Inappropriate use of the faecal occult blood test outside of the National Health Service colorectal cancer screening programme

Abstract

The faecal occult blood test (FOBT) is the screening test validated for use in the National Health Service (NHS) Bowel Cancer Screening Programme (BCSP) after trials demonstrated a 16% reduction in colorectal cancer-specific mortality. FOBT is not validated for use outside the BCSP. The aim was to investigate the number of FOBTs performed outside of the NHS BCSP at a single centre. All FOBTs performed over 1 year were identified. Basic patient demographics, requesting physician and FOBT results were obtained. Referrals and outcomes of the investigation following the FOBT were collected. A total of 758 FOBTs were requested in 701 patients (352 female; median age 69; range 16-99). The majority (91%) were requested by general practitioners. A total of 515 out of 758 tests (68%) were performed in patients outside the NHS BCSP age range. Thirty-seven out of 86 positive FOBTs were investigated, diagnosing four rectal cancers and two polyps. Forty-nine out of 87 patients with a positive FOBT were not investigated further by the requesting physician or the test repeated. Of the remaining 672 FOBTs, 615 were negative and 57 were either incomplete or unsuitable for analysis. A total of 111 patients (18%) were referred to hospital and 105 of these had FOBT performed as part of the referral process. Our study demonstrates significant misuse of the FOBT outside the NHS BCSP. Inappropriate use leads to false positives and exposes patients to unnecessary risk. False negatives provide reassurance to patients who may have symptoms that should be investigated. The FOBT should not be available to physicians in either primary or secondary care and be restricted to NHS BCSP.