Mammary tumors

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Mammary tumors

Post by Shalista » Sat Dec 16, 2017 6:54 am

Curious about risks/benefits of spaying. I always was under the mentality of a dogs lady parts being a feature, not a bug, and with proper management should be left intact. But lately I'm seeing unaltered females everywhere getting mammary tumors and they're saying the only way to prevent them is to spay. how high is the risk really for getting these tumors?
Baxter (AKA Bax, Chuckles, Chuckster) Rat Terrier, born 01/16/13

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Re: Mammary tumors

Post by Nettle » Sun Dec 17, 2017 5:12 am

Spayed and unspayed female dogs get mammary tumours, cancerous or benign. The only thing that does lessen the risk is very unpopular :lol: - females that have bred and suckled a litter seem less likely to get them. But puppy farm broods often do have them, so there may be either a genetic tendency or a matter of care/environment involved too. Same as us, really.

There is plenty of evidence on the 'net but of course has to be read intelligently - for instance, any place involved in dog rescue is going to push for neutering. And relatively few people these days keep unspayed female dogs. I'm amazed you are finding so many. I'm the only person for many miles here who has whole females.

My vet is firmly in the 'do not spay unless for medical necessity' camp. Because neutering increases the risk of other cancers e.g. osteosarcoma.

Here is an extract from a veterinary article in Dogs Monthly:

Assumption: Neutering reduces the risk of mammary cancer in the b itch and early
neutering prevents it
Canine View
Without doubt, studies show there is a benefit, but the statement is somewhat misleading.
Unneutered b itches have only a 3.4 per cent chance of developing this problem with age, with 50
per cent of those cases being malignant.
Early neutering reduces this risk to 0.5 per cent of the 3.4 per cent = 0.017 per cent, but spaying
the b itch after the first season and before the second reduces it also to eight per cent of 3.4 per
cent = 0.27 per cent.
So the argument for early neutering over leaving the ***** to have one season on the basis of this
argument doesn’t really stackup as particularl significant.
The risk of developing mammary cancer in later life increases with each subsequent season.
However, there is also a downside to counter this argument which is that some studies show
increased incidence of other cancers following neutering including:
Osteosarcoma (bone cancer) - by a factor of one to three times (normal incidence 0.2 per cent).
Heamangiosarcoma–there appears to be a five times greater risk of contracting this cancer in
neutered bitches and 2.4 times in neutered dogs. The normal incidence in unneutered canines is
approx 0.2 per cent.
Urinary tract cancer (in bitches only) - there is two to four times greater risk of developing urinary
tract cancers. The normal incidence is less than one per cent.
So what is seen as a benefit for bitches for mammary cancer risk is, arguably, roughly balanced by
the increased risk of other cancers. Net gain - zero?

So - like so many things - you're damned if you do, and damned if you don't. For many people, spayed is much easier to keep. So if they only allow the female to grow up first, have one, maybe two, seasons, then they might as well spay as not. As long as they are happy with the incontinence risk. No perfect answer.
A dog is never bad or naughty - it is simply being a dog


Joined:Tue Feb 17, 2015 10:04 pm

Re: Mammary tumors

Post by Shalista » Sun Dec 17, 2017 5:05 pm

ah excellent thank you for the thorough answer. I had been led to believe that the risk was much higher for unspayed females. clearly this isnt the case. thanks for the time and effort for your response!
Baxter (AKA Bax, Chuckles, Chuckster) Rat Terrier, born 01/16/13

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