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Why I'm saying no to a smear

Renew travel card. Book haircut. Go for screening test. Buy cinema tickets. Meet friends." You may have spotted the odd one out – for this is not a list of things to do at the weekend, but the front cover of the NHS Scotland's "Cervical Screening Test" information booklet.

Here's a confession. I am a GP, and I don't go for cervical smears. Nor do I know what my cholesterol level is, and when I reach 50 and am invited to mammography screening, I won't be turning up. I haven't decided about bowel-cancer screening, but at the moment, on the evidence, I'm unconvinced.

Why? Part of the problem is the trivialisation of the choices that are offered to us when it comes to screening tests. It's important to be clear – screening tests are for people who are well and who have no symptoms for disease. So if you have bleeding between periods, or a change in your bowel habit, you don't need screening tests – you need diagnostic tests.

Screening tests are different. Because they aim to find disease you don't know about, the trade-off between benefits and harms tends to be more nuanced compared with tests done to investigate symptoms. Cervical screening does prevent deaths from cervical cancer. But to get that reduction, you have to follow up and/or treat all the women who have cell changes on their screening test. However, most cervical-cell changes found at screening will not lead to cervical cancer. The problem is we can't predict which will, so all need further monitoring or treatment. A study from Bristol in 2003 found that 1,000 women have to be screened for 35 years to prevent one death from cervical cancer; and to prevent that death, 80 women have to have further investigation, with 50 women having treatment to their cervices. Four out of five women found at screening to have "high-grade" changes in their cervix did not go on to develop invasive cancer.

Clearly, there is a benefit – but overall, it's small. That potential for good has to be weighed against the risks of treatment. It's known that having a cervical biopsy – which is done to get more information about the degree of abnormality – raises the risk of pre-term birth in later pregnancies. And the worry and anxiety that the results cause shouldn't be underestimated.

I'm not against screening, but I am against unthinking screening. I weighed up my personal risk factors for cervical screening (for example, smoking is a risk factor), threw in my own priorities – and decided not to have it. And here's the problem. The NHS persists in sending me red-ink letters despite my written declaration to opt out. I'm made to feel a risk-taker in not having cervical screening – yet I'd also be taking my chances if I had it done.

Read on

TAGGED: CRITICAL THINKING, MEDICINE


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