Cancer

Cancer in Rabbits

The 80% study is from one colony in 1958. New evidence shows it's much much less likely, and highly tied to genetics

gleaned from these looks like the initial 1950's study was based in ONE herd and in latter studies instances were all less then 40% total occurrence of cancer . And that included all forms of tumors present at time of death. And the numbers were rabbits who died WITH lesions. Not rabbits that died FROM lesions. its grievously dishonest to claim an 80% chance of specifically uterine cancer , when uterine cancer conservatively was14%. And mostly occurred in rabbits older then 6 years.

There are multiple studies and opinions now arguing against spaying female rabbits.

"In my practice, for all 53 entire does presented for which we had both an age at death and an entry in the clinical records about the death, age at death averaged 4.9±2.9 years (median 5.0 years). Of the 61 entire does older than six months that were examined at or within a few days before death, only three (ages 5.5, >6, and 7.2 years) had evidence of caudal or midabdominal tumours – each euthanased because of the tumours. For one case, ultrasonography indicated the tumour was uterine, the others were palpated only. For one additional rabbit (6.8 years) the vet queried whether she was palpating an abdominal mass or the caecum. No currently living does have evidence of abdominal masses. These ‘messy’ first-opinion data indicate that (i) only 10 to 13 per cent of entire does of 5.0 years or older had a clinically detectable abdominal mass consistent with a uterine tumour at the time of death, and (ii) if my practice had spayed these 61 does when young, we would have prevented uterine tumours in only three, possibly four (five to six per cent), of them. In other words, to prevent one case of uterine cancer we would have to spay 16 to 20 does. As Bradbury and Dickens emphasise, spaying has welfare costs and health risks. The anaesthetic-related death rate of healthy rabbits within 48 hours is 0.73 per cent (Brodbelt and others 2008) and rabbits can have longer-term morbidity and mortality as a result of adhesions – our practice has lost a rabbit to caudal abdominal adhesions strangulating the colon. At what number of young rabbit spays does the welfare cost equal the benefit of preventing one uterine tumour in an older doe? There are other reasons to spay rabbits, but after consideration, my policy is to discourage spaying of does, whether kept singly, with other females, or with neutered or entire males (in which case I encourage castration), unless there is a specific indication to do so." -Martin L. Whitehead, Chipping Norton Veterinary Hospital.

Whitehead is referencing "Should we advocate neutering for all pet rabbits?" By AG Bradbury, GJE Dickens, Veterinary Record, 2016.

