Volume 185 - Issue 4
A comparison of colorectal neoplasia screening tests: a multicentre community-based study of the impact of consumer choice
Authors: Douglas R Taupin and Mike Corbett
Med J Aust 2006; 185 (4): 237-239. || doi: 10.5694/j.1326-5377.2006.tb00544.x
Published online: 21 August 2006
Published online: 21 August 2006
To the Editor: The recent report by the Multicentre Australian Colorectal-neoplasia Screening (MACS) Group1 offered some intriguing findings. Participation in bowel cancer screening was lower than expected, despite a range of tests being offered. In addition, people offered a choice of different faecal occult blood tests (FOBTs) were less likely to participate than those not offered this choice. The accompanying editorial by Salkeld and colleagues concluded that “Informed consumers making smart choices about screening . . . would be a public health success”.2 We believe the available evidence indicates otherwise.
As the MACS Group study showed, participation in FOBTs was lower than in the Australian Government FOBT pilot program,3 and participation in screening by colonoscopy was lower than for other studies, including our recent Australian study.4 They suggested this may be because local general practitioners were not engaged in the project. Our study was designed to address this issue, and concluded that involvement of GPs had a small, non-significant effect on participation rates and no effect on response to invitation.4 This is not to say that involvement of GPs is undesirable.
The MACS Group study found participation in FOBTs of 27.4% when only an FOBT kit was provided and a significantly lower participation when a choice of four screening modalities was offered, with an FOBT kit provided (18.6%, P = 0.03). These data confirm the findings of a large multicentre study from the SCORE2 Working Group.5 In that study, participation in FOBT was 30.1%, while participation in either FOBT or flexible sigmoidoscopy, when a choice of the two was offered, was 27.1%. The authors did not offer this analysis, but the difference was again significant (P = 0.015, two-tailed Fisher’s exact test).
The editorial by Salkeld et al suggested that the Australian bowel cancer screening program should incorporate decision-support systems to allow informed choice of screening options. The “choice paradox” reported by the MACS and SCORE2 studies argues against this. Further, there is no evidence that decision support improves rates of participation in screening, and some explicit evidence that it has no effect.6 This should not be troubling. At this time, most colon cancer screening is still performed after consultation between patient and doctor, and in this setting informed choice is possible and desirable. Decisionmakers such as the Australian Government Department of Health and Ageing use a different process, which is explicit and quantitative,7 in determining screening policy. With the evidence available, the Australian mass-screening program should offer and evaluate a single test modality.
References
- The Multicentre Australian Colorectal-neoplasia Screening (MACS) Group. A comparison of colorectal neoplasia screening tests: a multicentre community-based study of the impact of consumer choice. Med J Aust 2006; 184: 546-550. 0_CBBEDGFJ
- Salkeld GP, Young JM, Solomon MJ. Consumer choice and the National Bowel Cancer Screening Program [editorial]. Med J Aust 2006; 184: 541-542. 0_i1091796
- Bowel Cancer Screening Pilot Monitoring and Evaluation Steering Committee. Australia’s bowel cancer screening pilot and beyond: final evaluation report. Canberra: Australian Government Department of Health and Ageing, 2005. http://www.cancerscreening.gov.au/bowel/bcaust/pilot.htm (accessed Jun 2006).
- Corbett M, Chambers SL, Shadbolt B, et al. Colonoscopy screening for colorectal cancer: the outcomes of two recruitment methods. Med J Aust 2004; 181: 423-427. 0_i1091800
- Segnan N, Senore C, Andreoni B, et al. Randomized trial of different screening strategies for colorectal cancer: patient response and detection rates. J Natl Cancer Inst 2005; 97: 347-357. 0_i1091802
- Jepson RG, Forbes CA, Sowden AJ, Lewis RA. Increasing informed uptake and non-uptake of screening: evidence from a systematic review. Health Expect 2001; 4: 116-126. 0_i1091804
- Ransohoff DF. Challenges and opportunities in evaluating diagnostic tests. J Clin Epidemiol 2002; 55: 1178-1182. 0_i1091807