Mammograms and overdiagnosis

Fallleaves · October 2016

Even more evidence that mammograms have been oversold

"A study published online today by the The New England Journal of Medicine added to a growing body of evidence that for every woman who has been helped by a mammogram screening¹ for breast cancer, many more have been harmed.

"This latest study examined data from 1975 to 2012 on women ages 40 and older taken from a national program that tracks cancer cases. The researchers' goal was to determine whether this type of screening, which became widespread in the 1980s, was really catching cancer earlier and thus reducing the number of big tumors that were being diagnosed later."

"The results were sobering, as H. Gilbert Welch, a physician at Dartmouth and the study's lead author, explains in this short video. "

"But the new study found that although the incidence of cancers smaller than 2 centimeters rose quite dramatically after widespread mammography was introduced, by 162 cases per 100,000 women, the incidence of larger tumors fell by a much smaller amount — only 30 cases of cancer per 100,000 women."

"Most importantly, the incidence of metastatic cancer, which is the type that causes most deaths, was flat. Welch said that means that screening finds a lot of small cancers that would never have killed anyone."

"Screening did result in more cancers being detected, he said, but the data suggests that only about 30 of the 162 additional small tumors per 100,000 women that screening mammograms found would ever have progressed to a dangerous stage. That means that 132, or 81 percent, of the 162 extra tumors detected represented "overdiagnosis" — the discovery and treatment of tumors that were never destined to harm."

"Put this all together, and what it says is that whether to have a mammogram isn't a life-or-death decision, Welch said. As I wrote last year, science can't settle the mammogram debate — choices about whether to get screened are value judgments with no one correct answer. Women who want to get screened should, but women who opt out should not be demonized for their choice, Welch said."

http://fivethirtyeight.com/features/even-more-evid...

voraciousreader · October 2016

Yes. Once again Dr. Welch and his colleagues have published in the distinguished NEJM expressing their belief that population based screening mammography saves fewer lives than previously believe. Dr. Kopans... representing radiologists quickly...as always..denounced the findings.

voraciousreader · October 2016

Yes. Once again Dr. Welch and his colleagues have published in the distinguished NEJM expressing their belief that population based screening mammography saves fewer lives than previously believed. Dr. Kopans... representing radiologists quickly...as always..denounced the findings.

voraciousreader · October 2016

http://www.auntminnie.com/index.aspx?sec=ser&sub=d...

Dr.Kopens...

voraciousreader · October 2016

imho....I have read two of Dr.Welch's books and agree with him. I think we are owed a better way of screening. That said....I think the use of blood markers will make population based screening imaging nearly obsolete in the next decade.....

voraciousreader · October 2016

http://www.forbes.com/sites/elaineschattner/2016/1...

In all fairness....here is another opposing viewpoint.

Fallleaves · October 2016

Voracious, I read Dr. Welch's book, "Overdiagnosed" this summer and found it persuasive. If I remember correctly, he made the argument that while catching breast cancer while it is early is important, finding it before it is palpable provides no survival benefit and leads to a lot of overtreatment of disease that might not have progressed. He pointed to a Canadian study (I think the one I have below) that showed that women who received manual breast exams from trained nurses did not have higher mortality from breast cancer than women receiving mammograms. Makes me wonder if that shouldn't be the preferred screening technique, at least in women at normal risk before 50. I know people like Dr. Laura Esserman have questioned whether all DCIS needs to be treated, but once it is detected by mammogram, almost all cases are. I too, have read Dr. Kopans opposing viewpoint, which I'll post at the bottom.

A few other articles that question the value of mammograms, followed by a different opinion.

Effect of Three Decades of Screening Mammography on Breast-Cancer Incidence

"The introduction of screening mammography in the United States has been associated with a doubling in the number of cases of early-stage breast cancer that are detected each year, from 112 to 234 cases per 100,000 women — an absolute increase of 122 cases per 100,000 women. Concomitantly, the rate at which women present with late-stage cancer has decreased by 8%, from 102 to 94 cases per 100,000 women — an absolute decrease of 8 cases per 100,000 women. With the assumption of a constant underlying disease burden, only 8 of the 122 additional early-stage cancers diagnosed were expected to progress to advanced disease... we estimated that breast cancer was overdiagnosed (i.e., tumors were detected on screening that would never have led to clinical symptoms) in 1.3 million U.S. women in the past 30 years. We estimated that in 2008, breast cancer was overdiagnosed in more than 70,000 women; this accounted for 31% of all breast cancers diagnosed."

