Mitomics Introduces New Test To Detect Prostate Cancer

The radioimmunoassay technique was developed at the Bronx Veterans Administration Hospital here 20 years ago by the late Dr. Solomon Berson and Dr. Rosalyn S. Yalow. Dr. Yalow was named as winner of the Nobel Prize last October.

The radioimmunoassay technique is so sensitive that it is capable of detecting a billionth of a gram of a substance.

The Kaiser researchers, in applying the basic technique to a diagnostic test for prostate cancer, were able to measure much smaller amounts of the enzyme than was previously possible.

Because doctors generally believe that better chances for cure result from early detection of cancer, other experts raised the hope that the newer test developed in California would save more lives than is now possible.

In an editorial accompanying the Kaiser report, Dr. Ruben Gittes of the Peter Bent Brigham Hospital in Boston, called the newer prostate cancer test “an exciting finding because aggressive therapy in such patients” with early forms of prostate cancer “has been proved to yield a high cure rate.”

1,000 Patients a Month

Dr. Gittes raised the possibility that the newer test could ultimately be used on a mass screening basis once its value had been confirmed in larger trials. The Kaiser study involved just 330 men.

Dr. Foti said in a telephone interview that the radioimmunoassay test was being evaluated on 1.000 patients each month under a grant from the National Institutes of Health, a Federal agency, in Bethesda, Md. The aim is to determine the test's value on 30,000 patients.

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Cancer of the prostate accounts for 16 percent of cancers detected in men. This type of malignant tumor occurs with increasing frequency with advancing age to the point where it is the most common cause of death from cancer in the eighth decade in men.

About 57,000 Americans of all ages will develop prostate cancer in the next year, and 21,000 will die of it.

Doctors usually diagnose prostate cancer through information collected in the medical history, rectal and other parts of the physical examination and by blood and X‐ray tests.

The acid phosphatase test is the standard blood test used in detecting prostate cancer. The amounts of acid phosphatase rise in the blood when prostate cancer develops.

However, one of the test's serious limitations is that the conventional blood test can measure increased amounts of acid phosphatase only after the prostate cancer has spread beyond the gland to bone and other areas in the body. Once this spread has occurred, the chances for cure are less than when the cancer was confined to the prostate gland.

‘Gloomy Experience’

Over all, 90 percent of cancers of the prostate are detected after the cancer has spread beyond the prostate gland.

But Dr. Gittes said “the clear implication” from the Kaiser study “is that mass screening on the basis of a blood test alone can reverse this gloomy experience.”

The Kaiser researchers developed the more sensitive radioimmunoassay test for acid phosphatase. Then the researchers compared results obtained with those from the standard acid phosphatase test among patients with various stages of cancer of the prostate.

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Pathologists grade prostate cancers on a scale of I (least) to IV (greatest) on the basis of the spread of the cancer. .

The Kaiser team reported that the radioimmunoassay test detected prostatic cancer in 33, 79, 71 and 92 percent of patients with stage I, II, III and IV disease. In contrast, the standard test detected increased acid phosphatases in the blood of 12, 15, 29 and 60 percent respectively.

Dr. Foti credited Dr. J. Fenimore Cooper, a urologist member of the research team, with conceiving the idea of developing a radioimmunoassay test six years ago.

Early Problems Recalled

Dr. Foti said that the team had difficulties in the earliest stages of the research in adapting the radioimmunoassay technique for the acid phosphatase enzyme and in obtaining sufficient amounts of samples from patients with prostate cancer and other disease.

Other members of the research team included Dr. Harvey Herschman and Richard R. Malvaez.

When the Nobel Prize committee at the Karolinaks Institute in Stockholm named Dr. Yalow as a co‐winner of the medicine and physiology prize, it said that her research had opened new vistas within biological and medical research far beyond‐the original stage developed at the Bronx hospital.

Over the years, others have developed the test to measure the concentrations of hundreds of hormones, vitamins, viruses, enzymes, drugs and other substances to help determine changes between normalcy and disease.

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