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News

Self referral for cancer tests is to be piloted in England

BMJ 2015; 350 doi: https://doi.org/10.1136/bmj.h185 (Published 13 January 2015) Cite this as: BMJ 2015;350:h185

Rapid Response:

I heard this news on the radio, and my heart sank. Having read your more in depth account, sadly I feel no more reassured.

A key problem here is confusing the three related but different concepts: survival, disease-specific mortality, and overall mortality. When these are conflated with changing the paradigm from investigating relevant symptoms after initial assessment by a trained clinician (i.e. the previous UK model of 'primary care targeted gate-keeping') to open access self-referral (i.e. the US model) surely we are heading for a more expensive mess?

This is perhaps summed up in Rudy Giuliani's 2007 mayoral election campaign. He claimed prostate cancer survival was 87% in the US and 44% under 'socialized' medicine in the NHS. In fact the death rate from prostate cancer in the UK & US are almost identical - the difference quoted represents lead time bias (much earlier diagnosis in the US because of widespread PSA measurements). For a detailed analysis of this dangerously misleading rhetoric, see Risk Savvy, chapter 10.[1] Interestingly, Cancer UK - a joint sponsor of this project - also covers this aspect on its website.[2]

Negative tests for low probability serious diagnoses don't make people feel much better [3] and moreover 8 years of data from an open access melanoma clinic, originally set up because 'patients with pigmented lesions came to occupy most of the urgent outpatient appointments, to the detriment of patients with other significant skin disease,' provide a hint that such an approach does not necessarily work in terms of hard outcomes. Their study failed to show earlier detection of melanoma.[4]

People don't want not to die of a particular cancer, they want not to die prematurely, full stop. This lies behind much of the current controversy relating to prostate and breast cancer screening. There may be a reduction in disease-specific mortality, but if overall mortality is unaffected, little has been gained, as Gigerenzer elegantly shows.[1]

Finally, unless the potential damage from testing (both open-access and screening) has been quantified, how can we properly advise any given individual in front of us?[5]

As a general principle, more is not invariably better, and is very unlikely to be cheaper. Equally, to misquote Mencken, "For every complex problem there is an answer that is clear, simple, and wrong." Beware the law of unintended consequences!

Is this initiative really a good use of increasingly hard-pressed NHS resource? The evaluations will need to be very rigorous (including explicitly measuring any psychological impact, compared to controls) if national policy, and thus NHS expenditure, will depend on them.

References
1. Gigerenzer, G. Risk Savvy - How to Make Good Decisions. 2014 1st ed. Penguin. London

2. http://scienceblog.cancerresearchuk.org/2009/08/17/we-need-to-be-careful... (accessed 18 Jan 2015)

3. K. J. Petrie & R. Sherriff (2014). `Normal diagnostic test results do not reassure patients'. Evidence Based Medicine 19(1):14.

4. S.C. Weatherhead and C.M. Lawrence. (2006). Melanoma screening clinics: are we detecting moremelanomas or reassuring the worried well? British Journal of Dermatology 154, pp539–541

5. D. Shickle & R. Chadwick (1994). `The ethics of screening: is 'screeningitis' an incurable disease?'. Journal of Medical Ethics 20(1):12-18.

Competing interests: No competing interests

18 January 2015
Kit Byatt
Consultant general physician and geriatrician
Wye Valley NHS Trust
Union Walk, Hereford HR1 2ER