Skip to content

 Another large study looking at screening mammograms for breast cancer has raised the issue of overdiagnosis and overtreatment once again. The purpose of mammography screening is to find cancer when it is small and so prevent cancer from growing and becoming advanced cancer. However, the researchers did not find this - there was a major increase in finding small cancers (the kind that may grow so slowly as to never cause any problems or that may even regress), but the rate of advanced cancers stayed the same.

The problem of overdiagnosis (finding small tumors that may never cause problems) and overtreatment (treating unnecessarily), which is leading to medical experts "rethinking cancer screening" is a major shift in how cancer screening is being viewed for a number of cancers. This is because studies show that overall death rates are basically the same in screened vs non-screened persons for mammography, colon, prostate, and lung cancer screening (see post). The view of how cancer grows and spreads may have to be reexamined and changed. One possibility suggested by Dr. H. Gilbert Welch is that aggressive cancer is already "a systemic disease by the time it's detectable" (Oct. 28, 2015 post).

The following excerpts are from the thoughtful review of the study in Health News Review: Overdiagnosis of ductal carcinoma in situ: ‘the pathology equivalent of racial profiling’

Danish researchers are providing new evidence that many breast cancers found via screening mammograms don’t need to be treated. Women with these non-threatening tumors are said to be “overdiagnosed” with breast cancerOverdiagnosis occurs when breast screening such as mammography detects small, slow-growing cancers that may never cause the patient any trouble. Yet, women diagnosed with such tumors are exposed to very real harms–possible surgery, chemotherapy, radiation, and living life as a “cancer patient.”

How much overdiagnosis are we talking about? If you don’t include cases of ductal carcinoma in situ (DCIS) in the tallies, anywhere from 14.7% to 38.6% of breast cancers found via screening represent overdiagnosis, the study authors found. The rate ranges from 24.4% to as high as 48.3% when DCIS is included.

DCIS is a collection of abnormal cells inside a milk duct that may–but usually doesn’t–break out to become invasive and potentially lethal cancer. About 60,000 women are told they have DCIS each year in the United States. Some experts estimate that up to 80% of women with DCIS found via screening may not need any treatment at all–and instead should just keep an eye on things. Obviously, women need to be fully and accurately informed about the benefits and risks — including the risk of overdiagnosis — before embarking on any decision to get screened for breast cancer or choosing a course of action following a diagnosis.

Otis Brawley, MD, Chief Medical Officer for the American Cancer Society, says it’s been difficult for modern medicine to wrap its brain around the concept of overdiagnosis. The natural inclination is to assume that cancerous-looking cells “will grow, spread, and eventually kill,” he writes in an editorial accompanying the Danish study. “However, some of these lesions may be genomically predetermined to grow no further and may even regress. In many respects, considering all small breast lesions to be deadly and aggressive types of cancer is the pathologic equivalent of racial profiling.

Excerpts from the original study from the Annals of Internal Medicine: Breast Cancer Screening in Denmark: A Cohort Study of Tumor Size and Overdiagnosis

Background: Effective breast cancer screening should detect early-stage cancer and prevent advanced disease. Objective: To assess the association between screening and the size of detected tumors and to estimate overdiagnosis (detection of tumors that would not become clinically relevant).... Setting: Denmark from 1980 to 2010. Participants: Women aged 35 to 84 years. Intervention: Screening programs offering biennial mammography for women aged 50 to 69 years beginning in different regions at different times.

Conclusion: Breast cancer screening was not associated with a reduction in the incidence of advanced cancer. It is likely that 1 in every 3 invasive tumors and cases of DCIS (ductal carcinoma in situ) diagnosed in women offered screening represent overdiagnosis (incidence increase of 48.3%).

Breast screening is associated with a substantial increase in the incidence of nonadvanced tumors and DCIS (ductal carcinoma in situ) in Denmark but not with a reduction in the incidence of advanced tumors, and the overdiagnosis rate is substantial. These findings support that screening has not accomplished the promise of a reduction in invasive therapy or disease-specific mortality.

A report by 3 prominent specialists (including Gilbert Welch - who has been discussed in earlier posts) about trends in metastatic breast and prostate cancer came out today in the New England Journal of Medicine. The biggest finding was that mammograms have not cut the rate of metastatic breast cancer. Mammography screening is based on the hope that cancer that is detected in an early, localized phase can then be treated more easily and that it would reduce the numbers of metastastic cancers (that spread to lymph nodes and to more distant organs) that eventually kill. However, this has not happened.The incidence of metastatic breast cancer has been stable since 1975, and the average age of diagnosis among women older than 40 is still 63.7 years . The authors theorize that "breast cancer is a systemic disease by the time it's detectable". From Medical Xpress:

Study: Mammograms haven't cut rate of advanced breast cancer

A new report raises fresh questions about the value of mammograms. The rate of cancers that have already spread far beyond the breast when they are discovered has stayed stable for decades, suggesting that screening and early detection are not preventing the most dangerous forms of the disease. The report, in Thursday's New England Journal of Medicine, is by three prominent cancer specialists and is based on federal statistics going back to the 1970s.

