CHICAGO -- Shark fin soup might taste good. But it won't do much for cancer.
Shark cartilage, a widely used alternative therapy for cancer, did not help patients with lung cancer live longer, according to the results of one of the first rigorous studies of the approach.
But two smaller studies showed some preliminary but encouraging evidence that two other complementary therapies, ginseng and flaxseed, might have some benefit for cancer patients.
The studies were presented yesterday at the annual meeting of the American Society for Clinical Oncology, where the nation's cancer doctors usually discuss the latest in chemotherapy and new biotechnology drugs.
The shark cartilage clinical trial was required by Congress and was sponsored by the National Cancer Institute. It tested a shark cartilage extract being developed as a drug by Aeterna Zentaris, a Canadian company.
Dr. Charles Lu of the M.D. Anderson Cancer Center in Houston, the trial's lead investigator, said there was reason to believe the cartilage might work. Cartilage has been found to contain factors that can impede the formation of blood vessels. And cutting off the blood supply to tumors has been proven effective with other drugs.
But in the trial, those who received the shark cartilage extract lived a median of 14.4 months, meaning that half the patients had died by that point. Those who got a placebo had a median survival of 15.6 months.
The trial involved 384 patients in the United States and Canada with advanced non-small-cell lung cancer. The shark cartilage extract was given as a liquid that the patients drank twice a day.
Results were somewhat more promising, though far less definitive, for flaxseed.
That study, led by scientists at Duke University Medical Center, involved 161 men with prostate cancer who were scheduled to have their prostates removed. After the glands were removed about a month later, the tumors were studied. It was found that the tumors of the men who had taken the flaxseed had been growing about 30 percent to 40 percent more slowly than for those who did not.
The ginseng study suggested that the herb might help fight fatigue, which is common in people with cancer. The study involved 282 patients with various types of cancer.
About a quarter of the patients who took one of the two higher doses of powdered extract of ginseng root, either 1,000 or 2,000 milligrams a day, reported that their fatigue had become "moderately better" or "much better." That contrasted with only a tenth of those who took either a smaller amount of ginseng or a placebo.
In a more conventional study presented here, researchers in Europe found that preventive radiation therapy to the head reduces the risk that tumors will spread to the brain in patients with small-cell lung cancer. The treatment also helped patients live longer.
Small-cell lung cancer accounts for 15 percent to 20 percent of all lung cancer cases, but it is an aggressive type. Previous studies had shown the benefit of preventive radiation therapy to the head for patients whose tumors were concentrated in a small area. But the new study showed that the technique was helpful for patients whose tumor had spread further into the lung or elsewhere in the body.