Part 2: What to do if your pet has cancer |

Part 2: What to do if your pet has cancer

Stephen Sheldon, DVM
Pet Talk
For some cancers in pets, surgery is all that is needed. Others require chemo to prevent spread and others require radiation.
Special to the Daily |

In Part 1, we discussed some signs and symptoms of cancer in pets and how vets diagnose them. Now, let’s move on to some of the more common cancers and how to treat them.

Basically you have three choices for therapy: cut it out (surgery); poison it out (chemotherapy); or burn it out (radiation therapy).

Without being flippant, that is exactly what we are going to do. Dr. Greg Ogilve, CSU’s animal cancer guru advocates surgery as the first line of treatment and says: “When in doubt, cut it out” and “your best deal is cold blue steel.”

For some cancers, surgery is all that is needed; others require chemo to prevent spread, called metastasis, and still others require radiation therapy. Sometimes a combo of chemo and radiation is used. Often times a tumor cannot be removed or it is too large to remove so we try chemo or radiation to shrink the tumor to a more manageable size and then remove it.

Different Reactions to Chemo

Other cancers need chemo to control them. For example, lymphoma (cancer of the lymph nodes) or leukemia (cancer of the white blood cells) cannot be treated surgically. Staging, or determining how widespread the cancer is will tell us what type of chemo to use and for how long.

Yes, chemo is a scary word, but pets tolerate it a lot better than we do. I would say well over 95 percent of the owners who have had me do chemo on their pets would do it again if needed.

Dogs rarely lose their hair (except maybe whiskers) and usually only have a day or two of nausea between cycles.

There are two phases to chemo: the induction phase, which is rigorous and done weekly until the cancer is in remission; then a maintenance phase is started where a round of chemo is given every three to four weeks until all of the cancer is gone.

Chemo routines, called protocols, are changing all of the time; the line between where induction ends and maintenance begins is a hot topic today. Currently in vogue for some cancers is a type of therapy called metronomic chemotherapy, which is very low dose daily chemo.

Radiation therapy is done much less in my experience because it must be done very frequently; often up to three times a week. For us that means going to Denver (and hoping that Interstate 70 eastbound is not closed).

Common Cancers


Let’s move on to some common cancers.

Breast cancer in female dogs is very common and a good example where surgery alone can be curative. This cancer is almost 100 percent preventable by spaying your female dog before her first heat cycle (timing for spays is a hot topic now and very breed specific, so speak to your veterinarian).

If the breast cancer is malignant or advanced, then radiation is the preferred method to prevent spreading; however, I have used chemo successfully.

Mast cell tumors are a common dog skin tumor and need to have a very wide and deep surgical excision; therefore a pre-op needle biopsy should be done.

This tumor should be sent of to a pathologist to grade, (either from one to three or high to low depending on the pathologist), to tell us the degree of malignancy as this will dictate what or even if chemo is needed.

Other common canine cancers are lymphoma, bone cancer, intestinal cancer and oral cancers.


Cats are also prone to cancer.

Breast cancer is much more serious in cats than in dogs as almost all are malignant whereas only half are malignant in dogs.

In one large study of 439 cats, only 8 percent had benign tumors (meaning 92 percent were malignant). Early spaying is recommended but we can’t say for certain if it prevents breast cancer in cats.

Skin tumors are also more malignant in cats than dogs so if you see bumps on your cats, then get them checked out. Intestinal cancer is also more common in cats than dogs.

Treating cancer can be expensive but it is rewarding for both veterinarians and their pet owners and life extending for our pets. Just ask my last case, Tank, who can be seen hopping around Eagle.

Dr. Stephen Sheldon, DVM, a member of The Veterinary Cancer Society, practices at Gypsum Animal Hospital. He welcomes questions and can be reached at 970-524-DOGS, or

Support Local Journalism