Posted by - J. Rand Baggesen, M.D.

In past columns we have looked at how medicine is able to achieve the promise of prevention and early detection using technology to detect vascular disease before it causes damage like heart attack and stroke. This column will focus on the problem of cancer detection. How can technology help us find cancer in its earliest stage when treatment can lead to better survival or perhaps cure?

Cancer in its many forms is the second leading cause of death after vascular disease. Lung cancer is the leading cause of death due to cancer for both men and women, accounting for 32% of male cancer deaths and 25% of female cancer deaths in the United States. Only about one tenth of lung cancer victims survive more than 5 years after diagnosis. Colo-rectal cancer is the second most common cause of cancer death in the United States, after lung cancer. Breast and Prostate cancer are next on the list, followed by pancreatic, stomach, esophageal, ovarian, uterine, cervical, lymphoma’s, leukemia’s, liver, brain, kidney, bladder, skin and mouth cancer. Any tissue type is capable of undergoing unregulated cell growth with is the definition of cancer.

The American Cancer Society and many professional medical organizations have recommended cancer screening programs to aid in the early detection of cancer. Despite this important advice, many Americans with access to healthcare choose to forgo these recommendations and neglect getting a PSA, mammogram or colonoscopy. The important roll of prevention cannot be overstated in the fight against cancer. There are specific recommendations from the American Cancer Society for screening of breast, colo-rectal, cervical, endometrial and prostate in those people at average risk for cancer (unless otherwise specified) and without any specific symptoms. Other medical organizations have prevention recommendations as well.

Medical care in the United States is delivered within an allopathic model, that is to say, we usually treat a problem once it has surfaced. The United States currently spends about 16% of our GNP on medical care. Most other industrialized countries spend approximately 9.5% of their GNP on medical care and do so with a much greater focus on prevention and less on treatment of catastrophic disease. There are many tests that can aid in the early diagnosis of cancer not normally paid for by insurance because the cost benefit ratio (for the insurance company) is not high enough. Here below, are some examples of tests an individual might want to have performed if you are interested in early diagnosis and potentially life-saving treatment.

Many people are familiar with the prostate specific antigen, PSA test for prostate cancer in men. This is a specific protein that can be detected in blood produced by prostatic tumor cells. There are other tests that look for other specific blood proteins produced by other specific cancer cells. Just like the PSA test, these tests have varying sensitivity and specificity. Sensitivity is defined by the tests ability to flying disease if it is present. Specificity is defined by the likelihood of present disease in a positive test. It is of paramount importance to have a healthcare professional who has insight into this sensitivity and specificity of any test that looks for sub clinical disease.

Ovarian cancer has a tumor marker called CA-125. This test is usually not paid for by insurance for screening in people without symptoms or other findings of cancer. In postmenopausal women with a mass on their ovary found by ultrasound a CA-125 level of greater than 65 has a 97% positive predictive value for ovarian cancer. It can be elevated in other cancers and benign conditions and must be interpreted based upon the clinical setting.

CA 27.29 as a tumor marker for breast cancer. It is elevated in approximately one third of women with early stage (stage I-II) breast cancer and two thirds of women with late stage (stage III-IV) breast cancer. While studies have not shown a predictive value in large trials, for individuals willing to invest in early detection this simple blood test may provide useful information. For women who have a history of breast cancer this test showed an elevation on average five months before symptomatic disease presented.

The carcinoembryonic antigen, CEA is a protein found in the blood went expressed by adenocarcinoma of the colon and other malignancies. Levels over 10 are rarely associated with benign conditions. As with many of these early tumor markers, the sensitivity increases with advanced disease. Approximately 25% of colon cancer in an early stage can be found using CEA. Here again, for individuals who wish to do all that they can personally to watch for disease, I would rather be part of the 25% who might find an asymptomatic problem they than be blindsided by it later.

CA 19.9 is a tumor marker associated with pancreatic cancer. This tumor marker has a sensitivity and specificity of 80 to 90% for pancreatic cancer. Because pancreatic cancer is rare, it is often said that this blood test has a very low positive predictive value. Unfortunately, pancreatic cancer is usually found to late for effective treatment. Here again, our medical system views early detection as a low priority.

I hope I have challenged your thinking on early detection of cancer. No one test can be used in a vacuum to find this devastating disease. Most of the above tumor markers are not normally paid for by insurance. As a society, Americans often have no difficulty spending $4-$5 a day on a Starbucks latte. As a doctor who practices very individualized preventative medicine, I think we all might make better investment decisions in regard to own personalized healthcare.

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