Yesterday we received the worst possible news, something we knew was a possibility but were hoping wouldn’t be the case: the Princess Pooch has osteosarcoma, an extremely aggressive cancer that generally spreads rapidly to other parts of the dog’s body; in fact, the cancer has often metastasized by the time it is discovered. The National Canine Cancer Foundation reports that
Osteosarcoma is the most common primary bone tumor found in dogs. It accounts for up to 85% of all malignancies originating in the skeleton. It mostly occurs in middle aged to older dogs, with a median age of 7 years. Primary rib OS tends to occur in younger adult dogs with a median age of 4.5 to 5.4 years. Larger breeds have a high propensity for the disease. Dogs like Great Dane, Irish setter, Doberman pinscher, Rottweiler, German Shepherd and Golden Retriever are at greater risk of contracting osteosarcoma because of their size and weight. Intact males and females are also highly predisposed. Osteosarcoma can occur in any bone but the limbs account for 75%-85% of all affected bones and is called ‘appendicular osteosarcoma’. The remaining affects the axial skeleton comprising maxilla, mandible, spine, cranium, ribs, nasal cavity, paranasal sinuses and pelvis. Osteosarcoma of extraskeletal sites is rare, but primary OS has been reported in mammary tissue, sub-cutaneous tissue, spleen, bowel, liver, kidney, testicle, vagina, eye, gastric, ligament, synovium, meninges and adrenal gland. It develops deep within the bone and can become excruciatingly painful as it grows outward and the bone is destroyed from inside.
We knew this was a possibility when her fracture was diagnosed, and they used the bone removed during the surgery for the biopsy. The surgery, however, was necessary to address the fracture and, since the pre-surgery x-rays of her lungs were clear, this was the best first step. Often in the case of “appendicular osteosarcoma,” the limb where the cancer is located is amputated; we’re hoping the FHO surgery will stand in for the amputation and have decided we’re not going to put her through another surgery even if that’s not the case.
We’re devastated by this news but are doing our best to think about what’s best for the Princess. We’re waiting for an opportunity to talk with our own vet before moving forward, but our most likely next step will be to consult a veterinary oncologist. We’re lucky to live where there are a number of such specialists and facilities. A standard treatment for this cancer, in addition to amputation, is chemotherapy which apparently can present very few to no significant side effects in dogs. So, we’re open to that course of action if our vet and the oncologist believe it will help. From what I’ve learned, the surgery addresses the pain of the cancer, and in the Princess Pooch’s case the fracture, and the chemo provides additional time during which the dog doesn’t suffer the effects of the cancer.
According to the Princess Pooch’s surgeon and echoed by this canine osteosarcoma fact sheet, the prognosis is as follows:
- without any sort of intervention, the average survival time is approximately two months after diagnosis;
- if amputation is performed the average survival time is increased to six and a half months with 2% of patients alive after two years;
- if amputation is combined with chemotherapy the average survival time is increased to one year with 20% of dogs still enjoying a good quality of life two years after surgery.
So, if she’s a good candidate for chemo and we can afford it, that appears at this time to be our best option. In the meantime, she’s doing really well and is more active and more like herself everyday. She’s putting that foot down when she walks more often than not now, and she’s back to being aggressive toward Reilly, spinning at the door, and her other routines.
For now we’ve decided to be cautiously optimistic and give her all the love and care we can until we know what’s best for her.