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

Bladder and Prostate Cancer: Neutering Male Dogs Increases Risk

Updated: March 23rd, 2020

Oh man. This is going to make a lot of people in my field angry.  Apologies to classmates and veterinarian friends!

I came upon a study from the August, 2007 journal Prostate.  Probably not what a lot of us would be reading in our spare time, but I am busy with upcoming info products for dog cancer owners and I dig through lots of publications.

The short story is the following:

Data was gathered from North American Veterinary Hospitals on male dogs that had been neutered (testicles surgically removed, or castrated), to evaluate the trend that had been noted in some older articles that neutering increased prostate cancer.

Because if this were the case (and this is my comment, not the authors’), it would seem ethics demand that owners of male dogs were advised of this before consenting to neutering surgery.

Here is what they found.  Hold your hats, folks:

1. Castration of dogs increases total malignant prostate cancer by EIGHT times for some prostate cancers (prostate adenocarcinoma). So the answer is yes, castration does increase prostate cancer in dogs (which goes against what I was taught).

2. Castration of dogs increases the most common type of bladder cancer (transitional cell carcinoma) by about FOUR TIMES.  This is huge!!  Major, major, industry shaking information as far as I can tell.

Okay, the pundit gallery will argue, but castration helps control the unwanted dog population, helps unwanted behaviors like aggression and territorial urination in undesirable locations, etc.  Yes, yes, all true.

But, we must start informing owners of this, to use Al Gore’s phrase, inconvenient truth.

And that is one of the purposes of this blog!

Best to all,

Dr Dressler


Leave a Comment

  1. Dee Marie Dubois on April 29, 2019 at 6:57 am

    Does the age of the male dog when castrated have any impact on the animal getting cancer? I don’t know if true but had been told by a vet that the older a dog’s neuter was done the healthier for the dog’s urinary function and chance of developing cancer. Never do it when they were a pup but wait until they were 3 or 4 years old.

    • Dog Cancer Vet Team on April 29, 2019 at 9:28 am

      Hey Dee!

      Thanks for writing. Dr. D recommends trying to find a happy, middle ground to spay/neuter your dog as there are risks for spaying/neutering too early, and too late in a dog’s life. He recommends having a dog spayed/neutered when they are between 12-18 months old 🙂

      Dr. Sue, who is an oncologist and the co-author of the Dog Cancer Survival Guide wrote some really amazing articles on Spaying and Neutering and the Association with Cancer in Dogs that you may find informative 🙂

  2. Prevent Prostate Cancer Dogs - Prostacet for men on July 10, 2018 at 5:55 am

    […] Bladder and Prostate Cancer: Neutering Male Dogs Increases Risk. – Oh man. This is going to make a lot of people in my field angry. Apologies to classmates and veterinarian friends! I came upon a study from the August, 20. […]

  3. Heather on October 27, 2014 at 5:00 pm

    Interesting read-currently researching some issues my 6 year old neutered male is experiencing and stumbled upon this article. He was neutered at 6 months of age. In the past 3-5 months I have noticed that he is straining when urinating and defecating. At first it wasn’t every time he eliminated but it has become increasingly worse. I took him to the vet for an examination and nothing was found upon his initial examination. His prostate was checked and nothing abnormal was felt. We ran complete blood work but other than an elevated CK level he was otherwise normal. We forgot to run a urinalysis but he did have abdominal x-rays done and nothing was found. He did have a bit of fecal matter in his small intestines but this dog has been a quite the producer of poop so didn’t find that surprising though they suggested an enema. Tomorrow we will be getting an ultrasound done-the more and more I read I feel that we are looking at something either with his prostate or his bladder but leaning towards the first. He is pretty asymptomatic at the moment-he is active in sports, his behavior and energy are the same, eating and drinking normally. 2 years ago I added another dog to my house and I will say I learned a lot with my first dog and have chosen a more “minimal” and not always appreciated route with her and that’s okay to each their own. Do your research don’t always believe what you are told until you dig a bit on your own. Be an educated and responsible pet owner-most importantly an advocate for your pets. I hope to get answers tomorrow-of course hoping I waste my money on nothing but just something is not sitting right with me about him. Regardless I hope to be proven wrong…

