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Anal Gland Cancer in Dogs

Reviewed by Bill Saxon DVM, DACVIM, DACVECC on Monday, August 22, 2016
Posted September 28, 2016 in Dog Diseases & Conditions A-Z

Labrador with anal gland cancer can be helped with surgery

AJ Debiasse, a technician in Stroudsburg, PA, contributed to this article.

The obnoxious substance coming out of the anal glands is supposed to help dogs mark their territory when they defecate. In reality, anal glands can cause all kinds of problems in dogs (and occasionally in cats). They can get blocked, infected or even turn into cancer.

Anal gland cancer was the sad fate of Conan, a sweet 9-year-old Lab. His guardians had become concerned when they noticed that his stool seemed thinner than usual. Conan was healthy otherwise. Based on a physical exam including blood work and X-rays, he had a firm mass, about the size of a golf ball, in an anal gland It was highly likely to be cancer (adenocarcinoma).

What is adenocarcinoma?
Adenocarcinoma is the most common cancerous anal gland tumor in dogs. It's a very aggressive cancer and has a high probability of metastasizing (spreading) to the lymph nodes and other organs. The recommendation for treatment is surgical removal as soon as possible. This surgery is tricky and does not have a high success rate, if not done properly. The cancer may return even if surgery is done properly because there is very limited space around the tumor, making it difficult to remove the cancer entirely.

Using chemo beads to treat anal gland cancer
For about 7 years, I have used “chemo beads” in addition to surgery to help decrease the chances of the cancer returning in that area. Chemo beads are tiny pearls (about 1/10 of an inch in diameter) that contain a tiny dose of a chemo drug called cisplatin.

Chemo drugs kill cells that multiply rapidly, such as cancer cells. They can also affect cells that multiply in healing tissue, such as the skin. One of the few side-effects of the chemo beads is that they can slow down healing. After surgery and placement of the chemo beads, Conan did have problems with healing of the skin, but eventually healed completely and made an amazing recovery.

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Dr. Phil Zeltzman is a board-certified veterinary surgeon and author. His traveling practice takes him all over Eastern Pennsylvania and Western New Jersey. You can visit his website at, and follow him at