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FEATURE: Zosia Kmietowicz Better safe than sorry? BMJ 2007; 335: 1182-1184 [Full text]

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Date for publication of COMARE report

Zosia Kmietowicz   (7 December 2007)

Victim of Medical Investigative Technology

U Shaikh, Huw Lewis-Jones   (11 December 2007)

Date for publication of COMARE report 7 December 2007
Zosia Kmietowicz, Freelance Journalist London N16 7QJ Send response to journal: Re: Date for publication of COMARE report	I learned since this article went to the press that the Committee on Medical Aspects of Radiation in the Environment (COMARE) will be publishing its report on the safety CT screening on December 19 2007, not in January as stated. Competing interests: None declared
Victim of Medical Investigative Technology 11 December 2007
U Shaikh, Radiology SpR University Hospital Aintree, Longmoor Lane, Liverpool, L9 7AL, Huw Lewis-Jones Send response to journal: Re: Victim of Medical Investigative Technology	I read with interest the article about commercial body CT scanning and agreed with the caution voiced but I felt the article did not go far enough in highlighting the consumerist nature of these scans. Except for anecdotal inference there are no peer reviewed scientific studies to suggest that they confer any advantage with regards to morbidity or mortality. On the contrary the prevalence of diagnosed ‘pseudodisease’ can be as high 90% and follow-on investigations for positive or indeterminate findings will likely be absorbed into the NHS. Furthermore, ‘well’ patients are mired in uncertainty while they wait for their interval scan and ancillary tests on indeterminate lung nodules and sub centimetre low attenuation lesions in the liver. The majority of these scans are self referred so no doctor has impartially advised on the risks, benefits and uncertainties involved prior to scanning. Concepts such as lead time and length bias are central to screening tests but informed consent involving them would be impractical. Though it seems intuitively obvious that if one detects a cancer early a cure can achieved, patients undergoing CT screening investigations don’t necessarily appreciate that to confer an advantage the disease has to have an effective treatment and has to be found at a stage to benefit from this treatment. Well asymptomatic young and middle-aged patients have a low pre-test probability and wouldn’t benefit from a screening test. Furthermore non- symptom led, non-focused investigations are rife for misinterpretation and error. Kakinuma et al found that half the lung cancers detected on helical CT were retrospectively present on a prior screening CT. The legal ramifications of these false negative investigations are unknown but are unquestionably serious when potentially curable life threatening disease is missed. Interestingly the initial scanning centres in the USA targeted educated, affluent, health conscious neighbourhoods where there was a pre- occupation with wellness and immortality and advertisers fed into these insecurities. This reflects the ethos of big corporations’ intent on making profits rather than promoting health. We would do well to heed the lesson from America where there has been a decline in the number of patient funded scans following dissuasion from professional societies. Leaving asides the issue of stochastic effect of the radiation, there is also the issue of administering contrast – a double edged sword in scanning terms. Without contrast – the most common scenario in CT screening - the merit of the study is questionable with again a gamut of future medico-legal connotations with missed diagnoses. With contrast, nephrotoxicity remains a significant cause of renal impairment not to mention life threatening complications such as anaphylaxis. In a normal physician referred scan, because of the altered risk benefit balance, the use of contrast to demonstrate potential abnormalities becomes justified, indeed almost mandatory. In self referred studies, with inherent low sensitivity, the use of contrast becomes more ethically contentious. Further evidence may be available with regards to screening at least for lung carcinoma in the at risk population with the National Lung Screening Trial in America which has enrolled 50,000 subjects though won’t be ready to publish its findings for a number of years. Until then, the tongue in cheek medical acronym V.O.M.I.T. sums up the argument against consumer-led CT screening succinctly - victim of medical investigative technology. 1. Black WC, Welch HG. Screening for disease. AJR Am J Roentgenol. 1997 Jan;168(1):3-11. Review. 2. Kakinuma R, Ohmatsu H, Kaneko M, Eguchi K, Naruke T, Nagai K, Nishiwaki Y, Suzuki A, Moriyama N. Detection failures in spiral CT screening for lung cancer: analysis of CT findings. Radiology. 1999 Jul;212(1):61-6. 4. Illes J, Fan E, Koenig BA, Raffin TA, Kann D, Atlas SW. Self-referred whole-body CT imaging: current implications for health care consumers. Radiology. 2003 Aug;228(2):346-51. 5. Kolata G. Rapid Rise and fall for Body Scanning Clinics. The New York Times Jan 23 2005. 6. Berlin L. Should whole-body CT screening be performed with contrast media? AJR Am J Roentgenol. 2003 Feb;180(2):323-5. 7. Hillman BJ. CT screening: who benefits and who pays. Radiology. 2003 Jul;228(1):26-8. Competing interests: None declared