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Featuring Demian Dressler, DVM and Susan Ettinger, DVM, Dip. ACVIM (Oncology), authors of The Dog Cancer Survival Guide

Carcinoma of the Anal Gland

Updated: October 1st, 2018

One of the less common cancers is carcinoma of the anal gland.

Carcinoma of the anal gland occurs on the rear end of dogs, and are found on the anus, in it, or on the edge where the haired skin starts.  Sometimes they can be found only by doing a rectal exam, which is a good reason every senior (or early senior) dog should have a rectal exam, even females.

There are scent glands within the wall of the anus in dogs and many other animals, which are called anal sacs.  These sacs have anal glands within them which are used for marking territory.  Anal glands are also located in other areas in and around the anus.

These tumors start from an anal gland.

Most commonly, anal sac carcinomas are found in older female dogs who have been spayed.  Sometimes male dogs get the tumor however.

Whenever one of these growths is suspected, a test should be done to see whether the tumor is an anal gland carcinoma, or whether it is a different tumor type.

This type of tumor can sometimes cause elevated blood calcium levels, which will increase your vet’s suspicion of anal sac carcinomas.

However, for real diagnosis, a test of the actual tumor material is needed.  One of the most widely used is a fine needle aspirate.  Sometime though, a biopsy (either before or after removal) is the first step to get a diagnosis, since the tumor may be too sensitive, or in an area that  cannot be reached, using a fine needle aspirate procedure.  Another instance when a biopsy would be used is if the fine needle aspirate was not conclusive.

In this case the growth may be removed or sampled so a piece of tissue is submitted to the lab.

Results of the pathology report usually are returned in 10 days or so.

A plan should be made at this point. Usually the tumor is staged, and an assessment of spread is made.  Using the results of blood and urine testing, X-rays, ultrasound, and sometimes other tools, an idea of how much spread has already happened can be formed.

We should keep in mind though that some of these tumors will spread microscopically (micrometastasis).

The most important treatment step is to have them surgically removed, with as wide margins as possible.  Sometimes they will spread into lymph nodes under the lower spine, or to the lungs.  These tumor should be considered at moderately aggressive overall, and can endanger the lives of dogs with them.

Radiation and chemotherapy are used often along with these steps, depending on how aggressive the tumor is and whether spread has happened or is considered likely in the future.

In the next post, we will look at this dog cancer in more detail.


Dr D


Discover the Full Spectrum Approach to Dog Cancer

Leave a Comment

  1. Susan Kazara Harper on June 23, 2015 at 7:51 pm

    OH Dana, what wonderful news! Congratulations to you all and well done for changing those statistics. Give him a big “good boy” from us all!

  2. Susan Kazara Harper on June 16, 2015 at 7:29 pm

    Hi Dana, I’m guessing that the surgery either has, or has not happened now. And truly we could not make a recommendation in this post. These decisions must be made by you with guidance from your vet and all the information available to you. How is your boy?

  3. Dana Nuno on May 30, 2015 at 6:47 am

    My dog was diagnosed with this 2.5 years ago when he was 10. We did removal of the still small tumor and low dose c-cyclophosphamide chemo therapy for about 3 months. He did well for all this time with the exception of other issues related to hind legs and even a bout of pancreatitis due to steroid use. All resolved but now our vet found the tumor has grown back and presents itself to approx. The size of a plum!! We have surgery scheduled for next Friday but I am fearful due to its size and now his age, almost 13! He is a big fellow, lab mix and now weighs 64 lbs. he had weighed in at 75 lbs, but his bout with pancreatitis left him unable to eat for nearly 7 days. He also goes down and stays down for days due to his bad hind legs, but it always resolves ( without steroids)! And he gets back up. Do you feel that this surgery is recommended due to his history and the size of the new tumor, which is where the first tumor was located, left side anal gland area?? Any input would be great!! Thanks!

    • Dana Nuno on June 16, 2015 at 8:31 pm

      Yes, he had the surgery and it went well!!! He is recovering well!! We were so torn but knew his odds were bad if we didn’t do anything, so we took a chance!! He is a true miracle having made 2 1/2 years since his original diagnosis! Hopefully we will make another 2 1/2 years!! Thanks for your post!!

