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Check out in Dog Tales some of the Faces of Dogs who are enjoying their lives, despite their battle with cancer. Some have been with us over two years, some have just joined us.
The Dressler Book
No matter what you’ve heard, there are always steps you can take to help your dog fight cancer. This comprehensive guide is your complete reference for practical, evidence based strategies that can optimize the life quality and longevity for your dog. No matter what diagnosis or stage of cancer your dog has, this book is packed with precious advice that can help now. Call us to order now, only $39.95
Osteosarcoma in Dogs and the use of K-9 Immunity
Bone cancer is unfortunately very common in dogs. Osteosarcoma is the type most often encountered. This type of cancer starts on the surface of the bone and progresses into the center. The effectiveness of treatment depends on several factors, one of which is the degree to which the cancer has infiltrated the marrow space - the center of the bone. The treatment of choice is usually surgery to remove the tumor. Usually, the entire limb is amputated.
Radiation can be a good option at times especially in reducing the pain.
As Prof. Clements says,
"To me, the answer to cancer lies in the immune system. This is the major reason why I have trouble with Western chemotherapy. Spontaneous remission from cancer only occurs when the patient's immune system acts to clear the cancer. Therefore, stimulation of the patient's immune system to selectively attack the cancer seems to be the key to achieving a successful outcome. New methods in immunotherapy and immunotargeted chemotherapy are likely be the Western methods which lead to the greatest advances in cancer treatment over the next few decades."
(Quote from R.M. Clemmons, DVM, PhD
Types of Bone Cancers
The four primary bone tumors are osteosarcoma (OSA), chondrosarcoma (CSA), fibrosarcoma (FSA), and hemangiosarcoma (HSA). OSA is the most common primary bone tumor. Liposarcoma, rhabdomyosarcoma, plasma cell tumors (solitary plasmacytoma and multiple myeloma), and lymphoma can also involve bone, typically as part of a generalized cancer process.
OSA is the most common primary bone tumor, accounting for over 85% of all the bone tumors that occur in limbs (known as appendicular). It is estimated to occur in over 8,000 dogs each year in the US. It can also occur in the spine, jaw, skull and ribs. There is no known cause of OSA. Potential explanations for the development of OSA include repetitive bone injury, previous fractures, underlying bone disease, viral infections, genetic predisposition and previous radiation, but none of these theories have been proven.
OSA occurs primarily in large and giant breeds of dogs. Smaller breeds are 20 times less likely to develop OSA, but it can occur. Size and height seem to be more important risk factors than breed. Most dogs afflicted with OSA are either young, between 1 and 2 years of age, or older, between 7 and 9 years of age.
OSA develops deep within the bone and becomes progressively more painful as it grows outward and the bone is destroyed from the inside out.
This is the second most common primary bone tumor in dogs and accounts for approximately 5% to 10% of all primary bone tumors. It is a cartilage tumor, usually not as malignant as OSA. It generally occurs on flat bones such as ribs or skull bones, but can occur in the limbs, usually the thigh bone (femur). Symptoms are similar to OSA, and many cases are managed with removal of the tumor whenever possible. Chemotherapy has not been shown to be effective. Recent studies suggest that a specific type of antibiotic, called “fluoroquinolone” may be toxic to the cartilage cancer cells. Further studies are needed to see whether this antibiotic will have a role in treatment of this type of cancer.
This type of bone cancer is rare accounting for less than 5% of all primary bone tumors. This type of cancer occurs primarily in the axial skeleton (jaw bones, facial bones, ribs and vertebrae), but it can occur in the limbs. There are two types: central and parosteal. Surgical resection, amputation and limb salvage are the main treatment options. It can be confused with a specific type of OSA called fibroblastic osteosarcoma.
This type of bone cancer is rare accounting for less than 5% of all primary bone tumors. It tends to occur in a younger age group and can involve either the limbs or the axial skeleton. There is a higher incidence of metastases, so additional tests such as echocardiogram (ultrasound of the heart) or abdominal ultrasound are usually performed before surgical procedures. Management options include amputation and chemotherapy with doxorubicin (adriamycin) type drugs.
This is an uncommon tumor that develops off the lining of the bone (periosteum). The skull is most commonly involved. Other sites include the pelvis, ribs and hard palate. Symptoms depend on the location of the tumor. Computed tomography scans are often recommended to determine the detailed anatomy of the tumor and involvement of the surrounding structures, particularly when it involves the skull or facial bones.
Treatment includes surgical resection and radiation. Location of the tumor, histology of the tumor and evaluation of the surgical margins are important for prognosis and risk of recurrence or metastasis.
