Last week I fired some warning shots about unnecessary medical screening tests. This week I will share some of the screening recommendations from reputable medical research with which I agree. My timing couldn’t be better — in this past week, several studies have been published that have upended many long held medical beliefs. The first was that dietary cholesterol is probably not a significant determinant of the cholesterol level in your body and, as such, most likely does not need to be unduly restricted. The second was that it looks like adding peanuts to children’s diets early in life actually may significantly reduce the likelihood of a child developing a peanut allergy. These study results – published in all the major media so no need to link here — are exactly the opposite of long-held medical recommendations. This evolution of scientific recommendations is not as troubling as some would have you think. Recommendations based on science, not beliefs (see prior posts for the difference), should change as new data becomes available, and these changes should keep us, in the medical community, humble as well as more flexible in our own thinking. That is the beauty of scientific research. But I will agree, it is frustrating to think how much I have limited my egg consumption for years, and that such deprivation probably did not give me any health benefit. Who would have predicted ten years ago that a cheese and bacon omelet would ever be declared an acceptable breakfast choice?
Adult preventive medicine includes several components in order to be thorough: healthy lifestyle choices, appropriate medical screening for the early detection of disease, determination of risk factors for the development of medical problems coupled with appropriate risk factor modifications, and vaccinations to prevent illness. I find it interesting that so many people often focus exclusively on their “healthy lifestyle choices” to prevent future medical problems to the exclusion of the other essential components. “But, doctor, I exercise vigorously, eat right, and don’t smoke. I’m doing everything I can.” It amazes me how often these same health-focused people reject well-accepted recommendations for both screening tests and vaccines. Colonoscopy? Yuuuck, no way! Mammograms? Not for me! Other people ignore the basic requirements for a healthy lifestyle and then deposit the responsibility for their health on their doctor’s ability to find and treat problems early. Optimal health maintenance really is not an either/or proposition. How many times have you heard someone say, “He died of a heart attack at such a young age, and he didn’t smoke, he jogged daily, and he had a very healthy diet.” Appropriate screening tests to detect diseases early, vaccinations to prevent diseases, and risk modification through lifestyle choices, combined with appropriate medications, really do give people the best chance of reducing their rate of premature death and debilitating disease.
Exercise is an important component of maintaining both a healthy weight and fitness standard; here is the recommendation I support from The Harvard School of Public Health. Adequate exercise levels reduce the risk of cardiovascular disease and the development of both Type II diabetes and certain types of cancer. If you enjoy the challenge of running marathons or participating in cross fit and extreme body building, that’s great, but there is no data at all to suggest that “extreme fitness” regimes improve cardiovascular health to any degree beyond what a sensible moderate exercise program provides. Extreme fitness activities are sports to be enjoyed, until you tear your ACL, but they won’t give you any additional protection against developing disease.
Diet is an even more controversial topic. In my opinion, too many people have unsupportable emotional investments in their diets and carry convoluted and rigid beliefs about the supposed health benefits that derive from the more extreme diets. Vegan, gluten free, low carbohydrate, high protein, organic, boatloads of supplements….. My strong recommendation, based upon reams of scientific studies, is that dietary moderation is the key in building a successful diet that both keeps you healthy and encourages you to enjoy one of the basic benefits of being alive. See here for dietary recommendations that make sense to me from The American Cancer Society to help prevent specific cancers. To distill and reinforce what you already know, a diet rich in fruits, vegetables, low-fat proteins, and whole grains are the general recommendations that have been proven to reduce – not eliminate, but reduce — your chances of contracting the most common cancers. Consumption of the recommended amounts of whole grains has been proven to reduce the incidence of colon cancer. I am particularly concerned about the current gluten-free craze, which eliminates whole grains from the diet, as there are only five whole grains that are gluten-free: amaranth, teff, millet, quinoa, and buckwheat. If you do not have celiac disease – the only medically appropriate reason to conform to a gluten-free diet – and you have decided to go gluten-free, when was the last time you enjoyed three servings per day (ACS recommendation) of one of those five grains? Will we see an increase in colon cancers in the future among devotees of gluten-free diets?
How about screening tests for the early detection of certain types of cancer? About 5% of the population of first-world countries will develop colon cancer. See more information here. While admittedly anecdotal, when I was in an internal medical office practice between 1982 and 1998, the American Medical Association recommended a flexible sigmoidoscopy in conjunction with other tests (or just a colonoscopy) for colon cancer screening. I performed between one and two flex sigs a day in my office, and I discovered either an actual cancer or a precancerous polyp in a patient about every two months. In my practice, flexible sigmoidoscopy was the most effective cancer screening that I performed, far surpassing both pap smears and mammograms.
Beginning at age 50, for adults with an average risk of developing colon cancer, the recommended screening protocols are found here. People with higher risk (such as a family history of colon cancer or a personal history of disease that causes increased risk of colon cancer such as ulcerative colitis) will need earlier and more frequent screening. Adenomatous polyps can turn into colon cancer, and they are quite easily located through a colonoscopy that screens for both polyps and cancers. I agree with the standard recommendation for a screening colonoscopy every ten years. This screening is proven, beyond a doubt at this point in the evolution of medical science, to be effective and to save lives. The number of 60- year-old exercise fanatics whom I personally know who have still not undergone this procedure, despite my friendly recommendations as well as their own physician’s, astonishes me every time I have a conversation with one of them about this topic. You cannot run fast enough to beat colon cancer. And the only reliable detection method is a colon examination.
Colon cancer is an easy discussion topic as it is, unfortunately, a very common cancer, and the screening tests have been proven to be an effective tool against it. Unfortunately, that is not the case with some other screening tests. One of the most controversial tests in the medical community right now is the once-standard screening for prostate cancer in men over the age of fifty. Just because we can screen for a condition, doesn’t necessarily mean we should. If we had a screening test that was perfect, if it diagnosed cancer at an early stage 100% of the time and it never produced a false positive result, it would be an extraordinary test, wouldn’t it? But that is not always the case, so let’s talk about the problems with the commonly administered PSA, Prostate Specific Antigen, test.
One significant complication in evaluating the worth of a screening test is a concept called lead time bias, and the test that probably best exemplifies this complication is the PSA test. Let’s postulate that I know a certain patient will die from prostate cancer on November 16, 2022. If I conduct a screening PSA test in 2016, I will diagnose the disease, and the patient will then undergo a vigorous treatment protocol, usually consisting of a combination of surgery, radiation and/or chemotherapy. But – and here’s the rub — the patient still dies on November 16, 2022. Now let’s postulate that I don’t screen him using the PSA test in 2016, and I subsequently diagnose him with advanced metastatic prostate cancer in 2021, and he dies one year later on November 16, 2022. It might appear that the screening test allowed for the early detection of the disease and added six years to the patient’s life between diagnosis and death. But, in fact, there was no prolongation of life. The early diagnosis did not prolong his life, as our treatment did not change his eventual outcome. In fact, the screening and subsequent treatments negatively impacted our patient’s quality of life from 2016 to 2021. Not only did he endure the emotional anguish of dealing with a cancer diagnosis for five years, the patient also suffered from the side effects of the treatment of prostate cancer – impotence, incontinence, radiation proctitis in the form of diarrhea, as well as all the additional expected side effects from radiation and chemotherapy — for those five years without experiencing any benefit. None. It is very important to understand lead time bias when evaluating a screening test. Additionally, it is important to make sure that an early diagnosis of a particular cancer actually changes the course of the disease. If it doesn’t, why do it?
My father was diagnosed with prostate cancer when he was 68. He underwent surgery and radiation therapy, suffering all of the previously described side effects from the standard recommended treatments. Before he died at 82 — from kidney failure completely unrelated to his prostate cancer — he told me that he wished he had never been diagnosed and treated for prostate cancer. The side effects of the treatment had affected his life so negatively that he would have preferred even to have died at a younger age from the prostate cancer than at 82 from the renal failure. Unfortunately, no physician yet has the ability to tell him, or any patient with prostate cancer, whether or not the prostate cancer would have progressed to cause him any illness whatsoever. He might not ever have even known he had prostate cancer. It’s possible that his treatment gave him several years more of life, but research is now showing that it probably had no effect at all, and he just suffered the negative effects from the treatment. Obviously, this kind of statement can be made about the treatment of many diseases – we can go through all the terrible protocols of treating breast cancer and then the patient dies in a car wreck – but prostate cancer, in particular, is one disease where the screening tool, the PSA, is being seriously reconsidered because of the documented extremely slow growth of the disease in many patients combined with the advanced age at which most men are diagnosed.
