Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, May 22, 1990 TAG: 9005220565
SECTION: NATIONAL/INTERNATIONAL PAGE: A/1 EDITION: EVENING
SOURCE: Associated Press
DATELINE: WASHINGTON LENGTH: Medium
The work, though still in its preliminary stages, suggests that it may be possible to stop the disease by harnessing the body's own built-in defenses.
Antibodies are among the body's principal weapons for fighting off a variety of foreign invaders, including cancer. In this case, scientists crafted human antibodies in the test tube that were specifically targeted against the cancer. Then they injected them into cancerous growths on victims' skin.
"The lesions dry up and regress," said Dr. Donald Morton, director of the John Wayne Surgical Oncology Clinic at the University of California, Los Angeles.
In initial studies, Morton and colleagues gave the injections to 28 people whose melanoma came back after initial surgery. In 18 of them, the shots caused partial or complete disappearance of the growths.
The doctors injected three different kinds of antibodies. Each recognizes a different chemical structure that is unique to cancer cells.
The antibodies latch onto these chemical structures, marking the cancer cells for destruction by other patrolling white blood cells. To the researchers' surprise, they found that the cancer patients began making more of these antibodies on their own.
"We are actually stimulating immunity with this treatment," said Morton. "We don't know why, but it is happening."
Morton presented his findings Monday at the annual meeting of the American Society of Clinical Oncology.
"I was quite impressed by the response rate," commented Dr. Carol Westbook of the University of Chicago. "It appears to be a promising treatment that warrants further investigation."
However, Dr. Bruce Cheson of the National Cancer Institute cautioned that melanoma is particularly hard to study. The course of the disease can be difficult to predict, and the cancer may go away for reasons that have nothing to do with the experimental treatment.
Melanoma is curable in about 90 percent of cases when it is caught early. However, it is fatal if it progresses and spreads throughout the body.
Melanoma, like other, less dangerous forms of skin cancer, can result from over-exposure to the sun, and people with light complexions or irregularly shaped moles are at highest risk.
An estimated 27,000 new cases will be diagnosed in the United States this year, and the disease is believed to be increasing at a rate of 3 percent or 4 percent a year.
Among other research presented at the meeting:
The acne drug Accutane appears to significantly reduce the risk of second cancers in people who undergo treatment for smoking-related tumors of the mouth and throat. In a comparison study on 100 people, Dr. Waun Hong of M.D. Anderson Cancer Center in Houston presented evidence that the drug, a synthetic form of vitamin A, suppresses abnormal growths from turning cancerous.
Also on Monday, medical experts advising the Food and Drug Administration said stronger efforts are needed to make sure women do not use Accutane during pregnancy because it can cause birth defects. The advisory committees rejected the advice of some within FDA who want Accutane withheld from all women to eliminate any risk of birth defects from the drug.
Granulocyte colony stimulating factor, a genetically engineered substance that speeds up production of white blood cells, can offset a major side effect of cancer treatment. Often people receiving chemotherapy must stop their medication because the drugs lower their blood counts, leaving them open to infection.
Dr. Jeffrey Crawford of Duke University Medical Center tested the growth factor on 126 lung cancer patients and found that it reduced low blood counts and infected-related fever by 44 percent.
A study by Dr. Charles Moertel and others from the Mayo Clinic helps doctors handle the dilemma of how to treat colon cancer patients whose tumors have spread through the bowel wall but have not visibly invaded the lymph nodes. Since three-quarters can be saved with surgery alone, doctors are reluctant to offer chemotherapy.
The new study found ways of identifying the 25 percent whose tumors are highly likely to spread. Moertel found that those whose tumors have unusual genetic characteristics or have perforated the bowel would probably benefit from chemotherapy.
by CNB