The prognostic impact of number-indexes of lymph nodes in stage N1c colorectal cancer patients

Abstract

Objective: To evaluate the impact of number-indexes of lymph nodes for prognostic stratification in stage N1c colorectal cancer (CRC) patients. Methods: The clinicopathologic data of CRC patients with stage pTxN1cM0 who initially underwent radical surgery in Cancer Hospital, Chinese Academy of Medical Sciences and the Surveillance, Epidemiology and End Results (SEER) database from January 2010 to December 2015 were retrospectively analyzed. A total of 1 165 patients with stage N1c were included in this study. Among them, 85 patients (including 54 males and 31 females) were from Cancer Hospital, Chinese Academy of Medical Sciences and their median age was 58 (range: 32-80) years; 1 080 patients (including 566 males and 514 females) were from the SEER database and their median age was 66 (range: 24-98) years. The prognostic significance of total number of lymph node (TLN), number of negative lymph node (NLN), and log odds of positive lymph nodes (LODDS) in stage N1c CRC patients were explored. Results: The optimal cut-off value of TLN or NLN was 13, and the optimal cut-off value of LODDS was -1.43. Among the 85 patients of Cancer Hospital, Chinese Academy of Medical Sciences, the 5-year overall survival (OS) rates of stage N1c1 (TLN or NLN≥13, 69 cases) and group LODDS1 patients (LODDS≤-1.43, 69 cases) were both 80.9%, which higher than that of stage N1c2 (TLN or NLN<13, 16 cases) and group LODDS2 (LODDS>-1.43, 16 cases) patients (both 53.3%, P=0.002); In the SEER cohort, the 5-year OS rates of stage N1c1 (837 cases) and group LODDS1 patients (LODDS≤-1.43, 837 cases) were both 64.7%, which higher than that of stage N1c2 (243 cases) and group LODDS2 (LODDS>-1.43, 243 cases) patients (both 52.2%, P<0.001). Both in the NCC cohort and SEER cohort, the results of Cox multivariate analysis all demonstrated that TLN or NLN<13 was the risk factor of OS of CRC patients with stage N1c (HR=3.794, 95%CI: 1.539-9.349, P=0.004; and HR=1.588, 95%CI:1.232-2.048, P<0.001; respectively); LODDS≤-1.43 was the independent protective factor of OS of stage N1c CRC patients (HR=0.264, 95%CI: 0.107-0.650; and HR=0.630, 95%CI: 0.488-0.812; respectively). Conclusions: TLN or NLN and LODDS were all independent prognostic factors of CRC patients with stage N1c. The clinicians could use TLN or NLN and LODDS for prognostic stratification and make the different adjuvant therapeutic schemes for CRC patients with stage N1c.