Life expectancy by canine cancer type — what the survival numbers mean

The short answer

Five cancers account for the majority of consultation conversations. Their median survival times — with and without treatment — are well-characterised in the veterinary oncology literature. Use the numbers as orientation; trust the dog\u2019s welfare data, not the median, for the decision.

Cancer	No treatment	Standard treatment	Comfort-focus typical
Lymphoma (multicentric)	4-8 weeks	6-12 mo (CHOP) / 1-2 yr (low-grade GI)	Nausea, weight loss, lethargy
Hemangiosarcoma (splenic)	Days-2 wk after rupture	4-6 mo (splenectomy + chemo)	Sudden collapse risk; pain mild
Osteosarcoma (limb)	1-3 mo	12 mo (amputation + chemo)	Severe pain; lameness dominant
Mast cell tumour (high-grade)	6-12 mo	Variable; depends on grade & margins	Variable; pain not always dominant
Mammary carcinoma	6-12 mo	Up to years (early stage + surgery)	Pain at primary; respiratory if mets

Median survival times. Half of dogs do better; half do worse.

Lymphoma

The most common canine cancer. Multi-centric (B-cell or T-cell) presents as enlarged lymph nodes; the dog is often well at diagnosis. CHOP chemotherapy produces remission in 70-90% of cases, median survival 8-12 months for B-cell, shorter for T-cell. Without treatment, prednisolone-only palliation gives 6-8 weeks. Low-grade GI lymphoma (in cats and dogs) is meaningfully more treatable — chlorambucil + prednisolone produces years of remission in many cases.

Hemangiosarcoma

The cancer that often presents as a sudden collapse — splenic rupture, internal haemorrhage, an emergency vet visit. Splenectomy stabilises in the short term; doxorubicin chemotherapy modestly extends survival. Median survival post-diagnosis with full treatment: 4-6 months. Without splenectomy, days to weeks. The cancer is rarely painful in the conventional sense; what owners face is the tension between an apparently well dog and a known catastrophic-rupture risk.

Osteosarcoma

The classic large-breed cancer. Limb osteosarcoma presents as lameness; the bone is structurally compromised. Amputation removes the painful primary; chemotherapy targets micrometastases. Median survival with amputation + chemo: 11-12 months. Without amputation, the pain becomes very difficult to control; survival shorter and quality-of-life poor.

The decision in OSA is often whether to put a senior large-breed dog through amputation. Many dogs adapt well to three legs, but not all. Honest assessment of pre-existing mobility limits is essential before surgery.

Mast cell tumour

The cancer with the widest variability. Low-grade MCT may be cured by surgery alone with appropriate margins. High-grade MCT behaves aggressively — surgical excision, possibly with radiation and tyrosine-kinase-inhibitor chemotherapy. Median survival ranges from years (low-grade, well-resected) to months (high-grade, metastatic). Histopathology and grading drive prognosis more than tumour location.

Mammary carcinoma

About 50% of canine mammary tumours are malignant (in cats this is much higher, ~85%). Early-stage tumours managed by chain mastectomy have excellent long-term prognosis. Late-stage tumours metastasise to the lungs; survival 6-12 months once metastatic.

What the numbers mean (and what they don\u2019t)

The five things to keep in mind when reading any survival statistic:

Medians describe populations, not your dog. Half of dogs in the study lived longer than the median; half lived shorter. Your dog will land somewhere on that distribution; we cannot tell you where in advance.
Studies have eligibility criteria. A dog enrolled in a CHOP trial is, by definition, well enough to start CHOP. A dog who is not eligible for the study (older, comorbid, frail) has different prognoses than the study\u2019s median.
Survival is not the same as quality of life. An extra three months of comfortable life is meaningfully different from an extra three months of nausea, hospital visits, and disengagement.
The standard of care evolves. Numbers from a paper published in 2018 may understate current outcomes. Numbers from a 2024 protocol-introduction study may overstate them.
The right treatment decision is not the one with the highest median survival. It is the one that gives your specific dog the most days that are good days.

Common questions

How accurate are these survival numbers?

They are medians from veterinary oncology literature, which means half of dogs do better and half do worse. Your dog is one specific dog, not a median. The numbers are useful for orientation, not prediction.

Should I treat or palliate?

Depends on the cancer type, the stage, your dog’s baseline health, and what quality-of-life-during-treatment looks like. The honest question for any treatment decision is: how much of this time is actually good time? An extra three months of nausea is not the same as an extra three months of comfort.

What about CBD, mushroom extracts, and other supplements?

The data is, with current evidence, weak for most. Some specific supplements (Yunnan Baiyao for hemangiosarcoma bleeding control; turmeric / curcumin in some adjunct contexts) have modest support. Most over-the-counter cancer supplements have not been shown to extend survival.

When do most owners decide to euthanise?

When pain is no longer controlled despite multimodal analgesia, or when the dog has clearly disengaged from their own life. The threshold is welfare, not survival.

Editorial reference, not veterinary advice. — Dr. NRS, last reviewed 27 April 2026.