Primary Joint Tumors
Synovial cell sarcomas develop from the cells in joints, bursae and tendon sheaths. There are two types of synovial cell sarcomas: epithelioid and spindle. Other types of joint tumors include histiocytic sarcoma and malignant fibrous histiocytoma, synovial myxoma and myxosarcoma, OSA, FSA, CSA, HSA, liposarcoma, rhabdomyosarcoma, and undifferentiated sarcoma.
Typically, dogs will present with lameness, pain or swelling around the joint. Biopsy is required for a specific diagnosis. Joint fluid will only rarely show cancer cells. Amputation is the recommended treatment. There is no proven effect of either radiation or chemotherapy, although some studies suggest that doxorubicin-based chemotherapy protocols should be considered.
An Alternative Treatment for Osteosarcoma - Artemisinin
Please refer this article Osteosarcomas and Artemisinin on our website (article can also be found under the Research Information menu heading).
Cancer in Dogs - The 28th Annual Canine Symposium
The 28th Annual Canine Symposium was held January 31, 1998 at VHUP. The event was organized with the help of the School's Mari Lowe Center for Comparative Oncology and featured a series of presentations on Cancer in Dogs.
Quality of Life Issues for Canine Cancer Patients
"Quality of life concerns are important to veterinarians who want their patients to feel good, they are important to pet owners because pets are often considered family members, and quality of life is certainly important to our patients" explained Dr. Lillian Duda, lecturer in radiation oncology.
Once a diagnosis of cancer is made, the decision to pursue treatment hinges on the determination of the quality of life that can be expected for the animal from that point onward. The veterinarian can help the pet owner feel comfortable talking about the many issues involved, and they must work together toward a common goal. It is something that should also be discussed between family members and friends because the matter is both personal and emotionally charged.
The main goal in cancer treatment is to secure a high quality of life for as long as possible. A pet may be kept alive in the hospital using supportive measures such as oxygen and intravenous fluids, but, it may not be acceptable to do so if there is no hope of improving the pet enough that it can go home. Quality of life issues are more easily overlooked and more difficult to assess than quantity of life issues. There must be a balance between both. The veterinarian can help by remaining objective and providing information about the cancer and the effects of treatments on the animal. However, the veterinarian depends on the owner to report how their pet is feeling and behaving.
The side effects of cancer therapy are numerous and vary greatly between patients. In general, it is not acceptable to expect the animal to suffer side effects from the treatment without a good chance of a better life. The Animal Medical Center in New York City has developed a scale to assess the overall quality of life for dogs undergoing cancer treatment. They measure the dog's ability to carry out normal daily activities using five parameters. Eating is one of the parameters that is measured. As their quality of life begins to decrease, dogs will often show changes in their eating habits or may have a general loss of appetite, some other parameters are alertness, body conditions, and activity level. This scoring method makes the difficult task of assessing the dog's condition more objective and provides useful medical information. Studies have shown that individuals scoring closer to normal tend to do better overall.
Nutritional Needs of Canine Cancer Patients
Animals with serious chronic illness are often malnourished. One of the primary reasons this occurs is because their appetites are impaired by the illness and oftentimes the only food they accept -- table food -- is nutritionally inadequate. This may not be critical for short periods of time, but, when treatments extend for weeks or even months there can be serious effects on the animal's health related to malnourishment. "I like to tell people it is their job to find something their dog will eat adequate amounts of consistently and I can build a balanced diet around it," said Dr. Kathryn Michel, assistant professor of nutrition. Cancer not only affects the patient's quality of life, but, can also impair their ability to tolerate cancer treatments. Meeting the unique needs of patients undergoing cancer therapy is augmented by providing adequate nutrition, however, dietary therapy in this context is considered supportive rather than primary care.
Dr. Michel reviewed the six basic classes of nutrients. "I know that we don't normally think of water as a nutrient but really it is the most essential nutrient there is. An animal will die of dehydration in a much shorter time than it will die from starvation." After water, the body must have nutrients that provide energy such as carbohydrates, fats and protein. Protein not only supplies calories, it is also the source of amino acids which the body uses to make new proteins. Micronutrients are also derived from the minerals and vitamins in the diet. A dog with cancer will require water, adequate calories, protein, minerals and vitamins, however, cancer causes changes in normal metabolism that are not overcome by supplying calories and nutrients. At this time the specific nutritional requirements for dogs with cancer have not been established.