"We're undergoing what I think for the public is a very confusing debate" about screening, but it's really "a course correction" prompted by more awareness of its risks and benefits to various groups of women, said Dr. H. Gilbert Welch, a health policy expert at Dartmouth Medical School. "All they heard for years was, 'there are only benefits.'" He is the lead author of the report, co-written with Dr. David Gorski of Wayne State University School of Medicine in Detroit and Dr. Peter Albertsen of the University of Connecticut Health Center in Farmington.

"Screening offers hope that cancer can be detected in an early, localized phase when it's more amenable to treatment," they write, but that assumes that cancer starts in one place, grows and then spreads. If that was always true, screening would reduce the rate of advanced cancers. And that has not happened. The rate of breast cancers detected at an advanced stage has been stable since 1975, despite wide use of mammography since the 1980s. The average age of women diagnosed with cancer also has remained around 63, another sign cancers are not being found sooner.

The trends suggest that some breast cancers are already "systemic" or widely spread from the start, and that finding them sooner has limited impact. "Screening mammography has been unable to identify those bad cancers, destined to become metastatic, at an earlier stage. That doesn't say mammography doesn't help less aggressive cancers," but those are less likely to prove deadly, Welch said.

Dr. Barnett Kramer, a screening expert at the National Cancer Institute, said the report shows the limitations of mammography. "I wouldn't want to say it has had no effect but it certainly has not lived up to the anticipated effect," he said. For every tumor detected early because of mammography, "you would hope to see ... an equal reduction in metastatic disease, and that has not occurred."

The situation is very different with prostate cancer. The rate of advanced cases of that disease has been cut in half since screening with PSA blood tests came into wide use around 1988, and the average age at which men are diagnosed has fallen—from 72 to 70, the authors write. However, this does not prove PSA testing is good. Shifting the stage at which a disease is diagnosed is "only the first step for successful screening," which also has to save lives to be worthwhile, Welch said. "Just because you find something earlier doesn't mean you can change its course."

Again, Kramer agreed. Prostate screening, "when put to a definitive test, did not show a clear reduction in prostate cancer mortality" in large, rigorously done trials, he said. The government task force recommends against PSA testing, and says its risks outweigh its benefits for most men.

"Screening is a close call," Welch said. "My guess is few people are helped" by prostate or breast cancer screening while many are harmed by false alarms that trigger unnecessary tests and treatments, he said.

The original report, which also includes a discussion on prostate cancer and the PSA test, in the New England Journal of Medicine:  Trends in Metastatic Breast and Prostate Cancer — Lessons in Cancer Dynamics

  In the past few months there has been a lot of discussion about early screening tests for cancer (when there are no symptoms)  versus diagnostic tests (testing once symptoms appear), especially for prostate cancer and breast cancer. Because unfortunately screening also has harms - it is not without significant risks. So the following 2 articles discussing breast cancer are real eye openers. The first article discusses a large study that found that no matter how early the screening and no matter how tiny the cancer and extensive the treatment (e.g, mastectomy of both breasts), in a certain percentage of women the cancer will reappear in a deadly fashion and eventually kill about 3.3% even though they are treated early. The Medscape article points out that it is thought that 28% of early stage breast cancers will progress or reappear as deadly metastatic cancer (even years later) no matter the treatment.

As Dr. Welch has pointed out in his book Overdiagnosis and Less Medicine, More Health - these aggressive cancers are like "birds" - they fly away throughout the body and are deadly no matter when they are diagnosed. A certain percentage of tiny cancers regress (disappear) on their own, others just sit there doing nothing, others grow very slowly (and can be treated successfully when symptoms appear), and then there are those that are so very aggressive that they go throughout the body from the beginning (the birds). And we don't know which will be the aggressive ones when we first find them. So sad..... Meanwhile try to eat healthy foods, get enough sleep, lose weight if overweight, live a healthy lifestyle (don't smoke or drink to excess), and get plenty of exercise in hopes of cancer prevention. I also like to think that each week eating some turmeric (in foods), broccoli famiy foods, olive oil, and berries may also help. Do go read the full original articles. From NY Times:

Early-Stage Breast Condition May Not Require Cancer Treatment

As many as 60,000 American women each year are told they have a very early stage of breast cancer — Stage 0, as it is commonly known — a possible precursor to what could be a deadly tumor. And almost every one of the women has either a lumpectomy or a mastectomy, and often a double mastectomy, removing a healthy breast as well. Yet it now appears that treatment may make no difference in their outcomes. Patients with this condition had close to the same likelihood of dying of breast cancer as women in the general population, and the few who died did so despite treatment, not for lack of it, researchers reported Thursday in JAMA Oncology. 

