Mammography and molecular breast screening news story

Zero deaths' from breast cancer? NBC viewers misinformed by puff piece on screening test

It's hard to know where to begin with this story from NBC Nightly News about a supposedly "new" test that could be a "lifesaver" for women with dense breasts whose cancer might not show up on a normal mammogram.

NBC's top-rated newscast reaches some 8 million total viewers every night, so it's important to set the record straight about what the test, known as molecular breast imaging (MBI), is capable of and where NBC's fawning coverage went wrong.

The story is built around the experience of one woman with breast cancer who claims that molecular breast imaging "saved her life."

We're always concerned about stories that focus on one person's experience that may not be representative. And while we wish this woman the very best in her treatment, we think NBC has an obligation to vet her claims before broadcasting them to an audience of millions.

The unfortunate reality? We just can't know whether early detection will ultimately lengthen this woman's life or that of any other individual person with breast cancer.

Here's what's wrong with claiming the test 'saved her life' or will lead to 'zero deaths'

Breast cancers vary in their aggressiveness, and some will progress and prove fatal despite early detection and treatment, whereas others grow slowly and might never pose a problem to the patient.

"Survival in breast cancer patients is based on stage at diagnosis, tumor biology, and response to treatment, among other factors, breast surgeon Deanna Attai, MD, assistant clinical professor of surgery at the David Geffen School of Medicine, told me. "The patient in the story states that she was diagnosed with Stage III breast cancer but we have no information on the biology of her disease or how she has responded to treatment."

The story then quotes an expert, Dr. Deborah Rhodes of the Mayo Clinic, who claims that molecular breast imaging is "the most promising technique we have toward zero deaths from breast cancer."

Zero deaths? Really?

For the same reason that we can't say whether an individual's life has been "saved" by early detection, it's foolish to suggest that this technology will bring us anywhere close to "zero deaths" from this disease.

"This statement ignores the fact that some breast cancers are aggressive right from the start, and screening / early detection does not necessarily improve the survival rates from these lesions," Attai said. "In addition, in attempting to find every single lesion to achieve 'zero deaths,' it is likely that the rates of overdiagnosis and over treatment will increase."

Chris Norton, who co-founded the Minnesota Breast Cancer Coalition, an all-volunteer organization that focuses on education and advocacy, agreed.

"It's unfair to patients to proclaim that this imaging is the most promising technique we have toward zero deaths from breast cancer," she said.

Here's why health news stories need input from an independent expert

Rhodes, a staunch advocate for molecular breast imaging who delivered a TED talk praising the test (which she helped develop), is the only expert source consulted in the NBC segment–a problem we see often in our story reviews.

What would the story have looked like if it had featured the perspective of someone more independent?

We can get a flavor for some competing views from a 2011 blog post by David H. Gorski, MD, PhD, a surgical oncologist at the Barbara Ann Karmanos Cancer Institute specializing in breast cancer surgery.

He raised many uncertainties about MBI, notably that it delivers radiation throughout the body instead of focusing it in the breasts, as with a mammogram.

Also remember this: MBI subjects the entire body to radiation in order to try to save lives from breast cancer. How do we know that repeated doses of 99mTc sestamibi (a nuclear medicine imaging agent) won't result in the increased incidence of, for example, colorectal or ovarian cancer that cancel out any decrease in mortality observed that is attributable to better screening for breast cancer?

Gorski also points out that the technology, described as "new" in the NBC story and in Rhodes's TED talk, has been around for decades and yet has failed to catch on. (Claiming that something is new–when it likely isn't–is a problem we see often enough that "establishing novelty" is one of our 10 story review criteria.)

The concern with using these scans for breast imaging, as Gorski notes, "has always boiled down to an unacceptable lack of specificity and sensitivity." In other words, high-quality studies haven't proven that the test finds enough actual cancer — without flagging meaningless false-positives — to make it worth deploying on the scale that Rhodes is calling for.

Rhodes's own research shows that the risk of incurring an unnecessary biopsy because of a false positive exam increased with MBI, from 1 in 100 women with mammography to 4 in 100 women with mammography plus molecular breast imaging — context that was again missing from the NBC coverage.

TV newscasts can do better than this

I'm not saying that a two-minute newscast can or should try to deliver all of this nuance to its viewers. Nevertheless, NBC certainly could have:

Framed the story a little bit more cautiously to reflect legitimate uncertainty as to the value of the test

Avoided the hype of phrases like "zero deaths from breast cancer"

Consulted an independent source for a competing perspective on the technology.

That's not a very high bar to clear, and yet doing so would have made a tremendous difference to women trying to make sense of their breast cancer screening options.