Mammary Tumors


One of the most common forms of cancer reported in female dogs, mainly intact females, but either gender can be affected. About half of all diagnosed mammary tumors are found to be malignant. Early diagnosis and treatment produces the best outcome.  In the case of females that are not intended to be bred, spaying reduces the chances of mammary tumor development.

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Symptoms: Abnormal swelling, lumps or hard, irregular nodules in one or more breasts.  The size of these tumors may grow or shrink during and after heat cycles of intact females.  If left untreated there is increased risk for malignancy and metastatis.

Treatment Options: Surgical removal is usually the best option with biopsy and in some cases chemotherapy recommendation based on stage and malignancy of the tumor(s). Early diagnosis and treatment improves long term prognosis.

Known Mode of Inheritance: Unknown in Cardigans.  Some genetic markers have been explored with as many as 11 markers identified in association with tumors, but other factors such as hormones and environment/diet may also play a role.

Age of onset: 8-11 years, with increasing risk > age 6.

Breeds affected

  • Cardigan: yes
  • Pembroke: yes
  • Other Breeds: yes, many breeds and mixed breeds

Incidence in Cardigans: Unknown.


  • Cardigans: no
  • Other breeds: yes
  • Active?: yes

Registry: no

Tests Available: no

Research links:

Published papers and Articles:

Discussion Groups:


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