# Cancer in male and female rats



## SlingDash (Jul 30, 2010)

Hi all,

I have kept rats for around ten years, and have always kept small groups of boys.

In all that time, and with all the boys I've known, I have never once had a lumpy rat, or one that (as far as I know) developed any form of cancer in old age.

I know female rats are very prone to all kinds of tumours, so have I just been lucky?

:confused1:


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## owieprone (Nov 6, 2008)

dunno, i think benign tumours are more prevalent than actual cancer.

i've been keeping rats since 2003 ish (can't remember when i got my first).

we've only had one rat with actual cancer who had to be pts while under 1.5 y/o. She had the lump for a max of 2 months before being pts. I know this becuase, unusually for her she made the effort to let pick her up, which let me know she was ill. i felt the lump almost immediately. pea sized, was the size of a golfball 2 months later. we hoped it was benign but the speed of growth let us know otherwise. Caused her secondary problems, and was pts before she was unable to pee etc.

a few of my others have had benign lumps, none of was the cause of death and only stally had to be pts because hers had grown so large she could no longer move around properly lol. besides that Stalin was the picture of health, she didn't even have 'bedsores' from dragging her lump around, she didn't have any other problems associated with the lump itself and her fur was just beginning to thin.
It was actually a shame to have her pts, she was between 3/3.5 y/o! (can't remember which lol definately over 3 tho), i reckon she would have made it to 4 y/o had the lump started later or not at all. I think she had it for just under a year.

i think it's luck of the draw in some cases and breeding in others.


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## simplysardonic (Sep 1, 2009)

SlingDash said:


> Hi all,
> 
> I have kept rats for around ten years, and have always kept small groups of boys.
> 
> ...


I've never had a lumpy/cancerous boy & until 2009 I'd never had a female with this problem either but my 3 oldie girls have each had a benign tumour removed & 1 of them (Shadow) has had 2 ops so far. They all came from the same pet shop & I think much of it may be down to their breeding


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## SlingDash (Jul 30, 2010)

Forgive me. I made the post in haste. When I said cancer, I actually meant lumps.

I've never, ever, ever had a 'lumpy' boy! Must be luck, surely? :confused1:


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## simplysardonic (Sep 1, 2009)

SlingDash said:


> Forgive me. I made the post in haste. When I said cancer, I actually meant lumps.
> 
> I've never, ever, ever had a 'lumpy' boy! Must be luck, surely? :confused1:


They are less prone to lumps than girls, I think its got something to do with hormones as a lot of the lumps females get are benign mammary lumps, although I think 'benign' is a misnomer as the lumps if left will cause the rat problems


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## owieprone (Nov 6, 2008)

technically not a misnomer

benign tumour and malignant tumours (cancers) are different things. Benign means that it's not cancerous so "no danger to health" as it can only grow where it is and not spread to other tissues, unlike a cancer.

the benign tumours will usually grow slowly over many months, they may or may not cause direct/indirect problems with the rats other systems or body parts. they generally don't cause other health problems or pain. (in my experience anyway)

direct problems are things like the tissue they are growing on being damaged by the growth, so say it's growing on the bladder rather than a mammary tissue,it can cause bladder problems, misfunction due to reduced blood loss to the bladder wall etc.

indirect would be if it was growing near a limb and at size causes walking problems.

as sardonic says, if left they will cause problems, generally from the size it gets to. As they generally aren't painful and grow slowly the rats body manages to adapt to this change well.

However removing them is costly (even when peasized) and anaesthetic can be dangerous) and doesn't mean the rat won't get more.

As with any 'problem' it can be a genetic response to stimuli, if one lump is removed and the stimuli is still there along with the 'extra' growth hormones, so another lump will generally appear. If the lump has cropped up for another reason or the stimuli has disappeared then the rat may not get another lump, or it may occur months later. 
Where there is alot of stimulus more than one lump can appear, or can grow quicker than 'normal'.


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## magpie (Jan 3, 2009)

I've so far only had one boy that's had a lump, and that's my lovely Smokey. It was removed back in April, and (touch wood!) he hasn't had any further problems.