  4. Lynne on October 6, 2014 at 5:00 pm

    Thank you for this post. My 10-year-old mini Dachshund was just found to have an anal gland tumor. Since I began doing her grooming at home and he had not done any expressing of anal glands like the former groomer did, I thought the little bump might be the anal gland needing to be emptied. I took her to a new groomer who confirmed it was not that and that I should get her to that ASAP because it was probably a tumor. I discovered this only because I baby wipe her butt and paws every time she goes poop and have noticed a little bump on one side for the past few days. I believe that we got this early, fortunately. The blood test revealed that she is slightly anemic and I have vitamin drops for her. The lung x-ray looked beautiful. The vet is sending the tissue off to be biopsied and will know more in a few days.

    A friend of mine who also has a couple of small dogs asked how I found out about this. I told her that when your dog sleeps in your bed you probably want to have packages of baby wipes by the door so that when you take her out and bring your baby wiping her boss and her but when I baby wipes her but that’s how I found it. People who don’t do this with their dogs may never notice until they take their dog in for an annual exam.

    If you have any tips on how to make her more comfortable during her recovery I would really appreciate it. Roxie is not just a dog to me she is my co-pilot and I want her to be as comfortable as possible. She’s never been ill before and has never had to deal with a cone (don’t believe she had one when she was spayed). It’s driving her crazy so I took it off for her first night of recovery and have her on the pillow next to me so I can be sure she doesn’t get after it. I’m searching for a ProCollar or some similar cone alternative.

  5. Susan Kazara Harper on August 4, 2014 at 1:56 pm

    Barbara, you are definitely giving that boy all the love and care that he needs. Bless you both. Please let him guide you — don’t feel sad. When he wakes up like ‘let’s play”, just enjoy, and play. He will feel your sadness otherwise. And if there is a little bit of residue that he wants to clean up, consider letting him. It’s natural for him, and part of what dogs just do. Also, if he has nice, solid poos there should not be much residue. Check out the Dog Cancer Diet, if you haven’t already, and just keep loving that boy everyday. Good luck!

  6. Barbara on August 2, 2014 at 3:34 am

    My male 9 year old Brittany, Jazzy, was diagnosed with cancer of his anal gland in June of 2014. The tumor was quite large and when they removed it on July 8 the doctor had to remove part of his sphincter muscle. We were afraid that this would make him fecal incontinent. However, he has somewhat normal bowel movements but some is left behind in the hole that does not close due to his operation. So after every BM he has, I clean the residue from the hole with flushable wipes. Sometimes I put peroxide on the wipe. Sometimes I also take a cue tip and apply neosporin. He constantly try’s to lick his anus areas, so a lot of the time we have him wear a cone collar. We feel so sad for him but right now he seems to be his normal self in every way except for the bowel leakage at times. His appetite is extremely good. We elected not to do chemo or radiation. The vet said we will know when he is ready to leave us. My husband and I try not to dwell on this so we are doing everything we can to make his last days with us as happy and comfortable as we can. We love him so much.

  7. Pam Volland on April 28, 2013 at 2:31 am

    My sweet Max has completed his Chemo treatment as well as the Melphalan. Now 9 months after discovering he has AGC xrays have showed that the cancer has moved to his lymph nodes. His kidneys are not functioning properly too, he is drinking water excessively. The Cancer Dr. said that the lymph node will impede his ability to poop. My ? is what signs should I watch for that he is hurting? Will this be evident if he can’t poop? He is still eating and has not lost any weight. I don’t want him to suffer and I don’t know what to expect. Any advice is appreciated. Also how long does he have. Thank you. Pam

  8. Julie on March 3, 2013 at 3:40 pm


    How is your dog doing I just read your post and relate ….I just found out about our Jake has this type of cancer…Your story sounds alot like mine… would like to hear from you

  9. Sarah on January 21, 2013 at 6:58 am

    Just reading this back I can see how upset I was spelling is terrible. Unfortunately it appears the sub lumbar masses were Pancreas related tumours…. he started to wee lots of blood in his urine and on 14 January and we made the difficult decision to say goodnight to our wonderful dog of 10 years. RIP Ernie xx

  10. Sarah on January 12, 2013 at 12:17 pm

    Hi All,

    Our beautiful black lab was not concentrating his urine back as far as September…he had a petit Mal seizure just before Christmas and on new year day I noticed he was not right… Over the last week or so he has been diagnosed with anal carcinoma. There are a further two masses in his sub lumbar that are putting pressure on his poop pipe. Fine needle aspirate on anal mass confirmed but they did not get a good reading from the other mass.

