Cancer in animals

[loveoforganic2]

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Just a curious question as a med student - I know my dog as well as several friends' dogs have had to be euthanized due to cancer (over a year ago, this post was actually triggered by my landlords' dog), and this initially seemed weird to me given their significantly shorter life spans and thus opportunity to be exposed to carcinogens. Is cancer in dogs a feature of tight breeding lines? Or is it more a factor of dogs having DNA repair enzymes and whatnot that are less effective (time span wise) than humans, and the medical care we provide gives the repair enzymes the opportunity to fail? Or both?

Thanks - I think this question is appropriate for the forum, apologies if not

 

[katryn]

Cancer in pets is honestly just as complex in pets as it is in people. There are breed predispositions, definitely. But a single exposure to carcinogens can cause cancer in dogs just like people.

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[No Imagination]

...this initially seemed weird to me given their significantly shorter life spans and thus opportunity to be exposed to carcinogens. Is cancer in dogs a feature of tight breeding lines? Or is it more a factor of dogs having DNA repair enzymes and whatnot that are less effective (time span wise) than humans, and the medical care we provide gives the repair enzymes the opportunity to fail? Or both?

You know, I've often wondered the same thing. Considering the shortened lifespan of dogs (most (but not all) cancers are age related) you would suspect that dogs (and other animals) would not have to contend with (old age) cancer. Obviously, that is not the case.
On one hand you certainly have genetic/congenital factors; either due to line breeding (inbreeding being an issue more for unscrupulous breeders) or dumb luck/bottlenecking reducing genetic diversity. However that is IMHO more of a young dog cancer (Osteosarcomas in large/giant breed dogs or general neoplasia/lymphoma in boxers and Goldens, ect.) however it does not explain old dog cancer in mixed breed dogs.

I think that it probably has a lot to due to the mysteries of cellular aging; either telomere shortening or as you mentioned, increasing the lifespan beyond the point that DNA/RNA repair mechanisms can mathematically cope. A doctor once told me, all men, if they live long enough, will get prostate cancer (something to look forward to I guess).

There is certainly a lot we don’t know about companion animal cancer but it seems to me that there is the opportunity for some significant research that could potentially shine some additional light on aging and cancer.

There is a vet student (from Davis I think) who frequents these boards who did a bit of research on canine genetics/cancer if memory serves me correctly. Hopefully she? chimes in!

 

[NStarz]

I think "old age," too, is in the eye of the beholder. While we don't see dogs as old when they die at 13 or 14, that really is old to them comparatively speaking. So I think whatever mechanism happens in us that leads to old age cancer happens in them (telomeres shortening, faulty DNA repair mechanisms, what have you), just at a more accelerated rate because of their shortened life spans.

 

[No Imagination]

I think "old age," too, is in the eye of the beholder. While we don't see dogs as old when they die at 13 or 14

I think most people do (see 13 and 14 as old for a dog).

So I think whatever mechanism happens in us that leads to old age cancer happens in them (telomeres shortening, faulty DNA repair mechanisms, what have you), just at a more accelerated rate because of their shortened life spans.

I can't tell if its is your choice of words or if you are confusing 'cause and effect' here.

mechanism happens in us that leads to old age cancer happens in them (telomeres shortening, faulty DNA repair mechanisms, what have you), just at a more accelerated rate because of their shortened life spans

Telomere shortening and faulty DNA repair mechanisms are the (proposed) mechanism of old age. They are not accelerated BECAUSE of their shortened life span, but their life span is shortened BECAUSE of these mechanisms.

I am not jumping on your semantics here, it just seems like you might have it backwards.

 

[psilovethomas]

Just a curious question as a med student - I know my dog as well as several friends' dogs have had to be euthanized due to cancer (over a year ago, this post was actually triggered by my landlords' dog), and this initially seemed weird to me given their significantly shorter life spans and thus opportunity to be exposed to carcinogens. Is cancer in dogs a feature of tight breeding lines? Or is it more a factor of dogs having DNA repair enzymes and whatnot that are less effective (time span wise) than humans, and the medical care we provide gives the repair enzymes the opportunity to fail? Or both?

Thanks - I think this question is appropriate for the forum, apologies if not

There are certain breeds that I associate with certain cancers. For example, Rottweilers and osteocarcoma. But for the most part, it's just like human medicine. We are trying our best to understand. We have good treatment options and facilities.

 

[loveoforganic2]

Thank you all for the info, appreciate the replies!

 

[NStarz]

I think most people do (see 13 and 14 as old for a dog).



I can't tell if its is your choice of words or if you are confusing 'cause and effect' here.

mechanism happens in us that leads to old age cancer happens in them (telomeres shortening, faulty DNA repair mechanisms, what have you), just at a more accelerated rate because of their shortened life spans

Telomere shortening and faulty DNA repair mechanisms are the (proposed) mechanism of old age. They are not accelerated BECAUSE of their shortened life span, but their life span is shortened BECAUSE of these mechanisms.

I am not jumping on your semantics here, it just seems like you might have it backwards.

Totally what I meant to say. My brain is mushy because of finals. Thanks 🙂

 

[No Imagination]

My brain is mushy because of finals.

Good luck on finals!