Generally speaking I would always have a lump removed, so long as the rat is otherwise in good health. Even though Smokey did look very silly with a shaved bum!


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## simplysardonic (Sep 1, 2009)

magpie said:


> I've so far only had one boy that's had a lump, and that's my lovely Smokey. It was removed back in April, and (touch wood!) he hasn't had any further problems.
> 
> Generally speaking I would always have a lump removed, so long as the rat is otherwise in good health.


Did your vet tell you if it was benign or malignant? All of the girls' have been benign except possibly the one in Shadow's groin, this felt different & presented itself as a more 'attached' growth, it seems the vet did a very efficient job at removal as you wouldn't know she'd had one at all as she healed up well. I found this article which mentions that male rats CAN get benign mammary tumours, even though they have no nipples ( I assumed that no nipples= mammary tissue isn't present but I guess not)
the Rat Report


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## owieprone (Nov 6, 2008)

magpie said:


> I've so far only had one boy that's had a lump, and that's my lovely Smokey. It was removed back in April, and (touch wood!) he hasn't had any further problems.
> 
> Generally speaking I would always have a lump removed, so long as the rat is otherwise in good health.


on the flip side, i don't, I had one removed in Lenin (2nd rat i ever had), and within 6 months she had another one, which took over a year to get past pea size, never bothered since. Having said that we've not had a lumpy-bum for quite a while, out of the last 2, one was cancerous and the other with a benign lump died of an unrelated condition.

I'm of the opinion that if they have one they'll get another one if it's removed. so don't see the point in forking out 90 odd quid. I make sure any rat that has one is good up to the point it can no longer move around adequately and/or has a low quality of life. if there are no other problems i don't see the point in having them pts until they aren't enjoying life anymore.

Having gone through a cat with nasal cancer we've no intention of letting any rat with cancer or a problematic lump be miserable no matter what age.

however, that's just me.


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## owieprone (Nov 6, 2008)

simplysardonic said:


> Did your vet tell you if it was benign or malignant? All of the girls' have been benign except possibly the one in Shadow's groin, this felt different & presented itself as a more 'attached' growth, it seems the vet did a very efficient job at removal as you wouldn't know she'd had one at all as she healed up well. I found this article which mentions that male rats CAN get benign mammary tumours, even though they have no nipples ( I assumed that no nipples= mammary tissue isn't present but I guess not)
> the Rat Report


all mammals have mammary tissue, it's not sex related.


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## simplysardonic (Sep 1, 2009)

owieprone said:


> all mammals have mammary tissue, it's not sex related.


I knew that as men can get breast cancer, I didn't know it was present in male rats though due to them not having nipples, do they have as extensive mammary tissue as females do?


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## magpie (Jan 3, 2009)

As you say, it's very much a personal descision . As far as I'm concerned any lump has the potential to just keep growing, and the longer it's left the riskier the surgery if you do eventually decide it needs to be removed.

I'm lucky in that I currently work in a vets, so something like that doesn't cost me quite as much and I get to be there the whole time. I watched Smokey get sedated, I witnessed the entire op and I was there when he woke up, which I think probably made the whole experience easier on both of us!


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## spoiled_rat (Mar 24, 2008)

I tend to get lumps removed in rescue rat who come with lumps, and spay females at the same time, and havent had any further Hormone driven lumps on the spayed rats or incidence of Prolactinomas.

With the rats i have had from breeders or had since they were young, none have had any lumps so far, and thats mainly due to not overfeeding them, as you get fat rats and they have a much bigger chance of developing lumps, amongst other things.


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## magpie (Jan 3, 2009)

simplysardonic said:


> Did your vet tell you if it was benign or malignant?


It appeared to be a cyst. She even cut it open for me to see what it was like inside, and all this nasty grey sludgy stuff came out!