    He is also hypercalcimc since jan, elevated but in normal levels before that. He is 10 oncology is a flight away to the uk (we are in guernsey) our vet is doing all he xn calling oncology or advice does not think he will be with us long…. Operating at this ge carries complications… How ill we know when the me is right o o he right thing!?

    Sarah x

  11. Rachel on December 24, 2012 at 1:31 pm

    I have a six year old cockerspaniel, I just found a lump on my dogs anus, I took him to the vets who operated 4 weeks ago. He had an operation and they removed most of it, but four weeks on and it’s grown back. I took him back to the vets who are doing a biopsy, but said the outlook isn’t good as it’s spread internally and has covered half his bum. I can’t bare to lose my boy, if anyone has any advice id very much appreciate it. Also he’s still happy within himself, drinking, eating and playing. Very sorry to hear about anyone that’s lost a dog I know how special they become in the family.

    Kind regards

  12. Liz on December 11, 2012 at 4:16 am

    Hi, My sweet twelve year old female dog has just been diagnosed with an anal sac tumor. About a year and a half ago I noticed a red and bleeding growth on her anal area. Honestly, in my naivety I thought it was a hemmeroid from straining so I switched my dog to a gluten free easily digested diet and this seemed to do the trick. No more difficult bowel movements. The growth did not disappear but the redness did. I was prompted to take her to the vet because the swelling had started to ooze and my dog is chewing at it. The vet was upset I hadn’t brought her in sooner, ( finances had been the reason) and said my dog had cancer and needed to be put down…….but my dog is full of life. She plays and runs with me , eat and drinks well, sleeps well. She is happy. I know she is definitely in some pain due to the tumor. I am taking her to see a canine oncologist tomorrow to have the diagnosis confirmed but I am at a loss as what to do if she/he says there is nothing that can be done especially when my dog is otherwise behaving so healthy. After reading a lot of info on removing the tumor, I am also worried of worsening problems for her there. Right now she has no trouble with bowel movements. I just need advice. I don’t want to prolong suffering but i don’t want to put down an otherwise very happy little sweet loving dog. Any suggestions would be very much appreciated. Sincerely, Liz

  13. Pam on October 3, 2012 at 10:42 am

    Max is diagnosed with anal gland carcinoma. I think vet calls is AGA. He had 1st chemo that was with Carboplatin 150mg. He has gotten very sick with diarreah. The Vet has prescribed an additional drug called Melphalan 7.4mg. However he is so sick now Im wondering if the 2nd drug is worth giving him. I dont know how much help it will give. I hate to see him sick and put him thru this if not necessary. What is your suggestion? The Vet would not assign a “stage” and the surgery got the entire tumor, but he said there are usually small particles that creep out into the body. Thanks for your advice.

  14. Pam on September 15, 2012 at 2:17 am

    My 8 year old Lab-Mix had a Anal Sac tumor removed yesterday. My Vet said she got it ALL but it was the size of a Softball! She removed both anal glands and we are waiting on lab results next week. We plan on chemo treatments, etc to better the chances we got it all. What is the prognosis since it was such a large fast growing tumor? I feel encouraged she got it all and it was contained in the anal sac, but worried because of its size. Max is a very healthy active dog with no other medical problems ever. What should I expect in chemo and moving forward. Thank you. Pam

    • Dr. Demian Dressler on September 19, 2012 at 3:46 pm

      Dear Pam,
      you need to see the type of tumor from the biopsy report. the class of cancer will tell you about what is published as far as data is concerned. meanwhile, start thinking about at least diet and supplements (please read the Guide!! There is also a free download on top of this page. )
      Also see:
      I hope this helps
      Dr D

  15. Eric Boles on August 25, 2012 at 7:42 am

    My maltese was diagnosed with mast cell cancer, grade 3, three years ago. It was a spot on his foot but removed with not so clean margins because the area was so small, he is only 4 pounds. He has had a couple other spots removed over the past 3 years but he is hanging in there. Originally he was only given 6 months to live but with prayer and love he is still with me.

