Comments on: The mammography wars heat up again (2012 edition)

By: JesusR.

JesusR. — Tue, 28 Aug 2012 16:41:05 +0000

Thanks, Harriet Hall, SkepticalHealth.
Indeed, she is the kind of person prone to conspiracy theories, I´m afraid (though, fortunately, in the end she usually follow the physician advice).
Thanks again!

By: SkepticalHealth

SkepticalHealth — Tue, 28 Aug 2012 15:53:48 +0000

BTW, the ACOG, USPSTF, and ACS all agree re: mammography (slight disagreement on the practice of screening.) Your friend did not “uncover” some breast cancer conspiracy that we are all missing. Tell her she is putting her life at risk.

By: SkepticalHealth

SkepticalHealth — Tue, 28 Aug 2012 15:50:19 +0000

@Jesus, quite simply your friend is completely wrong. There is no evidence that ultrasound is better for mammography for breast cancer screening. She simply misinterpreted that study to suite her on beliefs.

By: Harriet Hall

Harriet Hall — Tue, 28 Aug 2012 15:43:46 +0000

The title of that study is misleading. According to the abstract, it did not show that ultrasound was better than mammography for screening. It was a study of patients who were already known to have cancer. It showed that it was as good as mammography for imaging invasive cancer and better than mammography in imaging cancer in patients who were already symptomatic. It showed that it was far inferior to mammography for detecting smaller non-invasive cancers. In other words, it is useful in diagnosis, but not for screening the general population.

By: JesusR.

JesusR. — Tue, 28 Aug 2012 08:32:47 +0000

A friend was complaining that there isn’t evedence that mammography is any better than ultrasound to screen for breast cancer, and, in spite of that, mamography (more uncomfortable and more expensive) is the standar method used to screen. She used this paper to support her view:

Ultrasound is now better than mammography for the detection of invasive breast cancer
Am. J. Surg. 2004
http://www.ncbi.nlm.nih.gov/pubmed/15474430

I would welcome any informed opinion about this.
Thanks!

By: Science-Based Medicine » Related by coincidence only? University and medical journal press releases versus journal articles

Mon, 20 Aug 2012 11:55:05 +0000

[...] Schwartz and colleagues (the same Lisa Schwartz who with Steven Woloshin at Dartmouth University co-authored an editorial criticizing the Susan G. Komen Foundation for having used an inappropriate measure in one of its ads) actually attempted to look at how much [...]

By: Jacob Riis

Jacob Riis — Wed, 08 Aug 2012 13:14:04 +0000

Why only “aggregate number of deaths from breast cancer prevented”? Aggregate number of women harmed might also be relevant…

By: mousethatroared

mousethatroared — Tue, 07 Aug 2012 16:45:42 +0000

Okay. Thank you Cervantes and Rork for clarifying. Just because I’m curious and might get a chance to read more, Cervantes, do you have the source for the estimate of 2 (over treated) to 1 (life saved)?

Sorry if it’s one of the links from David Gorski’s (most excellent) article. There’s a lot of links…

By: WilliamLawrenceUtridge

WilliamLawrenceUtridge — Tue, 07 Aug 2012 14:55:26 +0000

@ Scott:

And now she’s become an advocate (albeit not on a large scale) for that position, loudly declaring that “I’d definitely be dead now otherwise.” And woe betide anyone who, however gently, disagrees – because they’re obviously misogynists trying to kill all women, or brainwashed by one (depending on the target’s gender).

I was just listening to a TED talk from some guy who was discussing this – people faced with an irrevocable choice tend to rationalize and defend their choice (and regret it far less) than people faced with a choice they can later undo. She can’t get her breasts back, so it’s very, very important for her to justify her choice as having been a good one. One of the myriad cognitive biases of the human mind.

The take home message – always buy your clothes from stores where you can’t return them, you’ll be happier

By: David Gorski

David Gorski — Tue, 07 Aug 2012 14:40:47 +0000

They would also be interested in the aggregate number of deaths from breast cancer prevented.