Their conclusions were based on the most extensive collection of data ever analyzed on the condition, known as ductal carcinoma in situ, or D.C.I.S.: 100,000 women followed for 20 years. The findings are likely to fan debate about whether tens of thousands of patients are undergoing unnecessary and sometimes disfiguring treatments for premalignant conditions that are unlikely to develop into life-threatening cancers.

Diagnoses of D.C.I.S., involving abnormal cells confined to the milk ducts of the breast, have soared in recent decades. They now account for as much as a quarter of cancer diagnoses made with mammography, as radiologists find smaller and smaller lesions. But the new data on outcomes raises provocative questions: Is D.C.I.S. cancer, a precursor to the disease or just a risk factor for some women? Is there any reason for most patients with the diagnosis to receive brutal therapies? If treatment does not make a difference, should women even be told they have the condition?

A majority of the 100,000 patients in the database the researchers used, from a national cancer registry, had lumpectomies, and nearly all the rest had mastectomies, the new study found. Their chance of dying of breast cancer in the two decades after treatment was 3.3 percent, no matter which procedure they had, about the same as an average woman’s chance of dying of breast cancer, said Dr. Laura J. Esserman, a breast cancer surgeon and researcher at the University of California, San Francisco, who wrote an editorial accompanying the study.

The data showed that some patients were at higher risk: those younger than 40, black women, and those whose abnormal cells had molecular markers found in advanced cancers with poorer prognoses. D.C.I.S. has long been regarded as a precursor to potentially deadly invasive cancers, analogous to colon polyps that can turn into colon cancer, said Dr. Steven A. Narod, the lead author of the paper and a researcher at Women’s College Research Institute in Toronto. The treatment strategy has been to get rid of the tiny specks of abnormal breast cells, just as doctors get rid of colon polyps when they see them in a colonoscopy.

But if that understanding of the condition had played out as expected, women who had an entire breast removed, or even both breasts as a sort of double precaution, should have been protected from invasive breast cancer. Instead, the findings showed, they had the same risk as those who had a lumpectomy. Almost no women went untreated, so it is not clear if as a group, they did worse. But some women who died of breast cancer ended up with the disease throughout their body without ever having it recur in their breast — many, in fact, had no breast because they had had a mastectomy. Those very rare fatal cases of D.C.I.S. followed by fatal breast cancer, Dr. Narod concluded, had most likely already spread at the time of detection. As for the rest, he said, they were never going to spread anyway.

Dr. Esserman said that if deadly breast cancers started out as D.C.I.S., the incidence of invasive breast cancers should have plummeted with rising detection rates. That has not happened, even though in the pre-mammography era, before about 1980, the number of women found to have D.C.I.S. was only in the hundreds. Nearly 240,000 women receive diagnoses of invasive breast cancer each year.

Those facts lead Dr. Narod to a blunt view. After a surgeon has removed the aberrant cells for the biopsy, he said, “I think the best way to treat D.C.I.S. is to do nothing." ... Others drew back from that advice.

From Medscape:  The Mystery of a Common Breast Cancer Statistic

A commonly cited breast cancer statistic — that 30% of all early-stage breast cancers will progress, despite treatment, to deadly metastatic disease — appears to have no strong contemporary evidence to back it up. Nonetheless, the statistic appears widely...."It is estimated that 20% to 30% of all breast cancer cases will become metastatic," said the MBCN in response, repeating a statistic from its own website.

The primary source for this declaration is a 2005 CME review on metastatic disease published in the Oncologist by prominent medical oncologist Joyce O'Shaughnessy, MD, from Baylor University in Houston."Despite advances in the treatment of breast cancer, approximately 30% of women initially diagnosed with earlier stages of breast cancer eventually develop recurrent advanced or metastatic disease," Dr O'Shaughnessy wrote.

According to the National Cancer Institute (NCI), the definition of early-stage breast cancer is that which has not spread beyond the breast or the axillary lymph nodes. The range includes stage I, stage IIA, stage IIB, and stage IIIA disease....According to experts, early breast cancers are known to metastasize at 20 years or beyond.

