We had a fascinating lecture at the Forward Symposium on Sunday by Nick Bacon, who runs the oncology department at Fitzpatrick referrals Oncology and Soft tissue (FROST). There was so much within it that I simply couldn’t put it into a snippet on Facebook, and it felt right to take some of the information he imparted and write a blog post. Whilst this wasn’t strictly to do with canine athletes, it is important information for us all, as dog owners, to know and appreciate.
So, this blog post is dedicated to the thorny subject of neutering and cancer. Neutering has always been an area of debate in the veterinary world, and in general I would say that vets are fairly black and white about it (and I was very much one of those vets until a few years ago) - if you’re not going to breed then neuter, there are many medical benefits to do so for your dog. Over the last few years I’ve reached the conclusion that black and white is simply not going to cut it (I love getting older in some respects, when I qualified I knew what I knew and followed it, now I question what I know and try to make informed decisions as best I can rather than just going with the flow!). There are, as in many areas of veterinary medicine, a multitude of shades of grey and we, as vets need to be aware of the latest research and discuss it with our clients so that they can make a fully informed decision as to the best way forward for their pet. After all, each one is an individual! There is more and more research coming out that questions the status quo. The UK and USA have the highest routine neutering rates anywhere in the world, and we need to ascertain if we are doing the right thing for our pets.
One of the many pieces of information that Nick gave us was the knowledge that neutering, especially at a young age, seems to increase the incidence of certain cancers - these include osteosarcomas (bone cancer), bladder transitional cell carcinomas, prostate cancer, lymphoma and mast cell tumours. In a study of 683 Rottweilers (Cooley et al, 2002 - find the abstract on Pubmed here), early neutering (and by early neutering I mean before 1 year of age) was seen to increase the incidence of osteosarcoma (a type of bone cancer which in nearly all cases is fatal) by 3 times in bitches and 4 times in males. They had a 28% chance of developing osteosarcoma. That’s a significant increase. The counter argument is that neutering will reduce the incidence of other cancers and so we have to get a balance. For example, a bitch spayed before her first season will have no risk of ovarian or uterine cancer, and the chances of mammary cancer will reduce by 95-99.5% depending on when she was spayed relative to her first season. However, 50% of mammary cancers are benign, and of the malignant cancers only 50% spread - so 25% of all mammary cancers spread, whereas osteosarcoma has a much greater chance of killing the bitch. If you owned a rottweiler I'm sure you'd want to be aware of these facts so that you could have a discussion with your vet and make an informed decision as to whether to spay and if so, when to do it? We cannot extrapolate this to other breeds sadly, as a rottweiler is a distinct breed, and we know that cancer is a multifactorial disease, so it’s entirely possible that there are also genetic components at play here. But it is interesting information to be aware of, and most certainly relevant if you have a rottweiler puppy.
There are a plethora of other areas where neutering can have an impact on cancers. I had intended to do a comprehensive article on this, and then I found a three part blog by Dr Susan Ettinger, an American boarded oncology specialist. It seemed somewhat daft to write out what was in her articles all over again. What I love about these articles is that there is balance between the pros and the cons associated with neutering, with respect to cancer. In addition, she’s quick the emphasise that even intact dogs get cancer, and that it’s multifactorial - it’s too easy (and wrong) to advise not to neuter and your dog won’t get cancer. That simply isn’t the case. My only gripe is that the papers which the information comes from aren’t referenced at the bottom, although she does reference them in the comments when people have asked.
This information also looks purely at a relationship between neutering and cancer, but there is some work published showing the effects of neutering on other areas such as orthopaedics, behaviour and some medical areas.
Of course, most people don’t neuter for medical reasons, they do it for social reasons and to avoid producing more puppies in a world already inhabited by many unwanted, unloved dogs. This is a laudable reason. But do we need to look at our timing of this neutering, or even question whether we could do better by performing different procedures such as vasectomies rather than removing all of the sex organs? As more research comes out, this should help us answer these questions and determine that we achieve our aims: to promote the best health for our pets and the dog community at large. In the meantime, talk to your vet and do your research, make informed decisions as to what is the best option for your dog.