More on screening for cancer

Today I will mostly link to other medical blogs! 3 recent entries tell a compelling story. We start with KevinMD – Screen me or I’ll sue – who tells a story of a woman who demanded screening for ovarian cancer. RangelMD comments – A perfect example of so much that is wrong in modern medical practice. I must quote one of his several points about this story.

1. The erroneous idea that any “screening” blood tests and imaging modality can detect early and hence potentially curable cancer even when there is no evidence that it makes any difference. The real question that many patients (and most trial lawyers) do not understand is whether or not screening tests in a patient without symptoms can find a cancer in an early enough stage in order to potentially cure it. This question is “yes” in the case of cervical cancer detected by PAP smear and early colon cancer detected by endoscopy. The question is uncertain in breast cancer detected by mammography or prostate cancer detected by PSA. For all other cancers there are no screening tests that would make any difference in survival outcome. In other words, just because we can detect an “early” cancerous tumor on an imaging test before it causes symptoms does not automatically mean that the cancer will be at a potentially curable point in its development.

Medpundit weighs in, perhaps coincidently, with this timely post – Pop Screening She links to an excellent article from Slate – Screen Saver?: When it comes to cancer screening, more isn’t always better. Quoting from that article:

The public-health challenge, then, is to convey a more balanced, realistic message about cancer testing so that people will be receptive to negative as well as positive news about particular tests. There is good evidence to support regular Pap smears in women, no good evidence (at least not yet) to support routine lung-cancer screening for former smokers. Thus, it is particularly disheartening to see a large-scale screening program such as the New York Early Lung Cancer Action Program (full disclosure: NY-ELCAP is led by researchers at Cornell Medical School, where this writer studied medicine), which lacks a control group and so will not be able to clarify whether screening 10,000 former smokers actually saves lives. (A devastating critique of NY-ELCAP by Dr. Steven Woloshin, along with Schwartz and Welch, is available in the Lancet, but not for free.) That this massive project is heavily funded by New York’s tobacco settlement fund provides a further, unfortunate twist.

Ultimately, the public needs to set aside automatic enthusiasm for screening and develop a new kind of savvy – one that balances hope with a certain dose of healthy skepticism and leads people to embark on testing only after considering a host of variables, both personal and scientific. As it turns out, in cancer screening, as in so much else, there really isn’t a free lunch.

Please read all these links as the focus on a most important issue – right sizing our appetite for prevention. All 3 medical bloggers and the medical writer in Slate discuss the need for evidence. They warn that we must balance our quest for early diagnosis with some evidence that early diagnosis helps the patient.

Sometimes we do too much after screening. Our treatments can be harmful. Kevin MD was placed in a no win situation. He had to perform screening tests with no evidence that they can help the patient. If he finds something, the patient might suffer from the resultant medical Odyssey.

But, logic may not work with all patients, and clearly it does not work with all juries. Thus, Kevin is right between the rock and the hard place. But then, Kevin and his story really is a parable for us all.