http://www.nejm.org/doi/full/10.1056/NEJMoa1206809

(Bleyer, 2012)

Twenty five year follow-up for breast cancer incidence and mortality of the Canadian National Breast Screening Study: randomised screening trial

"Annual mammography in women aged 40-59 does not reduce mortality from breast cancer beyond that of physical examination or usual care when adjuvant therapy for breast cancer is freely available. Overall, 22% (106/484) of screen detected invasive breast cancers were over-diagnosed, representing one over-diagnosed breast cancer for every 424 women who received mammography screening in the trial."

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3921437/

(Miller, 2014)

Invasive Breast Cancer Incidence in 2,305,427 Screened Asymptomatic Women: Estimated Long Term Outcomes during Menopause Using a Systematic Review

"The overdiagnosis of breast cancer increases women's stress and fear, and also results in unnecessary and invasive surgical and medical treatments. Treatments can be painful, lead to adverse events, create financial burden, inhibit sexual relationships, and increase the risk of other diseases, including ischemic heart disease [5–7].Overdiagnosis also distorts mortality rate calculations because the mortality rate is defined as the number of women who died divided by the number diagnosed. Increasing the number of diagnosed women by 30–50% in the screened group lowers the apparent mortality rate [8]. The belief that early diagnosis has reduced breast cancer mortality in the populations of screened women is caused largely by a failure to appreciate the impact of overdiagnosis, which creates an artificial drop in the mortality rate."

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4479875/

(Cutler, 2015)

Breast cancer screening panels continue to confuse the facts and inject their own biases

"I recently outlined the scientific errors that I was concerned would be made by the U.S. Preventive Services Task Force (uspstf) and the International Agency for Research on Cancer (iarc) panels in their reviews of breast cancer screening guidelines¹. Based on the draft proposal by the uspstf, and now iarc², my concerns have been realized. Because the panels include few (if any) experts in screening, they are unable to sort out the validity of the various analyses involved, and they give credibility to analyses that have major flaws."

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4608412/

(Kopans, 2015)

Fallleaves · October 2016

This is from the Forbes article Voraciousreader posted above:

"There is no doubt that advanced breast cancer causes disability and death. Medications are expensive. Yet the financial and physical costs of treating stage 4, metastatic breast cancer, which remains incurable and requires treatment until life's end, go unstated here and in other anti-screening screeds. Why not mention the harms of late detection?"

I think the point Dr. Welch made in his study was the increased detection of cancers from mammograms, has NOT led to a decrease in metastatic breast cancer (the line has remained flat).

But on the other hand, there is a benefit of catching breast cancer before the point that chemotherapy is needed, due to the harms that causes. So reducing the cancers above 2 cm has a benefit, too. Although, there are molecular characteristics that influence the recommendation for chemotherapy, that early detection will have no effect on, so that benefit shouldn't be overstated.

I used to think blood testing would solve the mammogram problem, but now I wonder if it won't just lead to more overdiagnosis. The test for prostate cancer is a blood test, and look at the problem they've had with overdiagnosis and overtreatment! Once you find something, there is an overwhelming desire to "fix" it, even if it might not cause a problem and fixing it might cause more harm than good.

wallycat · October 2016

And for some of us, we are UNDER diagnosed. ILC cancers are rarely found on mammograms. I had 9 years of complacency thinking I was good to go.

voraciousreader · October 2016

wally... mammography missed mine too.

Sjacobs146 · October 2016

My Cancer was caught at age 48 by a routine mammogram that I considered skipping because of all the talk about not needing yearly mammograms before age 50. I had a positive lymph node. If I had skipped that mammogram, how far would my Cancer progressed in a year? Could it have metastasized? Survival is one thing, but quality of life is another. If I'd skipped that mammo, would I be Stage IV today. I guess there's no way to tell. I know that all of my docs get yearly mammos...

ksusan · October 2016

My DCIS showed on mammogram, which caused additional imaging that revealed IDC deep in the other breast and a positive node. Can't say it ever would have been palpable--nor would the widespread grade 3 DCIS have been.

Mammograms and overdiagnosis

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