Death-Defying

For decades the only true weapon against colon cancer has been surgery. If the scalpel could take out the entire tumor, the patient was cured; if not, the cancer recurred. But now, for the first time, researchers have developed a drug therapy that may reduce the high death rate from this form of cancer, which kills 53,500 Americans each year and is the third most common type of malignancy.

In a series of studies coordinated by Dr. Charles Moertel of the Mayo Clinic in Rochester, Minn., researchers tested a combination of two drugs: 5- fluorouracil, a proven anticancer agent, and levamisole, a medication commonly used by veterinarians to clear worms from the intestines of animals. Included in the studies were some 1,700 cancer patients, most of whom had been operated on for Dukes' C colon cancer. In this stage of the cancer, the tumor has penetrated the bowel wall but has not spread to the rest of the body. The results of the first study, which appeared in this month's Journal of Clinical Oncology, showed that 49% of patients receiving the treatment were still alive after five years, in contrast to 37% of another group that did not receive the drugs. In a second and much larger study, which has yet to be published, the benefit from the drug therapy "at least matched" the results achieved in the first experiment, said Dr. Moertel.

The researchers caution, however, that the drugs are not effective for patients with more severe colon cancer, in which the malignancy has already spread throughout the body. Nor have studies shown a benefit for those patients whose cancers were detected at an early stage. Still, Dr. Michael Friedman of the National Cancer Institute called this first success for drug therapy against colon cancer a "terrific intellectual breakthrough." The institute has alerted 35,000 cancer doctors across the country. And some experts are hopeful that the findings will lead to similar therapies for other cancers.