Colon to Rectum
United European Gastroenterol J. 2022;10(2):147–59
PICaSSO virtual electronic chromoendoscopy accurately reflects combined endoscopic and histological assessment for prediction of clinical outcomes in ulcerative colitis
Background and aims: A composite endoscopic-histologic remission is increasingly explored as an important end point in ulcerative colitis (UC). The authors investigated combined endoscopic-histologic remission for predicting clinical outcomes at 12 months compared with endoscopic remission alone using the high-definition virtual chromoendoscopy (VCE) Paddington International virtual ChromoendoScopy ScOre (PICaSSO) and histology scores.
Methods: UC patients, prospectively enrolled from 11 international centers, underwent VCE with targeted biopsies and followed up for 12 months. Endoscopic activity was assessed by Mayo Endoscopic Score (MES), UC Endoscopic Index Severity (UCEIS) followed by VCE-PICaSSO. Robarts Histopathological Index (RHI) index ≤ 3 without neutrophils in mucosa, and Nancy Histological Index (NHI) ≤ 1 were used to define histologic remission. Combined endoscopic-histologic remission was compared with endoscopic remission alone by Cox proportional hazards model and by 2- and 3-proportion analysis using pre-specified clinical outcomes.
Results: 307 patients were recruited and 302 analyzed. There was no difference in survival without specified clinical outcomes between PICaSSO-defined endoscopic remission alone and endoscopic plus histologic remission in the rectum (hazard ratio [HR] = 0.42, 95% confidence interval [CI]: 0.16–1.11 and HR = 1.03, 95% CI: 0.42–2.52 for RHI and NHI, respectively) at 12 months. There was, however, a significant survival advantage without specified clinical outcome events for UCEIS combined with histology compared with UCEIS alone (HR = 0.30, 95% CI: 0.12–0.75, p = 0.02) at 12 months (but not combined with NHI). For MES there was no advantage for predicting specified clinical outcomes at 12 months for endoscopy alone versus endoscopy plus histology, but there were differences in 2- and 3-proportion analysis at 6 months.
Conclusion: Endoscopic remission by virtual chromoendoscopy-PICaSSO alone was similar to combined endoscopic and histologic remission for predicting specified clinical outcomes at 12 months. Larger studies with specific therapeutic interventions are required to further confirm the findings.