USPTF vs Mammogram: The Prize Fight continues
There’s been a flurry on my twitter feed about an article that came out two weeks ago in the New England Journal of Medicine, a highly respected journal thought to be the last word on most things. The research examined more than 30 years of health statistics on breast cancer deaths and screening. Mammogram screening leads to an increase in breast cancers detected early. BUT the number of cancers diagnosed at an advanced stage was unchanged. Think about this. If more cancers are detected early, then less would be detected late right? But that’s not happening. Ok, so there may be lots of reasons for this, like advanced cancer patients never got screening earlier. Fair enough. BUT numerous studies have also been done on a total of like 600,000 people that show that women who get mammograms are just as likely to die as women without mammograms. AND the women who got mammograms were more likely to get treated for cancer and get mastectomies. SO mammograms increase diagnoses and surgeries, but don’t save lives. Guess what? Those studies were published 10 years ago.
The US Preventative Services task force (USPTF) recommends that mammograms be done every other year for women ages 50-74. That’s it. Everyone else either doesn’t need it or has to consider other factors like genetics and family history. The National Cancer Institute in it’s bulletin this month has an interview with the chair of the USPTF, Dr. Virginia Moyer. Here are some of the things she says:
1. How does the task force develop it’s recommendations? They carefully look at all the available research. They they grade the evidence, meaning they decide if the evidence is strong or weak. It’s a crazy complicated process. If you look at http://www.uspreventiveservicestaskforce.org you’ll see all the thinking and analysis that goes into these things. Anyone can look at the process.
2. All the task force members are volunteers and don’t represent any specific organization
3. When is screening beneficial? This is important. THE ONLY TIME SCREENING WORKS IS WHEN A TEST CAN DISTINGUISH PEOPLE WITH AND WITHOUT A TYPE OF CANCER FOR WHICH WE HAVE TREATMENT THAT WORKS, BUT NOT ALL THAT WELL. What does this mean?
– If treatment works great, it doesn’t matter when you catch it, you can always treat it.
-If no treatment works, there’s no point in detecting it early
-The better the treatment gets, the less useful screening is. In breast cancer, it used to be screening was good because the treatment wasn’t that great so it was better to treat if you caught it early. As treatment gets better, screening becomes less important.
-The task force does NOT do cost-benefit analysis
-Cancer is not linear. Some cells can look like cancer cells but never progress to cancer at all, and others look exactly the same but progress rapidly. WE CAN’T TELL THE DIFFERENCE.
The USPTF is doing a great job. People simply don’t believe them.
Here are two links: