Bladder and Prostate Cancer: Neutering Male Dogs Increases Risk
Dr. Demian Dressler is internationally recognized as “the dog cancer vet” because of his innovations in the field of dog cancer management, and the popularity of his blog here at Dog Cancer Blog. The owner of South Shore Veterinary Care, a full-service veterinary hospital in Maui, Hawaii, Dr. Dressler studied Animal Physiology and received a Bachelor of Science degree from the University of California at Davis before earning his Doctorate in Veterinary Medicine from Cornell University. After practicing at Killewald Animal Hospital in Amherst, New York, he returned to his home state, Hawaii, to practice at the East Honolulu Pet Hospital before heading home to Maui to open his own hospital. Dr. Dressler consults both dog lovers and veterinary professionals, and is sought after as a speaker on topics ranging from the links between lifestyle choices and disease, nutrition and cancer, and animal ethics. His television appearances include “Ask the Vet” segments on local news programs. He is the author of The Dog Cancer Survival Guide: Full Spectrum Treatments to Optimize Your Dog’s Life Quality and Longevity. He is a member of the American Veterinary Medical Association, the Hawaii Veterinary Medical Association, the American Association of Avian Veterinarians, the National Animal Supplement Council and CORE (Comparative Orthopedic Research Evaluation). He is also an advisory board member for Pacific Primate Sanctuary.
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
Dr. Demian Dressler is internationally recognized as “the dog cancer vet” because of his innovations in the field of dog cancer management, and the popularity of his blog here at Dog Cancer Blog. The owner of South Shore Veterinary Care, a full-service veterinary hospital in Maui, Hawaii, Dr. Dressler studied Animal Physiology and received a Bachelor of Science degree from the University of California at Davis before earning his Doctorate in Veterinary Medicine from Cornell University. After practicing at Killewald Animal Hospital in Amherst, New York, he returned to his home state, Hawaii, to practice at the East Honolulu Pet Hospital before heading home to Maui to open his own hospital. Dr. Dressler consults both dog lovers and veterinary professionals, and is sought after as a speaker on topics ranging from the links between lifestyle choices and disease, nutrition and cancer, and animal ethics. His television appearances include “Ask the Vet” segments on local news programs. He is the author of The Dog Cancer Survival Guide: Full Spectrum Treatments to Optimize Your Dog’s Life Quality and Longevity. He is a member of the American Veterinary Medical Association, the Hawaii Veterinary Medical Association, the American Association of Avian Veterinarians, the National Animal Supplement Council and CORE (Comparative Orthopedic Research Evaluation). He is also an advisory board member for Pacific Primate Sanctuary.
We recently had our 7 yr. old male golden neutered and after 4 days was ‘humping’ and ‘courting’ (licking ears, head, etc of our spayed 9 yr old golden female) more than ever! He spent over 12 hours mounting, humping, etc. and, although I believed this surgery would at least diminish this activity, to our great disappointment it has seemed to increase this behavior. How long does it take for the hormone levels to diminish after castration? Also, since new reports state that neutering increases the risk of prostate cancer, as you state here, why isn’t the prostate removed as a routine during neutering? What use is the prostate after removing the testicles? To use an example of a female who undergoes ‘hysterectomy’ which usually also means oophorectomy, removal of ovaries, why aren’t the same procedures used in males (dogs or humans) and simply remove the prostate also? I do not understand why this is not done as I cannot think of nor have read of any use whatsoever of the prostate after male canine neutering. And, if there is indeed an increased risk or prostate cancer or not, it seems logical to me to simply make it a standard practice to remove the testicles and the prostate when ‘neutering.’ Any reason for keeping prostate at all if one is proceeding with neutering a male dog is beyond me and would appreciate your input. Simply put, why isn’t the prostate removed routinely during the neutering surgery–sure seems like a sure preventative of prostate cancer and don’t understand why just the testicles, etc. are removed? Thank you so much.
