Want to Reduce Cancer Deaths? Give Everyone Cancer

I stole that headline from an amazing op-ed in Thursday’s The New York Times written by the co-author of what will likely be one of the most provocative medical studies published in years.

For their study, published online last week in The New England Journal of Medicine, the authors used trend data from the National Health Interview Survey on the proportion of women 40 years of age or older who underwent screening mammography, then compared those numbers against data on breast cancer incidence and survival rate.

They found that 1.5 million more women have received a diagnosis of early-stage breast cancer since the introduction of screening in the 1980s, but there was no change in the number of women with life-threatening metastatic breast cancer. This means that screening, which, as the authors point out, is touted as one of the most important thing women can do for their health and credited with saving millions of women from death from cancer, is neither. Plus, the data they relied on was produced before today’s more advanced mammography techniques, which are capable of picking up even earlier cancers.

So how to explain the drop in breast cancer deaths over the past 30 years that has been largely attributed to screening and the increased number of cancers picked up early? It’s due to better treatments, the authors found, not the stage at diagnosis. Also, if you pick up more early cancers that aren’t likely to kill anyone, then you will see a lower death rate. If one woman out of 10 dies of breast cancer, that’s a 10 percent rate. But if one woman out of 30 dies of breast cancer, and those additional 20 cancers wouldn’t have been diagnosed 30 years ago, that’s a death rate of just 0.3 percent.

As they wrote: “If [screening mammography] does not advance the time of diagnosis of late-stage cancer, it won’t reduce mortality.” In other words, just as many women will die of breast cancer whether or not they’d been screened.

Ok, you might be saying, but what’s the big deal? The amount of radiation in a mammogram is small. And you’re correct. But let’s put aside the fact that any unnecessary radiation is a risk for future cancers and think about the unnecessary surgery, chemotherapy, and radiation, not to mention fear, anxiety and cost, these overdiagnosed women experienced for a cancer that was unlikely to have killed them in the first place.

Not surprisingly, the reaction has been immediate and, generally, negative (you can read more here).

But as much as we like to put our heads in the sand and refuse to believe objective, scientific evidence that discounts what we think to be true (such as the fact that a bacterium causes most ulcers; that hormone therapy not only doesn’t protect against heart disease, but appears to contribute to it in older women; that bed rest is about the worst thing you can do for back pain; that climate change is a figment of scientists’ imagination), the facts are the facts.

Mammograms don’t save lives.

The NEJM article does not actually present new information. As the authors noted, their findings have been duplicated in numerous studies over the years, including three in the past two years. That’s why two years ago the US Preventive Services Task Force changed its recommendations on mammograms (covered here in an earlier blog). That policy also unleashed a firestorm of protest.

The authors of the NEJM don’t advocate eliminating screening altogether. Instead, they urge that it be limited to high-risk women — those with a family history of breast cancer and other risk factors–and, of course, to diagnostic mammograms for women who discover a lump in their breast.

They call on doctors to stop focusing on treating “pre-cancers” and, instead, to focus on better defining those cancers that are unlikely to grow and those that are. And they beg, literally beg, that we stop using the percentage of women who undergo screening mammograms as an indicator of the quality of our healthcare system.

As Dr. Gilbert wrote in his NYT piece:

“That’s beginning to look like a cruel joke: cruel because it leads doctors to harass women into compliance; a joke because no one can argue this is either a public health imperative or a valid measure of the quality of care.”