Background and purpose:With the aging population,the number of elderly patients with colorectal cancer(CRC)is increasing.To date,elderly patients with stage Ⅱ CRC often receive a weakened chemotherapy regimen or even no chemotherapy after radical surgery,and It is still unclear whether this will lead to adverse oncological outcomes.This study aimed to explore the prognostic impact of advanced age on stage Ⅱ CRC patients after removing bias through a multivariate COX regression approach.Methods:We retrospectively collected data of 3314 colorectal cancer patients with postoperative pathology of stage Ⅱ,no history of previous tumors,no secondary primary tumors within 5 years after surgery and no preoperative neoadjuvant therapy.This study was reviewed by the medical ethics committee of Fudan University Shanghai Cancer Center(ethics number:050432-4-2108*).The optimal threshold for calculating age relative to survival using survminer package of R software(version 3.0)(surv_cutpoint algorithm)was 73 years.We compared the clinical and pathological characteristics,overall survival(OS)and disease-free survival(DFS)between the older group(age＞73 years)and the younger group(age≤73 years).The alignment diagram prediction model was drawn using the survival package and RMS package.Results:The elderly and non-elderly groups were evenly comparable in terms of gender,tumor location,differentiation,vascular invasion,perineural invasion and pT stage.Multivariate COX regression showed that advanced age was an independent prognostic risk factor for OS[hazard ratio(HR)=3.725(3.051-4.549),P＜0.001]and DFS[HR=2.431(2.029-2.912),P＜0.001].The nomogram(alignment diagram)prediction model constructed based on multivariate COX regression could effectively evaluate the prognosis of stage Ⅱ CRC patients and provide guidance for practical clinical work.Conclusion:In stage Ⅱ CRC patients,older age is associated with shorter OS and DFS.Adequate intensity of adjuvant chemotherapy may be necessary.Treatment decisions can be adjusted based on the predicted model scores of the patient's alignment diagram.

Background and purpose:According to current consensus,adverse high-risk pathological features are only associated with adjuvant therapy for stage Ⅱ colorectal cancer(CRC).As important prognostic factors,we further explored the possibility of identifying patients with potential recurrence and poor prognosis based on these incorporating high-risk pathological features.Methods:This is a cohort study.A retrospective analysis was conducted on clinical data of CRC patients who underwent surgical treatment at the Second Department of Colorectal Surgery,Fudan University Affiliated Shanghai Cancer Center from 2008 to 2018.This study was approved by the Ethics Committee of the Fudan University Shanghai Cancer Center(approval No.:050432-4-2108*),and the study complies with the Declaration of Helsinki.A total of 9875 patients were enrolled,including 5859 males and 4016 females,aged[M(IQR)]60(16)years(range:16 to 94).Median follow-up time was 1779.0 days[95%CI:1750.1-1807.9].We used the Kaplan-Meier method to plot survival curves for different groups.Cox multivariate analysis was used to identify independent risk factors for 5-year overall survival(OS),disease-free survival(DFS)and recurrence-free survival(RFS).Finally,a column chart model was constructed to evaluate and stratify patient prognosis.The Strengthening the Reporting of Observational Studies in Epidemiology(STROBE)checklist was followed for this cohort study.Results:According to the number of incorporating high-risk pathological features,patients were divided into five groups:Hr_0 group(0 incorporating high-risk pathological feature),Hr_1 group(1 incorporating high-risk pathological feature),Hr_2 group(2 incorporating high-risk pathological features),Hr_3 group(3 incorporating high-risk pathological features),and Hr_4 group(4 or more incorporating high-risk pathological features).The Kaplan-Meier survival curve results indicated significant differences in OS,DFS and RFS among different groups(all P<0.001).Subgroup analysis was conducted on stage Ⅱ colorectal cancer,and the survival curves of OS,DFS and RFS in different Hr groups overlapped with each other.Compared to the overall population,the survival differences in different groups were significantly reduced,indicating that stage Ⅱ colon cancer patients with incorporating high-risk pathological features may benefit from adjuvant chemotherapy.The independent prognostic factors for RFS included age,pT stage,pN stage and Hr group.The survival curves of OS,DFS and RFS indicated that the prognosis of Hr_4 group was significantly worse than that of stage Ⅲc patients;5.2%and 14.1%of stage Ⅰ and Ⅱ patients had two or more incorporating high-risk pathological features(Hr group≥2),respectively.Finally,a column chart model was constructed by incorporating the independent prognostic risk factors for CRC mentioned above.The calibration curve showed a good consistency between the actual observations and the predictions made by the nomogram,and the decision curve analysis(DCA)indicated that the model constructed in this study had good efficacy in stratifying recurrence.Conclusion:The number of incorporating high-risk pathological features is an independent prognostic factor for RFS in patients with stage Ⅰ-ⅢCRC.Combining it as a multiclass variable with age,pT and pN stage has good prognostic stratification and recurrence stratification efficacy,which is expected to guide clinical treatment.