Dogs do the legwork for human cancer prevention

American researchers have launched a major cancer prevention trial in pet dogs to test the hypothesis that daily supplementation with dietary antioxidants can substantially reduce the incidence of bone cancer.

The study by the Gerald P Murphy Cancer Foundation at Purdue University in Indiana is a randomised, double blind, placebo-controlled trial involving 700 Rottweiler dogs, which have a strong predisposition to bone cancer. Murphy Foundation scientists have pioneered the application of new discoveries to both humans and animals, a field known as comparative oncology.

Healthy, cancer-free Rottweilers aged five to six years will be randomised into two treatment groups (supplements versus no supplements) and then followed for up to eight years. The primary endpoint of the study is bone cancer incidence. Secondary endpoints include overall cancer incidence and longevity.

The study is designed so that investigators can detect if their intervention significantly reduces the risk of bone cancer. Further, it will test whether antioxidants can increase the number of Rottweilers reaching exceptional longevity, which for this breed is levelled at 13 years old.

The nationwide study is being funded by Proctor & Gamble Pet Care, which manufactures pet food brands such as Eukanuba.

"The intervention we're testing is a potent antioxidant combination that significantly reduces the sensitivity of cells to oxidative stress," Dr Michael Hayek, associate director of research and development at P&G Pet Care, said. "In a pilot study, we teamed up with Murphy Foundation scientists to show that daily treatment with these supplements rendered the blood cells of dogs more resistant to oxidative stress challenge in the laboratory."

Lead investigator Dr David J. Waters, executive director of the Murphy Foundation, said the study would test whether a change in diet that heightens defences against oxidative stress translates into reduced cancer risk or increased longevity. "That's very exciting," he said.

"Rottweiler owners stand strongly committed to helping us figure out just how to reduce the number of dogs that succumb to cancer. This trial takes an important first step toward that goal. Our end goal is to help not only dogs, but their human owners as well, by preventing this devastating disease."

As the world's first cancer prevention study benefiting pet dogs and humans, this new trial is part of a larger research and education initiative of the Murphy Foundation known as 2 Steps Ahead. Whereas early detection of cancer through screening - such as the PSA blood test or mammography - keeps people one step ahead of a diagnosis of advanced cancer, the idea of cancer avoidance through prevention is that it keeps you two steps ahead of cancer.

As part of the 2 Steps Ahead program, the Murphy Foundation is also participating in SELECT, the largest human prostate cancer prevention trial ever conducted. SELECT is a 12-year study funded by the National Cancer Institute that is currently testing whether daily supplementation with two antioxidant nutrients (vitamin E and selenium) can reduce prostate cancer risk in more than 32,000 men.

The Gerald P. Murphy Cancer Foundation was named in memory of its founding director and the developer of the PSA test for early prostate cancer detection. Research by the Foundation has shown that supplementation with the trace mineral selenium significantly reduces DNA damage in the ageing prostate. This has led to the development of SeleniumHealth, a simple toenail test that men can use to adjust their selenium intake, reducing prostate cancer risk.

Source: P&G Pet Care