Dear Shelly-
prostatectomy is extremely complex and invasive and the benefit/cost ratio does not make sense for this reason.
Best,
Dr D
[…] one vet's blog about it, and there are many other vets out there trying to inform people about it: Bladder and Prostate Cancer: Neutering Male Dogs Increases Risk Sadly a lot of vets are apparently deliberately keeping it quiet because it would significantly […]
there is an ERROR in the conclusion above –
i have not read the full paper, but i quote the abstract –
QUOTE,
The Veterinary Medical Databases… were queried to yield
male dogs with …bladder transitional cell carcinoma (TCC),
prostate adenocarcinoma (ACA),
prostate TCC,
prostate carcinoma (CA),
and prostate tumors.
A second query yielded all male dogs over the age of 4 years
without a diagnosis of urinary tract cancer. These popns were
compared to determine relative risks for developing each…
singly and collectively, associated with neutering status.
Odds ratios were calculated for breed as a risk factor.
RESULTS:
Neutered males had a significantly increased risk for
each form of cancer. Neutered males had an odds ratio
of 3.56 (3.02-4.21) for urinary bladder TCC,
8.00 (5.60-11.42) for prostate TCC,
2.12 (1.80-2.49) for prostate adenocarcinoma,
3.86 (3.13-4.16) for prostate carcinoma,
and 2.84 (2.57-3.14) for all prostate cancers.
Relative risks were highly similar when… limited
to those with a histologically confirmed diagnosis.
—————— END QUOTE
the 8x risk is for prostate-TRANSITIONAL-CELL carcinoma,
**not p-ACA**… p-ACA risk-odds is 2.12, far less-dramatic.
also, may i point-out that without the Other Factor [8 x what?] we cannot make any conclusions about the real-risk; if the risk in intact-Ms of Disease-Y is 1 in every 10k dogs, that is exceedingly-low; if that risk in desexed-Ms is 8x that, it becomes 8 in every 10k dogs, which is still very-low.
added to that is AGE Of Onset –
carcinomas and neoplasms are generally-assoctd with AGE as a risk-factor; in the 1800s, if a child died of cholera, they did not live long-enough to develop cancer, let alone die of cancer.
so… what is the risk in INTACT M-dogs,
and what is the average Age-of-Onset or Dx?
then there is the speed factor:
* how rapidly does the cancer grow in situ?
* is it an aggressive metastatic – moving quickly to other tissue?
* or a slow-growing stay-at-home?
what about ** debility ** –
* does this cancer rapidly undermine normal function?
* or take a long-time to affect daily-life?
* are its symptoms profound or barely-noticeable?
if Dx with a rapidly-growing cancer that metastasizes FAST,
PLUS a rapid-onset of symptoms that will have me bedridden,
i would be far-more concerned –
conversely, Dx with a slow-growing cancer that stays-home,
and shows few if any symptoms for years, i will worry far-less.
in the second instance, i might live with it for a decade or more,
and in my day-to-day life, not notice a difference.
everyone has to die OF something; if instead i live WITH
something and die of something entirely-unrelated
[like an auto-accident – where i wear my seatbelt but am
hit head-on by a semi speeding downhill which crushes
my vehicle and me], then the cancer did not kill me;
eventually it might have, but it did not cause my death.
if ADDITIONALLY i am looking at a cancer that occurs in old-age,
and average Age-of-Onset is 80 to 85, i will not worry so much –
especially if i am 35-YO, it is exceedingly unlikely soon.
OTOH if average Age-of-Onset is 30 and i am 35 with risk-factors,
then i should be concerned to limit my risk, or monitor if the risk
cannot be limited [genetic, runs in the family, environmental and
applies to the western-half of the continent where i live, etc].
** what about the BREED risk-factor?
if my breed is extremely-unlikely to develop p-TCC,
i cannot get too exercised; if OTOH my breed once past 5-YO
has a much-higher susceptibility than most [say one in 100],
i will be a lot more concerned to limit risk, if possible.
