Page 11 - Clinical Connections - Summer 2023
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Research News






        THE EPIDEMIOLOGY OF                 MAMMARY TUMOURS IN                  ENGLISH COCKER
        BOXER DOGS                          FEMALE CATS                         SPANIELS – HEALTH AND
                                                                                TEMPERAMENT
        RVC VetCompass has undertaken the   An  RVC  VetCompass  study  can  help
        largest  ever  study  on  boxer  dogs  using   veterinary surgeons identify cats at greater   RVC VetCompass research has shown that
        veterinary clinical records. The study drew   risk of mammary tumours and better   dental  disease,  ear  infection,  obesity  and
        on a random sample of 3,219 boxers   advise  on  management  and  survival  after   aggression are among the most common
        (0.96%)  from  an  overall  population  of   diagnosis. Mammary tumours in cats are   problems  diagnosed  in  English  cocker
        336,865 UK dogs of all breeds under first   uncommon but can be highly aggressive   spaniels.
        opinion veterinary care during 2016.   when they do occur.               The  English  cocker  spaniel  has  long
          The results will help both owners and   The study aimed to report the clinical   been a popular family dog breed in the UK
        vets provide breed-focused preventative   signs and estimate the incidence and risk   and is generally considered fairly healthy.
        healthcare as well as help anyone thinking   factors  for  mammary  tumours  in  female   However,  there  has  been  relatively  little
        of getting a boxer to know what to expect.   cats  attending  UK  primary  care  practices.   information until now on the overall health
          There has been concern about the impact   The  study  included  259,869  cats  under   of the breed.
        of  their  brachycephalic  (flat-faced)  status   veterinary care in 2016.   The RVC team examined the records
        on health risks and that boxers with white   Key findings included:       of 10,313 English cocker spaniels from an
        coats may have a higher risk of deafness   •  The average age at diagnosis for   overall sample of 336,865 dogs of all breeds
        from birth. However, there has been limited   mammary tumours was 12.0 years  under first opinion veterinary care. It was the
        evidence on the overall health status of the   •  The proportion of cats diagnosed with   largest study ever carried out on the health
        breed, which the study sought to redress.   a mammary tumour in 2016 was 0.1%   of the breed based on veterinary clinical
          The most common colours of the dogs   •  The  most  common  clinical  signs  of   records.
        were brindle (23%) and dark red (23%) with   mammary tumours in female cats   The average adult bodyweight was 15.05
        11% being white. Despite previous concerns,   were ulceration in the mammary region   kg, which makes this breed an often ideal
        there was little evidence of comparatively   (18%),  weight  loss  (17%),  hard  mass   size as a family pet. Males were generally
        elevated health risks or shortened life spans   (16%),  loss  of  appetite  (10%)  and   heavier  than  females  (16.14  kg  vs  13.80
        of white boxers. However, low levels of   discharge from the mammary region   kg respectively). The average lifespan was
        information on deafness in clinical records   (7%)                      11.44 years, which is close to the typical
        and the possibility that some deaf dogs were   •  Purebred  cats  were  1.6  times  more   lifespan  of  11.2  years  previously  reported
        euthanised at an early age did not enable   likely to be diagnosed with mammary   across  all  dog  breeds  in  the  UK.  Female
        definitive conclusions on deafness.    tumours than crossbred cats.     English  cocker  spaniels  lived  longer
          The  average  lifespan was 10.5  years   •  Older age was significantly associated   than  males  (12.01  years  vs  11.00  years
                                               with  the  diagnosis.  Cats  aged  8-11
        –  similar  to  many  other  breeds  of  this   Mammary tumours in female cats  respectively).
        body size. Although many of the common   years were  2.5 and cats  ages  11-15   Periodontal  disease  was  diagnosed  in
        disorders of boxers were typical problems   Mammary tumours in cats are uncommon but can be   20.97%  of  dogs  each  year,  otitis  externa
                                               years were 5.1 times more likely to be
                                              highly aggressive when they do happen. Survival time
                                              from diagnosis has been previously reported at 8 to
        of  dogs  overall,  there  were  some  specific   12 months after diagnosis. Previous research using   (10.09%), obesity/overweight (9.88%), anal
                                               diagnosed than cats aged 5 to 8 years
                                              veterinary referral data suggested that breed, age and
                                              neuter status were associated with the risk of cats
        areas where health risks substantially higher   •  Average survival after mammary   sac  impaction  (8.07%),  diarrhoea  (4.87%)
                                              developing mammary tumours.
        in boxers, such as eye ulcers, masses on   This study aimed to report the clinical signs and estimate   and aggression (4.01%). The frequency of
                                               tumour diagnosis was 18.7 months
                                              the incidence and risk factors for mammary tumours in
                                              the wider population of female cats attending primary
        the gums and cancer in general.       care practices in the UK. The study included 259,869   each disorder was generally higher than the
                                              female cats under veterinary care in 2016.
