Screening

Over the past few weeks, I have been offered massages, gym visits, vitamin supplements, make-up tips and consultations with cosmetic surgeons. All these generous invitations came from PR companies keen to create a media glow for their clients’ products. Since an awful lot of column inches seem to be devoted to genome testing at the moment, I began to wonder if this was the latest thing being dangled under journalists’ noses.

There are numerous reports in the British media of how marvellous and easy it is to undergo genetic screening. You simply give a sample of your DNA (a swipe of your cheek on a swab will do) and hand over your cash (anything from hundreds to thousands of pounds, depending on the company). Voilà, by return of post, you are told your “genetic risk profile”.

Two themes emerge from the articles written by these journalists staring, rapt in wonder, at their own genetic code. First, they see this as a part of the information revolution: at last we are in charge of our destiny; no longer are paternalistic doctors preventing us from discovering what we have the right to know. Second, doctors better get themselves trained up on how to use this information; if they don’t, the service the consumer pays for won’t represent value for money. It’s doctors’ responsibility to help us use this information appropriately.

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There has been much press coverage of The Lancet Oncology’s paper this week on screening for ovarian cancer. Screening – looking for disease before a person has symptoms that suggest the disease – is often harder than it seems, thanks to the myriad problems it can create. That’s not to say that screening shouldn’t be considered or investigated as a way to try to add quality and years to life. But it is important to consider all the negatives as well as the positives when the screening is being tested – as the Lancet research is doing.

I have three concerns. First, this paper is an interim one – the study hasn’t finished, and as such, it isn’t possible to say whether or not screening for ovarian cancer will prevent deaths. However, it is a large, randomised trial, which is a good thing.

Second, the authors acknowledge that there is a degree of “over-diagnosis” going on: “44 per cent (22 of 45) of the primary ovarian cancers detected in the USS group were borderline.” (USS is ultrasound – one of the methods which was being compared as a tool to use for studying the effects of screening.) “Borderline ovarian tumours have 10-year survival rates in excess of 95 per cent… It could be argued that these cases would be best classified as false positives… Once borderline cancers are detected during screening, it is difficult not to operate given that borderline and stage I invasive ovarian cancers share common morphological features on ultrasound imaging.”

Third, we do not yet know about the full impact on health of patients who had to undergo more than one round of screening. These were cases where the first screening test was abnormal and further tests were run either right away or several weeks later. This may have an adverse impact on psychological wellbeing – some people may be made sick with worry.

None of this means that it might not be a worthwhile test to do. We have to wait for the full results of the trial.

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