* whats the risk of p-TCC for INTACT males?
[that pesky second-factor]
* whats the average Age-of-Onset?
4-YO? 12-YO? or something between?
* how RAPID and how DEBILITATING is p-TCC?
* does it grow fast and metastasize early –
or grow extremely-slow and rarely metastasize?
* does it put the dog in severe pain, limit activity and
profoundly affect the ability to maintain muscle-mass?
or hang-around and not do much?
* what BREEDS have higher-than-average risk of p-TCC?
and what’s that average-risk for any breed of dog?
[that pesky second-factor again.]
i would ask the same Qs re the other cancers –
are they very rare? very common? very-likely in certain breeds?
does each grow rapidly and aggressively metastasize…
or poke along growing slowly in one tissue?
is Age-of-Onset geriatric, or early-middle-age [over-10 or 5-YO]?
knowing something is TEN-Times as likely is not very informative;
if i move from an area where thunderstorms are very rare to FLORIDA
where thunderstorms are very-common, i have increased my risk
of being killed by lightning –
but it does not mean that i am doomed to die struck by a bolt.
AND there are simple precautions i can take to reduce my risk:
* don’t stand under tall trees – get indoors
* DO NOT use a cell-phone outside in a storm
* don’t be the tallest thing in the landscape
* get off the water if sailing, or OUT of it if swimming
if i do all those things, thunderstorms are unlikely to kill me…
at least with lightning; OTOH i may die in my car when an overhead traffic-light falls when the cable fails in the high wind associated with a severe storm, but that is a concatenation of factors – BEING under the traffic-signal at the time, being one of them. Location, location, location… at that precise moment.
not much i can do about that.
hoping for further info,
– terry
terry pride, APDT-Aus, apdt#1827, CVA; Truly Dog-Friendly
Hi Dr. Dressler,
Wondering if you could answer this. My 6yo Bulldog “needs” to be neutered. I found a growth on his testicle. On sonogram it shows up as benign and looks and feels harmless as per my vet, but he suggests that I should neuter him anyway.
He however has severe food allergies (now eating raw and cooked foods, grain free only). Currently he has a STAPH infection on his belly, and I am so worried about neutering him. Question, can I leave him as is? Benign tumors are common in testicles….
Thank you for ANY advice,
Alya
Dr. My 6 yr old in-tact male English Setter has TC cells showing up in urine samples but two Vets and a University pathologist say that they are not seeing enough to call it anything more than suspision of cancer. A prostate wash, x-rays, and blood work have been done also. Can you tell me what the possibilty is of TC”s showing up in urine and not endig up to be cancer? So far activity and appetite have maintained at a high level. I have not noticed straining of any kind. The next steps offered are chest x-ray and or ulta-sound. Thank you in advance for your opinion.
S
Dear Scott,
I wonder if the cells that are being seen are transitional cells as opposed to transitional carcinoma cells. Can you get some clarification? The former are normal lining of the urinary tract, the latter are cancer cells.
Stay in touch,
Dr D
Dr. Dressler~
A couple of weeks ago we had a boxer come up to our home and has not left since. We searched for his owners to no avail. He even has a microchip that was never registered. We have decided to keep him. He is a wonderful dog. Great with my children and very obedient. We have not allowed him in our home, but I have a feeling he was an inside dog. We plan on letting him in as soon as we get him checked out by a veterinarian. I have spoken with a couple local vets and each them has suggested neutering him. I am not sure about this. Through our searches for his microchip owners we found that he is about 7-8 years old. My previous experience with a female boxer was that her entire demeanor changed when I had her spayed at age 3. She was never the same. Would you suggest at his age to consider neutering?
