[Effect of adjuvant chemotherapy on the prognosis of stage II( colon cancer patients with high risk factors].

OBJECTIVE: To investigate the effect of adjuvant chemotherapy on the prognosis of stage II( colon cancer patients with high risk factors.

METHODS: Clinicopathological and follow-up data of stage II( colon cancer patients undergoing radical surgery from January 2001 to March 2012 at Gastrointestinal Cancer Center of Peking University Cancer Hospital were retrospectively analyzed. The effect of adjuvant chemotherapy (within postoperative 2 month, fluorine uracil as main drugs) on the prognosis of high-risk patients was analyzed. High risk factors were defined as having at least one of the following factors: (1) tumor stage T4; (2) poor differentiation; (3) with vascular cancer embolus; (4) number of harvested lymph node less than 12; (5) complicated with obstruction or perforation.

RESULTS: A total of 497 patients with stage II( colon cancer were included in this study, of whom 258 cases(51.9%) had high risk factors, including stage T4 tumor in 80 cases(16.1%), poor differentiation in 80 cases (16.1%), cancer embolus in 37 cases (7.4%), lymph node harvested number less than 12 in 88 cases (17.7%), and obstruction or perforation in 85 cases (17.1%). Among 497 patients, number of cases with 1 to 4 high risk factors was 170 (34.2%), 68 (13.7%), 16 (3.2%) and 4 (0.8%), respectively. The last follow-up time was December 2016. The 5-year overall survival rate of all the 497 patients was 81.7%. The 5-year overall survival rate of 239 patients without high risk factors was 87.0%. The 5-year survival rate in patients with 1 to 4 risk factors was 81.9%, 73.7%, 66.7% and 25.0%, respectively (P=0.001). There was no significant difference in 5-year survival rate between 103 patients with adjuvant chemotherapy and 394 patients without adjuvant chemotherapy (79.6% vs. 82.8%, P=0.814). In patients with high risk factors, 80(31.0%) received adjuvant chemotherapy. There was no significant difference of 5-year survival rate between 80 patients with adjuvant chemotherapy and 178 patients without adjuvant chemotherapy (81.4% vs. 74.7%, P=0.147). Multivariate analysis showed that preoperative CEA level, T4 stage, lymph node harvested number, and tumor differentiation were the independent prognostic factors of patients with stage II( colon cancer (all P<0.05).

CONCLUSIONS: The proportion of patients with at least one risk factor is quite high in stage II( colon cancer cases. Adjuvant chemotherapy can not prolong the overall survival time of high risk patients.