https://www.tesble.com/10.1136/vr.j826 Letters rabbit heath Neutering of pet rabbits BRADBURY and Dickens (VR, December 24/31, 2016, vol 179, pp 654-655) question whether vets should advocate neutering all pet rabbits and conclude that that recommendation may not be optimal for the welfare of single-housed rabbits. Saunders and Stidworthy of the Rabbit Welfare Association and Fund (RWAF) and British Veterinary Zoological Society (BVZS), disagree (VR, January 21, 2017, vol 180, p 77). For does, a large part of Saunders and Stidworthy’s argument is that, although uterine adenocarcinomas may not be as common in pet rabbits as historically believed (Whitehead 2015), they are nevertheless not rare, and spaying females prevents these tumours. Here, I argue that these tumours may be sufficiently uncommon that it is not clear that the health and welfare costs associated with spaying the number of rabbits needed to prevent a single case of uterine adenocarcinoma are justified. Three retrospective studies provide information on age of occurrence of uterine adenocarcinomas in pet rabbits. Saito and others (2002) reported on 47 rabbit laparotomies for uterine disease over 2.5 years, finding 10 adenocarcinomas and five adenomas (six cases/year). Walter and others (2010) reported on 59 rabbits with uterine disease over seven years, of which 29 had adenocarcinoma and one adenoma (4.3 cases/year). Kunzel and others (2015) found 27 adenocarcinomas and two adenomas in 50 pet rabbits with histopathological uterine changes over 6.3 years (4.6 cases/year). The mean age of the adenocarcinoma/adenoma cases was 5.0, 6.1 and 5.6 years, respectively. Some of the tumours were incidental findings. These studies do not indicate the incidence or prevalence of adenocarcinomas in the rabbit population, because the size of the populations the samples came from are unknown, although 4.3 to six tumours per year suggests that these tumours are neither rare nor very common. Ruelokke and others (2014) examined 33 pet rabbits over 42 months old and found a 24.4 per cent prevalence of firm uterine masses, all in rabbits over 60 months, with all three rabbits over 96 months having a palpable uterine mass. How many rabbits live to be five or more? In the Netherlands, average lifespan was 4.2 years (Schepers and others 2009). Craven and others (2016) reported a median age at death of rabbits in UK first-opinion practices in 2013 of four years (interquartile range: 1.9 to 6.7 years), with 39 per cent of rabbits living beyond five years. A small proportion of rabbits – less than five per cent of those presented to my practice – live to be 10 or more (Lennox 2010) and it is possible that rabbits that present to veterinary practices live longer on average than those that do not. The proportion of entire does living long enough to be at high risk of uterine tumours may be relatively small. In my practice, for all 53 entire does presented for which we had both an age at death and an entry in the clinical records about the death, age at death averaged 4.9±2.9 years (median 5.0 years). Of the 61 entire does older than six months that were examined at or within a few days before death, only three (ages 5.5, >6, and 7.2 years) had evidence of caudal or midabdominal tumours – each euthanased because of the tumours. For one case, ultrasonography indicated the tumour was uterine, the others were palpated only. For one additional rabbit (6.8 years) the vet queried whether she was palpating an abdominal mass or the caecum. No currently living does have evidence of abdominal masses. These ‘messy’ first-opinion data indicate that (i) only 10 to 13 per cent of entire does of 5.0 years or older had a clinically detectable abdominal mass consistent with a uterine tumour at the time of death, and (ii) if my practice had spayed these 61 does when young, we would have prevented uterine tumours in only three, possibly four (five to six per cent), of them. In other words, to prevent one case of uterine cancer we would have to spay 16 to 20 does. As Bradbury and Dickens emphasise, spaying has welfare costs and health risks. The anaesthetic-related death rate of healthy rabbits within 48 hours is 0.73 per cent (Brodbelt and others 2008) and rabbits can have longer-term morbidity and mortality as a result of adhesions – our practice has lost a rabbit to caudal abdominal adhesions strangulating the colon. At what number of young rabbit spays does the welfare cost equal the benefit of preventing one uterine tumour in an older doe? There are other reasons to spay rabbits, but after consideration, my policy is to discourage spaying of does, whether kept singly, with other females, or with neutered or entire males (in which case I encourage castration), unless there is a specific indication to do so. My future policy is contingent on better evidence. It took me about five hours to search our practice management system for deceased entire does, determine their age at death and whether there was any evidence of abdominal tumours in the period leading up to death. If the RWAF and BVZS could arrange for perhaps 20 other practices to do the same, that would constitute an empirically useful, if scientifically imperfect, estimate of number-needed-tospay to prevent one case of uterine tumour, to inform policy regarding whether to neuter does. Martin L. Whitehead, Chipping Norton Veterinary Hospital, Banbury Road, Chipping Norton, Oxon OX7 5SY e-mail: martincnvets@gmail.com

A January 2022 study found only 9% adenocarcinoma present in their sample. Thier main findings were cystic endometrial hyperplasia. They acknowledge the study limitations.... and do not account for rabbits lacking a steady estrus cycle, therefore the endometrial lining would remain thickened on histology findings. https://www.sciencedirect.com/science/article/pii/S1557506322000015 cystic endometrial hyperplasia is not cancer, it's simply the endometrial lining being thick and proliferating cells... which would be normal given that rabbits are induced ovulators and their uterus needs to be in a constant state of conception readiness. The findings in this study are concurrent with the logic from Martin Whitehead's policy on not spaying, as you'd have to spay 20 young rabbits to prevent 1 case of adenocarcinoma in an older doe. Given the risks from anesthesia, both on the table and post surgical anesthesia induced GI stasis, post operative abdominal adhesions. The risk to benefit ratio weighs much higher on risk to female rabbits being spayed.

Neoplasia and Tumor-Like Lesions in Pet Rabbits ( Oryctolagus cuniculus): A Retrospective Analysis of Cases Between 1995 and 2019 Christof A Bertram 1, Beate Bertram 1, Alexander Bartel 1, Anja Ewringmann 2, Marco A Fragoso-Garcia 1, Nancy A Erickson 1, Kerstin Müller 1, Robert Klopfleisch 1 Affiliations expand PMID: 33213301 DOI: 10.1177/0300985820973460

Types of Cancer

Kidney cancer looks like bumps of cauliflower coming out of the kidney.

Tumors

https://journals.sagepub.com/doi/10.1177/0300985820973460