Differences in Factors Predicting Lymph Node Metastasis Between pT1 Rectal Cancer and pT1 Colon Cancer: A Retrospective Study

Abstract

Background Studies have demonstrated conflicting results regarding factors that predict lymph node metastasis (LNM) in pT1 colorectal cancers. We hypothesized that these discrepancies could be related to different factors predicting LNM between rectal and colon cancer. This study aimed to compare predicting factors for LNM between pT1 rectal and colon cancer. Methods This retrospective study evaluated a prospectively maintained database that included 380 patients with pT1 colorectal cancer from January 2010 to December 2020. Patients were grouped according to whether they had rectal or colon cancer, with or without LNM, and factors predicting LNM were analyzed. Results In pT1 rectal cancer, LNM was associated with deeper submucosal (SM) invasion (P = .024) and a higher proportion of poorly differentiated tumors (P = .006). In pT1 colon cancer, LNM was associated with a higher proportion of moderately/poorly differentiated tumors (P = .002) and lymphatic invasion (P = .004). In the multivariate analysis for rectal cancer, depth of SM invasion (≥3000 μm) was an independent predictive factor for LNM (95% confidence interval [CI], 1.48-27.94; P = .013), whereas for colon cancer, moderately/poorly differentiated tumors (95% CI, 1.38-8.13; P = .008) and lymphatic invasion (95% CI, 1.44-11.78; P = .008) were independent predictive factors for LNM. Discussion There were distinct differences in the factors predicting LNM between pT1 rectal cancer and colon cancer. These results suggest the necessity in differentiating between rectal and colon cancer when performing studies on LNM in pT1 colorectal cancer.

Additional staining for lymphovascular invasion is associated with increased estimation of lymph node metastasis in patients with T1 colorectal cancer: Systematic review and meta‐analysis

“…However, CD31 staining for VI did not have sufficient data for evaluation because it was often assessed in conjunction with elastic staining, 37,76,83 and only a few studies evaluated CD31 staining alone for VI. 38,42 In a previous study, CD31 staining was found to be less likely to detect VI than elastic staining and was not associated with prognosis. 103 Further studies are needed to elucidate the optimal choice of staining methods and their appropriate utilization.…”

“…We identified 3451 records from various databases until December 10, 2022. After screening for duplicates, we included 64 studies with 18,097 patients, 17,18,22,36–96 of them, 59 studies evaluated the diagnostic accuracies of HE and additional staining for LVI in LNM in patients with T1 CRC, four reported the interobserver agreement among pathologists for positive LVI, and one reported both outcomes, with eight studies comprising 4062 patients in multivariable analysis.…”

“…The additional staining for VI did not show significant differences between EVG and VB staining among elastic staining. However, CD31 staining for VI did not have sufficient data for evaluation because it was often assessed in conjunction with elastic staining, 37,76,83 and only a few studies evaluated CD31 staining alone for VI 38,42 . In a previous study, CD31 staining was found to be less likely to detect VI than elastic staining and was not associated with prognosis 103 .…”