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Types of Dog Cancer

Dog Cancer is a word that can turn your world upside down, we’re here to help by offering you some types of dog cancer information to guide you. Cancer means the unrestrained cell division and growth. While symptoms of dog cancer are different, please be aware of a lump or a bump on your dog, a wound that does not heal any kind of swelling or enlarged lymph nodes, lameness or swelling in the bone, or abnormal bleeding. These signs may deliver some different information about his health, at least early on. Please contact your family veterinarian if you notice any of these symptoms in your dog. 



Dog lymphoma is one of the most common dog cancers today, accounting for up to 24% of all new canine cancers.  Many dogs may not feel sick or may have only felt tired or decreased appetite.  Other dogs may have more severe symptoms such as weight loss, vomiting, or difficulty breathing.  The severity of the signs depends upon the extent of the disease and on whether cancer has caused changes in organ function. Dog lymphoma is initially very sensitive to chemotherapy. Up to 95% of dogs treated will go into remission when the most effective treatment protocols are used.



The most common primary bone tumor in dogs is osteosarcoma and accounts for 85% of all skeletal tumors.  Tumors in the limbs often cause various degrees of lameness and pain, and a firm swelling may become evident as the tumor size increases.  It is common for pain to be intermittent initially, and it may improve initially with pain medications.  As the degree of discomfort increases, it can cause other signs such as irritability, aggression, loss of appetite, weight loss, sleeplessness, or reluctance to exercise.  Some dogs may go to the veterinarian as a result of a fracture due to the weakening of the affected bone. Treatment recommendations for bone tumors rely on many factors, and a complete physical examination and additional testing may be necessary.



Mast Cell Tumors are the most common dog cancers in dogs. Mast cell tumors can look and feel like anything, so it is impossible to diagnose without looking at cells under the microscope. After close examination, a grade of malignancy is assigned. The grade suggests how the tumor will behave and the best course of treatment. Low or intermediate-grade tumors are unlikely to spread, and surgery may be the only treatment required. High-grade tumors have a greater chance of spreading, so veterinary oncologists look very carefully for metastasis and consider using chemotherapy in addition to surgery. Radiation therapy is another option for some cases.



Melanomas are tumors arising from pigment cells.  In dogs, they most commonly occur on the skin, in the mouth, and on the toenails.  Most melanomas in the mouth or skin will present as dark, raised masses. Melanomas in the mouth can be associated with drooling, foul odor, bleeding from the mouth, or difficulty eating.  Those occurring on the toenail can cause toe swelling, loosening of the affected toenail, or lameness on the affected leg. Surgery is the first line of defense for melanomas. Tumor recurrence or spread (metastasis) is likely. In cases where surgery is not possible, radiation therapy, chemotherapy, or immunotherapy can sometimes be effective.


Cancer can torture dogs of all ages, especially older dogs. How horrible it can be to get a diagnosis of cancer in your dog. However, just like humans, cancers can be cured.