    I have two questions.
    First, there is a newer drug out thats by BA Science called Kinavet (Masitinib). It is suppose to inhibit the receptors in mast cell tumors and slow down the growth. What do you think about this drug and do you think it will help if the cancer has spread to other organs, (which I am not sure of but having it for 3 years theres a good possibility).

    Second, there is a diet called Budwig Diet that is a mixture of flax seed oil, flax seed, and cottage cheese. I have been giving him this daily since he was diagnosed with cancer. Are you familiar with this diet and what is your take on it.

    Many thanks
    Eric Boles

  16. Pippa on August 3, 2012 at 7:24 pm

    My little guy Oliver a multipoo had removal of a tumor on his right anal sac. This happened a week ago,all went well and he had an amazing recovery happy,playful loving the next day. I just heard from the vet hours ago the pathology report is grim.It is an invasive cancer and the chances of it coming back are high, He is only 7 and I am reeling in pain right now. I know it is not about me- my concern is only for him.I

    • Dr. Susan Ettinger on August 10, 2012 at 10:57 am

      I am sorry about Oliver’s tumor, but dogs with anal sac adenocarcinoma can do well, even though it is an aggressive tumor. Depending on the case, I sometimes recommend radiation after surgery, but I would also recommend chemotherapy. Before treatment, nake sure the tumor has not spread. Have you checked the Guide? I have a whole chapter there on these tumors. Plus there is a ton of other info for you and Oliver.
      All my best, Dr Sue

  17. Jane on April 13, 2012 at 2:15 am

    My experience with this particular type of tumor is this… My dog, a spayed 9-yr-old Rottweiler, was diagnosed in January 2011. We removed the affected gland and the sublumbar lymph nodes. Very THIN, but clean margins were obtained. We did 3 mitoxantrone and 3 carboplatin treatments, alternating drugs and spaced 3 weeks apart. Once completed, we started Masitinib (Kinavet) daily for 6 months. Dropped the dosage to every other day in month 7 and every 3rd day beginning in month 8. We’re still doing Masitinib every 3rd day. Abdominal ultrasound and chest x-rays clear through February of 2012. We’re due for an ultrasound now and I need to get it scheduled.
    In August of 2011, I had the second (unaffected) gland removed as a preventive measure. No evidence of disease in that one.
    My dog has been raw fed her entire life and we have continued with an all-raw diet throughout the process. She gets homeopathics daily as well as artemisinin and many other supplements, including fish oil. Also, I used Phytomucil instead of Pepcid for nausea prevention. She has not had any signs of nausea.
    I realize this is an aggressive disease, but I’m grateful for the results we’ve had so far. My dog had no ill effects from the IV chemo and she seems to be handling the Masitinib well thus far. She amazes all who meet her because she’s full of energy and looks like a much younger dog. My only requirement in the beginning was that I would do what I could as long as my dog’s quality of life remained good. I want quality days over quantity of days. So far, we’re continuing to have only good days.
    If our experience can help anyone, I’ll be happy. Masitinib is very new in the USA, so there’s not a lot of info out there on long-term use.
    Good luck with your journey, Cheryl!


  18. cheryl on April 2, 2012 at 11:05 pm

    Hi Dr Dressler,

    My 16 year old cocker spaniel had been diagnosed with Anal Sac Carcinoma (ASAC) 2 weeks back. I am very dishearten….. I want to do what I can to prolong her life with good quality as much as possible. She’s had a certain smell from her breath ( a foul smell) for about a month now.

    She was also diagnosed with oral melanoma 6 months back and is on the Oncept Vaccine. With this cancer, I believed it is being managed and treated very well on top of all the supplements and Apocaps that she is already on.

