Mammary Tumours is a medium-severity cancer condition that can affect dogs of all ages and breeds. Mammary tumours are among the most common tumours in intact female dogs, with approximately 50% being malignant. Early spaying significantly reduces risk. Malignant forms can metastasise to the lungs. It is documented across 1 breed, though prevalence and severity can differ significantly between them. It typically becomes apparent at 7-10 years. Early signs to watch for include palpable lump in mammary gland, ulceration or discharge from lump, rapid growth of mass, and weight loss in malignant cases. When treatment is required, costs are estimated at £1,500-£5,000 depending on severity, location, and the specific intervention needed. This page covers symptoms, treatment options, and preventive steps — along with breed-specific information where available.

Signs & Symptoms

The following symptoms are commonly associated with Mammary Tumours in dogs. If your dog displays several of these signs, consult your vet promptly — early diagnosis typically leads to better outcomes.

• Palpable lump in mammary gland
• Ulceration or discharge from lump
• Rapid growth of mass
• Weight loss in malignant cases
• Respiratory signs if lung metastasis

Treatment Overview

Surgical excision (lumpectomy, simple mastectomy, or regional chain mastectomy) is the primary treatment. Chemotherapy (doxorubicin) for high-grade malignant cases. Concurrent ovariohysterectomy may reduce recurrence.

Typical onset: 7-10 years

Prevention & Screening

While not all cases of Mammary Tumours can be prevented, the following steps reduce risk or enable earlier intervention:

• Spaying before first or second season dramatically reduces lifetime risk
• Regular mammary palpation in intact females from middle age