The Paddington International Virtual Chromoendoscopy Score (PICaSSO) can be considered in clinical practice and clinical trials to grade endoscopic inflammatory activity and define mucosal healing in patients with ulcerative colitis, according to the results of a prospective, multicenter study published in Gastroenterology.
Although endoscopic and histologic remission are important goals in the treatment of ulcerative colitis, a score is needed to accurately describe endoscopic remission, not just as the absence of mucosal changes but with a better correlation to histologic remission. The PICaSSO, a recently developed score, is the first to use virtual electronic chromoendoscopy to assess vascular and mucosal features of healing in ulcerative colitis.
Researchers investigated the correlation of PICaSSO and other established endoscopic scores against multiple histologic indices and prospectively assessed outcomes. They took targeted biopsies for assessment and obtained follow-up data at 6 and 12 months after colonoscopy in 307 patients from 11 international centers.
They found that although all the endoscopic scores correlated strongly with histology, the correlation of PICaSSO with all histology scores was significantly better than either the Mayo Endoscopic Score or the Ulcerative Colitis Endoscopic Index of Severity. A PICaSSO of 3 or less detected histologic remission by the Robarts Histopathology Index (≤3 + absence of neutrophils) with area under the receiver operator characteristics (AUROC) of 0.90 and the Nancy Histological index (≤1) of AUROC 0.82.
The interobserver agreement for PICASSO was 0.88. At 6- and 12-month follow-up, a PICaSSO of 3 or less predicted better outcomes than a PICaSSO of more than 3 and was similar to histologic remission.
The authors concluded, “In this first real-life multicenter study, the PICaSSO score correlated strongly with multiple histological indices. Furthermore, PICaSSO score predicted specified clinical outcomes at 6 and 12 months similar to histology.”
Iacucci M, Smith SCL, Bazarova A, et al. An international multicenter real-life prospective study of electronic chromoendoscopy score PICaSSO in ulcerative colitis. Gastroenterology. Published online December 18, 2020. doi:10.1053/j.gastro.2020.12.024