FP2.12 - 'To Evaluate Lower Threshold of Polyp Size for Tattooing Routinely, a Single Trust Observational Study.'

Abstract Aim The goal of the study is to establish the lowest polyp size for clinically effective tattooing routinely. Method Retrospective data collection of colonoscopy and flexible sigmoidoscopy for bowel screening and non-bowel screening patients; 450 patients underwent polypectomy of <20mm from September 2021 to September 2022 in MTW NHS Trust. Patients were included according to 'single patient single polyp' criteria. We excluded 20+ mm polyps, multiple polyp, known FAP, lynch syndrome and other genetic predisposed colorectal polyps. Histology was obtained from electronic patient records (Allscripts). SPSS version 25.0 was used for the statistical analysis, which also included ROC curve analysis and Chi-Square test. Results A total of 450 participants, 288 males (64.0%) and 162 females (36.0%), were enrolled. Polyp sizes: 0-9mm (42.2%) and 10-19mm (57.8%). 8.0% were tattooed. Polyps found in right- hemicolon, transverse, left-hemicolon, sigmoid and rectum accordingly 29.78%, 20.5%, 9.1%, 28.4% and 12.22%. Pedunculated polyps were found in 143 individuals (31.8%), while sessile polyps were observed in 256 individuals (56.9%). Furthermore, in histological analysis, 251 individuals (55.8%) exhibited tubular adenomas and the majority of the cohort (77.6%) presented with low-grade dysplasia. Malignant invasion was detected in 27 subjects (6%). Receiver operating system (ROC) curve analysis indicated that polyp size was a predictive factor for malignancy development, with a cut-off lower point identified at 8.5 mm. Conclusions The findings confirm the advice to tattoo polyps bigger than 8-9 mm to make tracing and follow- up easier.