Cancer is very common particularly in older age Corgis. Some are malignant, very aggressive and can spread. Some are benign, slow growing and unlikely to spread through the body. Because the cause of cancer in dogs is largely unknown, prevention is generally not possible. Of course it is suicidal to smoke cigarettes in the vicinity of a dog and to subject a dog to inhaling car exhaust fumes. Things that humans best steer clear from. In vet medicine the best strategy is to detect and treat cancer early.
The early signs of cancer are:
abnormal swellings or lumps that persist or continue to grow
sores that do not heal
loss of appetite
bleeding or discharge from any body opening
difficulty eating or swallowing
hesitation to exercise or loss of stamina
persistent lameness or stiffness
difficulty breathing or toileting.
Lumps may be just a case of fine needle biopsy and cytology. A more involved workup for other signs include blood tests, x-rays, ultrasound or surgery toi collect a portion of the cancer, otherwise known as a biopsy.
On an optimistic note, cancer is the most curable of all the chronic diseases in a dog. Surgery and chemotherapy are the two most used treatments. Chemo drugs can be given orally or by injection. The side effects in vet chemo treatment are usually less significant than those seen in human medication because lower dosages are used. Many dogs show no side effects at all and are much happier because their cancer is controlled.