Background: Development of non-invasive screening modalities for IBD-related colorectal cancer (CRC) is warranted. Red Cell Distribution Width to Platelet Ratio (RPR) has been previously associated with worse outcomes in inflammatory conditions, such as pancreatitis, though its elevation has been associated with improved overall survival in advanced and right sided colon cancers. RPR has not been investigated in IBD-related CRC, despite its apparent association with both inflammatory conditions and CRC and the established role of inflammation in IBD-related CRC.
Here, we evaluate the association of RPR to IBD-related dysplasia and CRC, with the hypothesis that RPR will be elevated in individuals with cancer or dysplasia compared to those without dysplasia.

Methods: Using an institutional database, we identified patients over 18 years who underwent resection for refractory IBD or dysplasia between 2002-2021 at Penn State Hershey Medical Center. Patient characteristics and laboratory data were abstracted. Kruskal-Wallis rank sum and Dunn post-testing were employed to examine differences in RPR between patients with low- and high-grade dysplasia (LGD, HGD), invasive cancer (CA), and no dysplasia (ND). Student’s t-test and Pearson’s c²with Fischer’s exact test were used to examine biologic and steroid use where appropriate.

Results/Outcomes: 713 patients met inclusion criteria 52.6% were male and 64.1% had Crohn’s disease. Median age at time of surgery was 42. Thirty-three (6.46%) individuals had LGD, 18 (2.5%) had HGD, while 36 had CA (5.1%). Forty-two percent had been on a biologic within 6 months prior to surgery, 65% had used steroids.
Kruskal-Wallis rank sum testing revealed significant differences in RPR between groups, (p = 0.0006). Dunn post testing reveals RPR was significantly elevated in patients with LGD compared to those with ND (0.078 vs 0.054, p = 0.001); no other differences between groups were detected. Patients who used biologics within 6 months prior to surgery did not have a significantly different RPR than those who did not (0.051 vs 0.058, p = 0.058), nor did RPR differ those who used steroids in the same time interval vs those who did not (0.054 vs 0.057, p = 0.3634).

Conclusion: Preoperative RPR is significantly higher in IBD patients with LGD compared to those with ND. Further, RPR was not impacted by steroid or biologic use, suggesting factors unique to the LGD group are driving changes in RPR. Overall, this suggests further investigation into RPR as a prognostic marker for dysplasia and cancer in IBD is warranted.

Elizabeth Olecki

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