"Have I Got Cancer?"

Detecting cancer early is half the battle, and for a generation medical researchers have sought a simple blood test to distinguish definitely between people who are free of cancer and those who have it, or at least may have it. So far their hopes have been raised only to be rudely dashed.* But this week members of the American Association for Cancer Research meeting in Atlantic City listened intently as Dr. Andrew H. Dowdy described the most promising blood test to date.

The new test got its start ten years ago when Dr. Harry S. Penn of the University of California at Los Angeles extracted a substance from the liver of victims killed by cancer. The substance usually had no effect on blood samples from healthy persons, but it left a precipitate in samples from patients with cancer or some other diseases. The biggest trouble was that the liver fractions Dr. Penn obtained were too variable, and other medical men could not duplicate his results. Then a team of U.C.L.A. researchers joined Dr. Penn, broadened the attack and succeeded in making from bile acid a chemical called ethyl choledienate. Uniform and more stable than the liver fraction, it reacts the same way with blood samples. By now, Dr. Dowdy reported, 10,000 subjects have been tested, with these encouraging results:

P: About 95% of the subjects tested were promptly assured: no sign of cancer.

P: The test was positive in 90% of cases with "invasive" cancer (one that has begun to grow into surrounding tissues), even when no symptoms of disease were evident. It detected not only typical cancer (carcinoma) but also leukemia and lymphosarcoma.

P: It registered a false positive in 3% of subjects who appeared to have no cancer or other illness.

P:Among the common noncancerous conditions that also cause a Penn test to show up positive are active rheumatoid arthritis, tuberculosis, cirrhosis of the liver, fever, pregnancy and hormone treatments.

The false positives are bad because they breed fear instead of allaying it. The researchers are working on refinements by which they hope to weed them out.

The great virtues of the Penn test are its simplicity and speed. Any competent doctor or technician can be trained in a couple of weeks to perform it accurately.

Made ultracautious by previous fiascos, Drs. Penn and Dowdy are not even calling their procedure a "cancer test," and they insist that it should be used only under strict hospital or clinic conditions and along with other procedures. But, clearly, they hope it will prove its worth as soon as the bugs can be worked out of it.

In Atlantic City, the consensus of cold-eyed experts from all over the U.S. was that the California team is ahead of the field in seeking a way to answer the agonized question, "Doctor, have I got cancer?"

* Notably by the idioactive test devised by Chicago's Surgeon Charles B. Huggins (TIME, April 25, 1949), which fizzled.

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