Abstract: Objective:To investigate the effect of extramural venous invasion (EMVI) detected by multislice spiral computed tomography (MSCT) on the overall prognosis in patients with stage Ⅲ colon cancer after radical resection.
Methods:The retrospective casecontrol study was adopted. The clinical data of 117 patients with stage Ⅲ colon cancer in Tangshan Gongren Hospital from March 2011 to March 2013 were collected. All the patients underwent MSCT examination preoperatively and the results were recorded from two radiologists′ doubleblinded independent imagereading. According to the results of MSCT examination, positive ctEMVI patients were allocated to the positive ctEMVI group, and negative ctEMVI patients were allocated to the negative ctEMVI group. Observation indices: (1) ctEMVI consistency and comparison of clinicopathological information between the 2 groups. (2) Followup and prognosis situations. (3) Univariate and multivariate analyses of prognosis. Followup was performed by telephone interview and outpatient examination once every 3 months within a year and once every 6 months after one year. If the patients had tumor recurrence and metastasis, then the patients were followed up once every 3 months. The followup included tumor metastasis and recurrence and patients′ survival, and the followup time was up to March 2016. The consistency of the image quality assessment of 2 observers was analyzed by the k test. Count data were analyzed using chisquare test. KaplanMeier method was used to draw survival curve and calculate tumorfree survival rate and overall survival rate, and the survival rate was compared with Logrank test. The univariate and multivariate analyses of prognosis were analyzed using COX regression model.
Results:(1) ctEMVI consistency and comparison of clinicopathological information between 2 groups: the results of the first observer were 35 cases in the positive ctEMVI group and 82 cases in the negative ctEMVI group; and the results of the second observer were 52 cases in the positive ctEMVI group and 65 cases in the negative ctEMVI group. Good interobservers agreement was found for the evaluation (k=0.689). The final results were reached with 42 cases in the positive ctEMVI group and 75 cases in the negative ctEMVI group after the disputed imaging of 17 patients evaluated by the third assessor. (2) Followup and prognosis situations: all the 117 patients were followed up for 6-73 months with an average time of 46 months. The 3year recurrence and metastasis rate of positive ctEMVI group and negative ctEMVI group were 90.48% and 74.67%, respectively, with a significant difference (χ²=4.261, P<0.05). The 3year tumorfree survival rate and 3year cumulative survival rate were 42.97% and 44.56% in the positive ctEMVI group, 78.77% and 83.79% in the negative ctEMVI group, respectively, showing significant differences between the 2 groups (χ²=31.321, 25.661, P<0.05). (3) Results of univariate and multivariate analyses of prognosis: results of univariate analysis showed that preoperative serum carcinoembryonic antigen (CEA) level, ctEMVI, tumor location and tumor N staging were related factors affecting 3year tumorfree survival rate of patients with stage Ⅲ colon cancer after radical resection ［HR=1.414, 3.480, 0.882, 1.681, 95% confidence interval(CI): 1.319-7.588, 1.525-9.425, 0.511-0.856, 1.135-3.485, P<0.05］. Age, preoperative serum CEA level, ctEMVI, number of examined lymph nodes, tumor T stage and degree of tumor differentiation were related factors influencing 3year cumulative survival rate of patients with stage Ⅲ colon cancer after radical operation (HR=3.314, 2.991, 4.232, 0.670, 3.620, 11.974, 95% CI: 1.745-9.889, 1.567-6.001, 2.428-7.252, 0.291-0.779, 2.077-8.438, 6.254-19.886, P<0.05). Results of multivariate analysis showed that preoperative serum CEA level ≥5 μg/L, positive ctEMVI, upper tumor location were independent risk factors affecting 3year tumorfree survival rate of patients with stage Ⅲ colon cancer after radical resection (RR=2.999, 6.519, 0.765, 95% CI: 1.774-6.259, 3.629-16.096, 0.232-0.884, P<0.05). Age≥65 years, preoperative serum CEA level ≥5 μg/L, positive ctEMVI, tumor T stage>T2, poor differentiation of tumor were independent risk factors affecting the 3year cumulative survival rate of patients with stage Ⅲ colon cancer after radical resection (RR=4.411, 2.236, 5.029, 1.573, 2.412, 95% CI: 1.907-10.206, 1.409-3.548, 2.649-9.614, 1.045-2.369, 1.215-6.789, P<0.05).
Conclusion:Positive ctEMVI is an independent risk factor affecting the poor prognosis of patients with stage Ⅲ colon cancer after radical resection, and the prognosis of positive ctEMVI patients is worse than negative ctEMVI patients.