A comparative prognostic performance of definitions of Crohn-like lymphoid reaction in colorectal carcinoma

Background: The prognostic potential of Crohn-like lymphoid reaction (CLR) in colorectal carcinoma (CRC) has been investigated through the assessment of different criteria. Methods: The prognostic impact of CLR was investigated in 636 CRC patients to compare methods from previously published articles. These methods included CLR measured by number of lymphoid aggregates (LAs) (CLR count), LA size greater than or equal to 1 mm (CLR size), CLR density with a cutoff value of 0.38, and subjective criteria as defined by intense CLR. Results: In univariate survival analysis, CLR-positive CRC as defined by the four aforementioned methods was associated with better overall survival (OS) (hazard ratio [HR], 0.463; 95% confidence interval [CI], 0.305 to 0.702; p <.001; HR, 0.656; 95% CI, 0.411 to 1.046; p =.077; HR, 0.363; 95% CI, 0.197 to 0.669; p =.001; and HR, 0.433; 95% CI, 0.271 to 0.690; p <.001, respectively) and disease-free survival (DFS) (HR, 0.411; 95% CI, 0.304 to 0.639; p <.001; HR, 0.528; 95% CI, 0.340 to 0.821; p =.004; HR, 0.382; 95% CI, 0.226 to 0.645, p=.004; and HR, 0.501; 95% CI, 0.339 to 0.741; p<.001, respectively) than CLR-negative CRC, regardless of criteria with the exception of OS for CLR density. In multivariate analysis, two objective criteria (CLR count and CLR density) and one subjective criterion (intense CLR) for defining CLR were considered independent prognostic factors of OS and DFS in CRC patients. Conclusions: CLR has similar traits regardless of criteria, but CLR-positivity should be defined by objective criteria for better reproducibility and prognostic value.