🎀 Vet-Approved Guide to Breast Cancer in Dogs and Cats (2025) 🐶🐱

By Dr Duncan Houston BVSc

Yes, pets can get breast cancer. Known medically as mammary cancer, this disease affects unspayed female dogs and cats—and often goes unnoticed until it’s advanced. In this 2025 guide, Dr Duncan Houston explains what mammary tumors are, how they’re diagnosed and treated, and why early spaying saves lives 🎗️.

🐾 What Is Mammary (Breast) Cancer in Pets?

Breast cancer in pets is also called mammary gland cancer. It arises from the same glandular tissue that produces milk during nursing 🍼. Like in humans, it can be benign (non-cancerous) or malignant (spreads to other organs).

📉 In dogs, 50% of mammary tumors are benign. In cats, more than 85% are malignant.

🎯 Who Is Most at Risk?

• 🐶 Female dogs who are not spayed and go through multiple heat cycles
• 🐱 Unspayed female cats have a higher risk than spayed cats
• 🧬 Genetics, hormones, and chronic inflammation may contribute

Spaying before the first heat cycle reduces the risk by over 90%—that’s the most powerful prevention available ✅.

🔍 Signs of Mammary Cancer in Pets

• 🦠 A lump or swelling in the mammary chain (chest to groin)
• 🔴 Ulceration or bleeding from a lump
• 🩸 Blood-tinged discharge from nipples
• 🚶‍♀️ Discomfort or difficulty walking (if tumor is large)

Some tumors are slow-growing, while others spread aggressively to lungs or lymph nodes 🧠.

🧪 How Is It Diagnosed?

1. Fine Needle Aspirate (FNA)

A small sample of cells is drawn from the mass using a needle and evaluated under a microscope 🧫. This is fast and inexpensive but may not be fully accurate.

2. Surgical Biopsy

A tissue sample is removed and sent to a pathologist. This is the gold standard for determining if a lump is cancerous (malignant) or not 🧬.

3. Imaging

• 📸 Chest X-rays to check for spread to lungs
• 🔍 Ultrasound to check abdominal organs

Tip: Early diagnosis = better outcomes 🩺.

💉 Treatment Options

1. Surgery

The primary treatment is surgical removal of the tumor. Options include:

• 🔪 Lumpectomy (removal of lump only)
• 🧵 Mastectomy (removal of one or more mammary glands)

Surgery may be curative for benign tumors and helpful for reducing spread in malignant cases.

2. Chemotherapy

• 🧬 Used if cancer has spread or surgery isn't possible
• 💊 Common drugs include doxorubicin and carboplatin

Cats are more likely to need chemotherapy due to higher malignancy rates.

3. Palliative Care

• 🩺 Pain control with anti-inflammatories or opioids
• 🍽️ Appetite stimulants if appetite declines
• 🧴 Wound care for ulcerated tumors

📊 Prognosis

Prognosis depends on tumor size, type, and how early treatment begins:

• ✅ Dogs: Small, benign tumors can be cured with surgery
• ⚠️ Cats: Malignant tumors are aggressive and often recur
• 🔁 Tumors <2 cm have significantly longer survival rates

🚫 Prevention Tips

• 🧬 Spay before first heat (typically by 6 months old)
• 🩺 Annual wellness exams to check for lumps
• 📋 Monitor for changes in previously benign masses

🐾 Lumps vs. Cancer: Know the Difference

Not all lumps are cancer—but any mammary lump should be evaluated 🧬. Biopsy or surgical removal is the only way to confirm the diagnosis and plan appropriate care.

📲 Final Advice from Dr Duncan Houston

Breast cancer awareness matters for pets too. Spaying is the best prevention, and early detection saves lives 🎗️. Don’t wait—if you find a lump, get it checked out right away.

📱 For help with diagnostics, treatment planning, or post-surgery recovery, download the Ask A Vet App or visit AskAVet.com. Together, we can protect our pets from this silent threat 🐶🐱🩺.