FIT stratification in the COVID era - Is it safe for rectal bleeding?

Abstract Aims Faecal Immunochemical Tests (FIT) are increasingly used for stratification of colorectal cancer risk in symptomatic patients. FIT is not currently recommended for use in patients with rectal bleeding, but recent studies have reported its safe use. We report our experiences of FIT in patients presenting with rectal bleeding during the COVID-19 pandemic. Methods Patients referred to NUH NHS Trust with rectal bleeding from 15/04/20-15/08/20 were invited to complete a postal-based FIT (OC-Sensor). Demographics, symptoms, investigations and results were recorded. Outcomes were retrospectively reviewed using an electronic hospital system. Result 344 patients were invited to participate, with 301 (87.5%) returning FITs in accordance with testing protocol. 36 patients declined to be seen, 4 were considered not fit for investigation, and 4 had incomplete records. 257 patients were included in the final analysis with 10 CRC detected (3.9%). Rectal bleeding (257, 100%) was the most common presenting symptom followed by change in bowel habit (133, 51.8%). 10 CRC were diagnosed (3.9%). 2 CRC were detected with FIT <4 µg Hb / g faeces (2/137, 1.5%) and 8 were detected >100 µg Hb / g faeces (8/45, 17.8%). FIT result was significantly associated with CRC diagnosis (p < 0.0001). 4 with CRC had anaemia (4/53, 7.5%), 1 had thrombocytosis (1/12, 8.3%). Conclusions FIT missed 20% of CRC in this patient group with the application of a very low threshold (<4 µg Hb / g faeces). Both cancers missed by FIT were detectable on digital rectal examination, emphasising the importance of this examination in primary care.