Shark cartilage no good for cancer

Shark cartilage has been used by many for the treatment of a variety of illnesses including cancer. But a new study suggests that shark cartilage does not benefit people with cancer and actually may make some patients feel worse.

In a study of patients with advanced breast or colorectal cancer, Mayo Clinic researchers found no improvement in overall survival rates or quality of life in those taking shark cartilage compared with those who took a placebo.

The study appears in this month's issue of the journal Cancer.

"There is no evidence to suggest a survival benefit from shark cartilage based on our data," Mayo researcher and cancer specialist Charles L. Loprinzi, MD concluded.

In fact, some measures of quality of life went down, possibly as a result of side effects, they add.

'Sharks Rarely Get Cancer'
The researchers chose to study shark cartilage as a cancer treatment because of its popularity as an alternative therapy. "The basis for this popularity is the claim that sharks rarely get cancer because of the high proportion of cartilage in the shark's body," they write.

In the study, Loprinzi and colleagues monitored 83 people with incurable advanced breast or colon cancer. They primarily looked at differences in survival time between patients in two groups: one group that received shark cartilage and another group that received an identical- appearing placebo product.

In addition, the patients continued to receive conventional treatments such as chemotherapy. The researchers show that there was no difference in overall survival time between the groups.

Patients taking shark cartilage had decreased quality-of-life scores and physical well-being compared to their baseline scores. The researchers also show that those taking the placebo had higher scores than baseline. This could reflect a result of side effects.

They add that while they found no benefits associated with shark cartilage in its current form, it is possible that future observation of shark health and the unique properties of cartilage may "eventually lead to a form of a drug that will have a role in cancer therapy."

They caution that the study ended sooner than planned. After one month, about half of the patients in both groups dropped out, and only 10% remained on the treatment for six months.

Patients that did not tolerate the shark cartilage reported diarrhea, heartburn, a decrease in infection-fighting white cells, and bone pain. Other symptoms such as fatigue and rectal bleeding were reported in those taking the placebo.

The researchers write that there is little enthusiasm for further study of shark cartilage in powdered form, considering that so many patients in this study dropped out or experienced a decline in quality of life.

Source: SharkTrust