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## owieprone (Nov 6, 2008)

simplysardonic said:


> I knew that as men can get breast cancer, I didn't know it was present in male rats though due to them not having nipples, do they have as extensive mammary tissue as females do?


no, as far as i'm aware their mammary tissue is mainly armpits, groin and belly.

one of the main theorys (dunno if its more than that, not something i've researched greatly) is that females while also having more mammary tissues they are more prone to tumours due to their much higher oestrogen production, testosterone is in some cases an inhibitor, which is produced less in females. so less mammary tissue, less oestrogen input, increased testosteron = less tumours


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## simplysardonic (Sep 1, 2009)

owieprone said:


> no, as far as i'm aware their mammary tissue is mainly armpits, groin and belly.
> 
> one of the main theorys (dunno if its more than that, not something i've researched greatly) is that females while also having more mammary tissues they are more prone to tumours due to their much higher oestrogen production, testosterone is in some cases an inhibitor, which is produced less in females. so less mammary tissue, less oestrogen input, increased testosteron = less tumours


Its such a shame, I wonder if wild rats get them too?
Does having higher oestrogen levels contribute to weight gain or weight gain contribute to higher oestrogen levels?
I'm convinced that diet does have some contrbuting factors & I won't feed the rats any of the known brands of rat food, especially the nuggets, as I heard that these can help cause tumours. Since switching to a home made mix a year ago & adding supplements to their moist food I've noticed their overall condition has improved


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## owieprone (Nov 6, 2008)

diet wise it's the same for any animal including humans. 

nuggets aren't a natural food (obviuosly) so they could in theory (proving it would be hard if there are no unnatural ingredients) contribute to tumours.

the improved condition of your rats though is more likely because you're feeding them food in its natural state and not preprocessed gunk, and foods/additives they shouldn't eat too much off or at all.

pretend for a second they're human, we've been told to cut down on processed foods because they have added this added that, reduced this reduced that.. this is carcinogenic, this causes some other disease..it's no different for pets. if you wouldn't eat it why should your pet? everything will contribute to something however it's genetics that are the be all and end all. if you've bad genes you could be predisposed to anything going, for rats one of those is tumours, mostly i suspect, due to their breeding cycle (lots of oestrogen alot of the time) and amount mammary tissue.

as for wild rats, i think it would depend on breeding, colony size and genetic distribution and genetic predispostions within the breeders, so no real difference from us or pets. 

Again abit like humans, inbreeding is outlawed for a reason, rats don't have that particular law and will make with just about anyone, and it's also why many petshop rats or bad breeders rats will be more prone to tumours and other ills. the more you use the same genetic material the more it will reproduce the errors and produce more causing all sorts of problems. So infact they should be more prone to it than well bred rats.

oestrogen wise, i'm not sure if it works the same in all mammals as it does for humans, it might not be a contributary factor for rats. on the other side of that though it could have the same effect on rats as it does us.. do your rats have moobs? 
if i remember i'll look that up  interesting question, erm.. not the moobs one, the oestrogen as a factor question.


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## owieprone (Nov 6, 2008)

just looked it up.. couldn't wait till i got home lol

it depends on who you ask apparently and what you're measuring exactly lmao, no change there then.


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## spoiled_rat (Mar 24, 2008)

owieprone said:


> Again abit like humans, inbreeding is outlawed for a reason, rats don't have that particular law and will make with just about anyone, and it's also why many petshop rats or bad breeders rats will be more prone to tumours and other ills. the more you use the same genetic material the more it will reproduce the errors and produce more causing all sorts of problems. So infact they should be more prone to it than well bred rats.


You will find most well bred rats, who are consistently healthy, are highly inbred/linebred, so the `same genetic material` is reproduced quite alot, without negative effects ifs done correctly


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## owieprone (Nov 6, 2008)

spoiled_rat said:


> You will find most well bred rats, who are consistently healthy, are highly inbred/linebred, so the `same genetic material` is reproduced quite alot, without negative effects ifs done correctly


lol breeds are a genetic inperfection in themselves.

by inbred do you actually mean breeding from immediate family?

Zoo's don't do this for the same reason rat breeders shouldn't, and the same reason it's outlawed for us. Breeding from the same male and female if fine, and then breeding from their offspring from another (non-related) same breed with 'pedigree' is fine, however breeding from immediate or even up to second maybe even third removed as far as genetics are concerned is abit worrying.

Dunno how much you's know about how genetics work?