 

Dr Brawley worked with two ACS epidemiologists to examine the issue. They looked at breast-cancer-specific mortality (as identified on death certificates) in 12 health districts in the United States from 2008 to 2012. They were surprised by the finding: "28% of the women who died of breast cancer during that time period had localized disease at diagnosis," said Dr Brawley. The result was unexpected. "We all thought 30% was too high," said Dr Brawley.

(NOTE: Photo credit: Wikipedia Commons of Edouard Manet- Blond Woman With Bare Breasts.)

 The following article supported what I have been reading over the past few years: that medical tests and treatments also have downsides, that it is possible to "know too much", that more harm than benefits can occur from certain tests, procedures, and medicines, and lifestyle changes (eat a less processed more plant-based diet, move more, and don't smoke) can be better than some medicines or certain procedures. The doctor mentioned in this article (Dr. H. Gilbert Welch) recently published a book aimed at the general public which I just read and highly recommend: Less Medicine, More Health. Dr. Welch is an academic physician, a professor at Dartmouth Medical School, and a nationally recognized expert on the effects of medical testing. In 2012 he published the well regarded and more technical and in-depth book on this issue: Overdiagnosed: Making People Sick in the Pursuit of Health. From The Atlantic:

The Downside of Medical Screening

If you had a disease, and you could find out sooner rather than later, why wouldn’t you?Medicine has long focused on early detection of diseases as part of a move toward preventive care. But imperfect tests, false positives, and overdiagnosis mean that sometimes the tests do more harm than good, and in recent years, there have been more recommendations to reduce some kinds of screening, including pap smears, colonoscopies, mammograms, and even annual pelvic exams.

“This is something we all need to understand, the two sides of early detection. It does help people, but it’s almost guaranteed to harm others,” said H. Gilbert Welch, a professor of medicine, public policy, and business administration at Dartmouth College, and author of the book Should I Be Tested for Cancer? (He reveals his answer in the book’s subtitle: “Maybe not.”)

The more you look for disease, the more you find it. And in the case of cancer, it’s hard for doctors to know if what they find is dangerous and needs to be addressed, or if it’s just a small tumor that won’t grow and poses no threat. “We can’t be sure which is which, so we treat everybody,” Welch explained at the Aspen Ideas Festival’s Spotlight Health session. “That means we’re treating people who will never experience problems from their disease.”

But they may experience problems from the treatment.The panel gave the example of prostate cancer, which is very common in men—one in seven American men will be diagnosed with it in their lifetimes. “But it turns out a lot of these cancers are very indolent,” said Jessica Herzstein, a preventive-medicine consultant and member of the U.S. Preventive Services Task Force. Around 30 to 40 percent of men who’ve been treated for prostate cancer likely had “slow-growing tumors that would never have become a threat to the man’s lifespan or health,” according to the Prostate Cancer Foundation.

In other words, “you’re going to die with them, not of them,” Herzstein said, “and the treatments are very very harmful.” Radiation therapy, for example, can cause incontinence and erectile dysfunction, and hormone therapy can cause osteoporosis and depression.

The possibility of a false positive is another downside. Not only could it lead to more invasive follow-up tests or treatments that aren’t needed, but it can also give patients unnecessary anxiety.“If we resolve the test by saying ‘The test was wrong, you’re fine!’, that’s one thing,” Welch said. “But most false alarms aren’t resolved that way. [It’s more like] ‘You don’t have cancer, but you have some abnormality that possibly puts you at a higher risk for cancer, but we’re not going to do anything about it. I think that’s where there can be [mental] harm.”

Ultimately, it comes down to a weighing of the benefits and the harms, and, in the absence of clear evidence, the preferences of the patient. The U.S. Preventive Services Task Force helps identify which tests are beneficial by evaluating and grading them. It gives tests an A if there’s a high certainty of substantial benefit, a B if there’s moderate certainty of substantial benefit, a C if there’s moderate certainty of a small benefit, a D if there’s moderate or high certainty of no benefit, and an I if the evidence is just too insufficient to say.

The task force gave prostate cancer screening a D. HIV screening got an A. For breast cancer screening, an always-controversial topic, the results vary. Breast self-exams got a D. Mammograms got a B, but only for women between 50 and 74 years old. For women in their 40s, the grade is a C, meaning the task force recommends patients and physicians discuss and decide together.

Before getting a screening test, patients should think about what would happen if they get a positive result, and if they’d be ready for it, Welch advised. “If I were to go through this, and have this diagnosis, would I want to have this surgery?” Herzstein asked, posing a hypothetical. Would you want to undergo the biopsy, the chemo, whatever treatments come next? “Maybe you don’t even want to go there if there is no treatment for the disease,” she added. Welch gives an example. “With Alzheimer’s disease that’s a fundamental question: What are you going to do with a positive result?” he asked.