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The myth of early detection

It takes a long time for a paradigm shift to occur in the medical world. And there’s always a lot of shouting and kicking while the fault lines rearrange themselves. Letting go of outdated concepts — particularly ones that provided some sense of control over a terrifying disease — is difficult.

Right now we’re seeing a paradigm shift in regard to the risks vs. benefits of certain types of cancer screening. Predictably, a lot of people are angry. But evidence is evidence, and in recent years there’s been a steady stream of good research questioning the effectiveness of many types of cancer screening.

As science writer and Newsweek columnist Sharon Begley wrote earlier this spring:

If the hype is right, then finding a tumor when it is small should mean a better chance that surgery, radiation and/or chemotherapy will eradicate it, allowing you to live until something else kills you. Early detection should produce clear, unquestionable benefits.
Yet it doesn’t. Not the PSA [for prostate cancer], not early detection of lung or testicular or pancreatic cancer, or glioblastomas, a type of brain cancer. Even mammography is iffy, since trials showing a decrease in mortality were done before the age of adjuvant therapy. Colonoscopy might cut mortality, but it has never been tested in a randomized, controlled trial….

Begley says you can be forgiven if you find this shift in thinking confusing:

If the failure of most early detection to strongly affect whether you live or die makes no sense to you, you’re not alone. “The medical community has done such an extraordinary job getting out the message that early detection is tantamount to cure, it’s incorporated into people’s bone marrow,” says [Barrett] Kramer, [associate director of disease prevention at the National Institutes of Health ].

An out-dated mindset
Nowhere is the early detection mantra repeated more often than to women worried about breast cancer. (And what woman doesn’t worry about breast cancer?) Indeed, many breast-cancer survivors believe they owe their lives to some form of regular breast-cancer screening. But the screening may have played no role in their survival, as women’s health advocate Susan Love, MD, explains on her website:

For decades, women have heard that the best hope of curing breast cancer is finding it early. To that end, doctors have taught women about the importance of three breast cancer screening techniques: breast self-exam, clinical breast exam (a breast exam done by a health professional), and mammography. This emphasis on breast cancer screening has perpetuated the belief that all breast cancers can be cured if they are found early. It also leads people to believe that all women who survive breast cancer do so because their cancer was found early.
The latest research, however, indicates that neither of these beliefs appears to be true. It now looks like there are about six different types of breast cancer that vary in how aggressive they are. Some of them are so “good” that they will never metastasize (spread throughout the body). And that means it doesn’t matter when you find them. They just don’t have the ability to cause someone to die of breast cancer. Others are very “bad” and so aggressive that no matter when you find them — which means even if you find them when they are still very small — they have already begun to wreak havoc. These are the types of cancers that cause women to die of this disease. Still others, probably about 30 percent, have the potential to become “bad” if not stopped early. These are the cancers whose outcomes are affected by breast cancer screening programs and early detection. These are also the cancers mammography is best at finding.

This is the paradigm shift that’s so difficult for many people to wrap their minds around: Early detection does not always save lives. In fact, it sometimes causes more harm than good, as I posted about yesterday in regard to breast-cancer screening and last week in regard to prostate-cancer screening.

Does that mean you shouldn’t undergo cancer screening? Of course not. But realize that the issue is not as clear-cut as you may have believed.

Many people, though, are reluctant to accept this paradigm shift — a reluctance that is, perhaps, understandable. As Begley wrote in her Newsweek article: “No matter what science says, it will be a cold day in hell before patients let go of the one slender hope they feel they have to beat cancer.”

Comments (3)

  1. Submitted by Paul Scott on 07/14/2009 - 03:21 pm.

    Thank you for this post. Every time I hear some reporter tell me that “early detection saves live”s I sort of feel like they have little idea of what they are talking about. It would seem to only apply to testicular and colon cancer, yes? Every where else it is perhaps often wishful thinking — more elevation of our screening technologies to hallowed status in an effort to make ourselves feel less powerless in the face of cancer. But the expression “early detection saves lives” is a convenient myth.

    The media started much of this. Media-wise, it’s simply not as self-flattering for health reporters to tell the more complicated truth, that quite often, as you say, by the time you can spot a cancer the train has left the station — or conversely, that the cancer you spot through early detection may just have been an artifact of medical screening technology with no medical consequence, were it not spotted in the first place. Who’s going to want to watch (or read) a health report with a downer message like that?

    Busy reporters with no time (or attention span) to get to the bottom of a very complex scenario likely believe that there’s no downside to telling everybody to get screened for everything. They confuse the paternalistic notion of” doing good” with reporting. Medical associations often settle onto a public health message and refuse to let it go as evidence to the contrary mounts all around them (the continued invocatioj of low fat or low sodium eating is just the most egregious examples right now).

    But as a close relative and friend to two people who died too young from cancer, I found the early detection message kind of unnecesarily blame-inducing. If only you had found it earlier, it seemed to suggest. One book on breast cancer from a few years back carries the title Your Life in Your Hands. Actually, no.

  2. Submitted by Bernice Vetsch on 07/15/2009 - 02:21 pm.

    It is my understanding that those physicians who do colonoscopies can recognize and remove with a simple snip the kind of small polyp that is likely to develop into colon cancer. This makes a colonoscopy every five years worthwhile, especially if family members/ancestors have died of that disease.

    Am I wrong?

  3. Submitted by Pat Laffin on 07/21/2009 - 12:13 am.

    You will find more eye-opening information about tests and drugs that are being foisted on unwitting patients without there being real proof of their benefits by reading the books by Dr. Nortin Hadler, MD:

    Worried Sick

    The Last Well Person

    He has also written several opinion pieces at abcnews.com You can tell by the comments he receives that people would rather shoot the messenger than honestly consider what is being said. Going against conventional wisdom is seldom easy.

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