Dr. Mike Bohlman

Wouldn’t it be great if there were such a thing as a “tricorder” — you know, that instrument that Bones used to wave over his patients on the old TV series Star Trek to immediately come up with a diagnosis?  While such an instrument would certainly be handy, I’m afraid it might just put me and my colleagues out of a job, or at the least change it dramatically! 

There is a certain level of mystery and excitement involved when doctors listen to a patient’s symptoms, examine him/her, and then come up with a diagnosis and treatment plan. That mystery and curing disease is what draws many physicians to medicine in the first place.     

I don’t think we are going to have any “tricorders” available in the near future, or at least during the span of my career! However, I often have patients who think that with all the advanced technology available in medicine these days:  “Can’t we just do a CT scan of my entire body and see inside me and find out what is wrong?”  Or, ”Shouldn’t I have an MRI to find out what is causing my pain?” “Maybe I need a blood test to make sure I don’t have cancer?” “How about that ‘Lifeline Screening’ flyer I got in the mail, shouldn’t I do that?”   

These are all valid questions and all have to do with wellness, prevention and screening. I would like to touch on general aspects of prevention and screening. Over the next year or so, we will also be posting videos and additional information to explore specific screening recommendations for various diseases on the Powell Valley Healthcare (PVHC) website and Facebook page.

Much of what primary care physicians do is referred to as preventative care.  All things considered, most people would prefer never to contract a disease in the first place; or, if they can’t avoid an illness, they prefer that it be caught early and stamped out before it causes them harm. To accomplish this, people without specific complaints undergo interventions to identify and modify risk factors to avoid the onset of disease or to find disease early in its course so that early treatment prevents illness. When these interventions take place in clinical practice, the activity is referred to as preventative care. 

A major barrier to preventative care is the fact that not all insurances pay for preventative or “wellness” visits. In my practice, I try to do a “wellness visit” once per year if the patient has insurance that would cover that type of visit. 

If they don’t, I still try to do a visit once per year to review all their medical problems and incorporate screening and prevention into that visit. It’s often difficult to do in a short period of time, particularly if the patient has other issues that need to be addressed during that visit that go beyond prevention or screening.  That being said, prevention and screening are certainly important.

Primary prevention involves interventions to keep disease from occurring (e.g. immunization for communicable disease, lifestyle and behavioral counseling, smoking cessation); secondary prevention involves detection of early asymptomatic disease (e.g. screening); and tertiary prevention consists of interventions that attempt to reduce complications of a disease once a patient has it (e.g. eye exams or controlling blood sugars in patients with diabetes). What we will primarily concentrate upon in our videos and postings is screening. 

Screening is the identification of an unrecognized disease or risk factor by history taking (e.g. asking if the patient smokes), physical exam (e.g. a blood pressure measurement), lab test (e.g. routine blood draws looking at kidney function or blood counts), or other procedure (e.g. mammograms,  bone mineral density tests) that can be applied reasonably rapidly to asymptomatic people. 

Screening tests sort out the apparently well people (for the condition of interest) who have an increased likelihood of the disease or have a risk factor for a disease, from the people who have a low likelihood of having the disease. Screening tests are part of all secondary and some primary and tertiary preventive activities. 

A screening test is usually not intended to be diagnostic. If the clinician and/or the patient are not committed to further investigation of abnormal results and treatment, the screening test should not be performed at all. One should never do a test if one is not going to act upon the results.

So for what diseases should we screen and what makes a good screening test?  The disease itself must have:  Serious consequences, a long “preclinical phase” (the period of time when it can be detected but is not causing symptoms or deleterious effects), and effective treatment.   The test itself should have high sensitivity (identifies true positives) and specificity (identifies true negatives), low cost, be acceptable to patients. In addition, the risks, consequences, and costs of false positives and false negatives must be low.

As you can imagine, meeting the above criteria can get pretty complicated and hard to determine. There are several methodologic issues to consider in evaluating studies of screening effectiveness including various types of bias in the studies. 

A lot of the problems involve statistical considerations that are beyond the scope of this article and difficult to understand. Other issues that are problematic with screening include physical injury from the screening test itself, negative labeling of the patient with an “abnormal” or worrisome result, false-positive tests resulting in unnecessary follow-up and “overdiagnosis”, and detection of “incidentalomas.”   

“Overdiagnosis” involves detecting a cancer, such as prostate cancer, by screening technology that would have grown so slowly (or even regressed) over time that it would have never caused any trouble for the patient.  Some estimates are that as many as 50% of prostate cancers diagnosed by screening are due to overdiagnosis. 

The problem then becomes trying to determine if that cancer found by screening will actually cause a real problem in an individual patient, which is nearly impossible! “Incidentalomas” are masses or lesions detected incidentally by an imaging procedure (CT scans, MRI, ultrasound, X-rays).   

Many of us know people who had a CT scan for one thing and they found a “spot” or something that they weren’t expecting. Now, the clinician has to determine if that accidently found “spot” is important or not.  This often involves more tests, more cost, possible complications of evaluation and a lot of stress for the patient!

So, you can see that screening and prevention gets kind of complicated. As physicians we often rely upon various professional organizations and societies to help us decide who, what and when to screen. Organizations such as The American Cancer Society, American Academy of Family Physicians, and the United States Preventative Services Task Force (USPSTF) can give us recommendations to follow. Sometimes the different organizations even have different recommendations. 

I hope this brief overview was helpful and shed some light on why screening tests can be complicated.  I hope it also revealed why doing a “whole body CAT scan”, or random screening can be of little help, expensive, and even dangerous.  We will try to make some informational

• Cervical cancer

• Lung cancer

• Breast cancer

• Sexually transmitted infections

• Colon cancer

• Hyperlipidemia
(high cholesterol)

• Osteoporosis

• Depression/suicide

• Abdominal aortic aneurysm        • Coronary artery disease

• Hypertension (blood pressure)    • Skin cancer

• Peripheral vascular disease        

We would all love to have a “tricorder!” But until then, I guess we’ll all do the best we can with the information and technology we have.

As tests and treatments improve and technology changes, there will no doubt be changes in all the recommendations. 

Make sure to watch for future videos on these topics on the PVHC website and Facebook page to learn more!

(Dr. Mike Bohlman is a family practitioner at Powell Valley Clinic. His special practice interests include pediatrics, care of the family unit, adolescents, sports medicine and endoscopy.)