Screening Can’t Hurt, Can it?

23 11 2009

The next Grand Rounds is hosted by How To Cope With Pain and, not surprisingly, the main theme will therefore be pain. Now, I had a personal story in mind on the downside of testing, but I didn’t have a good title that fit the theme. Till, this Saturday when I a saw a perfect headline in the Los Angeles Times (Nov 21th), reading:

Cancer screening: What could it hurt? A lot, actually

It is a very thoughtful article showing the downside of screening. It was prompted by “the furor over this week’s recommendation from the U.S. Preventive Services Task Force that most women wait until age 50 to start routine mammograms, and then get them only every other year.” (also see kaleidoscope 2009- wk47).

They started their article as follows:

It seemed like a good idea at the time.

In 1984, Japan began screening the urine of 6-month-old infants for neuroblastoma, the most common type of solid tumor in young children. The test was simple and could show signs of cancer long before clinical symptoms arose.

Hundreds of infants went through the ordeal of diagnosis and treatment, but it didn’t reduce the number of tumors, including deadly ones, found later. Almost none of the tumors caught by screening turned out to be dangerous — and more of the screened children died from complications of surgery and chemotherapy than from the cancer itself.

In 2004, health officials ended the program.

The article further describes the potential downsides of current cancer screening protocols, including breast cancer screening.

  • But finding cancers that respond to early treatment is only one of the potential outcomes from a screening test. Many tests produce false positives, prompting additional tests that can be invasive, expensive, time-consuming and anxiety-inducing.(……)
  • Other screening tests produce false negatives, giving patients and their doctors the incorrect impression that they have nothing to worry about.
  • Some detect aggressive cancers whose outcomes aren’t improved by early detection.
  • And some identify small cancers that grow so slowly they’d never compromise a patient’s health. Many would even go away on their own.

All true but the problem is that people see it as their right to be screened (Will Women in Their 40s Be Denied etc). Cancer survivors are furious about the new breast cancer screening guidelines, they think decisions are made on political grounds and/or fear Medicare will no longer cover screening at younger age.

Why people are upset about the softened screening recommendations is because cancer is a frightening and deadly disease and because (as the Los Angeles Times explains so well) it’s easy to identify cancer survivors whose tumors were caught by screening, but it’s nearly impossible to put a face on the woman or man who is hurt by over-screening.

The first time I heard about the downside of screening was in 2004, when I attended a meeting for  Conn patients  to write an article for the patients association NVACP (see page 11-16, Dutch). Prof. Kievit, a surgeon and professor in decision analysis said:

“Imaging techniques (CT-scan or MRI) should only be applied if the stature test is positive and the aldosterone blood levels proven to be abnormally high. This is important because people often have benign nodules. Innocent nodules (incidentalomas) can obscure the diagnosis, worry the patient or even lead to unnecessary interventions. Furthermore it is inefficient to randomly subject people to all kind of tests. And please do not follow the current US trend to ask a CT-scan for your birthday!

That the balance of harm and benefit of diagnostic tests and screening can dip the wrong way can be best understood when you experience it yourself.

from: Wikipedia

During my last pregnancy my daughter was diagnosed with a mild prenatal  hydronephrosis during routine pregnancy ultrasound. Hydronephrosis is distension and dilation of the renal pelvis, usually caused by obstruction of the free flow of urine from the kidney. Since this can lead to progressive atrophy of the kidney, my little girl also had to undergo several tests to check the function of the kidneys and the cause of this anomaly. For one of those tests she had to be injected with radioactive isotopes in the catacombs of another hospital. But everything seemed o.k.: the anatomy (no obstruction) and the kidney functions. It should also be stressed that the dilatation was near-normal and didn’t worsen. Nonetheless, because of complications often seen with children with severe dilatation my daughter had to take daily antibiotics as a preventive measure. We had to regularly visit the polyclinics for an ultrasound and urine testing (to exclude infection and resistance). After a year it was decided to discontinue the antibiotic treatment. Follow-up was not needed.  Later a pediatric urologist told us that the guidelines had been changed: preventive antibiotic treatment was no longer required in case of mild hydronephrosis with no underlying cause.

My daughter developed asthma at the age of 7. Both she and her sister had atopic eczema, a known predicting factor for asthma, when they were toddlers. In line with the hygiene-theory, that states that a lack of early childhood exposure to infectious agents, increases susceptibility to allergic diseases, I often wondered whether 1 year daily antibiotic treatment wasn’t the final trigger for my daughter’s asthma. Indeed @Allergy (Ves Dimov) recently twittered about a study in J Allergy Clin Immunol that showed an association between antibiotic use in the first year of life and current symptoms of asthma in children 6 and 7 years old. A  Systematic Review of observational studies came to the same conclusion: “Exposure to at least one course of antibiotics in the first year of life appears to be a risk factor for the development of childhood asthma.” These studies had some limitations, and don’t  prove there is a causal relationship between antibiotic treatment and asthma, but they do fuel my suspicion.

In any case, although prenatal diagnosis of hydronephrosis may help to prevent later development of serious kidney disease in children with real malformations, it only resulted in “harm” in our case. Unnecessary testing (all results negative), unnecessary polyclinic visits, worries (that stayed until she was 9, when we visited the pediatric urologist to exclude an UTI, because you never know..)), unnecessary antibiotic treatment and -perhaps- the triggering of asthma. Looking back, and knowing what I know now, I wished the somewhat dilated renal pelvis had never been observed.

Last Friday I was at a lottery offered by my Sports Club. The last 2 prices were mystery prices: A total body scan of 1000 Euros each. I heard a lot of “Aaahs” and “Oooohs”. But I whispered “not for me“. The women next to me turned their heads, looked at me perplexed with their eyes blanked. Of course it is difficult to understand why one would refuse such a price, because “if screening doesn’t help, it won’t harm either”.

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