I recall a few years ago there was this fad, or maybe it stayed, of getting a full body MRI (?) scan. What was the result of all this? Did the odds of finding signs of a potential tumor that just ended up being wasted exploratory surgery over nothing kill it? Or does it actually save some lives?
Speaking in broad generalities, such screening tests tend to not be cost-effective, and can often actually cause more harm than they prevent.
Gross oversimplification follows, but the general principle remains true:
MRI is horribly expensive, but can pick up such fine detail that people thought it would be a panacea in screening for disease. Only it can show so much fine detail that noone can decide “is it tumor or not” without doing a biopsy. And lo and behold, lots of biopsies, lots of complications of biopsies, lots of people sickened, and a few even dead, checking out something that turned out to not be a tumor. This is especially true for those rare tumors, where to find a single case early enough to make a difference, one will have to do a thousand or so surgical procedures on people without the cancer.
CT scan delivers a load of radiation along with the above drawbacks.
In brief, these days there are no conditions for which the general healthy public (excluding those with certain family histories of disease) would benefit from MRI or CT screening. Thus far, screening for colon cancer with testing of the stool for blood has not been shown to be any less effective than screening with sigmoidoscopy combined with barium enema, or full colonoscopy, or “virtual” colonsocopy using scanning devices. And screening the stool for blood costs about 1 1 thousandth as much as the next cheapest test.
If you want to know what tests are considered useful for screening asymptomatic populations, go here: http://www.ahrq.gov/clinic/uspstf/uspstopics.htm
Well, QtM has pretty much said it all. I read lots of CT scans (both screening and diagnostic) and our equipment is so good we can see every little detail. The difficulty is deciding whether a “spot” is pathological or just a normal variant. In the litigation climate in which we live this usually triggers another examination (sometimes invasive) or perhaps a biopsy. You should decide for yourself, but many physicians believe the added expense, possible complications, and worry are not worth the yield. That having been said, there are anecdotial cases where a screening CT scan has saved lives. You get to choose. FTR I have not had one.
What of blockages? I’ve heard of several people, now Clinton, that seemed fine and passed several tests and then whammo.
That should have been “anecdotal.”
Coronary angiography (an invasive catheter examination with some risk) remains the “gold standard” in demonstrating coronary artery disease, though we are working hard to refine CT and MRI to that level. Stress testing with or without nuclear medicine imaging of the heart is common, but less specific. At this time it is possible to have a normal stress test and still have significant coronary artery disease.
CT examination of the heart (at this time) consists primarily of measuring the amount of calcium in the coronary arteries without actually imaging the artery lumen. Opinions vary as to whether this is an accurate reflection of heart disease. Some would argue that your lipid profile is just as good an indicator. Once again, you get to choose.
What percentage of the population have benign and undetected tumors? I would guess that these would be detected during autopsies of people who died from external causes.
Interesting and important question.
If you’re old enough, not only is the likelihood of benign tumors high, but so is the chance of having clinically silent cancers. If you look hard enough, almost all elderly men will have small cancers of the prostate. Likewise, even among apparently young healthy adults (who die in, say, car accidents), the chance of having a small thyroid cancer is around 25%.
Benign tumors of the various endocrine glands (thyroid, adrenals, pituitary) occur in at least 10 - 20 percent of healthy people (thyroid 13%, pituitary 10 - 15 percent, and adrenal up to 5 percent. (these are just quick references. Figures in other studies would vary.)