| Methods |
Central randomisation of households identified from GP records (stratified by size, sex and average age of eligible members)
Analysis by intention to screen (however, authors report that Ss lost to follow‐up excluded from analysis)
1.7% (2,599) of randomised Ss lost to follow‐up
Blinded, standardised assessment for CRC mortality and other outcomes |
| Participants |
Individuals living in the Nottingham area aged 45‐74 years (50‐74 years main trial, 45‐74 years pilot study); 1053 (506 screen group, 547 control group) over 75 years at entry of study
Screen group: 76,466 (75,253 offered screening after exclusion); Control group: 76,384 (74, 998 after exclusion)
Trial group compatibility: age and sex similar for both groups |
| Interventions |
Biennial Haemoccult screening group Vs Control group
Haemoccult not rehydrated
Recruitment Feb 1985‐Jan 1991 (main study), Feb 1981‐June 1983 (pilot study); Screening ceased Feb 1995; follow‐up to end‐June 1995 |
| Outcomes |
Colorectal cancer screening mortality at median 7.8 years (range 4.5‐14.5 years)
Compliance with screening: 59.6% completed at least one screen (38.2% completed all FOBt offered, between 3 to 6 screens)
Haemoccult sensitivity for CRC: 53.6% (Robinson et al 95)
Positive predictive value: 1st invite = 47.1%, later invite to 1st refusers = 54.5% (first screening); Within 27 mnths = 44.8%, after 27 mnths = 42.8% (re screening); 46.2% average
2.1% (960) Ss needed full investigation after first screen; 1.2% (1090) FOB tests positive after re screening
Detection rates for adenomas and CRC higher for over 65 (7.7 vs 4.4/1000 and 3.4 vs 1.1/1000); also higher in men (7.2 vs 3.8/1000 and 2.3 vs 1.5/1000)
1778 screen group underwent COL (4% of FOBt Ss with one+ screen) one 1+ occasions)
74% (174/236) of CRC detected at screening in rectum or sigmoid colon
Number of CRC cases: Screening group 893; 236 FOBt, 249 interval, 400 non‐responders, 8 endoscopic adenoma follow‐up (1.49 per 1000 person‐years); Control group 856 (1.44 per 1000 person‐years)
Number of CRC deaths: Screening group verified 360 (0.60/1000py), Control group verified 420 (0.70/1000py); Screening group certified 350 (0.59/1000py), Control group 398 (0.67/1000py)
Deaths from all causes: 12,624 (21.1/1000py), Control group 12,515 (21.0/1000py)
Proportion of Dukes A: Screening group 20% (42 1st invite, 6 later invite, 49 rescreen, 39 interval, 3 adenoma follow‐up) and Control group 11% (95)
Mortality reduction: 15% reduction in cumulative CRC morality in screening group (OR=0.85, CI 0.74‐0.98; p=0.026) |
| Notes |
4.3% more cancers diagnosed in the screening group in comparison to control group |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Allocation concealment? |
Low risk |
A ‐ Adequate |
