Getting Smart About Cancer: How to Achieve an Accurate Diagnosis
An avid participant and judge of hunting tests, Noel Cacchio knows a great deal about training Cocker Spaniels to find, flush and retrieve game. She does not know a lot about lumps on dogs, especially if the dog appears healthy.
When Cacchio felt a lump on the throat of her Senior Hunter Cocker Spaniel, Dungarvan Harmony's Spirit, WDX, JH, SH, CD ("Spirit"), she wasted no time getting the dog into the veterinarian. The 5-year-old bitch wasn't acting sick, so Cacchio thought the lump was a reaction from a bee sting. Still, she wanted to know for certain that Spirit was OK.
"I knew from the way everybody was acting that it wasn't good," says Cacchio, who breeds field Cocker Spaniels in Rhinebeck, N.Y., under the Dungarvan prefix.
The veterinarian suspected Spirit's lump was lymphoma, the third most common canine cancer. A biopsy confirmed that Spirit had lymphoma.
Though Spirit's diagnosis and referral to veterinary oncology specialists at Cornell University College of Veterinary Medicine came quickly, sometimes the road to an accurate and timely diagnosis isn't so smooth. Most dogs show no signs of cancer until the disease is far advanced.
"Unfortunately, there is no one-size-fits-all way to diagnose cancer," says Jaime Modiano, V.M.D., Ph.D., the Alvin S. and June Perlman Endowed Chairman in Animal Oncology at the Comprehensive Cancer Center of the University of Minnesota College of Veterinary Medicine.
Regardless, experts agree, a few strategies can be used to help maximize the chance for a successful diagnosis and favorable outcome. When it comes to treating cancer, vigilance is crucial.
Observation Is Important You don't have to be a veterinarian to be instrumental in getting an accurate and timely cancer diagnosis. You do, however, have to be observant, assertive and diligent. The observation part is easy and costs nothing.
"It's common sense when you are petting your dog to pay attention for lumps and bumps," Modiano advises. "If you feel something, don't delay in having it checked out."
Lumps could be due to many different things. For example, they could be fatty lumps, benign growths arising from the sebaceous gland, swelling from an injury, or swollen lymph nodes indicating anything from a systemic infection to tick-borne disease to lymphoma. Regardless what causes a lump, veterinarians are in the best position to work with owners and diagnose the problem.
Since lymphoma is a common cancer in dogs, owners are encouraged to pay attention to the neck and jaw areas, behind the stifle (knee), and in front of the shoulder blades, advises Roe Froman, D.V.M., senior veterinary research scientist at the Van Andel Research Institute in Grand Rapids, Mich.
"Swollen lymph nodes don't mean your dog definitely has lymphoma," Froman says. "It could be something else, like an infection or tick-borne disease, but because of the potentially aggressive nature of lymphoma, if you do feel something swollen, you should have the veterinarian look at it."
In some cases, tick-borne disease can be mistaken for lymphoma or vice versa. This was the case when the veterinarian examined CH Vanity Fair's Mystic Sunrise, RN ("Dawn"), an English Springer Spaniel bred and owned by Larry and Betty Schwartz of Seal Rock, Ore. The veterinarian suspected the swollen lymph nodes were due to lymphoma, but the Schwartzes requested a "tick panel" since Dawn had recently competed in outdoor conformation shows in heavily infested tick areas.
In this case, the results showed that Dawn had been exposed to the parasitic organism Ehrlichia canis, which causes ehrlichiosis, the most common tick-borne disease seen in dogs. Dawn's veterinarian prescribed the antibiotic doxycycline, which cleared up the infection.
Still, Dawn suffered some heart wall damage, which is a common development in dogs with certain tick-borne infections. After Dawn's ehrlichiosis was resolved, a biopsy was performed to rule out that she did not also have lymphoma. Fortunately, it was negative.
"Most tick diseases are treatable, and it's generally a much better diagnostic picture than lymphoma," says Larry Schwartz. "We waited to see if the doxycycline would help before testing Dawn for lymphoma."
Ehrlichiosis was also the eventual diagnosis for MACH Tallymark's Country Classic, CD ("Ricky"), a master agility champion Cocker Spaniel who suddenly began having severe gastrointestinal problems. "Ricky lost about 20 percent of his body weight," says owner Felicia Mazur of Spotsylvania, Va.
Mazur spent $5,000 and months getting a definitive diagnosis for Ricky. In retrospect, she says, "It seems odd that we did not originally do a tick panel because we live in a heavy tick area. After two weeks and $50 of doxycycline, Ricky was his old self."
What to Expect "Owners should develop a relationship with their family veterinarian and take their dogs for complete well health visits at least once a year," advises Modiano. "A veterinarian will explain which tests are reasonable for an individual dog, based on age and lifestyle, what to expect from testing and whether there is any risk involved. Importantly, there is no substitute for regular hands-on veterinary examinations to help monitor health changes and signs of cancer."
When a dog presents with swollen lymph nodes or a lump, a veterinarian usually suggests a needle aspiration biopsy or surgical removal of the lymph node or lump with a biopsy of the tissue sample. The veterinarian will probably suggest other appropriate tests, such as a complete blood panel.
"Needle aspiration biopsies involve pulling out cells, staining them and looking at them under a microscope," Froman says. "Though they are quick and easy, they are not 100 percent reliable."
Surgical removal of the lymph node or lump and a tissue biopsy can be more reliable and reveal the specific type of cancer. "A tissue biopsy is more expensive as it involves anesthesia and is not an outpatient procedure," Froman says.
When Froman's Clumber Spaniel, AM/CAN CH Critter's Hungry Heart, TD, CD, JH ("Duncan"), was diagnosed with lymphoma the day after Thanksgiving several years ago, Froman realized how quickly a dog can decline. "By Saturday, Duncan was so sick I didn't think he would survive the weekend," she says.
Ultimately, owners hold the power when it comes to getting a dog properly and efficiently diagnosed. "Only an owner can become educated and empowered on behalf of his or her dog," Modiano says. "You should learn what cancers occur commonly in your breed. You also should commit to regular physical exams and monitoring at home. If you get a cancer diagnosis, educate yourself about the disease."
An accurate cancer diagnosis allows for treatment to begin sooner. Spirit, Cacchio's accomplished Senior Hunter Cocker Spaniel, lived an additional year and a half, after being diagnosed with lymphoma and undergoing chemotherapy.
"The treatment allowed Spirit to carry on a full life — she was never sick a day in those first 16 months of chemo," Cacchio says. "Finally, the protocol stopped working, and the other drugs we tried caused painful side effects. When Spirit lost the quality of life she had enjoyed, we discontinued treatment except for prednisone, which helped make her more comfortable. Cancer may have claimed Spirit, but a timely diagnosis helped to make the end of her life worth living." Purina appreciates the support of the American Spaniel Club and particularly Bobbie Kolehouse, director of the grants committee and member of the scientific research committee of the ASC Foundation, in helping to identify topics for the Purina Pro Club Cocker Spaniel Update newsletter.