The Impact Of Adjuvant Chemotherapy Cycle On Survival In Postoperative Colon Cancer Patients

Objective: Six months of 5-fluorouracil-based adjuvant chemotherapy is the standard of care for postoperative treatment of colon cancer patients.Recent studies showed that shortening the duration of adjuvant chemotherapy could reduce the side effects,and resulted in similar efficacy.This present retrospective analysis evaluated the outcomes of patients with colon cancer treated with different cycles of fluorouracil-based adjuvant therapy,and explored the prognostic factor of postoperative colon cancer patients.Methods: The present study was a retrospective study.Patients with stage II~III colorectal cancer treated in the First Hospital of China Medical University from August 2005 to January 2017 were collected,and the relationship between adjuvant chemotherapy cycle and survival was analyzed.The primary end point was disease-free survival,and the secondary end point was overall survival.Results: A total of 306 patients were included in the studies,disease-free survival was analyzed in 298 patients,and overall survival was analyzed in 283 patients.In disease-free survival analysis,45 patients were treated with four cycles of adjuvant chemotherapy,105 patients were treated with six cycles,and 148 patients were treated with eight cycles.Survival analysis showed that the estimated 3-year disease-free survival rates for the four cycles,six cycles,eight cycles cohorts were 56.3%,75.9%,77.5%,respectively;and the estimated 5-year disease-free survival rates were 56.3%,68.4%,75.7%,respectively.Compared with four cycles,six cycles of adjuvant chemotherapy,the disease-free survival in eight cycles was longer(P=0.018).In overall survival analysis,33 patients were treated with four cycles,103 patients were treated with six cycles,and 147 patients were treated with eight cycles.Overall survival analysis showed that the estimated 3-year overall survival rates for the four cycles,six cycles,eight cycles cohorts were 68.9%,86.2%,93.6%,respectively;and the estimated 5-year overall survival rates were 68.9%,80.3%,92.1%,respectively.Eight cycles of adjuvant chemotherapy might lead to a favorable outcome(P=0.004).Subgroup analysis showed that patients in stage III,high-risk stage III,adjuvantchemotherapy with XELOX or FOLFOX,and adjuvant chemotherapy with XELOX or FOLFOX for stage III,eight cycles of adjuvant chemotherapy were associated with a statistically significant benefit of survival compared with four cycles and six cycles(P<0.050).For patients in stage II or low-risk stage III,compared with four cycles,six cycles of adjuvant chemotherapy,eight cycles could not provide additional clinical benefit(P>0.050).To further explore the relationship between clinical pathological features and survival,univariate and multivariate analysis were performed.The data showed that the number of chemotherapy cycles,histological grade,TNM stage and pathological N stage were the factors that affect disease-free survival of patients with colon cancer(P<0.050).The number of chemotherapy cycles,histological grade,TNM stage,and pathological N stage were correlated with overall survival of patients with colon cancer(P<0.050),too.Multivariate analysis showed that the number of chemotherapy cycles(P=0.001)and TNM stage(P=0.002)were independent prognostic factors for disease-free survival,and the number of chemotherapy cycles(P<0.001),TNM stage(P<0.001)and pathological N stage(P=0.005)were independent prognostic factors for overall survival.Conclusion: Eight cycles of adjuvant chemotherapy might lead to a favorable outcome for patients with colon cancer,and the number of chemotherapy cycles was an independent prognostic factor.