Pre-operative Predictive Factors for Intra-operative Pathological Lymph Node Metastasis in Rectal Cancers

Background: A number of clinicopathologic factors have been found to be associated with pathologicallymph node metastasis (pLNM) in rectal cancer; however, most of them can only be identified by expensivehigh resolution imaging or obtained after surgical treatment. Just like the Child-Turcotte-Pugh (CTP) and themodel for end-stage liver disease (MELD) scores which have been widely used in clinical practice, our study wasdesigned to assess the pre-operative factors which could be obtained easily to predict intra-operative pLNM inrectal cancer.
Methods: A cohort of 469 patients who were treated at our hospital in the period from January2003 to June 2011, and with a pathologically hospital discharge diagnosis of rectal cancer, were included. Clinical,laboratory and pathologic parameters were analyzed. A multivariate unconditional logistic regression model,areas under the curve (AUC), the Kaplan-Meier method (log-rank test) and the Cox regression model were used.
Results: Of the 469 patients, 231 were diagnosed with pLNM (49.3%). Four variables were associated with pLNMby multivariate logistic analysis, age<60 yr (OR=1.819; 95% CI, 1.231-2.687; P=0.003), presence of abdominalpain or discomfort (OR=1.637; 95% CI, 1.052-2.547; P=0.029), absence of allergic history (OR=1.879; 95%CI, 1.041-3.392; P=0.036), and direct bilirubin≥2.60 μmol/L (OR=1.540; 95% CI, 1.054-2.250; P=0.026). Thecombination of all 4 variables had the highest sensitivity (98.7%) for diagnostic performance. In addition, age<60yr and direct bilirubin≥2.60 μmol/L were found to be associated with prognosis.
Conclusion: Age, abdominalpain or discomfort, allergic history and direct bilirubin were associated with pLNM, which may be helpful forpreoperative selection.