By: BillyJoe

BillyJoe — Tue, 07 Aug 2012 13:22:32 +0000

cervantes is looking at this purely from the point of view of an individual woman comtemplating breast cancer screening. And, of course, she wants to know the absolute reduction in risk of getting breast cancer as a result of screening. The absolute risk reduction is always going to be much less impressive than relative risk reduction.
On the other hand, the health department is interested in a cost/benefit analysis. They would therefore be almost entirely interested in relative risk reduction and hardly at all interested in absolute risk reduction.

By: cervantes

cervantes — Tue, 07 Aug 2012 12:55:03 +0000

To clarify: The number of women who are overtreated has been estimated, as at least two per each woman whose death from breast cancer is averted as a result of screening. (Note that many women who are treated as a result of screening would have been diagnosed and treated successfully even if they weren’t screened.) What has not been calculated is the lost years of life as a result of overtreatment. It is usually assumed to be expensive and painful, but not otherwise harmful. I’m saying, yes it is potentially otherwise harmful, as is any severe trauma, and this needs to be considered.

By: rork

rork — Tue, 07 Aug 2012 12:38:09 +0000

I’ll put the cervantes argument differently, with some trepidation, cause I actually don’t do breast cancer research, and may not be perfectly up-to-date.
I still don’t think we have proven that for average risk women screening decreases overall mortality. I think I’ve left lists here before about how many ways there are to have your life made shorter (and more miserable) by screening. Car crash on the way to mammogram is rare, as are second cancers, but we don’t need that many such risks to make the benefits look even smaller. I think the story for colonoscopy is similar, with results still given in terms of colon cancer deaths averted, not overall mortality. I’m sympathetic: the number of patients required to be on trial to show such an effect is enormous, and the followup time needed is long. If you have a new idea about how it should be done, you may need millions of dollars and 20 years to devote to the subject.
Perhaps Coyne’s post of the other day should be cautionary too. There are radiologists doing diagnosis and treatment, surgeons cutting away (often twice), pathologists looking at dead things through lenses, hospitals moving patients, all of who we can worry are willing to continue with less concern about benefit/risk than we would wish. I except our noble blogger ofcourse, who obviously does soul-search, but he is exceptional in case you haven’t noticed. Your own doc may not even get it. Exactly when and how to do radiation is something I’ve studied and it is a mess, with everyone wanting to do it their pet way. For example the brachytherapy folks push convenience, rightly, but how often do they admit that the evidence hints that it is inferior (but perhaps not by much, this is a very tough choice). Similarly the folks doing colonoscopies want you to have another pretty early, based on data that is not nearly perfect last time I studied it (for a reason: I’d need 100,000 people and 20 years to test competing schedules, and I’d get a clear answer only maybe, and it would tell me what is better only on average).

I also don’t think there are agreed on criteria for how much more we should be doing for higher risk women, or good criteria for how many levels of risk there are, and how to categorize women into risk levels. I’m not well studied there. I again am sympathetic: it’s a damn hard problem.

By: mousethatroared

mousethatroared — Tue, 07 Aug 2012 12:06:35 +0000

@ Cervantes – okay. I was going to let it go, but it’s still bugging me.

“And btw the women who are overdiagnosed — who are treated for DCIS that if left untreated would never have caused any symptoms — probably have their lives shortened by the treatment. They may even get cancer as a result! There are at least two such women, and probably more, for every one whose life is “saved.” I have never seen anyone try to calculate this effect.”

If you have never seen anyone calculate the effect, how did you come up with at least two women (probably more) whose lives are shortened for everyone whose life is saved?

It seemed that David Gorski was saying we don’t have a good idea which DCIS are going to progress or not. How could you come up with any number?

By: DavidRLogan

DavidRLogan — Tue, 07 Aug 2012 00:13:02 +0000

I, too, am intrigued by Cervantes’ number crunching/Fight-Club-esque take on this.

