The Impact Of Adjuvant Chemotherapy Length On Survival In Patients With Postoperative Stage Ⅲ Colorectal Cancer

Objective: The study has confirmed that stage III colorectal cancer patients can benefit significantly from adjuvant chemotherapy.If there is no contraindication,postoperative adjuvant chemotherapy should be recommended.The standard treatment for stage III colorectal cancer after radical surgery is a 6-month oxaliplatin-containing chemotherapy regimen.Although the addition of oxaliplatin provides survival benefits to patients,it also increases toxicity.Recent studies have shown that for low-risk(T1-3N1)stage III colorectal cancer,properly shortening of chemotherapy does not affect patient survival but significantly reduce chemotherapy-related side effects.This study was designed to investigate the effect of postoperative adjuvant chemotherapy at different durations on the survival of patients with stage III colorectal cancer.Methods: A retrospective analysis of 105 patients with stage III colorectal cancer underwent adjuvant chemotherapy after radical resection and the follow-up data were complete.To analyze the effect of chemotherapy with different durations on the survival of patients with different risk stratification.The primary endpoint of the study was disease-free survival(DFS)and the secondary endpoint was overall survival(OS).Results: As of the last follow-up,30 patients died and 49 patients relapsed.All patients underwent disease-free survival analysis: the 3-year DFS in the <8-cycle group and the ≥8-cycle group were 63.3% and 85.7%,respectively.The 5-year DFS was 55.1% and 78.6%,respectively.For the overall survival analysis,the 3-year OS of the <8-cycle group and the ≥8-cycle group were 77.6% and 85.7%,respectively,and the 5-year total OS was 65.3% and 80.4%,respectively.It is shown that the≥8-cycle group showed significant disease-free survival and overall survival advantages in patients with stage III colorectal cancer.Subgroup analysis was then performed.The DFS and OS scores in the low-risk group showed that the 3-year DFS in the <8-cycle group and the ≥8-cycle group were 54.5%,88.0%,and the 3-year OS was 68.2%,92.0%,respectively.The annual DFS was 54.5%,80.0%,and the 5-year OS was 63.6% and 88.0%(p>0.05).The DFS and OS analysis were performed in thehigh-risk group: the 3-year DFS in the <8-cycle group and the ≥8-cycle group,respectively.66.7%,87.1%,3 years OS were 88.9%,90.3%,5 years DFS were 55.6%,80.6%,5 years OS was 74.1%,87.1%(p<0.05);the results showed that For patients in the low-risk group,prolonged chemotherapy did not show a significant survival advantage,while for high-risk patients,prolonged chemotherapy time to obtain survival benefits.Univariate analysis showed that the chemotherapy regimen and pathological type were the relevant factors affecting DFS,and the pathological type and the presence or absence of vascular invasion were related factors affecting OS(p<0.05).Multivariate analysis showed that chemotherapy regimen,pathological type,and number of chemotherapy cycles(p<0.05)were independent prognostic factors for patients with DFS.Pathological types and number of chemotherapy cycles(p<0.05)were independent prognostic factors for OS.Conclusion: In patients with stage III colorectal cancer after radical surgery,at least 8cycles of oxaliplatin-containing chemotherapy can achieve a more significant survival advantage;but for low-risk stage III patients,≥8 cycles of chemotherapy It did not show a better prognosis,but increased the incidence of adverse events.Pathological types and chemotherapy cycles are independent factors that influence the survival of patients.