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.

Interval cancers in a FOBT-based colorectal cancer population screening programme: implications for stage, gender and tumour site.

BACKGROUND: Between 2000 and 2007, a demonstration pilot of biennial guaiac faecal occult blood test (GFOBT) screening was carried out in Scotland. METHODS: Interval cancers were defined as cancers diagnosed within 2 years (ie, a complete screening round) of a negative GFOBT. The stage and outcome of the interval cancers were compared with those arising contemporaneously in the non-screened Scottish population. In addition, the gender and site distributions of the interval cancers were compared with those in the screen-detected group and the non-screened population. RESULTS: Of the cancers diagnosed in the screened population, interval cancers comprised 31.2% in the first round, 47.7% in the second, and 58.9% in the third, although this was due to a decline in the numbers of screen-detected cancers rather than an increase in interval cancers. There were no consistent differences in the stage distribution of interval cancers and cancers from the non-screened population, and, in all three rounds, both overall and cancer-specific survival were significantly better for patients diagnosed with interval cancers (p<0.01). The percentage of cancers arising in women was significantly higher in the interval cancer group (50.2%) than in either the screen-detected group (35.3%, p<0.001) or the non-screened group (40.6%, p<0.001). In addition, the proportion of both right-sided and rectal cancers was significantly higher in the interval cancer group than in either the screen-detected (p<0.001) or non-screened (p<0.004) groups. CONCLUSIONS: Although GFOBT screening is associated with substantial interval cancer rates that increase with screening round, the absolute numbers do not. Interval cancers are associated with a better prognosis than cancers arising in a non-screened population, and GFOBT appears to preferentially detect cancers in men and the left side of the colon at the expense of cancers in women and in the right colon and rectum.

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.

A survey of reporting of colorectal cancer in Scotland: compliance with guidelines and effect of proforma reporting.

AIMS: The main purpose of the study was to present a baseline audit of reporting of colorectal cancers resection specimens in Scotland, audited against the Royal College of Pathologists (RCPath) standards (2007) and NHS Quality Improvement Scotland (NHS QIS) standards. METHODS: 50 consecutive rectal and 50 consecutive colonic cancer cases from 2011 were audited from 10 Scottish health boards involved in colorectal cancer reporting (n=953). The rates of reporting of serosal involvement, extramural venous invasion (EMVI) and the mean numbers of lymph nodes found were audited against RCPath standards and compared between units that routinely used a reporting proforma versus those that did not. RESULTS: The performance in reporting of rectal cancer was generally worse than for colonic cancer, with only three units meeting the RCPath standards for reporting of rectal cancer. There were significant differences between units that routinely used a proforma, with the non-proforma group failing to meet the minimum standards for both serosal involvement (6%) and EMVI (24%). In the non-proforma group, 56% of rectal cases had a mean lymph node count of 12 or more compared with 81% in the proforma group. CONCLUSIONS: Significant differences exist in the frequencies with which important adverse prognostic features are reported by pathologists across 10 Scottish health boards. This has potential implications for patient care. Health boards that make routine use of reporting proformas are more likely to meet RCPath guidelines for reporting of these important pathological parameters.

Effect of gender, age and deprivation on key performance indicators in a FOBT-based colorectal screening programme.

OBJECTIVES: To assess the effect of gender, age and deprivation on key performance indicators in a colorectal cancer screening programme. SETTING: Between March 2000 and May 2006 a demonstration pilot of biennial guaiac faecal occult blood test (gFOBT) colorectal screening was carried out in North-East Scotland for all individuals aged 50-69 years. METHODS: The relevant populations were subdivided, by gender, into four age groups and into five deprivation categories according to the Scottish Index of Multiple Deprivation (SIMD), and key performance indicators analysed within these groups. RESULTS: In all rounds, uptake of the gFOBT increased with age (P < 0.001), decreased with increasing deprivation in both genders (P < 0.001), and was consistently higher in women than in men in all age and all SIMD groups. In addition, increasing deprivation was negatively associated with uptake of colonoscopy in men with a positive gFOBT (P < 0.001) although this effect was not observed in women. Positivity rates increased with age (P < 0.001) and increasing deprivation (P < 0.001) in both genders in all rounds, although they were higher in men than in women for all age and SIMD categories. Cancer detection rates increased with age (P < 0.001), were higher in men than in women in all age and SIMD categories, but were not consistently related to deprivation. In both genders, the positive predictive value (PPV) for cancer increased with age (P < 0.001) and decreased with increasing deprivation (P < 0.001) in all rounds and was consistently higher in men than in women in all age and SIMD categories. CONCLUSIONS: In this population-based colorectal screening programme gender, age, and deprivation had marked effects on key performance indicators, and this has implications both for the evaluation of screening programmes and for strategies designed to reduce inequalities.

Effect of repeated invitations on uptake of colorectal cancer screening using faecal occult blood testing: analysis of prevalence and incidence screening.

OBJECTIVE: To analyse the effects of prevalence and incidence screening on uptake and detection of cancer in an ongoing, dynamic programme for colorectal screening using faecal occult blood testing. DESIGN: Analysis of prevalence and incidence screening. SETTING: Three rounds of biennial colorectal screening using the guaiac faecal occult blood test in east and north east Scotland, March 2000 to May 2007. PARTICIPANTS: Adults aged 50-69. MAIN OUTCOME MEASURES: Uptake of screening, test positivity (percentage of those invited who returned a test that was positive and triggered an invitation for colonoscopy), positive predictive value, and stage of cancer. RESULTS: Of 510 990 screening episodes in all three rounds, 248 998 (48.7%) were for prevalence, 163 483 (32.0%) were for first incidence, and 98 509 (19.3%) were for second incidence. Uptake of a first invitation for prevalence screening was 53% and for a second and third invitation was 15% and 12%. In the cohort invited for the first round, uptake of prevalence screening rose from 55% in the first round to 63% in the third. The uptake of first incidence screening on a first invitation was 54% and on a second invitation was 86% and on a first invitation for second incidence screening was 46%. The positivity rate in prevalence screening was 1.9% and the uptake of colonoscopy was 87%. The corresponding values for a first incidence screen were 1.7% and 90% and for a second incidence screen were 1.1% and 94.5%. The positive predictive value of a positive faecal occult blood test result for cancer was 11.0% for prevalence screening, 6.5% for the first incidence screen, and 7.5% for the second incidence screen. The corresponding values for the positive predictive value for adenoma were 35.5%, 29.4%, and 26.7%. The proportion of cancers at stage I dropped from 46.5% for prevalence screening to 41% for first incidence screening and 35% for second incidence screening. CONCLUSIONS: Repeat invitations to those who do not take up the offer of screening increases the number of those who accept, for both prevalence screening and incidence screening. Although the positive predictive value for both cancer and adenomas fell between the prevalence screen and the first incidence screen, they did not fall between the first and second incidence screens. The deterioration in cancer stage from prevalence to incidence screening suggests that some cancers picked up at incidence screening may have been missed on prevalence screening, but the stage distribution is still favourable. These data vindicate the policies of continuing to offer screening to those who fail to participate and continuing to offer biennial screening to those who have accepted previous offers.