If there is a problem with the initial genetic lot (recessive genetic disease) you use first, the more you breed from it the more likely the problem will become evident and not 'recessive' as most errors are. So if one parent has a ancestoral genetic problem but the other doesn't.. 50/50 chance. breed from the son and daughter of those parents ( the kids would both be genetic carriers) and it's 60/40 recessive.. again.. 70/30.. again 80/20.. again... times up you're likely to have the health problem, once past 60/40 you are more likely to have a reduced symptom or related health problems to the genetic error, the more you breed from that strain the higher the likelyhood of the full disease being active. and it is more difficult that actually first thought to get rid of these recessive genes altogether, you may by inbreeding reduce the risk but it will always be there, you will eventually get a 'throw back'.
With Tumours, you can merely reduce the susceptibility as this is what is inhereted, the immune response mechanism.

for instance in humans, tay sachs, haemophilia, cystic fibrosis and sickle cell.

breeding for specific features, of course, can mean that predispositions to tumours and other diseases/illnesses can be bred out to be recessive. However this can cause other problems. Breeding for specific features can mean that these features become so prominant that they become themselves the problem.

inbreeding can also cause reduced efficacy of the immune system (which would increase the likelihood of resp being a problem in some rats). So to inbreed for a specific trait you could be breeding the mutations needed for other more recessive genes to come to the forefront.

a veritable gene-mine field.

What are the general effects of inbreeding


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## simplysardonic (Sep 1, 2009)

This thread's really interesting, as I've heard that quite a lot of rat breeders say line & in breeding os OK amongst rats, yet it's discouraged in most species (the problems with dogs being a fairly publicised case recently) as you say, a veritable minefield! I've only recently looked at genetics for college but its quite fascinating (heavy going though!)


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## owieprone (Nov 6, 2008)

yeah i did genetics in college, one of the best subjects we did, didn't hit on it much in uni, but i love reading stuff about it.. yes, i'm a complete science nerd. :thumbup: i'm :001_cool:

i dunno why most rat breeders say that it's ok, cos even the labs know not to do it if they need particular results.
We all know not to do it for us and what it does to dogs, horses etc why would it not do the same with rats? bit on the bizarro side of thinking for people who want the 'best'.

it's like tigers and lions.. same cat different skin (and a few other parts) common genetic ancestor, which is why they can successfully produce offspring.

dumbos are an inbreeding produced recessive-genetic-error,
thank the gods! some errors are worthy.


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## Tapir (Mar 20, 2010)

how much is it for lump removal? do you think it is always worth having it done?


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## spoiled_rat (Mar 24, 2008)

owieprone said:


> lol breeds are a genetic inperfection in themselves.


Ahh but this dosent apply to fancy rats as they are all the same breed (rattus norvegicus)

Inbreeding does not create problems itself, it just shows any bad genes up which are already there, and enables them you to work away from them, if you keep breeding unrelated rats together then you dont actually even know if your rats are carrying serious issues, and could be a ticking timebomb.

Alot of the issues you mention with humans, cannot be applied to rats either, as they dont have those issues, but if you inbreed from crap rats, then you will get a whole litter of crap out, hence why breeders should employ good selection 

I wrote this in relatively simple terms for a ratty website a while back,



> The importance of Inbreeding & Linebreeding
> 
> Breeding rats to improve them, will need a combination of breeding styles and methods, some of which are very misunderstood.
> 
> ...


More links aimed specifically at rat inbreeding here:

Inbreeding, Linebreeding & Outcrossing
Breeding Guide: Breeding Methods
Spoiled Ratten Rattery-Outcrossing, Linebreeding and Inbreeding in Rats, by Elisabeth Brooks
National Fancy Rat Society


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## SlingDash (Jul 30, 2010)

As I've never had a lump removed, I can't comment on price.

I suppose it has to be done if it's interfering with the rat's day-to-day life, but if it's small and not getting in the way of anything, if it's benign and the ratty seems happy with life in general, then I don't think it's necessary to get it removed.


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## spoiled_rat (Mar 24, 2008)

owieprone said:


> i dunno why most rat breeders say that it's ok, cos even the labs know not to do it if they need particular results.


