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Study Finds No Benefit of Shark Cartilage for Cancer Patients (dateline October 6, 2000)


Shark cartilage capsules are ineffective and cancer  patients should stop taking them to treat their disease, said researchers at the Second European Breast Cancer Conference. Shark cartilage is an alternative therapy that became popular after the book, Sharks Don’t Get Cancer by William Lance, was first published in 1993. Researchers have since found that sharks do develop cancer, and now, a new study shows that shark cartilage does not have any effect on cancer.

In the study, Dr. Lene Adrian of Copenhagen University Hospital in Denmark, and her colleagues tested the effects of shark cartilage capsules on 17 women with advanced breast cancer who had not responded to other treatments (such as chemotherapy, radiation, or tamoxifen). The women took 24 shark cartilage capsules a day for three months. After the study, breast cancer had progressed in 15 of the women and one woman developed brain cancer.

Cancer did stabilize in one woman in the study, though researchers say that the result is not unusual for patients with metastatic breast cancer (cancer that has spread past the breast to distant regions of the body).

At the European Breast Cancer Conference in Brussels, Belgium, Dr. Adrian said that she would not advise patients to use shark cartilage and that the results of her study showed no benefit of shark cartilage in the treatment of cancer. Earlier this year, researchers discovered that sharks do indeed get cancer.

Previously, researchers have claimed that shark cartilage can treat cancer by preventing the growth of new blood vessels that feed tumors (a process called antiangiogenesis ). According to Gary K. Ostrander, PhD, a professor of biology and comparative medicine at Johns Hopkins University, there are no published studies in peer-reviewed medical journals that support this claim.

The evidence is growing stronger that shark cartilage should not be used in cancer treatment, said Dr. Adrian. Furthermore, according to the National Cancer Institute, shark cartilage can produce side effects such as dyspepsia (digestive problems), nausea, fever, dizziness, fatigue, and dysgeusia (a bad taste in the mouth).

The study presented at the European Breast Cancer Conference confirms previous research that shark cartilage does not have an effect on cancer. In a study published in the Journal of Clinical Oncology in 1998, researchers studied patients with advanced forms of a variety of cancer (including breast, colorectal, lung, and prostate) who did not respond to previous treatment. The results of the studied revealed that shark cartilage did not affect the patients’ quality of life and that the tumor response rates were similar to those seen with standard treatments.

According to the National Cancer Institute, more than 50,000 American used shark cartilage in 1992, and that number is expected to have increased significantly in the late 1990s as alternative therapies have received more media attention. In 1995, there were more than 40 difference brand names of shark cartilage. It is estimated that the sale of shark cartilage supplements has created a $50 million a year market.

Two additional studies, one led by the National Cancer Institute and the other led by the Mayo Clinic, will continue the investigation of shark cartilage supplements as a possible means of treating cancer.

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