Consumer Reports on cancer screening

Consumer Reports is a magazine we tend to associate with helping us pick out our next microwave or digital camera. But in the new March 2013 issue, they have done an article on cancer screening tests. Now, keep in mind that this is a commercial publication, and their bottom line is selling copies, so they've made it a bit more sensational then necessary, but they have many valid points. As usual, I neither condone or condemn the article, I'm just summarizing and relaying with a little commentary. After writing this, I've realized this has gotten quite lengthy, so I'll put the rest of the text after the jump.





Early on they use a quote to catch attention: " 'The medical and public health community has systematically exaggerated the benefits of screening for years and dowplayed [sic] the harms,' says H. Gilbert Welch, M.D." They follow this up with a statistic from Welch that "more than 70,000 women 40 and older were found to have small, nonaggressive cancers that were treated even though they probably wouldn't be life-threatening."  What I infer from these statements (and others I haven't copied) is that Welch believes many people, who are not at high risk for cancer, are getting screened because the public health policy has dictated that we should, on the logic of better-safe-than-sorry. If you screen enough people, you will either get 1) a false-positive on the test or 2) find cancer cells in the body that may not develop into the big CANCER.

Something to remember on that point is that, at any given time in our body, "cancer" cells (cells which are not replicated correctly / replicate with a mutation) are constantly being created and then almost immediately destroyed and recycled. For the most part, our body handles these aberrations with simple mechanistic efficiency. It's when they get out of control that CANCER arises.

Back to the article: they point out that "some tests just aren't very good," citing how there are no early screening tests for cancers like pancreatic or ovarian, resulting in people not knowing they have the cancer until it's at a late stage and may be untreatable.

They go on to extoll the benefits of testing people who are at high risk for a disease. For many cancers, there is an age profile; family history obviously indicates a high risk; and behaviors such as smoking can greatly increase the risk of developing a cancer.

Next the article discusses how some tests, while maybe able to indicate something is happening, may not tell you what exactly is going on. The prime example of this is the PSA test for prostate cancer. On the surface, it seems very good: quick and easy blood draw, send the sample to a lab, track it over your golden years. The rule of thumb for the PSA is that the absolute value doesn't matter as much as the rate of change, however, this still doesn't tell you what's going on inside the body. You won't know that until you do a biopsy, which is invasive and has a small risk associated with it (infection, which comes with any hospital visit).

Then in true Consumer Reports fashion, they create a table and rate a set of tests on a scale of "do the benefits outweigh the harms." They say there are 3 that you should definitely do:

1. Pap smear for cervical cancer for women age 21-65
2. A test for colon cancer (**see text below for more) for people age 50-75
3. Mammogram for breast cancer for women age 50-74

Ones they said to skip for people who aren't at high risk:

1. bladder cancer, because early screening won't improve cure rate
2. lung cancer, because it's a fairly environmentally driven cancer (i.e. you probably know it's coming)
3. skin cancer, because "the effectiveness of screening has not been proven"
4. oral cancer, for the same reasons as lung cancer
5. prostate cancer, for above stated reason and it's usually a slowly progressing disease (one set of statistics declare you're more likely to die with it than from it)
6. ovarian cancer, because it's not "likely to detect the disease at a curable stage"
7. pancreatic cancer, "because no test is likely to detect the disease at a curable stage"
8. testicular cancer, because "most cancers found without screening are curable"

Remember, these anti-recommendations are for people who are not at high risk (no family history or other reason to suspect they would ever develop that form of cancer)

In summary, I think their take home message was trying to be: don't be so afraid of cancer. Take necessary precautions when they make sense, such as if one of your parents or grandparents had a cancer, but don't turn yourself into a lab rat.