Prostate cancer screening recommendations and explanations are best described by the most recent statements from the United States Preventive Services Task Force (USPST) found here. I recommend all men read this link and see that the recommendation is specifically against screening most men for prostate cancer with the commonly-used PSA.
Men with screen-detected cancer can potentially fall into 1 of 3 categories: those whose cancer will result in death despite early diagnosis and treatment, those who will have good outcomes in the absence of screening, and those for whom early diagnosis and treatment improves survival. Only randomized trials of screening allow an accurate estimate of the number of men who fall into the latter category. There is convincing evidence that the number of men who avoid dying of prostate cancer because of screening after 10 to 14 years is, at best, very small.
Convincing evidence demonstrates that the PSA test often produces false-positive results (approximately 80% of positive PSA test results are false-positive when cutoffs between 2.5 and 4.0 μg/L are used) 4. There is adequate evidence that false-positive PSA test results are associated with negative psychological effects, including persistent worry about prostate cancer.
There is convincing evidence that PSA-based screening leads to substantial over diagnosis of prostate tumors. The amount of over diagnosis of prostate cancer is of important concern because a man with cancer that would remain asymptomatic for the remainder of his life cannot benefit from screening or treatment. There is a high propensity for physicians and patients to elect to treat most cases of screen-detected cancer, given our current inability to distinguish tumors that will remain indolent from those destined to be lethal 7, 11. Thus, many men are being subjected to the harms of treatment of prostate cancer that will never become symptomatic. Even for men whose screen-detected cancer would otherwise have been later identified without screening, most experience the same outcome and are, therefore, subjected to the harms of treatment for a much longer period of time 12, 13. There is convincing evidence that PSA-based screening for prostate cancer results in considerable overtreatment and its associated harms.
I am at a higher risk for developing prostate cancer because my father had it. I have gotten a PSA in the past (which was normal), but based on what I now know from evolving medical research about early detection for this particular disease, I will not get that test again. For me, that is the right decision.
Finally, let me share both the research and my thoughts on lung cancer screening. Lung cancer is the most common cause of cancer death in the US. There are more cancer deaths from lung cancer alone than from the next three most common cancers – colon, breast, and pancreatic — combined. Medical research has made little progress in the treatment of lung cancer over the past seventy years. If the cancer cannot be surgically removed from the patient’s lung, the patient is rarely cured. Until recently, there were no screening tests that affected mortality. The curable cancers were small tumors that were usually detected when a chest x-ray was conducted for another reason and thus the cancer was detected at an early enough stage to be successfully treated. (As I’ve stated before, never discount the value of medical luck!) Chemotherapy for lung cancer has not had the efficacy that it has with breast or colon cancer. Long remissions and prolonged life is not something often seen with metastatic lung cancer.
85% of all lung cancer is directly related to smoking. If you smoke, quit NOW. If you don’t smoke, don’t start. That is real preventive medicine. Recommendations for lung cancer screening can be found here and here. A summation from The US Preventive Services Task Force is that if you are between 55 and 80 years old, have smoked the equivalent of 1 pack per day for 30 years, or have smoked at all within the last fifteen years, you should undergo an annual screening with a low-dose CT chest scan.
With all screening tests, it is essential to look at the individual patient as well as the projected effect on lifespan. If a patient currently has an illness that is likely to limit their remaining lifespan to one year, does it make any sense at all to screen for a disease that might cause illness, or even death, five to ten years in the future? Is there any purpose to that other than financial gain to the healthcare provider?
Next week I will continue this series on preventive care and screening tests for cancer with a discussion of breast and cervical cancer, and adult vaccinations. I hope you are finding these posts informative, and I hope you are stimulated to make thoughtful decisions about the health choices you and your family make. Please share using your favorite social media link below and consider subscribing to receive email notifications of new posts.
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