  4. Susan Kazara Harper on October 8, 2014 at 2:38 pm

    Hi Sarah,
    So sorry to hear of this diagnosis. I had a beloved Beagle when growing up and they are such lovely pups!
    Some people do use Chinese herbs alongside chemo and/or other treatment protocols, and if you want to go that route, please find a qualified veterinary TCM practitioner; don’t dabble yourself unless you have the training. Like everything else that may be used help, TCM needs to be correctly assessed and balanced. Stedman is not a statistic, so please don’t fret over the prognosis you’ve been given. They are based on medium life expectancy (basically, averages), and we know he’s not average. I hope you have or are going to consult an oncologist if possible. Full respect to the internal medicine vet; cancer is quite a speciality and if you can find a vet oncologist, perhaps even one who practices holistical as well as conventional treatments, you may find the best balance for your boy. Fighting cancer requires big guns, and gentle love. If Stedman is a candidate for chemo, talk with your vet (or that oncologist) to get all your questions answers… what will it do, what can I expect, how many dog with this diagnosis have you treated like this… etc. Top nutrition i vital as well. Do you have the Dog Cancer Survival Guide? It can help you with many of the information you need to make the best decisions for him. The Dog Cancer Diet is one of the chapters, and you can also download that at Give Stedman a special cuddle, and take a deep breath as you proceed. Good luck!

  5. Cookie M on September 27, 2014 at 1:54 pm

    So is it possible to do a vasectomy on dogs? What would the costs and health issues be compared to complete castration?

  6. Sarah on September 27, 2014 at 5:28 am

    My 11 year old beagle was just diagnosed with prostate cancer after an ultrasound showed the tumor on his prostate. The internal medicine vet said he has a year to live. Stedman is already on Chinese herbs as well as gets acupuncture. Do u recommend chemo along with the Chinese meds?

  7. Susan Kazara Harper on August 4, 2014 at 2:43 pm

    Hello Ash,

    Statistically the usual risk for testicular cancer may increase with an undescended testicle which is not removed. I believe the numbers are something like 2-3% risk increases to a 5-6% risk. These numbers seem low, unless you fall into those percentages. You need to decide how you’d feel if you did not act, and somewhere down the road received a cancer diagnosis. Work with your vet. If your dog if healthy and well otherwise, it may be worth considering eliminating the risk before it becomes a problem. As with everything for your boy, it’s up to you. Good luck!

  8. ash on August 3, 2014 at 4:39 am

    Hi, I have a 7yr old maltese. We were told by our vet that he has an undescended testicle, and that it could lead to cancer. Should he have the operation to remove the testicles?
    Really just want what’s best for him. Thanks

  9. Susan Kazara Harper on June 17, 2014 at 12:40 pm

    Hi Ann,
    I’m so sorry that you had to let your little boy go. That leaves a gap in your heart that can never be filled, I know. My boy passed away a few months ago, and nothing’s the same. Yet giving love and nurture to another young life can help so much. There is a lot of information in our blog posts on the neuter/prostate cancer relationship. Does it affect all dogs? No. It’s also not the only reason dogs get cancer. But if you learn all you can and make an informed decision with your next pup, you can greatly reduce the odds of having a similar experience. For example, one of my male dogs was left intact until he was 12 years old. At that point we had just begun to notice some of the signs that things were going a bit awry “down under” and he had this surgery for his 12th birthday. Not a great present on the day, but we had him with us a further 4 years. So you can find your next pup with a ‘lessons learned’ mindset. Raise him with excellent nutrition of real food, learn and watch for any signs along the way that you have to act, and then just enjoy him. We can’t live in fear, or we’ll be doing no good for us OR our dogs. “Worry is a prayer for what we don’t want” so please let your first dog’s legacy be the wisdom to move forward and give a happy, healthy home to a new dog. Im’ sure the right one will find you.

  10. ann on June 12, 2014 at 2:50 pm

    Our dog was diagnosed with Prostate cancer just last month and it came on all of a sudden. He seemed fine to us but in April he was having problems going to urinate and defecate he couldn’t jump up or down as much and from that time he went down hill so much that we had to make a decision for his quality of life and so we let me go with broken hearts and miss him terribly… we want to adopt again but we are concerned about this statistic of neutered dogs and not neutered getting prostate cancer. It’s sad… we are a committed family to having our dog with us for 20 years. Is this prominent in all dogs prostate cancer? We are looking for another yorki. Please advice.

Scroll To Top