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You’ve Heard of the CAT Scan? Now, Here’s the Dog Scan: Canine Helps With Cancer Detection (dateline October 25, 2000)


Dogs have been trained to detect bombs, sniff out drugs, and even smell gas leaks in pipelines 20 feet below the ground. But can canines detect cancer?  Well, in Tallahassee, Florida, a 43-pound Standard Schnauzer named George has been trained to successfully detect melanoma (a type of skin cancer) on humans. In one case, George pointed out a mole that had previously been examined by three different doctors and biopsied twice. After doctors finally removed the lesion and sent it to the pathology laboratory for a cell-by-cell analysis, they discovered that the patient had Stage II melanoma. If the mole had been left alone for another year, the patient could very well have died from skin cancer.

Armand Cognetta, MD, a dermatologist whose specializes in skin cancer, has always been bothered by the fact that one in five melanomas are not discovered in time to successfully treat the patient. Dr. Cognetta believes that earlier methods of detection are needed to help treat melanoma before it progresses to advanced cancer. After hearing a radio report of a dog who helped police search for a body at the bottom of a lake by sniffing the air from the bow of a boat, Dr. Cognetta decided to search the medical journals to see if canines had ever been trained to help detect skin cancer.

A brief report in the 1989 Lancet medical journal describes how a dog discovered a malignant (cancerous) skin tumor on her owner’s leg. According to the report, the 44-year old woman insisted that doctors examine the mole after her half Border Collie, half Doberman kept sniffing at the same spot on her leg. After an excision and biopsy of the mole, doctors confirmed the presence of melanoma. "This dog may have saved her owner’s life by prompting her to seek treatment when the lesion was still at a thin and curable stage," wrote the researchers.

Intrigued by the idea of training a dog to detect skin cancer, Dr. Cognetta contacted Duane Pickel, an expert dog trainer and former head of the Tallahassee Police K-9 Department, to ask if the task might be possible. Pickel, who has trained over 15,000 military, police, and citizen dogs, answered "yes" immediately and volunteered his Standard Schnauzer, George, who was already a certified bomb-detecting dog.

"A dog can be trained to find anything you need it to find," said Pickel, who spent eight years in the military police K-9 service in addition to 22 years in the Tallahassee K-9 department. Pickel’s longtime police dog, Duke, had contributed to 272 arrests.

To begin the training, Pickel taught George to retrieve melanoma samples in test tubes. Gradually, Pickel began hiding the tubes under furniture and in cabinets, rewarding George with cookies and treats when he discovered the melanoma samples. Eventually, George was able to find a melanoma sample when it was placed in one of 10 holes in a long rectangular box.

"It was actually easier to train George to detect melanoma than it would be to train a dog to detect bombs or drugs," said Pickel. "With a cancer dog like George, he only has to learn to find half as many items since there are many more components involved in the training of bomb-detecting and drug-detecting dogs."

In April 1994, Dr. Cognetta and Pickel took George’s training to the next level with Kim Edwards, RN, head nurse of the outpatient surgical unit at Tallahassee Memorial Regional Medical Center. Edwards, who had a family history of melanoma skin cancer and was at risk of the disease herself, was happy to help.

Pickel designed a special, low-to-the-ground examining table, and taped dozens of bandages to Edwards’ body. Under one of the bandages was a live melanoma sample. Over more than a year, George repeatedly sniffed the bandages on Edwards’ body until he could detect the bandage with melanoma 99.7% of the time. Eventually, Pickel and Dr. Cognetta tested George’s ability on seven skin cancer patients. Over a 10-month period, George was able to correctly identify melanoma on six of the seven patients.

George’s success at detecting melanoma has proven that dogs can play key roles in medical advancement. In fact, dogs have also been trained to alert patients when they (the patients) are about to experience epileptic seizures and to assist patients with severe Parkinson’s disease. Dr. Cognetta and other physicians believe canines could also be useful in helping to screen for tuberculosis in poor communities.

According to Pickel, dogs can smell 220,000,000 (220 million) times better than humans. However, Dr. Cognetta says that dogs will probably never be used in physicians’ offices because there are too many people that need to be involved in the process: the patient, the physicians, the dog handler, the dog, and possibly a nurse. Also, many patients may not approve of having a dog sniff their bodies.

Nonetheless, understanding how dogs are able to detect cancer by smell may help scientists develop new technology to help detect melanoma and other cancers at earlier stages. In fact, researchers believe that dogs may also be able to detect early-stage lung cancer by sniffing deep-breath samples.

Though scientists do not yet know whether dogs smell enzymes, proteins, antibodies, or other components of melanomas, further research with canines may one day allow them to develop new medical equipment. An "electronic nose" or "smelling machine," designed to mimic the action of a dog’s nose, could one day help to save lives by detecting cancer early-stage cancers when they are highly treatable.

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