Patterns of uptake in a biennial faecal occult blood test screening programme for colorectal cancer.

AIM: The patterns of response in faecal occult blood test (FOBT) screening were studied. METHOD: A total of 251,578 people invited three times for faecal occult blood testing were categorized according to how they responded to the invitations, as follows: YNN, NYN, NNY, NYY, YNY, YYN, YYY or NNN (Y = response; N = no response). RESULTS: Overall, 163,038 (64.8%) responded at least once, and of those the biggest category was YYY (98,494, 60.4%). Of 1927 cancers diagnosed in the age group eligible for screening, there were 405 screen-detected cancers, 529 interval cancers and 993 cancers arising in people who had not been screened for over 2 years (i.e. falling outside the interval cancer category). In the YYY group, 79 screen-detected cancers would have been missed had the members of this group responded YNN and 65 had they responded YYN. In the YYN group, 104 screening cancers would have been missed if they had followed the YNN pattern. In most cases, the screen-detected cancers were diagnosed at the last invitation accepted, indicating that, after a diagnosis of cancer, further screening invitations were rarely accepted. Accordingly, the numbers of screen-detected and interval cancers were adjusted for likely pattern of response according to the proportion of the whole population falling into each pattern. With this adjustment, 40.9% of the cancers in the YYY group were screen detected compared with 29.3% in the YYN group and 20.7% in the YNN group (P < 0.001). Among those who responded once, twice and three times, the stage distribution of screen-detected cancers was similar, indicating that the prognosis of screen-detected cancer is unlikely to be poorer if not detected at the first screen. CONCLUSION: This study is the first to examine patterns of response to screening invitations and confirms the importance to individuals of continuing to accept repeated screening invitations.

The impact of population-based faecal occult blood test screening on colorectal cancer mortality: a matched cohort study.

BACKGROUND: Randomised trials show reduced colorectal cancer (CRC) mortality with faecal occult blood testing (FOBT). This outcome is now examined in a routine, population-based, screening programme. METHODS: Three biennial rounds of the UK CRC screening pilot were completed in Scotland (2000-2007) before the roll out of a national programme. All residents (50-69 years) in the three pilot Health Boards were invited for screening. They received a FOBT test by post to complete at home and return for analysis. Positive tests were followed up with colonoscopy. Controls, selected from non-pilot Health Boards, were matched by age, gender, and deprivation and assigned the invitation date of matched invitee. Follow-up was from invitation date to 31 December 2009 or date of death if earlier. RESULTS: There were 379 655 people in each group (median age 55.6 years, 51.6% male). Participation was 60.6%. There were 961 (0.25%) CRC deaths in invitees, 1056 (0.28%) in controls, rate ratio (RR) 0.90 (95% confidence interval (CI) 0.83-0.99) overall and 0.73 (95% CI 0.65-0.82) for participants. Non-participants had increased CRC mortality compared with controls, RR 1.21 (95% CI 1.06-1.38). CONCLUSION: There was a 10% relative reduction in CRC mortality in a routine screening programme, rising to 27% in participants.

Negative screening colonoscopy after a positive guaiac faecal occult blood test: not a contraindication to continued screening.

AIM: In guaiac faecal occult blood test (gFOBT) screening at least 50% of positive individuals will have a colonoscopy negative for colorectal neoplasia. The question of continuing screening in this group has not been addressed. METHOD: Data on participants aged 50-69 years with a positive gFOBT result and a negative colonoscopy were followed through the biennial screening pilot conducted between 2000 and 2007 in Scotland. RESULTS: In the first screening round, 1527 colonoscopies were negative for neoplasia. 1300 were re-invited in the second round, 905 accepted, and 157 had a positive gFOBT result, giving a positivity rate of 17.4%. Colonoscopy revealed 20 subjects with adenoma and six with invasive cancer. In the third screening round 1031 were invited for a third time and 730 accepted: 55 had a positive gFOBT test, giving a positivity rate of 7.5%. In this group, six colonoscopies revealed adenomas but there were no cancers diagnosed. In the third screening round, 108 individuals had had two positive gFOBT results and two subsequent negative colonoscopies. Eighty-four were invited for a third gFOBT, 66 accepted and 19 (25.6%) had a positive result none of whom had an adenoma or carcinoma. CONCLUSION: These data indicate that a negative colonoscopy following a positive gFOBT is not a contraindication for further screening, although this is likely to have a low yield of neoplastic pathology after two negative colonoscopies.

Results from the first three rounds of the Scottish demonstration pilot of FOBT screening for colorectal cancer.

OBJECTIVES: To assess the effects of the first three rounds of a pilot colorectal screening programme based on guaiac faecal occult blood testing (gFOBT) and their implications for a national population-based programme. METHODS: A demonstration pilot programme was conducted in three Scottish NHS Boards. Residents aged between 50 and 69 years registered on the Community Health Index were included in the study. RESULTS: In the first round, the uptake was 55.0%, the positivity rate was 2.07% and the cancer detection rate was 2.1/1000 screened. In the second round, these were 53.0%, 1.90% and 1.2/1000, respectively, and in the third round, 55.3%, 1.16% and 0.7/1000, respectively. In the first round, the positive predictive value of the gFOBT was 12.0% for cancer and 36.5% for adenoma; these fell to 7.0% and 30.3% in the second round and were maintained at 7.5% and 29.1% in the third round. The percentage of screen-detected cancers diagnosed at Dukes' stage A was 49.2% in the first round, 40.1% in the second round and 36.3% in the third round. CONCLUSIONS: These results are compatible with those of previous randomised trials done in research settings, demonstrating that population-based colorectal cancer screening is feasible in Scotland and should lead to a comparable reduction in disease-specific mortality.