A Critical Look at Screening Tests

review by Verna Hunt, BSc, DC, ND

www.healthandwellbeing.info

,

by Alan Cassels

Greystone Books, D & M Publishers Inc.; 2323 Quebec St., Suite 201, Vancouver, B.C., Canada V5T 4S7

© 2012; $16.95; paperback; 176 pp.

The debate continues on early detection of diseases and the subsequent treatment that follows vs. allowing the body to resolve the situation and avoid costly or iatrogenic interference. Many theorize that time and money spent on prevention outweigh megacosts spent on unnecessary treatment, particularly when the extensive probing is expensive and the meaning of results unclear as to what they indicate.

Alan Cassels takes on this complex issue in Seeking Sickness: Medical Screening and the Misguided Hunt for Disease. This informative book is a must-read for all practitioners within holistic and naturopathic medicine.

At the outset, Cassels clearly lays out how medical screening that is often marketed as preventive can be costly and can lead a person deep into more and more testing with possible side effects. Ordering of screening, scanning, and testing is often driven by the financial gain for the pharmaceuticals, technomedicine, and doctors themselves, and giving people the false impression they are doing something for their health. The whole-body scan is his first inquiry as to the value of the information gained. His research into this and many more tests show that some are useful and based on sound science and clinical application, yet others are more and more ill informed and based on economic gain.

In one study of 1192 full body-screenings (76% of these people were self-referred), 86% had abnormal findings. Of those, 37% were referred for follow-up testing, which meant more imaging. The amount of radiation exposure by the time this is all done can be in excess of allowable limits as set by governments.

Screening is often advertised as something that must be done or you will get the disease in question and die. Mammography has been promoted in this way, persuading women to do what is “right” for them instead of helping them make an informed decision. The message about medical screening is that you are in a good person if you start screening early to find the disease early so that you can be treated early and survive. But what are possible iatrogenic effects of this early treatment?

Cassels makes an excellent distinction that a screening scan occurs on well people trying to find things wrong with them vs. a person with symptoms getting a diagnostic scan that is for the purpose of diagnosis. Practitioners must consider when ordering testing if the results will affect how the patient care is decided upon and delivered.

Some screening can convey “inappropriate reassurance” when the results show no detectable problems, implying that the person is disease free. This is known as the false-negative phenomenon. However, there are many life-limiting conditions that may be asymptomatic and not show up at the time of testing.

Who is protecting the public from ineffective screening? It depends. When it comes to total-body scans, governments often claim that practitioners qualified to use total body scans can use them as they deem appropriate!

Cassels has developed a list of questions for people to consider (pp. 23, 26):

1. Is this screening test recommended by a quality independent body, such as the US Preventive Services Task Force (USPSTF)?

2. Is it for a disease that significantly affects public health, is prevalent enough to require screening, and comes with an acceptable probability that I could have it?

3. If my doctor detects predisease, will it be at a point at which a cure can be enacted for the disease that could follow?

4. Is the test sensitive (meaning it can accurately find disease that is there), and is it specific (meaning that it won’t find disease that isn’t there)?

5. Who is pushing this test, and why?

6. If I have a positive test, what does further evaluation look like, and is medical care available to effectively treat this disease in a manner that I find acceptable?

7. What happens if I do nothing?

There are many commonly used screening tests that Cassels critiques, including glaucoma, cholesterol, syndrome X, heart, PSA, mammography, colon, cervix, mental health, lung, bone, gene, and more. Each chapter is a real page-turner and is information that health practitioners will want to know. The writing is clear and flowing and the reasoning objective and sound.

Read this book for the sake of patients whom you are endeavouring to help. It will assist you in decisive clinical thinking about screening and testing.