Robyn Elmslie, DVM, ACVIM (Oncology)
Bernese Mountain dogs are arguably among the most lovable and popular dog breeds in the United States and Europe. They are also at greatly increased risk for developing fatal histiocytic cancer (histiocytic sarcoma and malignant histiocytosis) compared to most other breeds. Histiocytic cancer typically afflicts dogs between the ages of 5-8 years of age. At the most recent Veterinary Cancer Society meeting (Las Vegas, Oct 2012), Dr Audrey Ruple presented data from 216 Bernese Mountain dogs registered through the Berner Garde Foundation. Her analysis revealed that dogs with orthopedic disease were 2.5 times more likely to develop histiocytic cancer compared to dogs without orthopedic disease. van Kuijk et al; (JVIM 2013) found similar results when investigating the incidence of peri-articular (around the joint) histiocytic sarcoma in a population of 920 Bernese Mountain dogs in the Netherlands. In their study, van Kuijk et al found that dogs with pre-existing joint disease were 5 times more likely to develop peri-articular histiocytic sarcoma than dogs that did not have pre-existing joint disease. In addition, the authors found a strong association between pre-existing joint disease and development of peri-articular histiocytic sarcoma in the same joint, particularly when the stifles or elbows were affected. Craig LE et al (Vet Pathol 2002) were the first to suggest an association between anterior cruciate ligament (ACL) tears and the development of peri-articular histiocytic sarcoma, in a small population of Rottweilers, a breed also known to be at high risk for histiocytic cancer.
In her presentation, Dr. Ruple also reported that Bernese Mountain dogs receiving long-term medications, particularly anti-inflammatory medications, were at lower risk of developing histiocytic cancer compared to dogs not treated chronically with these medications. While NSAIDs have not yet been carefully evaluated in dogs as a cancer prevention treatment, studies in humans have shown a decrease incidence in certain cancers (colon, prostate) in patients treated chronically with NSAIDs. Several NSAIDs have been FDA approved for administration to dogs, including carprofen, Deramaxx, Etogesic, metacam, previcox. These drugs may be given chronically to improve the arthritic patient’s quality of life, with careful veterinary oversight to avoid side-effects. Over-the-counter NSAIDs (Ascription, aspirin, ibuprofen) are not recommended in dogs due to their potential for causing gastrointestinal bleeding.
Survival time of Bernese Mountain dogs with peri-articular histiocytic sarcoma has been reported to be shorter in dogs with pre-existing joint disease compared to dogs without pre-existing joint disease. This shorter survival time may simply be due to the difficulty in early detection of lameness due to the developing sarcoma in a joint that is already painful from pre-existing arthritis. Methods for differentiating between arthritis and peri-articular sarcoma include serial x-rays of the affected joint, advanced imaging (MRI or CT scan) and biopsy. Early detection may allow for aggressive treatment and improved survival times. Nielsen et al (Vet Comp Oncol 2012) reported that a cancer screening program for Bernese Mountain dogs, developed in Denmark, consisting of diagnostic imaging (thoracic radiographs, abdominal ultrasound) and blood tests every 6 months beginning at 4 years of age, allowed for early detection of histiocytic cancer in dogs otherwise completely symptom free. At Veterinary Cancer Specialists, we provide pet owners and family veterinarians with comprehensive information so that their pet’s quality of life can be maximized and that diagnostic and treatment options are tailored to their needs and goals.