If your dog has recently been diagnosed with cancer, it can be overwhelming. You may be filled with anxiety, sadness, denial, frustration and other emotions. These are all normal reactions. You may also have a lot of questions — to start, how long will your dog live? How long can a dog live with cancer without treatment? Here are the most common cancers in dogs and the treatment options and general life expectancy for each. Remember, your veterinarian is the best resource to discuss treatment options and expected outcomes unique to your pet. We recommend working with your veterinarian if your pet is dealing with this topic as your best resource to improve your pet's care.

How Long Can a Dog Live With Cancer?

The answer to this question is never straightforward. Ultimately, many factors will affect this outcome, including the type of cancer, treatment choices, progression and health at diagnosis. While this answer may vary, it can help to have a framework for understanding what you and your canine companion are up against.

Lymphoma Prognosis

One of the most common cancers in dogs, lymphoma, affects the lymph nodes and can spread to other organs, such as the intestines and skin. Lymphoma has several different forms that range in severity. Life expectancy after diagnosis depends on the type of lymphoma and whether your dog undergoes treatment. Approximately 80% of dogs go into remission after the first month of chemotherapy, and, compared to humans, most dogs enjoy an excellent quality of life while receiving chemotherapy. Dogs with low-grade lymphoma can live years; however, the median survival time is 12 to 14 months for most dogs and six to nine months for dogs with high-grade lymphoma. How long can a dog live with cancer without treatment? When you take treatment out of the equation, the survival time is much shorter.

Mast Cell Tumors Prognosis

Mast cell tumors are the most common skin tumor seen in dogs. They occur as a red, raised bump on the skin. Mast cell tumors are treated with surgery, and it's recommended to follow surgery with chemotherapy and/or radiation, depending on the malignancy and location of the cancer. Additionally, surgically removing low-grade tumors often cures the dog of cancer. If the mast cell cancer has spread to the lymph nodes or if the cancer is considered high-grade malignant, life expectancy after diagnosis and treatment is six to 12 months.

Oral Melanoma Prognosis

Melanoma is cancer of the pigmented cells, and it's the most common tumor seen in the mouth of older dogs. It's considered a malignant tumor when it appears in the mouth and, from there, it can spread to other organs. Treatment includes surgery, chemotherapy and radiation. Without treatment, survival time is two months or less. How long can a dog live with cancer if treated? It depends on the stage of the cancer: dogs who have low-grade oral melanoma (stages 1 through 3) can live more than 18 months, while dogs with high-grade (stage 4) melanoma typically have less than three months.

Osteosarcoma Prognosis

The most common bone cancer in dogs, osteosarcoma is a malignant cancer that spreads to other bones and organs. Prognosis is poor for most dogs who are diagnosed with osteosarcoma, and treatment is aimed at comfort and prolonging life as much as possible. Surgery, radiation and chemotherapy are all available. Without any treatment, the life expectancy for osteosarcoma is less than a month, and it would be extremely painful for your dog. With palliative surgery or radiation therapy, life expectancy after diagnosis and treatment is four months. Survival time increases to six to 12 months when chemotherapy is added to treatment.