Table 1.
Characteristics of trials of Hemoccult screening for colorectal cancer
| Mandel et al (1993)8 | Hardcastle et al (1996)9 | Kronborg et al (1996)10 | Kewenter et al (1994)11 | Winawer et al (1993)12 | Faive et al (1991)13 | |
|---|---|---|---|---|---|---|
| Study population | Minnesota, USA, volunteers aged 50-80 | Nottingham, UK, subjects aged 45-74 | Funen, Denmark, inhabitants aged 45-75 | Gothenburg, Sweden, inhabitants aged 60-64 | New York, USA, clients attending clinic aged ⩾40 | Burgundy, France, inhabitants aged 45-74 |
| Study groups (No of subjects allocated) | Annual screen (15 570) Biennial screen (15 587) Control (15 394) | Biennial screen (76 466) Control (76 384) | Biennial screen (30 967) Control (30 966) | 2 screens, 16-22 months apart, (34 144) Control (34 164) | Regular attenders*: Annual screen (7168) Control (2109) First time attenders*: Annual screen (5806) Control (6673) | 3 screens planned, 1-2 years apart, (45 500) Control (45 500) |
| Hemoccult screening: | ||||||
| Type of tests | 82.5% rehydrated | Unhydrated | Unhydrated | Most rehydrated (all of 2nd screen) | Most unhydrated | Unhydrated |
| Screening periods | 1975-82 and 1986-92 | Recruitment Feb 1981 to Jan 1991, screening ceased Feb 1995 | Aug 1985 to Aug 1995, 5 screening rounds | Started 1982, rescreening offered 16-22 months later | Recruitment Mar 1975 to Jul 1979 | 1st screen Jan-Jul 1988 and Jan-Jul 1989 2nd screen Jan-Jul 1990 |
| Follow up | Continuing at last report in 1993 | To Jun 1995 (possibly continuing) | Continues | Continues | Ceased Jul 1984 | Continues |
| Completed screening | Annual screen: 90% ⩾1 screen, 46% all screens Biennial screen: 90% ⩾1 screen, 60% all screens | 60% ⩾1 screen, 38% all screens (3-6) | 67% 1st screen, 46% all 5 screens (rescreening offered only to prior attenders) | 63% 1st screen, 60% 2nd screen, 68% ⩾1 screen | Regular attenders: 70% 1st screen First timers: 80% 1st screen, 20% 2nd screen, 16% 3rd screen | 54% 1st screen, 56% 2nd screen, 64% ⩾1 screen |
| Positivity rate | 2.4% unhydrated, 9.8% rehydrated | 2.1% 1st screen, 1.2% 2nd screen | 1.0% 1st screen, 0.8% 2nd screen, 0.9% 3rd screen, 1.3% 4th screen, 1.8% 5th screen | Unhydrated 1st screen: 1.9% 1st screen, 8.0% 2nd screen Rehydrated 1st screen: 5.8% 1st screen, 4.8% 2nd screen | 1.4% regular attenders 2.6% first timers | 2.3% 1st screen |
*
All offered sigmoidoscopy.