ABSTRACT
Aim: UK endoscopy services faced challenges prior to SARS-CoV- 2. During the first months of the pandemic, activity fell by 92%. Consequently, in June 2020, NHS England recommended Faecal immunochemical testing (FIT) for all symptomatic patients to rationalise endoscopy. This study sought to evaluate the real-world safety and effectiveness of this approach. Method(s): Patients referred with suspected colorectal cancer (CRC) on the two-week wait (2ww) pathway were asked to complete a FIT. Samples were analysed using the OC-Sensor. While a FIT > 100 mug Hb/g was used to prioritise investigation, all patients were subsequently investigated. FIT results were correlated with diagnostic studies. Result(s): Between January to December 2020, 48% of referred patients had a FIT. 26% was above the threshold of 10 mug Hb/g in and 8.6% above 100mug Hb/g. 347 patients also had a positive FIT but were not referred. The sensitivity, specificity, NPV, PPV, and likelihood ratio at a threshold of 10mug Hb/g were 78.6%(95%CI0.69-0.86%), 36.8%(95%CI0.34-0.39%), 7.1%(95%CI0.057-0.088%), 96.5% (95%CI 0.95-0.98%) and 1.24 respectively. At 100mug Hb/g, this was 37.8%(95%CI0.29-0.48%), 80.2%(95%CI0.78-0.82%), 10.5%(95%CI0.077-0.14%), 95.4%(95%CI0.94-0.96%) and 1.9 respectively. Conclusion(s): FIT shows promise in trials, but our data raises concerns about real-world performance. Only 48% of patients completed FIT before referral, and we are exploring why 347 FIT-positive patients were not referred. While results are broadly congruent with reported literature that suggested 10% of CRC are FIT negative, this is greater in our cohort at 25%. This raises concerns about the safety of discharging patients based on FIT alone. Modifying the FIT threshold may be required and improving safety-netting where FIT is known to be ineffective, such as patients with iron deficiency anaemia.
ABSTRACT
Aim: NHS England, in June 2020, published guidance that required Faecal Immunochemical Testing (FIT) for all symptomatic patients, including high and low-risk patients, prior to the referral to the suspected colorectal cancer pathway. FIT was utilised as a stratification tool to ration limited diagnostic services during the COVID-19 pandemic. This study investigates the feasibility of the recommended guidelines in a Northeast London catchment population. Method(s): Patients considered for referral on the two-week wait (2WW) pathway for suspected colorectal cancer provided stool samples for FIT analysis. Samples were analysed at a single centre using an OC-Sensor FIT-Screening System, with FIT >10 mug Hb/g warranting urgent investigation. Results were then retrospectively correlated with patient records. Result(s): From January 2021 to June 2021, there was a 111.4% increase in FIT requests compared to the previous 12 months. However, of the 8475 samples, 19% (1607) were unprocessed by the lab. There were 20% (1718) FIT positive above the NICE threshold of 10 mug Hb/g, while 61% (5150) were negative. 27% underwent referral and urgent investigation. 314 patients were also identified as FIT positive, though not referred. Conclusion(s): This study highlights concerns about FIT's real-world feasibility and acceptance as a risk stratification tool prior to referral. Despite recommendations implemented in mid-2020, significant proportions of patients referred lacked a FIT result prior to referral. Furthermore, literature suggests FIT is widely accepted;however, this is not congruent with the study results demonstrating a substantial proportion of 19% of unprocessed samples due to incorrectly labelled and inadequate samples received by the lab. This, therefore, raises concerns about relying on FIT and the potential delays in the diagnosis of CRC due to repeating unprocessed samples. Finally, we are investigating the outcome for the 314 patients with FIT results above the 10 mug Hb/g threshold that were not referred.