          The  most  commonly  recorded  specific          Proportion           general  dog  population,  possibly  because
                                               Proportion of cats with
                                                           of diagnoses
        disorders of boxers included otitis externa   mammary tumour diagnosed   histopathology  Average age at diagnosis   a number of them are related to the longer
                                                           that included
                                                 in 2016
                                                                    for mammary tumours
        (7.15%,  epulis  (5.84%)  corneal  ulceration                           ears  and  lips  and  generally  looser  skin  of
        (5.00%), periodontal disease (4.63%), heart   0.1%   19.3%  12 years    English cockers.
                                                 (270 cases
        murmur (4.29%) and skin mass (4.29%).   from 259,869 cats)  (52/270)  (interquartile range:   Aggression was more common in males
                                                                      8.5-14.0)
          The  most  commonly  reported  overall                                than  females,  and  in single-coloured
        groups of disorders were skin disorders                                 than  multi-coloured  dogs.  Aggression
        (17.74%),  neoplasia  (tumours/cancers)   Clinical signs of mammary tumours   risk varied widely between  the four most
        (14.20%)  and  ear  disorders  (10.41%).   Cats generally presented with multiple clinical signs.   common  single-coloured  coat  colours.
        The most common causes of death were          The 5 most common clincal signs  Discharge   Golden-coloured dogs showed the highest
                                                                        from the
        neoplasia (12.43%), brain disorders (9.54%)   Ulceration    of mammary tumours   mammary   frequency of aggression (12.08%), followed
                                                in the
                                                         in female cats were:
                                              mammary region             region
        and mass lesions (8.38%).                (18%)               Loss   (7%)  by  red  (6.52%),  black  (6.29%),  and  liver
                                                                     of
                                                                    appetite
                                                       Weight   Hard   (10%)    (4.33%).
                                                        loss   mass
                                                        (17%)  (16%)
            Research paper: O’Neill et al. (2023)
            ‘Demography, common disorders and mortality of
        Boxer dogs under primary veterinary care in the UK’,   Risk factors for mammary tumour diagnosis  Research paper: Engdahl et al.. (2023)
        Canine Genetics and Medicine            Research paper: Pickard Price et al. (2023)     ‘Demography and disorders of English Cocker
                                                ‘Epidemiology and risk factors for mammary   Spaniels under primary veterinary care in the UK’,
                                            tumours in female cats’, Journal of Small Animal   Canine Medicine and Genetics
                                                           11 to <15
                                                5
                                                           years
                                            Practice
                                                4  (compared to cats
                                              Relative risk of mammary tumour diagnosis  TIMES INCREASED RISK  3 2  8 to <11  years  to crossbred         Summer 2023   11
                                                    Age
                                                   5 to <8 years)
                                                                  15+
                                                                        Breed
                                                                        (compared
                                                     years
                                                                         cats)
                                                1                       Purebred
                                               65% of cases did not undergo
                                               surgery. Of those that did receive
                                              surgery, the most common types   The average survival time after
                                               were tumour/mass local removal   mammary tumour diagnosis was
                                                (23%), followed by unilateral   18.7 months.
                                               mastectomy (11%) and bilateral
                                                  mastectomy (2%).
                                                           Conclusions
                                                         Survival after diagnosis   The study can help
                                              Older age and purebred   was longer than previously   veterinary surgeons
                                              status were significantly   reported and may reflect the   identify cats at greater risk of
                                              associated with mammary   reality of primary-care cancer   mammary tumour and advise
                                               tumour diagnosis.   compared to referral centre   on survival after diagnosis.
                                                         and insurance based
                                                           studies.
                                                      CLICK TO READ THE FULL STUDY
                                                  Pickard Price, P. et al. (2023) “Epidemiology and Risk Factors for Mammary Tumours in female cats”
                                             RVC VetCompass https://www.rvc.ac.uk/vetcompass carries out welfare research based on anonymised clinical information shared from over 30%
                                              of UK veterinary practices. We are very grateful to the owners and veterinary professionals who contribute to VetCompass research.
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