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Other common
name(s): Carticin, Cartilade™,
BeneFin™, Neovastat (AE-941)
Scientific/medical
name(s): none
Description
Shark cartilage is extracted from the heads and fins of
sharks. Cartilage is a type of connective tissue that is found in the
skeletal systems of many animals, including humans. Sharks' skeletons
are made up almost entirely of cartilage. The major compounds in shark
cartilage are proteoglycans and glycoproteins (large molecules with
protein and carbohydrate components), as well as protein and calcium
salts. Shark cartilage is promoted mainly as an alternative to
conventional cancer treatment, but some forms are being studied for use
along with standard therapies.
Overview
Most shark cartilage products are sold as dietary supplements
in the form of pills or powders. Most have not been tested for
effectiveness, safety, or to verify the purity of ingredients.
Available scientific evidence does not support claims that shark
cartilage supplements sold as food supplements are an effective
treatment for cancer, osteoporosis, or any other disease. One shark
cartilage product, called AE-941, is in the early phases of development
as an investigational new drug.
Although some laboratory and animal studies have shown that
some components in shark cartilage have the ability to slow the growth
of new blood vessels, these effects have not been proven in humans. The
few small clinical studies of shark cartilage products published to
date have not shown any benefit against cancer. Further clinical trials
of the supplements and of a purified cartilage extract are currently
under way.
How is it promoted for use?
Supporters believe that shark cartilage supplements or
cartilage from other animals, such as cows, can slow or stop the growth
of cancer (see also Bovine Cartilage).
According to its supporters, shark cartilage contains proteins that
stop angiogenesis, the process of blood vessel development. Tumors need
a network of blood vessels to survive and grow, so cutting off the
tumor's blood supply starves it of nutrients, causing it to shrink or
disappear. Some supporters also claim that shark cartilage can help
against other diseases such as osteoporosis, arthritis, psoriasis,
macular degeneration, and inflammation of the intestinal tract.
What does it involve?
Shark cartilage is usually taken by mouth as a capsule,
powder, or liquid extract, but some people have trouble taking it by
mouth because of the strong fishy smell and taste. It is sometimes used
as an enema. The dose and length of treatment varies widely.
Manufacturers often recommend large doses (up to 1 cup a day).
Chondroitin, a supplement often used with glucosamine to help
arthritis, is also made from cartilage. Either bovine or shark
cartilage may be used to produce chondroitin.
Shark cartilage dietary supplements are different from AE-941,
a liquid shark extract known as Neovastat. This extract is regulated by
the U. S. Food and Drug Administration (FDA) as an investigational new
drug. AE-941 is being used in carefully controlled clinical trials for
people who have agreed to be part of the study.
What is the history behind it?
A New York surgeon named John Prudden began investigating the
use of animal cartilage as a medical treatment in the early 1950s. He
used powdered cow cartilage to help heal the wounds of surgical
patients and later used it to treat cancer. He reported that tumors
shrank in more than half of the patients he treated, but the results
have not been repeated in other studies.
Since then, many kinds of cartilage, from animals such as
pigs, sheep, chickens, cows, and sharks, have been studied. After the
1992 publication of a popular book titled Sharks Don't Get Cancer,
written by I. William Lane, PhD, shark cartilage supplements became
very popular among people interested in alternative medicine. The idea
was that since cancer does not seem to develop in sharks as much as in
humans, there may be something in the sharks' systems that protects
them from the disease.
Interest in shark cartilage increased after a television news
magazine aired a segment in 1993 showing a study of patients with
advanced cancer in Cuba who had gone into remission after being treated
with shark cartilage. The results, however, have not been published in
a peer-reviewed medical journal. The National Cancer Institute (NCI)
later concluded that the results of the Cuban study were "incomplete
and unimpressive."
According to the FDA and the Federal Trade Commission, some
manufacturers of shark cartilage supplements have been fined and/or
forced to remove their products from the market for making unproven
claims that they have cancer-fighting abilities. Such claims can only
be made for drugs with proven effects.