Cancer therapies that reduce the chances of deleterious side effects are always sought, but, they are not always completely successful. Some patients may have nausea, vomiting or diarrhea as a result of their treatment. If an animal associates side effects such as nausea with the act of eating they may stop eating for that reason. This phenomenon is termed a learned food aversion and presents quite a challenge when we try to feed these animals. An important part of nursing a dog or cat through an illness is coaxed feeding. It is very important not to push food on an animal that does not want to eat. It is best to wait until the pet is comfortable and not stressed before presenting food. Do not attempt feeding right after changing bandages or giving medications. It may be best to feed them cold food directly from the refrigerator, as it will not have much taste or aroma. Drugs may be used to reduce nausea as a short term approach if the dogs are having gastrointestinal side effects. Appetite stimulants are most useful in convalescent animals to "jump-start" their appetites, but, really have very limited application. They are not intended for long term use. If the dog shows some interest in food try feeding novel food items or offer food in a different setting or at different times. You can also divide the day's food up into a number of small meals instead of one or two large ones.
Some patients may benefit from nutritional support. These patients often show signs of malnourishment and have not responded well to coaxed feeding. It may be necessary to feed these dogs using a nasoesophageal or esophageal tube. In critical patients intravenous feeding is given to help animals through a short time period until the chemotherapy takes effect. This is not complete nutritional support, nor is it meant to be used as life support. It is providing adequate nutritional care for a limited time to cancer patients who are unable to nourish themselves during the treatment of their disease.
Osteosarcoma is the most common primary bone tumor in dogs, accounting for some 85 percent of canine bone tumors. VHUP clinical specialists Drs. Kim Cronin and Amy Kapatkin explained the disease process of -- and treatments for -- osteosarcoma.
The average osteosarcoma patient is seven or eight years of age, although dogs as young as six months old have been diagnosed with this cancer. It typically strikes large- and giant-breed dogs like great Danes, golden retrievers and German shepherds. Associated with high amounts of stress on weight-bearing limbs, osteosarcoma is almost 500 times as likely to affect dogs over 35 kg than dogs weighing less than 10 kg.
Osteosarcomas tend to anchor themselves in areas of increased bone remodeling, said Dr. Cronin, lecturer in oncology. "Every time you have cell damage or increased turnover, the DNA is more likely to make a mistake when coding for new cells, which can lead to tumor formation." So naturally, previous fractures and chronic bone infections are predisposing factors. These tumors are more likely to occur in the limbs, particularly the forelimbs, which bear most of the body weight; other bones, such as the ribs and skull, can also be affected.
Osteosarcoma is both locally invasive and metastatic. It infiltrates the bone and weakens it. It then spreads throughout the body. The chief presenting signs for osteosarcoma are lameness and pain (which may be intermittent), limb swellings and pathologic fractures at the tumor site.
Because osteosarcoma shares common clinical signs with other conditions like degenerative joint disease (arthritis), infectious diseases and other tumors of the bone (i.e. fibrosarcoma, chondrosarcoma, hemangiosarcoma and synovial cell tumor), a thorough physical exam, radiographs and biopsy are used to make the final diagnosis. Chest radiographs should be performed in dogs diagnosed with osteosarcoma. According to Dr. Cronin, over 90 percent of afflicted dogs have pulmonary metastasis at the time of diagnosis, although lung nodules may not yet be visible radiographically.
Because of its high metastatic potential, osteosarcoma carries a guarded prognosis. Most patients eventually die of metastasis to the lungs or other organs. The average survival time from the date of diagnosis is 8-12 months. Only 20 percent of patients are alive two years after diagnosis. Without treatment, most patients succumb to the disease within a couple of months.
Treatment is aimed at removing neoplastic sites and preventing further seeding. If the tumor is on a leg, amputation is the usual course. "We must be very aggressive in our initial approach so we don't get regrowth," said Dr. Kapatkin, assistant professor of orthopedics and neurosurgery. The leg is typically disarticulated at the coxofemoral (hip) or scapulohumeral (shoulder) joint. "Amputation is very cosmetic and most of our patients can ambulate well on three legs and are incredibly happy," said Dr. Kapatkin.
Limb sparing is the other surgical approach. Here, the tumor is resected en bloc with 3-5 cm margins, and the gap is filled with bone graft or donor bone. Potential complications include infection, implant failure and tumor recurrence. However, the survival rate is the same for limb-sparing as for amputation.
Surgery can be performed also to excise metastases. Prolonged survival rates have been achieved in cases where three or fewer nodules were present and survival until metastasis was diagnosed radiographically was 300+ days, Dr. Kapatkin said.
Radiation therapy can be potent in destroying neoplastic cells at the primary tumor site and chemotherapy may be employed to prevent or delay metastasis. Several drugs -- including carboplatin, cisplatin and doxorubicin, are part of the osteosarcoma chemotherapy protocol, which is typically initiated 10-14 days after surgery. Immunotherapy, which activates the immune system to combat cancer cells, is part of newer treatment protocols.