Screening in medicine is a preventative measure to identify potential diseases in people without problems or symptoms; early intervention giving the best hope of cure. Smears, breast cancer screening, scans in pregnancy and now bowel cancer screening are routinely offered to certain groups of the population. Screening for prostate cancer is also on the horizon. Having just received a doctor’s letter reminding me I am overdue for a smear test I have been giving the pros and cons of screening some thought.

Many have no issues at all with screening, what, after all , could be so bad about early detection of a disease? It may indeed save your life. Speaking to a friend and cousin, both nurses, about wavering over going for a smear test, they were both convinced it was the right thing to do. “Think of Jade Goody,” I was warned. Last year in The Independent I read an article by Dr Margaret McCartney, a GP, about why she doesn’t have cervical smears, doesn’t know what her cholesterol level is and will be declining mammograms and bowel cancer screening. Here is her rationale for saying no to smear tests:”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.”  Having a cervical biopsy raises the risk of pre-term birth in pregnancy and the worry and anxiety caused by finding any abnormalities could also give rise to health complaints. Dr Ben Goldacre has similarly written about his scepticism of prostate screening highlighting that 1,410 men would need to be screened to prevent one death. Second, for each death prevented, 48 people would need to be treated; and prostate cancer treatment has a high risk of very serious side-effects such as impotence and incontinence.

This is my problem; not all screening tests are of benefit to the person being screened. False positive results lead to overdiagnosis, misdiagnosis, stress or creating a false sense of security (a person is given the all clear on a screening so subsequently ignores possible symptoms of a disease.) As Margaret McCartney put it, ” I am not against screening, I am against unthinking screening.” I too don’t like the way the letters arrive reminding you of your smear test or whatever it is and stressing the importance of making an appointment. In much the same way as when you choose to not have your child vaccinated, if you refuse screening you are regarded as being a hippy risk-taker with a cavalier attitude to your health rather than someone who has weighed up the risks and made an informed choice. The point is that the public aren’t given the full facts about the benefits and pitfalls of screening. If they were, more people would opt out and companies and shareholders would start to lose money. Which is, after all, what it’s all about.