Predictors of Colorectal Carcinoma in Patients With Colonic Wall Thickening

Introduction: Colonic wall thickening (CWT) is a common incidental finding on abdominal computed tomography (CT). Previous data has suggested a significant prevalence of colorectal cancer (CRC) in subjects with CWT, but predictors of CRC in those patients remain unclear. The aim of this study was to identify clinical factors associated with and predictive of colorectal cancer in subjects with CWT. Methods: Subjects with an abnormal abdominal CT and a follow-up colonoscopy between 2010-2020 were retrospectively reviewed. Patients with CWT in the CT were included in this study. Subjects with age < 18 or pre-existing gastrointestinal malignancy were excluded from this study. Focal CWT was defined as CWT that was localized and present in only one site. Pearson chi-square test and Mann-Whitney U test were used to compare categorical and continuous variables, respectively. A multivariable logistic regression model was performed to assess for factors independently associated with colorectal carcinoma in CWT subjects. Receiver operating characteristic (ROC) curve analysis was used to examine significant parameters in multivariable analysis. Area under the curve (AUC) > 0.7 was used for significant predictive value. Results: Overall, 1184 patients with abnormal abdominal CT underwent a colonoscopy with biopsy and 269 subjects (23%) with CWT on abdominal CT were identified and included in the analysis. In total, 36 subjects (13%) were found to have CRC on pathology. Distinct characteristics for patients with CRC included older age (68 vs 56; p< 0.05), lower hematocrit (29 vs 36; p< 0.05), higher platelet count (340 vs 249; p< 0.05), lower albumin (2.8 vs 3.3; p< 0.05), and more frequent focal CWT (92 vs 72%; p< 0.05) compared to those without CRC. No significant differences were found in terms of gender, race, BMI, tobacco use, BUN, AST, and ALT levels (all p >0.05). Based on the multivariable logistic regression, low hematocrit (OR 0.86; CI 0.80-0.92), elevated platelets (OR 1.003; CI 1.001-1.005), and focal CWT (OR 4.31; CI 1.06-17.59) were independently associated with CRC in subjects with CWT (all p< 0.05). In ROC curve analysis of the independent variables, AUC for hematocrit, platelets, and focal CWT was 0.773, 0.732, and 0.600 respectively. Conclusion: Based on this study, low hematocrit, elevated platelets, and focal CWT were independently associated with CRC in patients with CWT. In addition, low hematocrit and elevated platelets could potentially be used as predictors of CRC in these subjects.Figure 1.: Receiver operating characteristic (ROC) curve analysis of significant parameters associated with colorectal cancer in patients with colonic wall thickening.Table 1.: Baseline characteristics and laboratory findings of patients with incidental colonic wall thickening with malignancy vs no malignancy