You will find 99% of all lab strains are inbred, often 40+ generations of sibling to sibling matings in order to produce similar rats with the same pluses/negatives in order not to skew any data needed off them 

Outbred strains are no use in a lab setting.


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## simplysardonic (Sep 1, 2009)

Tapir said:


> how much is it for lump removal? do you think it is always worth having it done?


Its around £110 here, Shadow was £125 for the 1st one & £200 for the 2nd (she had 4 removed at once though)
I think its worth doing, Shadow developed a new lump just a month after her 2nd op though & if her health improves (she lost a lot of weight & condition after her 2nd op) she'll have that one removed too


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## magpie (Jan 3, 2009)

simplysardonic said:


> Its around £110 here



I think I paid just under £50 for Smokey, but even if I'd been charged full price it would only have been about £65 tops.

Personally I think yes, it's usually worth doing. Smokeys lump was on his back just by his tail so it wasn't bothering him, but I didn't want to take the chance of it getting bigger and causing him problems later.


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## simplysardonic (Sep 1, 2009)

magpie said:


> I think I paid just under £50 for Smokey, but even if I'd been charged full price it would only have been about £65 tops.
> 
> Personally I think yes, it's usually worth doing. Smokeys lump was on his back just by his tail so it wasn't bothering him, but I didn't want to take the chance of it getting bigger and causing him problems later.


I compared the vets in Norfolk to other parts of the country on a ratty forum & it seems to be normal, plus as we have no transport some vets are too out of the way even if they were cheaper


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## owieprone (Nov 6, 2008)

it was £90 up in aberdeen 6 odd years ago for a pea sized lump off Lenin.


as i said spoiled, 'particular results'. that 1%. 
Still doesn't mean inbreeding's a good thing.


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## niki87 (Nov 18, 2009)

spoiled_rat said:


> Ahh but this dosent apply to fancy rats as they are all the same breed (rattus norvegicus)
> 
> Inbreeding does not create problems itself, it just shows any bad genes up which are already there, and enables them you to work away from them, if you keep breeding unrelated rats together then you dont actually even know if your rats are carrying serious issues, and could be a ticking timebomb.
> 
> ...


Having never studied genetics....I found this FASCINATING! Thanks Laura. xx


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## spoiled_rat (Mar 24, 2008)

owieprone said:


> Still doesn't mean inbreeding's a good thing.


I work with a highly inbred line of rats aswell as rescuing/rehoming, with quite an unusual coat type in the UK, and most live in excess of 30+ months, with next to no incidence of lumps, respiratory illness, and are overall very hardy and adaptable rats, but a bit crap for showing as they are often complete with white feet.

In comparison to constantly outcrossed pet shop/byb lines who are riddled with health issues, both minor and severe and often don't make 22 months(national average between pet shop/byb/breeder origins), i think that's pretty good really 

So i'd still vote for the fact that inbreeding, when done correctly, is a damn good thing if you know what you are doing and can really push lifespans and health beyond what we expect.


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## owieprone (Nov 6, 2008)

i completely missed your massive post on the other page.. somehow! I'll warn you now though, my brain died this morning... resucitation techniques didn't work, so i may type complete ******** which i will deny all knowledge of at a later date/time 

i'm still of the opinion that inbreeding isn't a great idea. Of course, you're going to get 'bad' rats when you breed from another 'strain', while not 100% it's higher than if using rats with better-known genetics. Do you know the instance % of inbreds of other varieties being bred and causing the usual problems? Would be interesting to find out, it would obviously depend on strains but as breeding is no guarantee i wonder how often it causes problems instead of giving just the desired 'effects'?

while i understand that without it it's difficult and expensive to find out if genetic problems are within one family of rats, it's a bit of a minefield to then produce from them just to see what happens and hope for the best, then attempt to breed that problem out.

outcrossing once you've found the 'perfect' breeding pair(s) is fine but getting to that point is the bit i'm sure a few breeders don't care about (not saying ALL so don't jump down my throat anyone).

i think inbreeding to an extent is fine if it does mean we all get a better class of pet with less worries and with only the occasional unlucky throwback. the problem i have with inbreeding being the norm is how many breeders know as much as you obviously do?


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