Causes
A clear hormonal influence: females that are unneutered, or neutered late, have a much higher risk. Early neutering dramatically reduces the risk.
Diagnosis
Physical examination plus fine-needle aspiration or biopsy. Staging tests (chest, lymph nodes) because they can metastasise.
Treatment
Surgery to remove the tumours. Depending on the biopsy result and the extent of spread, further treatment may be added. Early detection, with small tumours, greatly improves the prognosis.
Prevention
EARLY NEUTERING is the most effective preventive measure: it hugely reduces the risk. Check the mammary chain regularly in entire females.

