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Cancer and Dog Anal Gland Expression

I think it’s fair to say that most people have seen dogs pulling their behinds across the floor or the yard.

It happens from time to time for different reasons.   Dogs do it to relieve intense itchiness and/or pain.  In this post, I’ll talk about dog anal gland expression and the rare cancer sometimes found.

Reasons for butt scooting could include anything from worm infestation, to bug bites, to (most common) plugged anal sac glands. 

Cancer and dog anal gland expression isn’t something you hear a lot, but it’s worth understanding, especially if you have one of the following dog breeds:

  • Cocker Spaniel
  • Springer Spaniel
  • German Sheperd
  • Dachshund
  • Alaskan Malamute

How Cancer is Detected Through Dog Anal Gland Expression

Cancer of the anal sac is rare in most dogs. However, among the breeds listed above, studies show a higher incidence.

Anal sac cancer tends to spread to the dog’s iliac lymph nodes and become quite aggressive.

In order for veterinarians to eliminate the possibility of other cancers (mast cell, melanoma skin cancer, lymphoma), he/she has to perform a fine-needle aspirate to examine the mass.

If the cancer has already spread to the lymph nodes, the prognosis is poor.

However, through early detection through dog anal gland expression, it’s possible to improve that prognosis through a combination of surgery, radiation, and possibly chemotherapy. 

One of the first signs of anal gland cancer is swelling in the perineum.  The perineum is the area located between the dog’s genitals and anus.

Other Symptoms of Cancer in The Dog’s Anal Gland

  • Perineal swelling
  • Constipation
  • Painful defecation
  • Frequently attempting to defecate/straining
  • Flat, long stools

Should You Perform Dog Anal Gland Expression Yourself?

It’s not as easy as the videos make it look, and unless you’re very confident in your ability, it’s probably best to have a veterinarian or groomer do it. 

Yes, I tried to help my dog after I noticed excessive butt scooting. I put on a pair of latex gloves, lubed up my finger, held my breath, and went for it.

Things got weird.

The anal glands are located at 4:00 o’clock and 8:00 o’clock just under the skin beneath the anus. Sounds easy to find, but it isn’t if you don’t really know what you’re feeling for. 

I spent a few seconds trying to find a small lump but my dog was too distressed for me to continue. I couldn’t do it.

Later, in the veterinarian’s office, the groomer was able to express the anal glands in seconds!  It hurts, and my dog let out a yelp, but it was done quickly and efficiently. 

Until recently, I didn’t know much about dog anal gland expression. 

Did you know the dog’s anal glands contain the pheromones released when a dog is “marking” territory?  It’s also a distinct odor that other dogs interpret when they sniff each other.

Anal Gland Cancer is Unlikely

The truth is, this type of cancer is rare.  A peer-reviewed study published in the February, 2009, edition of Veterinary Medicine suggests that only 2% of the canine population ever develop skin cancer on the perineum, and only 17% develop perineal tumors.

If you’re anything like me, you might worry that your dog will be within the 2%.  Just your luck, right? I wouldn’t worry about it, but I still think it’s important to have a good understanding of what’s normal for your dog, and what’s not.

You probably know your dog’s movements, behaviors, and habits like the back of your hand. 

That’s good! It means that if something starts to go wrong, you’ll be the first to notice.

If Cancer is Found Through Dog Anal Gland Expression

Treatment options for adenocarcinoma in dogs involves a three-pronged approach:

  • surgery
  • radiation
  • sometimes chemotherapy

Early Signs of Adenocarcinoma in Dogs

The best reason for having a professional perform the dog anal gland expression is because he/she is trained to recognize abnormalities that could signal cancer.

If cancer is present, the person conducting the gland expression might feel:

  • a suspicious mass
  • peritoneal swelling
  • enlarged iliac lymph nodes

Next Step…

Once adenocarcinoma is suspected, a series of tests will be conducted. 

A complete blood count, urinalysis, and serum chemistry profile will be performed.  These tests will determine the extent (if any) of neoplastic hypercalcemia.  Definition below.

Neoplastic hypercalcemia is a disorder caused by the action of the tumor secretions.

These secretions carry hormones and peptides (amino acids) and cytokines (small proteins important in cell signaling) that affect normal and cancerous tissue.

The process can affect the healthy functioning of the nervous system and the immune system, among others.

Grading and Treatment Options for Adenocarcinoma

If the blood work and urinalysis suggest anal gland cancer, the veterinarian will order staging tests such as:

  • abdominal ultrasound
  • three-view thoracic radiography

These tests enable the veterinarian to determine the size of the tumor, the number of lymph nodes affected, and whether the cancer has spread to distant organs.


Surgical removal of the tumor and the infected lymph nodes can provide a better outcome for your dog; however, it’s possible that undetected cancer is not removed during the process.

That said, it’s thought that there is a “significant survival advantage” with the removal of the primary tumor and affected lymph nodes.

Preoperative Care – Radiation

The intent of radiation therapy before surgery is to make sure that all cancer cells are killed, including any unseen ones that are just extending outwards from the primary tumor. 

The hope is also that the tumor will shrink.

Postoperative Care – Maybe More Radiation

If the surgeon feels he/she was unable to remove all of the cancer, additional radiation may be an option.

At this point, radiation is only started after the stitches have healed or have been removed. Further radiation is administered for the next 3 or 4 weeks.

Unfortunately, this added radiation can cause severe side effects affecting the perineum, rectum, and colon.


From what I understand, the true effects of chemotherapy on adenocarcinoma is hard to determine because it’s often used in combination with radiation and surgery. 

Chemotherapy is only used in dogs as a last ditch effort when the dog is at an advanced stage.

The Next Months and/or Years

Unfortunately, the tumor can come back. Surgery and radiation may offer you and your dog the gift of added time, but it’s not necessarily a cure.

Obviously, the bigger the tumor and the further it has spread significantly lowers the prognosis. 

Chances are good that you won’t find cancer from a dog anal gland expression.

After all of this bad news, I thought it would be important to let you know that this type of cancer is pretty rare in most dog breeds.

The list of breeds above would be an exception, but even in those breeds, the chances are relatively small.

Maintaining veterinarian check-ups and periodic dog anal gland expression are two ways to stay ahead of the game and catch cancer in its earliest stage.

Let the professionals do the Dog Anal Gland Expression

I’m not a veterinarian and I am not authorized to give medical advice regarding your dog’s health. However, I think I’m safe in advising you not to try dog anal gland expression yourself.

If you’re a groomer…that’s different. It’s not as easy as it looks, it’s messy, and if there is anything going on in there, you need a professional to detect it.


Ultimately, dog anal gland cancer is rare and unlikely. That said, you should never assume there’s no problem, especially if your dog is showing signs of irritation around the rectum.

Scooting, redness, and other signs of discomfort should be examined by a veterinarian.

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