How can you have an overdiagnosis of cancer? Either it's there, or it's not.

"How can you have an overdiagnosis of #cancer?  Either it's there, or it's not." – @susila55

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Rates of new diagnosis and death for five types of cancer in the US, 1975-2005. Adapted from Welch and Black, in Preventing overdiagnosis: how to stop harming the healthy. BMJ 2012; 344:e3502

In response to tweets about a potential for overdiagnosis in thyroid cancer cases, a twitter user, Susan Burke Mangano (@susila55), asked this question.

There have been many articles lately on overdiagnosis of almost all kinds of cancer. Our twitter discussion was mainly around thyroid cancer (with Dr Gilbert Welch leading in publications eg. Current Thyroid Cancer Trends in the United States).

Whether breast or prostate, thyroid or renal, the conclusions are generally the same: we are diagnosing more and more cancer, but it is not affecting mortality rates.

How? What?

"There is an ongoing epidemic of thyroid cancer in the United States. The epidemiology of the increased incidence, however, suggests that it is not an epidemic of disease but rather an epidemic of diagnosis." – Welch et al.

I'm not going to explain it here myself since it has already been done well in many places, the most straightforward of which is this video/article combo, by the Wall Street Journal.

I highly recommend you take a look.

Read Some Cancer Experts See 'Overdiagnosis,' Question Emphasis on Early Detection in the Wall Street Journal.


* As they have just locked this article (you need a WSJ subscription or institutional access eg. university library account), I will include a few pertinent quotes here:


While it's clear that early-stage cancers are more treatable than late-stage ones, some leading cancer experts say that zealous screening and advanced diagnostic tools are finding ever-smaller abnormalities in prostate, breast, thyroid and other tissues. Many are being labeled cancer or precancer and treated aggressively, even though they may never have caused harm . . .
"We're not finding enough of the really lethal cancers, and we're finding too many of the slow-moving ones that probably don't need to be found," says Laura Esserman, a breast-cancer surgeon at the University of California, San Francisco. . . .
"Unfortunately, when patients hear the word cancer, most assume they have a disease that will progress, metastasize and cause death," the group wrote in the journal Lancet Oncology in May. "Many physicians think so as well, and act or advise their patients accordingly." . . .
Overdiagnosis--the detection of tumors that aren't likely to cause harm--is now a hot topic in other cancers as well. A growing volume of studies estimate that as many as 30% of invasive breast cancers, 18% of lung cancers and 90% of papillary thyroid cancers may not pose a lethal threat. . . .
"Everyone says they'd be willing to be overtreated if it means not dying--but that's a big fallacy," says Dr. Esserman. "By treating 1,000 people who have low-risk disease, we're not going to save the one person with aggressive disease." . . .
Says Dr. Esserman: "We need to start testing some of these ideas, rather than just fighting over them. People are afraid to do less. We want to figure out how to do less safely."
- Melinda Beck, WSJ

Follow Up: The Name of Cancer: Even Aboriginal Languages are Changing

In my last post, I shared an article that advocated for changing the name of "pre-cancers" and "early cancers" to reflect their benign, watchable, or treatable natures. The hope in doing so is to remove the stigma of "The Big C" for patients, allowing them to see a clear difference between aggressive cancers and their indolent cousins.

Working in the NWT and Nunavut, I must say that it warms my heart to see that Canadian Aboriginals are taking a big part in changing the terminology. Some of the words and phrases are so remarkably apt, perhaps we'll be borrowing them into English.

Language officials in Nunavut released their new word for cancer this week.

The new term “kagguti” comes from the Inuktitut word kagguaq, which means “knocked down out of natural order."

It replaces “annia aaqqijuajunnangituq” or “an incurable ailment," which officials felt was giving people the wrong impression of the disease.

I love the translation of the word kagguti, it explains cancer at a cellular level and on a personal one too. The cells have lost the signals that keep them from over-replicating, and the cancer could prevent a person from living their life in the expected or natural way.

Read more on CBC News.

What’s in a name? Why we need to reconsider the word cancer

doctor: "You have cancer."
our brains: Panic! Cancer! What!? Cancer!
our mouths:  "Oh . . . Uh oh! Well, is it a BAD kind of Cancer?"

It's the "Big C." It's a scary word. And fortunately there is a lot we can do with screening, advanced tools for diagnosis, and treatment in many modalities to combat the Big C.

These days, everyone gets cancer, unless something else gets them first. Cancer is part of the natural process of cells replicating, and it's all explained elegantly by the New York Times Sunday Review: Why Everyone Seems to Have Cancer.

But not all cancers will end our lives. There are "pre-cancers" and there are "early cancers," and these are often not going to hurt us, so they are okay to manage with a 'watch and wait' strategy. People can be scared into seeking aggressive treatment because they lump these "pre-cancers" in with the "very much cancers," which usually warrant a good battle in the right patient.

Sometimes it does matter if we can catch things early and treat them before they progress, like when we see changes of the cervix during pap screening; these can be treated to prevent progression to invasive cancers. That's really important, and it saves lives, but it only applies to a certain population, under certain circumstances.

Sometimes it doesn't much matter when we catch things, as we are learning with most cases of prostate cancer, for example. In recent years we have started to discover that the treatment might be worse than the disease, and maybe we shouldn't be screening for prostate cancer the way we have been.

Perhaps we should be more careful then with what we label "CANCER." That word tends to lead to a cascade of troubled thoughts, and we wind up worried about writing a will, rather than understanding what those dastardly – but potentially harmless – cells in our body are doing.

Alexandra Barratt, Professor in the Department of Public Health at University of Sydney writes:

Early cancers and pre-cancers (abnormal cells that could turn cancerous) found by screening tests, such as mammograms and PSA tests, should be renamed without (scary) words such as carcinoma or neoplasia in their title. They suggested they could be renamed IDLEs – indolent lesions of epithelial origin.

She goes on to explain the risks of overdiagnosis, the fallacy of lead-time-bias, and what we can do about all this as patients and providers, with the guidance of the National Cancer Institute.

Read more on The Conversation.