Dr. G these posts are amazingly helpful and informative. Thanks so much for doing all the leg work

By: mousethatroared

mousethatroared — Mon, 06 Aug 2012 23:24:34 +0000

@ Cervantes – That’s quite an existential argument.

By: Scott

Scott — Mon, 06 Aug 2012 20:29:59 +0000

Screening isn’t the only thing that’s oversold – so is treatment, in at least some cases. One woman I know of (with no family history or other specific risk factors) had “minor” (whatever that meant) DCIS in one breast detected by a screening mammogram a few years back (~3, I think; IIRC she was ~55 at the time). Her oncologist apparently insisted that she receive a double radical mastectomy because “anyone who doesn’t is crazy.” She did so. Even allowing for a lot of misreporting between what he actually said and what she later reported, that’s way out of line with all other recommendations I’ve ever heard.

And now she’s become an advocate (albeit not on a large scale) for that position, loudly declaring that “I’d definitely be dead now otherwise.” And woe betide anyone who, however gently, disagrees – because they’re obviously misogynists trying to kill all women, or brainwashed by one (depending on the target’s gender).

I tell this story mainly to illustrate that the science is, for many people, completely irrelevant. Reactions are driven by emotion and anecdote.

By: cervantes

cervantes — Mon, 06 Aug 2012 19:32:44 +0000

Well Carl, we’d all wish to be like the Wonderful One-Horse Shay, and just go on without any mechanical problems well past our design expectancy, and then just suddenly fall apart in a cloud of dust and be done with it. Alas, dying of old age usually means dying of cancer, or dementia, or heart failure. So the Gambinos probably couldn’t grant you your wish even if they did let you off from the stabbing.

The important point is to complete the process of making comparisons, and to make the right ones. If I’m a woman of say, age 50, of average risk, contemplating getting a screening mammogram, I have to look at where that fork in the road is likely to lead. In the first place, my chance of dying from breast cancer in the next ten years is little more than 1 in 200 if I just walk away. It’s literally impossible to reduce that by very much because it’s so small in the first place. I should probably worry more about the Gambinos. But the amount by which I will in fact reduce it by undergoing screening is just a small fraction of 1/200. As I say, it’s 7/10,000. And even so, I might be hit by a bus the day after you would have died of breast cancer.

And the price I will pay is a much higher chance of getting the shit scared out of me, followed by a somewhat lower but still much higher than 7/10,000 chance of getting very painful, sickening, expensive treatment that does not benefit me and might even kill me. So the bottom line is, you don’t actually get to pick.

By: ConspicuousCarl

ConspicuousCarl — Mon, 06 Aug 2012 19:21:22 +0000

I appreciate Cervantes’ we’re-gonna-die-of-something philosophy, but if the Gambinos ever kidnap me and ask me how I want to die, I’m still going to pick old age over cancer or stabbing.

By: cervantes

cervantes — Mon, 06 Aug 2012 18:51:42 +0000

It’s also important to remember that in fact, no-one’s life is ever saved. Dr. G actually doesn’t state the really key statistic, which is that the best estimate is that screening mammography for women in their 50s results in a reduction in 10-year deaths from breast cancer of 7 out of 10,000 women. That’s how many will avoid that specific fate thanks to screening. However, they will, every one of them, still die. We have not saved the lives of 7 out of 10,000 women, rather we have deflected their deaths onto some other cause, perhaps much later or just possibly not much later at all or even earlier, as there is significant morbidity associated with treating breast cancer. And btw the women who are overdiagnosed — who are treated for DCIS that if left untreated would never have caused any symptoms — probably have their lives shortened by the treatment. They may even get cancer as a result! There are at least two such women, and probably more, for every one whose life is “saved.” I have never seen anyone try to calculate this effect.

It is that benefit which must be weighed against the harms, including by the way the almost never mentioned opportunity costs, i.e. we could be spending the money on something else.

Think about it.