🩺 Multiple Myeloma in Dogs – Vet‑Led Guide 2025 🐶🩸

By Dr. Duncan Houston BVSc

Hello, I’m Dr Duncan Houston, BVSc, founder of Ask A Vet. In this 2025 guide, we delve into multiple myeloma—a rare but treatable cancer of plasma cells. We’ll cover causes, symptoms, diagnosis, first-line chemo, prognosis, and home care strategies to support your pup’s quality of life. 🐾

📘 What Is Multiple Myeloma?

Multiple myeloma is a cancer of plasma cells that develop in the bone marrow. These malignant cells overproduce monoclonal antibodies (M-component) and infiltrate multiple sites—leading to bone lesions, blood thickness (hyperviscosity), bleeding, anemia, kidney damage, and immune suppression.

It accounts for < 1% of dog cancers, typically affects older breeds like Labradors, Golden Retrievers, and German Shepherds.

🚩 Clinical Signs

• Lethargy, weakness, weight loss
• Lameness or bone pain; fractures are possible
• Bleeding issues (gums, nose, bruising)
• Excessive thirst/urination, hypercalcemia
• Eye issues: retinal hemorrhage, vision changes
• Infections due to immune suppression
• Neurological signs or organ involvement

🔬 How We Diagnose It

At least two of the following criteria are required:

1. Bone lesions on X-ray/CT (up to 65% of dogs)
2. Bone marrow plasma cells >20–25%
3. Monoclonal gammopathy in serum via electrophoresis (99% include M-component)
4. Detection of Bence‑Jones proteins in urine

Additional tests include CBC, chemistry, urinalysis, abdominal ultrasound, and coagulation profiles to assess systemic impact.

💉 Treatment Plans

1. Chemotherapy (First-Line)

• Melphalan + Prednisone: oral, daily-then-maintenance protocol, or pulse dosing
• Tolerated well; monitor CBC every 2–4 weeks
• 80–95% response; clinical improvement in 3–6 weeks; MST 18–30 months (∼540 days)

2. Rescue Protocols

At relapse, use alkylating agents (cyclophosphamide, chlorambucil, lomustine), or chemo combos (vincristine + doxorubicin), or emerging rabacfosadine (∼80% response in small study).

3. Supportive & Adjunct Therapies

• Bisphosphonates (pamidronate) for bone pain & hypercalcemia
• IV fluids for hyperviscosity or renal support
• Packed cell/platelet transfusions for bleeding
• Plasmapheresis in acute hyperviscosity (rare use)
• Pain relief: NSAIDs, opiates, supportive care
• Antibiotics to prevent infections
• Radiation therapy for focal bone pain

📅 Prognosis & What to Expect

• 92% of dogs achieve remission (complete: 43%, partial: 49%) with melphalan/prednisone
• MST ~540 days (~18 mo); some reach 2–2.5 years
• Negative prognostic factors: hypercalcemia, renal failure, extensive bone lesions, Bence‑Jones proteinuria
• Regular bloodwork tracks response, warns of relapse
• Relapse anticipated—response to rescue therapies can extend life further

🏡 Home Care & Quality‑of‑Life Support

1. Regular CBC/chem follow-ups (every 4 weeks or per vet)
2. Pain management: give medications as prescribed
3. Bone-strengthening diet & omega‑3 fatty acids
4. Comfortable environment: soft bedding, ramps
5. Hydration support—ensure available fresh water or wet foods
6. Gentle exercise—avoid fractures but maintain muscle tone
7. Monitor appetite, energy, lameness, bleeding, thirst, or urination changes

🐾 Supporting Owners & Pets

Facing cancer? Get 24/7 answers from Ask A Vet—on dosing, side effects care, or wellness. Together, we focus on comfort, connection, and hope. 💕

✨ Key Takeaways

• Multiple myeloma is treatable—chemo leads to remission in over 90% of dogs.
• Diagnosis requires ≥2 criteria: bone lesions, plasmacytosis, monoclonal proteins, or Bence‑Jones proteinuria.
• First-line melphalan + prednisone offers MST ~18 mo; relapse treatments extend lifespan further.
• Supportive care—bisphosphonates, fluids, pain relief—is vital for comfort.
• Frequent monitoring ensures early detection of relapse or complications.
• Combining clinical care with home comfort resources keeps happy days in focus.

If you suspect multiple myeloma, or have a diagnosis and treatment questions, contact your vet or Ask A Vet. We’re here with science, empathy, and your pup’s well-being at heart. 🐾❤️