Dear Mandy-
I do feel that neutering dogs has its place, and you are getting to the age where you will start to see the prostate-related problems like enlargement, infection of prostate, and prostate abcess. In these cases I feel it is worth doing, although there may be some mellowing and you need to watch his weight and if he starts getting overweight reduce his calories and increase his exercise.
best
Dr D
Dr. Dressler,
my wonderful 12 year old border collie mix began to vomit and strain to defecate 2 days ago. His urination pattern changed. He stopped eating. I took him to the vet and learned that his bloodwork and temperature are normal but his prostate is huge. He was neutered at less than a year of age. The vet prescribed metronidazole, guessing at colitis. I don’t think the flagyl is helping and he hates it. He is still not eating and is obviously in discomfort. I know that further testing is needed to diagnose the problem but I suspect he may have prostate cancer. His back legs are also very weak and shaky. He has been a great dog and while I don’t regret neutering him, I wish I could help him more now… is there anything I can do to reduce the size of the prostate, so that he can at least pee and defecate comfortably while we figure this out? Any ideas about how to make him comfortable? I want to discontinue the flagy.
Your thoughts appreciated. Thank you.
Elise
Dear Elise,
Good question. To shrink the growth you have to know what it is. An infected prostate can be cured with simple antibiotics, so work with your vet to get an actual diagnosis before treating a cancer.. stay in touch.
Best,
Dr D
I have a two year old English Mastiff who just got fixed right before his second birthday.The Vet did not send him home with a c-collar and Diesel developed an infection shortly after getting fixed my husband and I had him boarded at the vets office for three days where he dropped the majority of his weight. Diesel in about a two week span of time went from 113lbs to 93lbs where he has maintained with a pound or two difference + or – on either side of the scale. I have not been given any answers I’ve been told it could be auto immune or cancer. I asked the Vet several times if all the added stresses could have triggered his weight loss and his anemia vet says no. Or could the vet have screwed up I had a perfectly healthy dog 2months ago a normal wieght for his age and very active.Now I have a dog I have to force feed and give a small pharmacy too everyday. Can anyone tell me what could have created his condition?
I have a male Boxer. He is 2.5 yrs old. I took him to the vet as he seemed to be losing weight after being boarded during the holidays. The vet told me his prostate is “enlarged” and put him on antibiotics. They at that point started pushing me to have him neutered. He is a beautiful, healthy, calm, non-agressive dog. I have been doing some internet searching regarding this matter. The vet makes it sound as tho the pro’s of having him neutered out weight the con’s. HOWEVER, I am seeing things a little bit differently! Any input you may have would be greatly appreciated!
Dear Mandy
I will confess that in many cases I lean towards neutering myself for cases like these. You don’t have to though. When you are done with the antibiotics get an ultrasound guided fine needle aspirate to collect a sample for culture and senstivity. Also get a specimen for a pathologist to look at to check for cancer or benign prostatic hypertrophy. That way you can test to see if there are germs in the prostate or if there is something else going on. If negative, get a follow up ultrasound by the same person in about 4 months or so (of course, clear all this with your vet, or a second opinion vet). If the prostate is still growing but was negative on the culture, you may really want to reconsider the choice to not neuter. If it is not growing or shrinks, then perhaps you are home free.
Hope this helps,
Dr D
This is a bad and scary post – Desexing is valid and does decrease the risk of problems – shameful article that goes against all veternary advice – you can make peopel believe the earth is flat if you post an article.
be careful people
Dear Neil,
Please do your own independent research and come to your own conclusions. Is is dangerous indeed believing everything you read, or hear for that matter, regardless of the source. It takes a certain kind of bravery to be bold enough to conclude the earth is round when you are told from all sides that it is flat. Get your ship and set sail.
Good luck to you
Dr D
[…] to look after an entire dog. Desexing of dogs is purely for human convenience. Nothing else. Here Bladder and Prostate Cancer: Neutering Male Dogs Increases Risk google some more if you are interested in learning. I will no doubt not be back if anyone wants to […]