Dr. A. Nelson Avery, director of the General Preventive Medicine Residency Program at the Texas A&M Health Science Center College of Medicine, offered a wide-ranging discussion of the science and politics behind cancer screening guidelines at a recent Mini Medical School public lecture on the TAMHSC Bryan campus. His presentation, and the Q&A that follows it, can be viewed via the Mini Medical School Lecture Archive, where you can also download a copy of his presentation.
We sat down with Dr. Avery to find out why patients sometimes can’t get screening tests their doctors recommend, and how patients can ensure they’re getting the care that will be best for their health – which, Avery says, is not always the “most” care possible.
TAMHSC-COM: What would you say is the greatest public misconception surrounding cancer screening guidelines today? Maybe it’s hard to name one, considering that there are strong views coming from very different perspectives.
Dr. A. Nelson Avery: I’d say the number one problem is just the total amount of confusion. There are a multitude of guidelines that say opposite things. This leaves the patient, the consumer, thinking that either we aren’t telling them the truth, or that there is someone gaming the system.
COM: And what do you think?
Avery: I think maybe there’s some of all of the above. Whatever the causes, the result is that ensuring you’re getting appropriate healthcare is worse than trying to buy a car. People have to be so educated about what they want and stand up for their rights, and the bottom line is, they need a conversation with an educated physician who understands them as an individual, and not as a population. These recommendations are population-based; they don’t really dictate what’s important for an individual.
COM: What’s important?
Avery: Family history, current symptoms, your history of exposures to possible carcinogens. These are the things that help guide diagnosis.
COM: I understand that those affect levels of risk. But look at it this way. Let’s assume I agree that costs should be contained, that the underserved need health care too, and so on, but I also really don’t want to let a tumor get past me undetected until it’s too late. Why would it not be in my best interest – my personal interest – to have every test there is, for every type of cancer? You brought in the distinction between seeing a population and seeing an individual. Could a screening test ever be a bad option?
Avery: Healthy living is the better option. And yes, too much screening can be bad for your health, for several reasons.
First of all, there are false positives. These include true false positive results in a test, but a lot are due to laboratory error. Over the years when I’ve chased some of these false positives down, it has usually ended up being a bad laboratory. You send the same test to another lab and it ends up being negative. A false positive means you may end up having an invasive and dangerous procedure you didn’t need.
Second, context matters. In most of these screening tests, we’re looking at biomarkers. When we’re looking at blood, we can see the red blood cells, and if there aren’t enough red cells you’re anemic. But let’s say you’ve got chest pain, and you draw blood for a biomarker and it shows muscle enzymes going up; that doesn’t automatically mean you’ve had a heart attack. You’ve got to do it in combination with an electrocardiogram and risk history.
COM: So the test itself does not tell the whole story.
COM: So we have false positives, and we have positive results that must be interpreted in the context of the patient, and sometimes aren’t. Are there other ways a screening test might do more harm than good?
Avery: Yes, and this is the big one. Let me explain through an example.
A patient of mine in private practice had some very minor head trauma, was in the ER, and for some reason they decided to do a CT scan, and they came back and told her she was fine from the trauma but that she had an aneurysm. That it could break at any time, and where it is, they can’t operate. She was about 45 years of age, and she became a virtual recluse. Within a year she was divorced, stayed at home, wouldn’t get in a car. Up until that time her favorite thing to do was swim and dive from a high dive, and she loved rock climbing. And this diagnosis destroyed her life. Because she suddenly knew that at any moment she could die. Up until that moment that the CT scan was reported to her, she was living her life to the fullest.
It is one of those ironies that has stuck with me all those years.
COM: So you’re saying, why hear bad news you can’t do anything about?
Avery: No, it’s more than that. That’s an extreme example of what can happen, but I think it’s happening increasingly as we see a more widespread use of some cancer screening tests. And it is cropping up in situations where we think of risks as being high, when in fact they are low.
Let me tell you another story. A long time ago, I worked on a project that involved testing individuals who had to be in exceptional health for a particular job assignment. We gave them the executive-level physicals that screened them for everything under the sun, all of the screening tests you were fantasizing about earlier, including biomarkers for every rare disease. These were people in a low-risk age group, in very healthy condition, no symptoms of any problems. And when all this screening was done, we had found “significant” risks in every single person on that team. Every one. And these were not high-risk individuals.
COM: Okay, okay. I’ll skip the 120-point inspection.
Avery: You say that now. But as the tools and the guidelines evolve, you get the service without realizing it. Half of all the breast cancer we’re detecting now is the low-grade breast cancer we never used to detect at all. So now it appears that one woman in eight gets breast cancer, and that this is a major increase. The reason that number is so high is that we’re finding all of these low-grade malignancies, but most of them will never cause the patient a problem. The same thing is happening in prostate screening. Low-grade malignancies are detected, so you get biopsied, but you don’t even necessarily know if you’re clear even after you’re biopsied. So you get another one. They could take four or five biopsies and still miss the cancer cluster. And every biopsy increases the chance that you’re going to be rendered impotent, or have bleeding, or have a potentially life-threatening infection.
COM: So… Americans need less cancer screening?
Avery: Who knows? There is a new, relevant article on this topic at least once a week. In the last four months I’ve probably amended this talk fifteen times. I almost changed it again today. I have three articles in front of me that I haven’t worked in.
COM: Give me an example.
Avery: Well, here’s one on cervical cancer screening. This just came out last week. They changed cervical cancer screenings in 2009; before the change, women had been getting screened from the age of 18, and the new guidelines said to wait until the age of 21. So anyone of college age had been getting a Pap test, and now the guideline says don’t start until you’re 21 – that the statistics say Pap smears in those years are essentially wasted effort, because they don’t yield results. And women listened: The number of women who had not been screened in that age group increased from 26% to 47%. But they discovered that these women who now aren’t getting Pap tests in college are also less apt to get them after they hit 21, and are supposed to start doing it. Now we have a reduction in the twenty-two- to thirty-year-olds who, the guidelines say, should still be getting Pap test. That had an increase from 6% to 9% who have never had one. No one planned for that. It’s an unintended consequence of the policy.
COM: It sounds like we need a placebo Pap test for those early years.
Avery: In my talk I’ll offer some specific questions you should ask yourself before you and your doctor undertake any type of cancer screening. Ultimately, it’s a decision that needs to be made by patients and doctors together, based on individual circumstances and on a careful consideration of the goals and possible outcomes of screening.
COM: And as long as the patient and doctor don’t decide they need something the insurance won’t cover, everything works out fine.
Avery: Yes, at that point the doctor is no longer under fire – it’s the insurer. And that is an evolving landscape as well, in part based on all this data.
The only certainty is that if the public is angry enough about any one aspect of any guideline, then they have the ability to get it changed. Eventually, our systems are responsive not just to the expertise of doctors, but to the perceived needs of the public at large.
Click here for an archive of completed 2013 Spring Mini Medical School talks, print interviews, and presentations.