Cancer is the leading cause of death among older dogs and, though it can occur at any age, it is more common in senior dogs. Hemangiosarcoma, lymphoma, mammary tumors, osteosarcoma, prostate cancer, and squamous cell carcinoma are some of the more common types of cancers occurring in older dogs. Hemangiosarcoma stems from blood vessels and often affects the liver or spleen, while lymphoma is a cancer of the white blood cells. Mammary tumors, or breast cancer, are most often found in unspayed female dogs. Osteosarcoma is a form of bone cancer that most often affects large breed dogs, prostate cancer most often affects unneutered male dogs, and squamous cell carcinoma is a cancer affecting the mouth

Diagnosing these cancers can be difficult as there are no specific blood tests for them. However, there are certain signs that you can watch out for, including the following: a bloated abdomen; the presence of blood or mucous in the stool or urine; constipation; diarrhea; difficulty urinating or defecating; and sudden weight loss. A sore that will not heal or appears raw, bleeding or scabby may be indicative of skin cancer. Also, bleeding from the ears, mouth or nose may indicate a tumor, while difficulty swallowing or drooling may indicate a throat tumor. Heart and lung cancer may include symptoms of excessive panting, hoarseness, persistent cough, and tiring easily. If you suspect that your dog may have cancer, contact your veterinarian immediately. It's important that cancer be detected early on while it's still treatable.