Flaxseed, Ginseng Show Promise for Cancer Patients
But Shark Cartilage No Help, Study Shows
Yahoo! Health: Cancer News
Flaxseed and ginseng appear to be useful for certain cancer patients and should be studied further, researchers said Saturday at the annual meeting of the American Society of Clinical Oncology. Shark cartilage, however, did not appear to hold any benefits.
Three studies discussed during a press briefing are some of the first and most rigorous to evaluate complementary and alternative cancer therapies, said Bruce Cheson, MD, director of hematology services at
"One of the most common questions my patients ask me is about these things that they have snookered away in their purses or pocketbooks," Cheson told reporters. "They pull out a whole big bag of things and say 'Can I take this? Is this going to help me? Is this going to stop it from coming back?' and most of the time we can't answer because we haven't done the appropriate clinical studies."
The new research brings scientists a step closer to having some answers. And in two cases, the news looks good.
The researchers cautioned, however, that the compounds used in their studies were pure -- which might not be the case for supplements bought in a grocery or health food store.
"It's just not a good idea to grab the nearest bottle on the supermarket shelf," said Debra Barton, PhD, a registered nurse at the Mayo Clinic in Rochester, Minnesota, and the lead investigator of the ginseng study. "Because there is less federal regulation of dietary supplements, there is no consistency in currently available products. In fact, some research has shown various supplements contain little or no amount of the ingredient on the label, and sometimes even harmful contaminants."
Ginseng May Fight Fatigue
Barton's study suggests American ginseng may help fight cancer-related fatigue, a problem that touches some 90% of patients. Exercise is the only remedy that has been shown to help so far, "so other treatments are needed," she noted.
In her study, 282 people were randomly assigned to take 750 mg, 1,000 mg, or 2,000 mg doses of
After the 8 weeks, people on placebo and on the lowest dose of ginseng showed similar levels of improvement in energy level and physical well-being, while people taking higher ginseng doses showed greater improvements. People taking 1,000 mg per day had the biggest gains: an increase of more than 14 points (on a scale of 1-100 points) in energy level, and more than 12 points in physical well-being.
Twice as many people taking the 2 higher doses of ginseng said their fatigue was moderately or very much improved. There were no reported problems with side effects like nausea or sleeping problems.
The findings are so promising, Barton said she and her team are planning a new clinical trial next year to confirm and refine these results.
Flaxseed May Slow Prostate Cancer
In another promising finding presented Saturday, researchers from
About a month before surgery, the men were randomly assigned to one of 4 groups: one group took 30 grams of flaxseed (about 3 rounded tablespoons) every day; another took the same amount of flaxseed and followed a low-fat diet; a third group followed only a low-fat diet without taking flaxseed; and the fourth group made no changes in their diet or supplement use. Men who took flaxseed used a ground form that they could mix into drinks or sprinkle on food.
After surgery, the researchers examined each man's prostate tumor. In the men who had been taking flaxseed, with or without the low-fat diet, the cancer cells were dividing more slowly, suggesting slower tumor growth.
Lead researcher Wendy Demark-Wahnefried, PhD, said previous studies of flaxseed and a low-fat diet have shown good results in prostate cancer, but researchers weren't sure if the benefits came from the diet, the flaxseed, or both.
"The [new] results showed that the men who took just flaxseed as well as those who took flaxseed combined with a low-fat diet did the best, indicating that it is the flaxseed which is making the difference," she said.
"These results demonstrate that flaxseed may well protect against prostate cancer growth," she added. "But this is just the first study. We will need to replicate these results before we can make recommendations."
Shark Cartilage a Bust for Lung Cancer
The news was not so good for a form of shark cartilage, however. Researchers from the University of Texas M.D. Anderson Cancer Center showed that it did nothing to improve survival of people with stage 3 non-small cell lung cancer who were also being treated with chemotherapy and radiation.
The researchers used a purified form of shark cartilage derived from dogfish sharks called AE-941 (Neovastat). In lab studies, shark cartilage appears to inhibit blood vessel growth in tumors, and earlier, smaller studies in lung cancer patients suggested those who got high doses of the stuff lived longer than expected with only a few mild side effects (nausea, vomiting, diarrhea).
But in this larger, phase 3 study, those results didn't hold up. Patients were randomly assigned to get 4 ounces a day of either shark cartilage extract or a placebo along with standard chemotherapy and chest radiation.
Those on shark cartilage survived about 14 months, while those on placebo lived an average of about 15 months -- a difference that was not statistically significant.
This is the first large phase 3 trial of shark cartilage in cancer patients, said lead researcher Charles Lu, MD. Smaller studies, however, have also shown no benefit from other forms of shark cartilage.
"We have absolutely no data showing improvements in survival, tumor shrinkage and/or clinical benefits to patients," said Lu. "Now when patients ask their oncologists about shark cartilage, physicians can point to this large NCI-sponsored phase 3 trial and tell patients that, at this point, the only studies that have been done with cartilage-derived products have been negative."
Citations: "A pilot, multi-dose, placebo-controlled evaluation of American ginseng (panax quinquefolius) to improve cancer-related fatigue: NCCTG trial N03CA." Presented
"Impact of flaxseed supplementation and dietary fat restriction on prostate cancer proliferation and other biomarkers: Results of a Phase II randomized controlled trial using a presurgical model." Presented
"A Phase III st udy of AE-941 with induction chemotherapy and concomitant chemoradiotherapy for stage III non-small cell lung cancer." Presented