Finding drugs that halt the spread of cancer by stopping the
growth of blood vessels has been the subject of many conventional
research studies in recent years. Some researchers believe that this
therapy, called anti-angiogenesis therapy, holds a great deal of
promise for certain types of cancer. A number of anti-angiogenesis
drugs are currently being studied, and one is already approved to treat
certain types of cancer. In addition, several drugs that were approved
for other uses, including cancer treatment, have anti-angiogenic
effects. These are now being studied more carefully for their role in
anti-angiogenesis. Some researchers are trying to purify compounds in
cartilage that stop the growth of blood vessels. But the most promising
anti-angiogenic substances now in existence are those that have been
purified from sources other than cartilage or have been made in
laboratories.
What is the evidence?
The consensus of available scientific evidence does not
support claims that whole shark cartilage supplements are an effective
treatment for cancer in humans. Although studies using cow and shark
cartilage in people with cancer began in the early 1980s, few have been
published. The scientific truth of many of these studies is open to
question because they do not describe how treatment was given, how
patients were assessed, long-term survival outcomes, or information
about the cartilage used and its components.
Some experiments have shown that some forms of shark cartilage
possess a modest ability to slow the growth of new blood vessels in
laboratory cell cultures and in animals, but the effects on humans are
not known. According to one review, results from 9 clinical series of
patients receiving shark cartilage were mixed. None of the series were
done under strict scientific controls.
In one clinical trial involving about 50 patients, researchers
concluded that shark cartilage supplements had no effect on patients
with advanced-stage cancers. When a more recent placebo-controlled
clinical trial tested shark cartilage in more than 80 patients with
advanced cancer, no benefit was found. "It wasn't well tolerated, there
wasn't any suggestion of benefit in terms of quality of life, there
wasn't any suggestion of benefit in terms of survival," commented
Charles L. Loprinzi, the physician who authored the study report.
Researchers generally agree that the protein molecules in
shark cartilage may be too large to be absorbed by the digestive tract
and are simply excreted without ever reaching tumors in the body.
However, some scientists have suggested that these substances may be
more readily absorbed when taken in a liquid form. One study concluded
that the liquid shark cartilage extract AE-941 (Neovastat) taken by
mouth effectively slowed the growth of new blood vessels in healthy
men, suggesting to the study authors that the active ingredients in
liquid shark cartilage were available for use by the body's healing
systems.
A small study of the extract found that larger doses were
better than smaller doses at prolonging survival in patients with
advanced kidney cancer. A larger study was then done. While the results
of this study have not been published, the manufacturer has stopped
testing it against kidney cancer, suggesting that the results may not
have been positive. The NCI sponsored a large, placebo-controlled
randomized clinical trial using the extract with conventional
chemotherapy and radiation therapy for the treatment of advanced (stage
III) lung cancer. Preliminary results in this study were reported at
the 2007 meeting of the American Society of Clinical Oncology. Based on
analysis of outcomes from 379 patients, the researchers concluded that
AE-941 did not improve overall survival.
Are there any possible problems or
complications?
This product is sold as a
dietary supplement in the United States. Unlike drugs (which must be
tested before being allowed to be sold), the companies that make
supplements are not required to prove to the Food and Drug
Administration that their supplements are safe or effective, as long as
they don't claim the supplements can prevent, treat, or cure any
specific disease.
Some such products may not
contain the amount of the herb or substance that is written on the
label, and some may include other substances (contaminants). Actual
amounts per dose may vary between brands or even between different
batches of the same brand.
Most such
supplements have not been tested to find out if they interact with
medicines, foods, or other herbs and supplements. Even though some
reports of interactions and harmful effects may be published, full
studies of interactions and effects are not often available. Because of
these limitations, any information on ill effects and interactions
below should be considered incomplete.
Shark cartilage is not thought to be toxic, although it has
been known to cause nausea, indigestion, fatigue, fever, and dizziness
in some people. It may affect liver function, so ask your doctor before
taking it if you have any kind of liver disease. It may also slow down
the healing process for people recovering from surgery. People with a
low white blood cell count should not take shark cartilage enemas,
because there is a risk of life-threatening infection. Children should
not take it because it could interfere with body growth and
development.
Allergic reactions are possible. People with seafood allergies
should avoid shark cartilage and chondroitin that is made from it.
Women who are pregnant or breast-feeding should also avoid these
supplements.
It is not known whether shark cartilage could cause any
problems from interactions with other medicines. Relying on this type
of treatment alone and avoiding or delaying conventional medical care
for cancer, may have serious health consequences.
