The Value Of Pericolonic Tumor Deposits Of Colorectal Cancer And Their Number In Staging

Background:Colorectal cancer is one of the most common malignancies of the digestive system and both the incidence and mortality still are high.Recurrence and metastasis are the primary cause of the poor prognosis.The main forms of metastasis are lymphatic metastasis and hematogenous metastasis.The veins around metastatic lymph nodes often are susceptible to cancer tissue invasion and sometimes around the vessels,around the nerve or intravascular cancer tissue could form isolated tumor nodules,which are called pericolonic tumor deposits(PTDs).Previous studies had shown that PTDs is closely related to the prognosis of colorectal cancer.However,the value of PTDs in staging is still controversial.At present,there is no large sample to analyze the value of PTDs and their number in the staging.Objective:To clarify whether PTDs and their number can provide new meaningful clinical information for staging,so as to evaluate the value of PTDs and their number in staging.Methods:We identified 63942 patients who the number of PTDs are known between 2010 and 2013 from SEER Database in this study.The Kaplan-Meier method was used to evaluate the survival.The univariate and multivariate Cox regression model was used to evaluate the effect of PTDs on all-cause mortality.Subsequently,we analyzed the impact of LNMs and TDs on distant metastases using a logistic regression model.All the statistical methods are performed using the statistical software SPSS.V20.0.Results:Multivariate Cox regression analysis demonstrated that PTDs was significant independent predictor of all-cause mortality.The patients with one or two PTDs and three or more PTDs carried a 1.24-fold and 1.51-fold increased risk of all-cause mortality compared with the patients without PTDs respectively.Logistic regression analysis showed that the combination of TDs and LNMs were associated with significantly greater odds of having distant metastases than LNMs alone.PTDs in combination with NO The possibility of distant metastasis in patients with PTDs and without LNMs is similar to that in patients with N1 alone.N1 in combination with three or more PTDs was significant with OR of 8.80,which was stronger predictor for distant metastases compared with N2 alone(OR,5.98).Similar trends were observed for liver metastases and lung metastases.N2 in combination with three or more TDs was a strongest predictor for distant metastases.In survival analysis,the median survival of patients with N1 combined with three or more PTDs was shorter than that of patients with N2 alone(37 months vs 41 months)and the median survival of patients with N2 combined with three or more PTDs was similar to that of patients with distant metastasis(23 months vs 24 months).Conclusion:PTDs was an independent negative prognostic factor for survival of colorectal andenocarcinoma.PTDs in combination with LNMs can provided more information to staging.We lose potential prognostic information by only considering PTDs in the absence of LNMs.Therefore,we have four suggestions:First,PTDs can be regarded as N1 in the absence of LNMs.Second,PTDs should be added to N category to derive a final N stage.Third,the N1 in combination with three or more TDs should be regarded as N2.Fourth,maybe we can regard three or more TDs in combination N2 as a distinct form of metastatic disease and can be classified as pM.Of course,these recommendations require further evidence of evidence support.