Introduction Latest NICE guidance (NG12) on criteria warranting urgent referral for investigation for colorectal cancer (CRC) includes the use of faecal occult blood testing. We present an interim analysis of the ‘Getting FIT’ project – a service evaluation of faecal immunochemical testing (FIT) in symptomatic patients suspected of having CRC.
Method In September 2016 we incorporated FIT into our Straight to test (STT) pathway with the support of our local commissioners. GPs were given access to FIT for eligible low risk patients using a specific referral form vetted by the STT team. In two week wait (2WW) referrals, excluding those for rectal bleeding, a FIT kit is posted to patients. STT patients received a vetting telephone call and were told they shall receive a FIT test. Patients are investigated as normal and FIT results, when available, used for prioritisation within our 2WW pathway. Anaemia was defined as haemoglobin <120 g/L women, <130 g/L men(WHO).
We present the results of kits analysed on the OC Sensor according to manufacturer’s protocols (EIKEN OC-Sensor io) expressed in µgHb/gFaeces. Patient outcomes are prospectively recorded on our STT database. Data on patients who returned kits between 6/9/16 and 10/2/17 are included.
Results 17 of 19 (89.5%) GP requests and 348 of 441 (78.9%) 2WW kits were returned. Median time for kit return was 7 days (Range 2–24 days) with 94.9% of returned kits received within 14 days.
343 kits yielded results that were analysable and of 325 patients undergoing investigation 14 had confirmed CRC (4.3%). FIT results were significantly higher in patients who were anaemic compared to non-anaemic patients (MannWhitney p<0.01).
24.9% of FIT samples yielded a zero result, 68.6% a faecal haemoglobin <10 µgHb/gFaeces and 91.1% a result <150 µgHb/gFaeces. Using a cut off of <10 µgHb/gFaeces the sensitivity for diagnosis of colorectal cancer was 85.7% (95% CI 57.2%–98.2%) and specificity 71.1% (95% CI 65.7%–76.0%) with a cut off of <150 µgHb/gFaeces the sensitivity was 78.6% (95%CI 49.2%–95.3%) and specificity of 94% (95% CI 91.0%–96.5%). The PPV was 11.7% and 37.9% respectively for <10 µgHb/gFaeces and <150 µgHb/gFaeces with a NPV of 99% for both. All cancers were diagnosed in patients who were either anaemic or had a FIT>150 µgHb/gFaeces.
Conclusion We report a high return rate for FIT within a 2WW pathway and a turnaround time of <14 days in most cases. The most appropriate cut-off for FIT in symptomatic patients is yet to be determined but other factors such as anaemia should be considered when designing pathway.
Disclosure of Interest None Declared
- COLORECTAL CANCER
- Faecal immunochemical test