The yellow ribbon symbolizes Sarcoma Awareness during the month of July. As part of our commitment to education within the Sighthound community, we are launching a Sarcoma Awareness fundraising campaign. Our distinctive yellow ribbon decals (shown on the left and right) will be available year round on our website, while our uniquely designed t-shirt will be available on Bonfire for our fundraising campaign through the end of July; then the design will be retired. Your donations will directly support our education and research initiatives.
There are very few of us within the Sighthound world who have not been affected by cancer, both personally or within our circles of Sighthound families and friends. Through our Sarcoma Awareness campaign we want to help raise awareness of the potentially devastating sarcomas, especially osteosarcoma. Not only does osteosarcoma account for approximately 85% of bone tumors in dogs, it is also the eight most common cancer in children. By treating and investigating dogs with cancer, veterinarians gain important insights into improving treatments for humans and often consult with physicians. Larger breeds are at higher risk for osteosarcoma, including sighthounds like the Greyhound and Irish Wolfhound. The risk for osteosarcoma in Greyhounds is 17 times higher than in mixed breed dogs; moreover, osteosarcoma represents the most common cause of death in Greyhounds from racing blood lines.
Most sarcomas arise spontaneously but, because we don’t really understand what causes them, there is no proven way to prevent sarcomas. As a general rule, all cancers are genetically determined. Work in progress is aiming at identifying specific cancer genes in Greyhounds and Irish Wolfhounds with osteosarcoma. As for all cancers, early detection and treatment are the best ways to address these tumors — knowing what to look for and keeping a vigilant eye out for those signs will give you a better chance at identifying the disease in it’s early stages, which can improve the prognosis.
What is a Sarcoma?
Sarcomas are malignant tumors of connective tissue that can originate on a variety of tissues, from blood vessels and bone to cartilage, from muscles and organs to nerves and lymphatic tissues. There are many different sarcomas in dogs and, combined, these account for roughly 15% of all canine cancers, making sarcomas approximately 5x more prevalent in dogs than humans. About 15% of skin lumps and 7% of subcutaneous (under the skin) lumps in dogs are soft-tissue sarcomas. Some of the most common ones in dogs are (listed alphabetically):
• Fibrosarcoma • Hemangiosarcoma • Liposarcoma
• Lymphangiosarcoma • Neurofibrosarcoma
• Osteosarcoma • Schwannoma • Synovial cell sarcoma
Symptoms To Watch Out For
Unfortunately, signs can be hard to spot, when they’re present at all. Sarcomas usually grow slowly and some can metastasize (spread to other parts of the body) after the primary tumor has become well established. The liver and lungs are the most common sites of metastasis and, in some sarcomas, micro-tumors are often present even before the primary tumor is detected. Osteosarcoma most frequently occurs in the long bones of large dogs’ legs, though it can also arise on ribs and spinal bones. A dog with osteosarcoma in the leg may start to limp for no reason or the owner may notice a hard lump on the dog’s leg. It’s not unusual for the dog to show no clinical signs until it develops a spontaneous fracture (break) at the spot where the bone has been weakened by the tumor. You should consult with your vet for any new lump, especially if it is hard or irregular, and feels “fixed in place” or if it continues getting larger. Other sarcomas may have different signs: tumors in the GI tract can cause vomiting, diarrhea, inappetence, and anemia, whereas a tumor in the mouth or throat could cause difficulty eating or swallowing and bad breath. Sarcomas that are not outwardly visible (arising on internal organs) often go undetected for extended periods and can therefore be advanced before the dog starts showing any signs — and may occasionally only be diagnosed posthumously.
Diagnosis involves either cytological (fine needle aspirate) or histopathological (biopsy) evaluation. Because these tumors can be locally invasive (different than metastatic disease in that the primary tumor spreads out into surrounding tissue, not to other parts of the body), diagnostic tests such as a CT scan may help to identify the extent of the mass and whether it has “well-defined margins”, meaning that there is a better chance of removing all of the cancerous cells by doing surgery. If the tumor does not have well-defined margins, then more of the surrounding tissue may need to be removed, if possible, to get as much, if not all, of the cancerous cells. The primary goal of the surgery is to get rid of 100% of the tumor cells. Radiation may be recommended before surgical removal, especially if the tumor is located in an area that isn’t easily accessible for the surgeons, or after, if there are no clean margins and surgery is not thought to have gotten 100% of the cancerous cells. As in humans, chemotherapy is available for dogs with highly aggressive tumors, such as osteosarcoma, hemamgiosarcoma, and high grade sarcomas, or those that already have metastatic disease. A number of different drugs, including carboplatin and doxorubicin, have been used with varying degrees of success to treat osteosarcoma in dogs. And, no, their hair won’t fall out from the chemo.
The prognosis for dogs with sarcomas varies almost on an individual basis: location, the type and grade of the sarcoma, the aggressiveness/invasiveness, how advanced it is, evidence of metastasis and even the age and overall health of the dog are all factors in determining the prognosis. Dogs with metastatic osteosarcoma at the time of diagnosis usually have a poorer prognosis. In low-grade soft tissue sarcomas, local injection of chemotherapy may be effective in preventing tumor regrowth.
Do You Need Help With Your Diagnosis or Treatments?
Whether you’ve already consulted with an oncologist and are looking for a second opinion, or if you’re struggling to find an oncologist in your area, Dr. Guillermo Couto, our President, does remote consultations with you and your vet. For more information, please see his website here. If you need financial help for your dog’s cancer treatment or surgery, please see the list of resources we’ve compiled here.
Though a great deal is still unknown about cancer, researchers are making progress every day both on furthering their understanding of what causes sarcomas and what the best treatment options are. There are ongoing research studies in the US that have shown promising results, some focusing on bolstering the dog’s own immune system to help fight the cancer. The Greyhound Health Initiative is raising funds to both promote awareness of the different types of sarcomas, and to support research projects we think are both clinically relevant and that have shown positive early results. Your donations will directly support these education and research initiatives.