Pilot radiogenomic evaluation of colorectal cancer - Are there preoperative radiological features of the dMMR phenotype?

Abstract

BackgroundMicrosatellite instability (MSI) is reflective of a deficient mismatch repair system (dMMR) and occurs in approximately 15–20% of all colorectal cancers (CRC). MMR status is increasingly tested due to its prognostic and predictive significance in CRC. AimTo investigate preoperative computed tomography (CT) features associated with dMMR CRC. Materials and methodsConsecutive patients undergoing curative resection for dMMR CRC were identified from a prospectively maintained institutional database. Preoperative CT and post-resection histological features of dMMR CRC were compared to a cohort of MMR proficient (pMMR) disease. ResultsA total of 141 dMMR and 120 pMMR tumours were included. A visible primary (p = 0.039), synchronous tumours(p = 0.022), longer(p < 0.001) and thicker appearance(p < 0.001), more luminal narrowing(p = 0.032) but less obstruction(p = 0.032), fat stranding(p = 0.004), larger node size(p = 0.006) and peritoneal nodules(p = 0.034) were all associated with dMMR on preoperative CT. The median overall survival time of pMMR tumours and dMMR was 60.1 vs. 83.2 months respectively (Hazard ratio[HR] 0.66, 95% confidence interval [c.i.] 0.40 to 0.90; p = 0.04). On multivariable analysis CT free fluid (HR 4.30; 95% c.i. 1.1 to 16.4; p = 0.02), tumour calcification (HR 9.5; 95% c.i. 2.21 to 45.8; p = 0.005) and tumour margin (HR 3.50; 95% c.i. 1.05 to 11.8; p = 0.04) were all associated with worse DFS with dMMR. While dMMR tumours with CT free fluid (HR 3.10; 95% c.i. 1.1 to 8.3; p = 0.02) and tumour calcification (HR 8.90; 95% c.i. 4.57 to 51.0; p = 0.03) were associated with worse OS. ConclusiondMMR has distinct radiological features as compared to pMMR. Radiomic data may have the potential to allow for the preoperative recognition of dMMR CRC. This may provide several clinical advantages, including tailored neoadjuvant therapies and surgical strategies.