P122 Low Risk of new dysplastic lesions during inflammatory bowel disease surveillance with dye-cromoendoscopy: a multicenter population-based retrospective study

Abstract

Abstract Background The 21st century has witnessed advances in endoscopic surveillance technology such as high-definition imaging and virtual or dye-based chromoendoscopy, which have led to increased detection of dysplasia. It is unknown the rates of new dysplastic lesions or cancer progression with these techniques though it seems lower than previously described. Methods We developed a multicenter, population-based and retrospective cohort from 7 Spanish hospitals from the Group of Inflammatory bowel disease of Castilla Y Leon (GEICYL) including sequentially all patients with inflammatory bowel disease and colonic dysplastic lesions completely resected (R0) in surveillance with dye-based indigo carmine chromoendoscopy between January 2013 and December 2019, with a minimum endoscopic follow-up of 12 months. The aim was to evaluate the risk of developing more advanced metachronous neoplasia during follow-up, analysing possible associated risk factors. Results A total of 99 patients and 148 index lesions (145 low-grade dysplasias [LGD] and 3 high-grade dysplasias [HGD]) with a medium follow-up of 48.76 months (IQR: 36.34 – 67.15) were included. Patients and IBD baseline characteristics are reflected in table 1. During follow-up, 37 patients developed 97 new dysplastic lesions (92 LGD, 4 HGD and 1 CRC) and 1 patient developed multifocal invisible dysplasia (3 HGD). The overall incidence rate for new dysplastic lesions was 0.23 per 100 patient-year, 1.15 per 100 patients at 5 years and 2.29 per 100 patients at 10 years (Figure 1). Personal history of dysplasia was associated with higher risk of developing any grade of dysplasia during follow-up (p 0.025), meanwhile, left colon lesions was associated with a lower risk (p 0.043). 6 patients developed more advanced lesions (5 patients HGD and 1 CCR) with an incidence rate at year and 10 years of 1% and 14% respectively; LGD lesion >1cm was a risk factor for developing HGD or CRC (p 0.041), meanwhile LGD lesion < 1 cm was a protective factor (p 0.013) (table 2,3). 1/8 patients (13%) with HGD lesions developed CRC during follow-up. 3 patients were colectomized (2 by HGD and 1 by CRC). Neither mesalamine treatment or immunosuppressive or biological treatment were associated with a lower risk of dysplasia development. Conclusion Risk of dysplasia progression to advanced neoplasia and specifically risk of new neoplastic lesions after endoscopic resection of colitis-associated dysplasia are very low in our cohort with dye-chromoendoscopy. Personal history of dysplasia, as risk factor, and left colon location, as protective factor, were associated with new dysplastic lesions. Finally, size above 1 cm was the only risk factor for progression to advanced lesions.