    Now I have the challenge of having to treat her ASAC.

    Radiotherapy is not available in my country. In any case, if you find this is the way to go, I’ll find a way to see if I can make special arrangements. How effective is Cyberknife on this cancer?

    Considering she’s 16 years old and currently have 2 types of cancer, should I start her on metronomic chemotherapy. Her ultrasound shows some irregularity in her spleen and liver. Vets says it is not conclusive though the likely chance of it being a cancer is likely, could also be due to old age.

    If I opt for chemotherapy and her immune system weakens, then I am afraid it will affect the immunotherapy Oncept treatment for her oral melanoma.

    Dr Dressler, what should I do? I want to keep her happy and healthy as much as possible, by any chance are there any immunotherapy for ASAC which I can consider.

    Many Thanks in advance,

    • Dr. Demian Dressler on April 12, 2012 at 3:09 pm

      Dear Cheryl
      This sounds very difficult Cheryl, I am sorry.
      Dr. Ettinger should answer the cyberknife question as she has one of the few in her pratice. I will cc her on this. One way to keep up the immunity is beta gluans, or active hoxose correlated compounds, or bio bran. would not use astralagus with the metronomic.
      I would also be considering neoplasene right now. have your vet contact dr. fox at buck mountain botanicals.
      use mirtazipine or metoclopramide first to help with nausea, but again have your vet (not you) call dr fox for the info. i hope this helps
      Dr D

    • Dr. Susan Ettinger on April 24, 2012 at 3:43 pm

      Hi Cheryl,
      For ASAC, surgery is the most important treatment when considering surgery, radiation, and chemo. Studies show that having surgery as part of the treatment plan will benefit the dog’s overall survival. CyberKnife RadioSurgery is best used for measurable (not microscopic cells) tumors that are non-resectable. It is best for brain and nasal cancers. We did use CyberKnife in at least one non-resectable ASAC and when it shrunk by over 50%, that dog went to surgery. So I would first consider when the ASAC can be removed by surgery. Metronomic chemo is a reasonable alternative, but may not help the primary ASAC the way surgery can.
      Good luck!
      All my best, Dr Sue

  19. Kathy McLeod on June 23, 2011 at 10:11 am

    It’s Kathy again! One of my 2 dogs that passed away from anal sac carcinoma had his anal glands removed before there were any signs of a problem. His father and sister both developed it, so as a pro active move, I had his removed. He still developed the cancer several years later. The mistake I think I made was not insisting that the glands were tested for microscopic signs at the time they were removed…I just assumed the vet would know to do that sort of thing, considering the family history, which they were aware of. Maybe it wouldn’t have shown anything anyway, I’m not sure.
    So owners that have them removed after finding a lump should probably be clear about checking the surgical margins….some of the previous owners mentioned narrow surgical margins….a problem if they haven’t removed enough surrounding tissue. Once again, the cancer will have a good chance of cropping up somewhere else, if not the original spot. The lymph nodes that Dr Dressler mentions in his article, are a likely spot….that’s what happened to my boy who had glands removed as precaution…the cancer moved into the lymph nodes in his lower back area…sorry I don’t know the correct name..I think it’s sublumbar area? As a result there was no growth to find in the anal area, only with ultrasound or something similar will you find it. You have to ask for this, to keep ahead of it, other wise your not likely to see obvious external symptoms. It will likely spread to sublumbar area and then internal organs,,spleen, liver ect. It’s hidden.
    I hope this and my 2 previous posts are helpful for people. I’m not a vet, just an owner who had the unfortunate experience of dealing with this cancer, and tried very hard to help my guys. I learned alot, but sometimes it was a little late.

    Good luck to everyone

  20. Vicky on June 22, 2011 at 4:41 am

    if a dog had its anal glands removed previously due to chronic problems earlier in life have there been dogs that still get this form of cancer later in that same area or does it have to start because of actual anal gland tissue being there?

    • DemianDressler on June 29, 2011 at 6:31 pm

      Dear Vicky,
      these cancers come from cells there, but do not have to come from anal glands.

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