Monday, July 27, 2009

Cancer Screening Tests

I sat with non-medical friends last night and the discussion turned to "health", as it often does. One guy related the terrible story of a woman who went to her doctor with a certain pain which turned out to be cancer that had spread and she died within a week. The inevitable question; "How do you detect early cancer, so you can catch it and cure it?"

The answer I gave was less than satisfactory for my friends. In fact, they were a bit incredulous with the answer.

All cancer is genetic, in that it is caused by genes that change. Only a few types are inherited. Most cancers come from random mutations that develop in body cells during one's lifetime - either as a mistake when cells are going through cell division or in response to injuries from environmental agents such as radiation or chemicals.

Different types of cancer show up differently in the body. We have screening tests for some types of cancer. We can detect early breast cancer with mammography. We detect early colon cancer with colonoscopy and hemocult stool tests. We do screening for cervical cancer with pap smears. Early prostate cancer can be detected with PSA, but it is not very specific. Skin cancers can be found early with visualization and biopsy.

What about brain cancer, testicular cancer, leukemia, sarcoma, lung cancer, ovarian cancer and a number of other less common malignancies? We have no screening tests for these diseases. Perhaps we will discover some gene test or imaging test or breath test in the future, but right now, a person would need to have symptoms that would point to the disease.

This is a scary thought for people...especially those who try to live healthy lives.

It is the randomness of life that has always made us feel vulnerable to things we cannot control.


Michael Kirsch, M.D. said...


I think that the benefits of many screening tests are exaggerated, including colonscopy, which I perform daily. The worst perfomer by far is the PSA test for prostate cancer. (See recent post at I have been a PSA skeptic since I first learned about it a few decades ago. It is widely advocated and practiced, costs tons of money, leads to treatments that have serious complications and harms many more men that it benefits. Before a patient consents to this thest, he should have a sober discussion with his physician, a conversation that only rarely occurs. THe PSA is one of medicine's most slippery 'Black Diamond' slopes.

Toni Brayer MD said...

MichaelKirschM.D.: I agree but it is a very very difficult conversation to have with a patient, especially a young one. 100% of the men I talk to say they want it, even if it is not specific for prostate cancer. Patients do not understand the nuances of these screening tests. They feel the same about total body scans. They say; "If there is a 1/10,000 chance of finding an early tumor it is worth it." The concept of false positives is not appreciated, or the risks of procedures to diagnose.

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