| AIM:Tumor deposits(TDs)are considered as an important prognostic indictor and associated with the poor prognosis in rectal cancer patients.In the current TNM staging system,the present of TDs are categorized to the Nlc stage when patients without lymph node metastases(LNM).However,the majority of the studies investigated the prognostic value of TDs exclude the patients who received NCRT.The prognostic value of TDs in patients with NCRT remains unclear.In this study,we analyzed the prognostic value of TDs in patients with rectal cancer after NCRT treatment,and explored whether the classification method of N1c is suitable for patients with rectal cancer after NCRT.Material and Methods:A retrospective cohort study was conducted using an institutional database.The patients with rectal cancer who received NCRT and radical surgery at the Cancer Institute and Hospital of the Chinese Academy of Medical Sciences(CICAMS)between January 2004 and December 2016 were enrolled in the study.The Kaplan-Meier method and the log-rank test were used for survival analysis.Multivariate analysis was conducted using a Cox proportional hazards model.Results:Total 530 rectal cancer patients who received radical surgery after NCRT were included in this study.TDs were identified in 44(8.3%)patients.For the entire cohort,the 3-year OS and DFS were significantly lower for patients with TDs than those without TDs(3-year OS:68.7%vs 92.0%,and 3-year DFS:47.0%vs 78.8%,respectively,both P<0.001).Compared to stage ypN0 patients,stage ypN1c patients had a remarkably lower 3-year disease-free survival rate(54.2%vs 88.2%,P=0.002).A significant difference in the prognosis was observed between the LNM+TD+and LNM+TD-groups,in which the LNM+TD+patients had significantly lower 3-year DFS(42.2%vs 59.3%,P=0.036).In addition,no significant difference in 3-year disease-free survival rate was observed among subgroups of patients with stage ypN1a,ypN1b,and ypN1c disease(65.6%vs 57.2%vs 54.2%,P=0.86).However,stage ypN2 patients with TDs had a remarkably lower disease-free survival rate than the patients without TDs(25.0%vs 53.1%,P=0.004).Multivariate analyses showed that the presence of lymph node metastases,tumour regression grade,vascular invasion,and TDs were strongly associated with the prognosis.Conclusion:Our study highlighted the poor prognostic effect of TDs.in patients with rectal cancer after NCRT.The classification of TDs was reasonable for ypN0 and ypN1 stage patients in the current TNM staging system but inappropriate for ypN2 stage patients.Patients with ypN2TD(+)disease had a remarkably lower 3-year DFS than patients with ypN2TD(-)disease.The classification of TDs should be refined in ypN2 stage patients with rectal cancer after NCRT.AIM:Distant metastasis has become the most important factor to damage the long-term prognosis of patients with rectal cancer after neoadjuvant chemoradiotherapy(NCRT),and NCRT may change the metastasis pattern,including the metastatic site and time,according to the previous studies.It is of great clinical significance to fully study and understand the characteristics of distant metastases in patients with rectal cancer after NCRT.The purpose of this study is to investigate the pattern of distant metastasis,and establish a risk-predict model for effectively predicting distant metastasis.Material and methods:This study included two groups of patients.The NCRT group including 373 rectal cancer patients who received NCRT and radical surgery at the Cancer Institute and Hospital of the Chinese Academy of Medical Sciences(CICAMS)from January 2004 to December 2015.The control group included 961 patients who received radical surgical resection and received postoperative chemoradiotherapy(PCRT)from January 2008 to December 2015 in the same hospital.The clinicopathological characteristics of patients were collected and analyzed,and the distant metastases patterns of the two groups were compared after propensity score-matching.In order to establish a nomogram model,the NCRT group was randomly divided into a development group and a validation group according 6:4 ratio.Results:The NCRT group had significantly lower local recurrence rate than PCRT group(4.1%vs 10.3%,P=0.004).However,there was no significantly difference in the distant metastasis rate between the NCRT group and the PCRT group(28.2%vs.27.9%,P=0.92),and the predominant sites of distant metastases were lungs in both the NCRT group and PCRT group(the incidences:12.2%and 13.5%,respectively),followed by the liver(the incidences:6.5%and 6.7%,respectively).However,the occurrence of distant metastases in the NCRT group was delayed compared with the PCRT group(median time 21.2 months vs.16.4 months).After COX univariate analysis and LASSO regression analysis,the three variables of ypTNM stage,tumor regression grade(TRG)and maximum lymph node regression grade(LRGmax)were significant correlation with distant metastasis.The nomogram risk prediction model was developed to predict distant metastasis risk.The C-index of the nomogram in the development group and validation group are 0.75(95%CI:0.69-0.81)and 0.80(95%CI:0.73-0.87),respectively.The calibration curve indicated that the risk of distant metastasis at 3 and 5 years after surgery according to nomogram was in good agreement with the actual situation.Decision curve analysis(DCA)and time-dependent ROC curve suggested that the nomogram predictability was better than ypTNM staging system.According to the nomogram score,patients were divided into low-risk group,middle-risk group and high-risk group for distant metastasis,and the discrimination of nomogram was better than that of ypTNM stage.Patients in the low-risk group and the middle-risk group could not benefit from receiving postoperative adjuvant chemotherapy,while patients in high-risk group could improve overall survival by receiving postoperative adjuvant chemotherapy.Conclusion:NCRT did not change the predominant organs of distant metastases in patients with rectal cancer,but it would delay the appearance time of distant metastases.Therefore,the follow up strategy for rectal patients with NCRT should be adjusted.The nomogram model for predicting the risk of distant metastasis in patients with rectal cancer after NCRT had better predictive efficacy than the TNM staging system.The nomogram model had good clinical practicality,which can help to guide individualized postoperative follow-up and treatment strategies. |
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