Interval cancers in a national colorectal screening programme based on faecal immunochemical testing: Implications for faecal haemoglobin concentration threshold and sex inequality.

OBJECTIVE: To compare interval cancer proportions (ICP) in the faecal immunochemical test (FIT)-based Scottish Bowel Screening Programme (SBoSP) with the former guaiac faecal occult blood test (gFOBT)-based SBoSP and investigate associations between interval cancer (IC) and faecal haemoglobin concentration (f-Hb) threshold, sex, age, deprivation, site, and stage. METHODS: The ICP data from first year of the FIT-based SBoSP and the penultimate year of the gFOBT-based SBoSP were compared in a prospective cohort design. RESULTS: With FIT, 801 colorectal cancers (CRCs) were screen detected (SDC), 802 were in non-participants, 548 were ICs, 39 were colonoscopy missed and 72 were diagnosed after incomplete screening; with gFOBT: 540, 904, 556, 45, and 13, respectively. FIT had a significantly higher proportion of SDC compared to IC than gFOBT. For FIT and gFOBT, ICP was significantly higher in women than men. As f-Hb threshold increased, ICP increased and, for any f-Hb threshold for men, a lower threshold was required for comparable ICP in women. In Scotland, the current threshold of ≥80 µg Hb/g faeces would have to be lowered to ≥40 µg Hb/g faeces for women to achieve sex equality for ICP. In the FIT-based SBoSP, there were four times as many stage I SDC than IC. This was reversed in advanced stages, with twice as many stage IV CRC diagnosed as IC versus SDC. CONCLUSIONS: Reducing the numbers of IC requires lowering the f-Hb threshold. Using different f-Hb thresholds for women and men could eliminate the sex disparity, but with additional colonoscopy.

Emergency and non-emergency routes to cancer diagnoses in 2020 and 2021: A Population-based study of 154,863 patients.

INTRODUCTION: The COVID-19 pandemic disrupted normal pathways to cancer diagnosis, particularly for screening and non-acute symptomatic patients. While reductions in overall cancer diagnoses have been reported elsewhere, any differential effects on emergency presentations, which are associated with poorer outcomes, have not been described. MATERIAL AND METHODS: Cross-sectional descriptive study from 2015 to 2021, based on International Cancer Benchmarking Partnership methods, where emergency route to diagnosis is defined as presenting as an emergency admission in the 30 days prior to cancer incidence date. Acute hospital records and cancer registrations were individually linked. Includes all individuals with a new diagnosis of specific cancers on the national cancer registry. RESULTS: All cancers included showed reductions in non-emergency diagnoses in 2020, with varying recovery in 2021. The largest reductions in non-emergency diagnoses of about a third were for colorectal and cervical cancers in 2020. Non-emergency diagnoses of prostate cancer remained lower but upper GI higher in 2021. Emergency routes to diagnosis were significantly higher in 2020 for breast, cervical, colorectal and upper GI cancers and were higher in 2021 for breast and cervical cancers. The absolute magnitude of reductions in non-emergency diagnoses was greater than any increases in emergency diagnoses. CONCLUSIONS: In 2020, there were large reductions in numbers of cancers diagnosed through non-emergency pathways in Scotland, while those diagnosed via emergency routes fell only for prostate cancer. Some effects persisted or emerged through 2021. It is likely that opportunities to diagnose cancers in a favourable, elective manner have been lost. Further work is needed to describe outcomes among these patients.