Note: See Lymphomainfo.net's Canine Lymphoma page for an overview and additional symptomatic information.
Cancer is the number one cause of death in dogs, killing almost 1 in 2 dogs over the age of 10. Lymphoma is the most common form.
The good news is that canine lymphoma is treatable. Combination therapies that feature chemotherapy, radiation, and/or surgery can treat (but rarely if ever cure) your dog without (further) compromising his overall health or quality of life; rather, remission of up to 2 years is not uncommon for dogs following successful lymphoma treatment.
Chemotherapy as the Gold Standard
The gold standard for treating aggressive forms of canine lymphomas remains a chemotherapy protocol (featuring more than a single agent, or drug), and while this naturally will frighten most pet owners, dogs tend to respond extremely well to chemotherapy. The typical protocol includes vincristine, adriamycin, cyclophosphamide, L-asparaginase, and prednisone; keep in mind that the dosages, duration, number of cycles, etc will depend on your dog and the conclusions of your oncologist following a complete exam and associated tests.
Wisconsin Lymphoma Protocol
The Wisconsin Lymphoma Protocol (also known as the Wisconsin Protocol, the Madison Wisconsin Protocol and other mixed terms) is a shorter, but dose-intense chemotherapy regimen currently popular with oncologists as the primary canine lymphoma treatment, with a success rate of around 91%, according to Dr. Mike Richards, DVM. This chemotherapy protocol uses vincristine, doxorubicin, cyclophosphamide, and/or 1-asparagnase by IV, along with prednisone and/or cyclophosphamide orally.
To Keep in Mind
Whatever the case, keep in mind that each chemotherapy cycle can take between 2-3 hours to complete; side effects vary but can include vomiting, diarrhea, and appetite loss (but not hair loss, unlike in humans) and during treatment it is not uncommon for dosages and drugs to change according to effectiveness. For this reason it's best to have an oncologist on your dog's health team with plenty of chemotherapy experience.
Sources:
--Gregory K. Ogilvie, DVM, DACVIM on the Wisconsin Lymphoma Protocol
--Merck Veterinary Manual: Canine Malignant Lymphoma and Tumors of the Immune System
