Undescended Testicle

This forum is for dog lovers seeking everyday advice and suggestions on health-related issues. Remember, however, that advice on a public forum simply can't be a substitute for proper medical attention. Only your vet can say assuredly what is best for your dog.


Big Boy
Barked: Fri Aug 28, '09 2:19am PST 
Well I just thought I'd pass on my thoughts about undescended testicles, as given that our boy had to be anesthetised for another reason, I decided to get his undescended testicle removed at the same time.

Undescended testicles are bad in that there is something like a 14 times higher chance that they will turn cancerous than a descended testicle. As about 7% of dogs with descended testicles develop testicular cancers, this implies that 80% of undescended testicles will turn cancerous. Testicular cancers are generally eminently treatable, and of those 7% of dogs with testicular cancer in descended testicles, only about 1% will die of it. Also testicular cancers do not readily spread. So this is not really in fact one of the good reasons for neutering your dog, despite being stated as such repeatedly.

But the problem with an undescended testicle is that the cancerous tumour in an undescended testicle will obviously be missed in any routine examination. I don't have figures, but speculate that if say only half of testicular cancers in undescended testicles were found in time, and half not, this could imply as many as 40% of dogs with undescended testicles dying of testicular cancer. Even if these figures are inflated, there is clearly a much higher risk with undescended testicles, as any vet will tell you.

As a personal aside, I am personally not in favour of neutering, after proper consideration of the matter. (Please don't get into an argument about this; my post here is about a specific health risk). However because of this, we instructed the vet to remove only the undescended testicle ie our boy is not neutered. However it is bad practice to breed a dog with an undescended testicle, as doing so passes on this hereditary health risk.

I have to say it was a tough decision to at quite short notice decide to get pain inflicted on our boy by the operation. However one has to make the best decisions one can, in the long term health interest of our beloved animals.

Edited by author Fri Aug 28, '09 2:20am PST


I'm a trilingual- dog!
Barked: Fri Aug 28, '09 5:13am PST 
Good post, Aibou.

And you're completely within your rights not to neuter your dog as long as you keep the necessary precautions in owning one - ie, not letting him get out and make tons of puppies. blue dog

All that lives- is holy.
Barked: Fri Aug 28, '09 8:08am PST 
I agree with everything you said. It drives me crazy when people quote testicular cancer as a reason to neuter your dog. I think your percentages are off, though. I'm BAD at math, but according to Comparative Veterinary Oncology, 2007, only 2 out of every 1000 unneutered dogs gets testicular cancer- wouldn't that be closer to .02%?

Jessica CGC

Will work for- food
Barked: Fri Aug 28, '09 9:11am PST 
Testicular cancer is the third leading cancer in ALL dogs not neutered. Not just undescended testicles.
Telly Lam

Never met a- lampost I- couldn't pee on
Barked: Fri Aug 28, '09 11:33am PST 
Testicular neoplasias are common in un-neutered older dogs, but tend to be benign, with low rates of metastases (in contrast to humans). Most commonly occurring ones are the mixed germ cell sex cord stromal tumors (MGSCT, typically seminoma + Sertoli cell type) and are often surgically resectable. The biggest problem with testicular tumors (specifically the Sertoli cell type) is that they can produce hormones, especially estrogen. Long term estrogen exposure can wreak havoc with your blood cells and hair growth, among other things.

Prostatic cancers, on the other hand, occur in both neutered and un-neutered males with almost equal frequency. In fact, the more histologically anaplastic types of prostatic cancers tend to occur in un-neutered males. Neutering does not reduce overall incidence of prostatic cancer, but fortunately prostatic cancers are very uncommon overall in dogs (again, in contrast to people).

Neutering does, however, prevent other types of tumors, such as perianal gland tumors (which can be a pain in the butt, literally).

Pros and cons of neutering should be weighed. North American veterinarians tend to have a very stringent attitude regarding neutering, in contrast to those in Europe. I suspect it has a lot to do with pet overpopulation issues that are not necessarily encountered in a lot of EU countries, and differences in attitudes in animal husbandry and welfare.

Changing one- mind at a time - APBT style
Barked: Fri Aug 28, '09 1:24pm PST 
Testicular cancer only afflicts about 7% of all unaltered male dogs, less than 1% of these based on studies, are so severe that the dog dies as a result; I don't see how 7% is considered one of the top cancers in dogs. Dogs that are exposed to harsh pesticide chemicals and have one or both testicles undescended are at a higher risk of testicular cancer than the average dog. The much more common medical reason to alter a male dog would be to prevent the non-cancerous prostate disorder BPH which about 80% of male dogs over the age of 5 years in the study were afflicted with (for most dogs in the study it causes no problems at all, but for others it caused problems urinating and defecating, and even benign tumors of the prostate; neutering resolves BPH in male dogs), and perenial fistulas (which are more common in older unaltered male dogs than older altered male dogs) which also are common in older unaltered male dogs and are a lot more likely to cause problems than even an enlarged prostate, both are a lot more common of a problem in dogs over 5 years than testicular tumors.

Last I'd seen, the most common cancers in dogs based on research were Lymphosarcoma, Hemangiosarcoma (most common in medium and larger breeds and is more common in altered male dogs than unaltered male dogs, especially in dogs altered prior to 1.5 years of age), Osteosarcoma, Mammary cancer (the risk of this is heavily reduced if the dog is spayed before or right after her first heat and certainly before the third cycle), and Mast Cell cancer.

Many cancer risks are heavily breed and size related, so I personally it's important to evaluate a dog individually when choosing to alter OR not alter based on the basis of canine cancers as long as they can keep the dog from producing unwanted litters if they are to remain unaltered for any period of time after 6 months.


Prymak C, McKee LJ, Goldschmidt MH, Glickman LT. Epidemiologic, clinical, pathologic, and prognostic characteristics of splenic hemangiosarcoma and splenic hematoma in dogs: 217 cases (1985). J Am Vet Med Assoc 1988 Sep; 193(6):706-12

Ware WA, Hopper, DL. Cardiac Tumors in Dogs: 1982-1995. J Vet Intern Med 1999;13:95–103

Bonagura, J. Current Veterinary Therapy 12. W.B. Saunders Co. Philadelphia, PA; 1995.

Ettinger, S. Textbook of Veterinary Internal Medicine. W.B. Saunders Co. Philadelphia, PA; 1989.

Rutteman, GR; Withrow, SJ; MacEwen, EG. Tumors of the mammary gland. In Withrow, SJ; MacEwen, EG (eds). Small Animal Clinical Oncology. W.B. Saunders Co. Philadelphia, PA; 2001455-477.

Moe L. Population-based incidence of mammary tumours in some dog breeds. J of Reproduction and Fertility Supplment 57, 439-443

Johnston SD, Kamolpatana K, Root-Kustritz MV, Johnston GR, Prostatic disorders in the dog. Anim Reprod. Sci Jul 2;60-61:405-415

National Canine Cancer Foundation

Edited by author Fri Aug 28, '09 1:26pm PST