by Kaplan-Meier method, and compared by log-rank test. Cox proportional hazard models were used to investigate the effect on survival of univariate analysis or multivariable analysis. P values less than 0.05 were considered to denote statistical significance.Results: The mean age of SRCC was lower than MC and AC(all P<0.05). The length-diameter of tumor of SRCC was longer than AC(P<0.05). SRCC patients presented more frequently with stage N1+N2 than MC and AC(all P<0.05). SRCC patients presented more frequently with stage M1 than AC(P<0.05). SRCC patients presented more frequently with stage Ⅲ or Ⅳ than MC and AC(all P<0.05). The ratio of radical operation in SRCC was lower than that in AC(P<0.05). The ratio of peritoneal metastases in SRCC was higher than that in AC(P<0.05). However, there was no significant difference in sex, the ratio of intestinal obstruction, CEA level, CA19-9 level between SRCC and the other two groups(P>0.05). The time for follow-up visits was 3-80 months. The 1-, 3-, 5- year cumulative survival rates of SRCC were 60.40%、43.29%、32.47%, with a median survival time of 29 months; The 1-, 3-, 5- year cumulative survival rates of MC were 2.93%、58.02%、40.61%, with a median survival time of 58 months; The 1-, 3-, 5- year cumulative survival rates of MC were 77.30%、67.14%、59.14%. To the end of follow-up, more than 50% of patients of AC survived. The survival rates in SRCC was significantly worse in comparison to MC and AC(P<0.05). Univariate analysis showed that age, location of tumor, presence or absence of intestinal obstruction, staging, CA19-9, surgical procedure,adjunctive therapy and histopathological subtypes were the prognostic factors in patients with colorectal adenocarcinomas. Cox multivariable analysis showed that age group 41 to 59 and absence of intestinal obstruction were the independent protective factors in patients with colorectal adenocarcinomas. Palliative operation and absence of adjunctive therapy were the independent risk factors. TNM stage was the independent risk factor. TNM stage was more advanced and risk ratio was higher. SRCC was the independent risk factors of colorectal adenocarcinoma(HR=2.783, P=0.023). On univariate analysis, intestinal obstruction, pathological TNM stage, surgical procedure, adjunctive therapy was the prognostic factors of SRCC.Conclusion:(1) Colorectal signet-ring cell carcinoma is a rare form of malignant tumor, which has unique clinicopathological features. The onset age was lower. The length-diameter of tumor was longer. The pathological TNM stage was more advanced. The ratio of radical operation was lower. The ratio of peritoneal metastases was higher.(2) The prognosis of SRCC was worse in comparison to MC or AC. SRCC was independent prognostic factors of colorectal adenocarcinoma.(3) Intestinal obstruction, pathological TNM stage, surgical procedure, adjunctive therapy was prognostic factors of SRCC, which can guide the prognosis and selection of therapeutic regimens in clinical practice.