Dogs With Cancer Helping to Find a Cure

[yamaha147]

TweetWhen her black Lab, Emmy, started limping in 2008, Kathi Streeter suspected the normal aches and pains of aging. Then came the devastating diagnosis: osteosarcoma, a deadly bone tumor. Osteosarcoma affects humans, too—mostly children, whose long-term survival rate, if the cancer spreads, is under 40 percent. Though Emmy died in May at the ripe old age of 13, she gained nearly three years of healthy living, and one day her treatment may help those kids.

[Learn more about how dogs help mankind in Mysteries of Science: Amazing Animals.]

In her quest to save Emmy, Streeter learned about a study underway at Colorado State University's Animal Cancer Center in Fort Collins, about 100 miles from her home in Franktown, Colo. It was testing a gene therapy that could be injected straight into osteosarcoma tumors. The gene delivers a molecule designed to induce the cancer cells to self-destruct. Veterinarians there wanted to see how well dogs reacted to the treatment, as part of an effort to determine whether it might also be investigated for use in children.

Streeter is a cancer survivor herself—in 2004, she underwent a double mastectomy and chemotherapy to treat breast cancer—and didn't hesitate to sign Emmy up. After the injection, CSU vets gave Emmy the standard treatment, too: amputation of her leg plus six rounds of chemo. They're now evaluating how the injection affected the tumor. Although the results of this trial have not yet been published, previous trials suggest that the therapy may enhance the immune system's ability to combat the tumor.

CSU is one of 20 participants in the Comparative Oncology Trials Consortium (COTC), a growing program started in 2003 and managed by the National Cancer Institute to study cancer in dogs and to recruit them for clinical trials of new treatments. The goal is more effective, more personalized treatments for man as well as his best friend. "Several tumor types in dogs mimic human cancers in their biologic behavior and genetic signature," says Susan Lana, associate professor of clinical oncology at CSU. "Dogs can help us try to answer questions like, 'Why does this cancer spread?' and 'Are there genetic pathways we can explore for treatment?' "

Dogs are ideal models, Lana says, because they're genetically similar to humans and share the same environment. They develop cancer naturally, unlike mice and rats, which must be engineered to have the disease. And dogs are big enough to undergo MRIs as well as blood tests and biopsies, so scientists can better observe changes in the cancer over time. Thanks to advances in genomics and gene sequencing, researchers have established which canine cancers are most similar to their human counterparts. Besides osteosarcoma, they include prostate and breast cancer, melanoma, soft tissue sarcoma, and non-Hodgkin's lymphoma.

Vaccine success. Comparative oncology has already produced some success stories. In 2010, the U.S. Department of Agriculture approved Oncept, a therapeutic vaccine for dogs with melanoma. Therapeutic vaccines are designed to mobilize the immune system to make antibodies against cancer cells, which ideally then destroy the cells and keep the cancer from coming back, and they've long been the holy grail of cancer drug development. But many of the vaccines tested have proved disappointing. If Oncept is any indication, dogs might hold the key to fine-tuning cancer vaccines. Some dogs in the Oncept trials lived more than a year after their diagnosis—far outpacing the typical lifespan of one to five months with conventional therapies.

The data from the dog trials were impressive enough to prompt the Food and Drug Administration to green-light a small human trial of a similar drug. Jedd Wolchok, a physician at Memorial Sloan-Kettering Cancer Center in New York and the drug's codeveloper, is hoping a pharmaceutical company will fund the large clinical trials that would be needed to get the human version of the vaccine approved. "These trials can take over five years and they're exorbitantly expensive, but the risk could lead to a long-term payoff," he says.

Veterinarian Gerald Post learned the benefits of canine cancer trials as a pet owner. "Instead of living three months, he lived 2½ years," Post says of his miniature schnauzer, Smokey, a participant in the Oncept trials. "He taught me to leave no stone unturned." Post is now an investigator for several canine clinical trials, which he runs out of his Norwalk, Conn., office.

Joining a trial offers twin rewards for dog owners: access to cutting-edge treatments they might not otherwise be able to find or afford, and, even when there's little hope, the satisfaction of contributing to the quest for cures. "We knew the trial wouldn't resolve the cancer," says Richard Liscinsky, whose golden retriever, Samantha, 6, was part of a one-week trial of a protein-based lymphoma drug designed to restrict the growth of cancer cells. Liscinsky and his wife, Ann, who live in Bronxville, N.Y., hoped the treatment regimen would offer up some answers and give them one more summer in Vermont with their beloved pet. Lymphoma is all too common in golden retrievers; Samantha is the second of the three goldens the Liscinskys have owned that has contracted the disease. "It's frightening that cancer is so rampant—for all of us," Ann says.

Owners who participate in trials typically get at least part of the care at no charge. The funding comes from a variety of sources, including federal grants, pharmaceutical companies, and philanthropists with a soft spot for dogs. Among the last group are Dave and LuAnn Runkle of Wayzata, Minn., who lost their golden retriever, William, to a rare and aggressive form of cancer called histiocytosis and then launched the Will-Power Cancer Research Fund to support comparative oncology trials at the University of Minnesota. The $10,000 they've raised so far is helping to fund trials in both dogs and cats, which also develop tumors that are similar to human cancers. Dave's motto? "Help your animal, help yourself," he says.

Shelter rescues. Some comparative oncology programs are reaching out to dogs that have no owners to rely on. In the summer of 2009, the University of Pennsylvania's School of Veterinary Medicine launched the Shelter Canine Mammary Tumor Program, for example. Veterinarians there rescue dogs with mammary tumors from shelters, remove the tumors, and then adopt the dogs out to local families. More than 30 dogs have benefited so far, says Karin Sorenmo, Penn Vet's chief of medical oncology.

Sorenmo's team is studying the tumors to try to figure out what causes benign breast cells to turn malignant and spread. "It's metastasis that kills the cancer patient," Sorenmo says. "If we can learn what genetic events make tumors spread, it opens up a lot of possibilities for new treatments."

For Mildred Edmond, that possibility is intriguing on several levels. Edmond adopted Cali, a 6-year-old bichon frise in the Penn trial who had 11 tumors removed. "Poor little Cali—she had a full mastectomy," Edmond says. Edmond herself survived breast cancer six years ago, so she is eager for the scientists at Penn to unravel the complexities of the disease. "I have two granddaughters and a great granddaughter. I'd hate for them to go through what I went through," she says. (Edmond and Cali are both now cancer-free.)

Dog survivors sometimes play more than a research role. After Emmy survived her bout with cancer, Streeter signed her up for a program at Children's Hospital of Denver called YAPS, for Youth and Pet Survivors. With Streeter's help, Emmy sent letters and photos to a young girl being treated for brain cancer. "I became [the patient's] pen pal," Streeter says. "She brought pictures of Emmy to surgery."

Streeter likes to think that giving Emmy the opportunity to contribute to a fuller understanding of a cancer that affects kids made the disease more bearable for everyone involved. Emmy loved children, she says. "If I could have asked her permission to do the trial, she would have said, 'Yeah, let's do it.' "

Arlene Weintraub is the New York editor of Xconomy.com.

This story is excerpted from Amazing Animals, a U.S. News & World Report special edition.

[MrzDiva]

TweetAww this brought tears to my eyes. I hope that one day they do find a cure for cancer.