Prognostic Value Of Tumor Deposit In Colorectal Cancer Patients With Different Mismatch Repair Types

Objective: To explore the impact of tumor deposit(TD)on disease-free survival(DFS)and overall survival(OS)in primary colorectal cancer(CRC)patients with different mismatch repair(MMR)types.Methods: This study retrospectively collected the data of patients who underwent radical colorectal cancer surgery in Guizhou Provincial People’s Hospital from January 2013 to December 2017,from which the clinical and pathological characteristics of the patients were analyzed,and the survival of the patients was followed up.Categorical data were expressed as number and percentage,and compared using the Chi-square test,Kaplan-Meier method was used to plot the survival curve,Log-rank test and Cox proportional hazard model was used to explore the impact of TD on DFS and OS.Results: 1.Totally 658 patients were included.Among them,88 patients(13.37%)were TD positive and 570 patients(86.63%)were TD negative,93(14.13%)were deficient mismatch repair(d MMR)and 565(85.87%)were proficient mismatch repair(p MMR).The patients were divided into 2 groups according to the existence of TD,and the MMR type,age,neurological invasion,vascular carcinoma embolus,lymph node metastasis,number of lymph nodes,stages,and number of postoperative adjuvant chemotherapy cycles were significantly different between the two groups(P<0.05).2.Kaplan-Meier analysis showed that median DFS and median OS of TD positive patients were 28 months and 51 months,respectively.The 3-year overall survival rate was56.80% and the 5-year overall survival rate was 45.30%.The median DFS of TD negative patients was 92 months,with no median OS time.The 3-year overall survival rate was81.40%,and the 5-year overall survival rate was 71.40%.The 3-year overall survival rate was 79.60% and the 5-year overall survival rate was 70.70% for d MMR patients before median DFS and median OS time.The median DFS and OS of p MMR patients were 89 months,90 months,and the 3-year overall survival rate was 77.90% and the 5-year overall survival rate was 60.50%.3.The result of the univariable analysis showed that tumor site,invasion depth,neurological invasion,vascular carcinoma embolus,lymph node metastasis,stages,number of postoperative adjuvant chemotherapy cycles and TD were risk factors for DFS in patients(P<0.05).Tumor site,invasion depth,neurological invasion,vascular carcinoma embolus,lymph node metastasis,stages,and TD were risk factors for OS in patients(P<0.05).And the multivariable analysis showed tumor site,invasion depth,stages and TD were independent risk factors for DFS in patients(P<0.05).Stages and TD were independent risk factors for OS in patients(P<0.05).4.Patients were divided into different subgroups according to the MMR types,in the d MMR subgroup,the median DFS and OS of TD positive d MMR patients were 7 months and 18 months respectively.TD negative d MMR patients did not arrive at median DFS and median OS time.Univariate analysis showed that pathological type,stages,number of postoperative adjuvant chemotherapy cycles,and TD were risk factors for DFS(P<0.05).Age,vascular carcinoma embolus,stages,and TD were risk factors for OS(P<0.05).Further multivariate analysis showed that stages and number of postoperative adjuvant chemotherapy cycles were independent risk factors for DFS(P<0.05),but TD was not.Stages and TD were independent risk factors for OS(P<0.05).In the p MMR subgroup,the median DFS and OS of TD positive p MMR patients were 33 months and 57 months respectively.The median DFS and median OS for TD negative p MMR patients were both92 months.Univariate analysis showed that tumor site,invasion depth,neurological invasion,lymph node metastasis,stages,number of postoperative adjuvant chemotherapy cycles,and TD were risk factors for DFS(P<0.05).Tumor site,pathological type,invasion depth,lymph node metastasis,stages,and TD were risk factors for OS(P<0.05).Further multivariate analysis showed that tumor site,invasion depth and stage were independent risk factors for DFS(P<0.05),but TD was not.Stages was an independent risk factor for OS(P<0.05),but TD was not.5.In univariate analysis,the HR values of DFS for d MMR and p MMR patients were6.617 times(95.0% CI: 2.691,16.271,P<0.001)and 2.184 times(95.0% CI: 1.598,2.987,P<0.001),respectively.HR values were higher or lower than those in the total population,but after factor correction with statistical difference in univariate analysis in each subgroup,the influence of TD on DFS was only statistically significant in the total population.The HR values of OS for d MMR and p MMR patients were 9.264 times(95%CI: 3.621,23.701,P<0.001)and 2.167 times(95%CI: 1.542,3.046,P<0.001),respectively higher or lower than the HR values in the total population,but after factor correction with statistical difference in univariate analysis in each subgroup,the influence of TD on OS was statistically significant in the total population and d MMR subgroup(P<0.05),but not in p MMR subgroup.Conclusion:(1)The incidence of tumor deposit(TD)in rectal cancer was 20.69%,of which 4.93% were d MMR patients.The incidence of TD in colon cancer was 10.11%,of which 18.24% were d MMR patients.(2)There were differences between mismatch repair types and presence of TD,and the proportion of p MMR in patients with positive TD is high.(3)TD was an independent risk factor for DFS and OS in primary colorectal cancer patients.(4)For d MMR patients,TD is an independent risk factor affecting their OS,and the occurrence of TD may be a more significant risk factor affecting the survival of such patients.