Additional Resources
More information from your American Cancer
Society
The following information on complementary and alternative
therapies may also be helpful to you. These materials may be found on
our Web site (www.cancer.org)
or ordered from our toll-free number (1-800-ACS-2345).
References
Batist G, Patenaude F, Champagne P, et al. Neovastat (AE-941)
in refractory renal cell carcinoma patients: report of a phase II trial
with two dose levels. Ann
Oncol. 2002;13:1259-1263.
Berbari P, Thibodeau A, Germain L, et al. Antiangiogenic
effects of the oral administration of liquid cartilage extract in
humans. J Surg Res.
1999;87;108-113.
Ebube NK, Mark W, Hahm H. Preformulation studies and
characterization of proposed chondroprotective agents: glucosamine HCl
and chondroitin sulfate.
Pharm Dev Technol. 2002;7:457-469.
Ernst E, Cassileth B. How useful are unconventional cancer
treatments? Eur J Cancer.
1999;35:1608-1613.
Federal Trade Commission. FTC v Heritage Health Products
Company (suit filed April 16, 2004). Accessed at:
www.ftc.gov/os/caselist/heritagehealth/040427stipheritagehealth.pdf.
Accessed June 11, 2008.
Federal Trade Commission. Complaints. Accessed at:
www.ftc.gov/os/1998/09/9723071.cmp.htm,
www.ftc.gov/os/1999/09/bodysystemcmp.htm, and
www.ftc.gov/os/2001/08/formorcmp.htm on July 11, 2007.
Finkelstein JB. Sharks do get cancer: few surprises in
cartilage research. J
Natl Cancer Inst. 2005;97:1562-1563.
Food and Drug Administration. Company ordered to halt sales of
unapproved drugs, reimburse buyers. FDA Consumer Magazine,
September-October 2004. Accessed at:
http://www.fda.gov/fdac/departs/2004/504_upd.html#sales on June 11,
2008.
Loprinzi CL, Levitt R, Barton DL, et al, and the North Central
Cancer Treatment Group. Evaluation of shark cartilage in patients with
advanced cancer: a North Central Cancer Treatment Group trial. Cancer.
2005;104:176-182.
Lu C, Lee JJ, Komaki R, Herbst RS, Evans WK, Choy H,
Desjardins P, Esparaz BT, Truong M, Fisch MJ. A phase III study of
Æ-941 with induction chemotherapy (IC) and concomitant
chemoradiotherapy (CRT) for stage III non- small cell lung cancer
(NSCLC) (NCI T99-0046, RTOG 02-70, MDA 99-303). J Clin Oncol, 2007
ASCO Annual Meeting Proceedings Part I. Vol 25, No. 18S (June 20
Supplement), 2007: 7527.
Medline Plus. Herbs and supplements: Shark cartilage 2006.
Available at:
http://www.nlm.nih.gov/medlineplus/druginfo/natural/patient-sharkcartilage.html.
Accessed July 11, 2007. Content no longer available.
Memorial Sloan-Kettering Cancer Center. About herbs: Shark
cartilage. 2006. Accessed at: www.mskcc.org/mskcc/html/69374.cfm on
June 11, 2008.
Miller DR, Anderson GT, Stark JJ, Granick JL, Richardson D.
Phase I/II trial of the safety and efficacy of shark cartilage in the
treatment of advanced cancer. J
Clin Oncol. 1998;16:3649-3655.
Ostrander GK. Cheng KC. Wolf JC. Wolfe MJ. Shark cartilage,
cancer and the growing threat of pseudoscience. Cancer Research.
2004;64:8485-8491.
National Cancer Institute Physician Data Query (PDQ).
Cartilage (Bovine and Shark). 2006. Accessed at:
www.cancer.gov/cancertopics/pdq/cam/cartilage/healthprofessional onJune
11, 2008.
Raloff J. A fishy therapy: A thriving but controversial
dietary supplement. Science News Online. 2005; 167(10):154. Accessed
at: www.sciencenews.org/articles/20050305/bob9.asp on July 11, 2007.
Content no longer available.
Note:
This
information may not cover all possible claims, uses, actions,
precautions, side effects or interactions. It is not intended as
medical advice, and should not be relied upon as a substitute for
consultation with your doctor, who is familiar with your medical
situation.
Last Medical Review: 11/01/2008
Last Revised: 11/01/2008
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