Haemangiosarcoma: What UK Vet Records Show About Survival
In UK first-opinion practice, nearly half of dogs diagnosed with haemangiosarcoma died on the day of diagnosis. Skin tumours did far better.
Written by thecanineledger
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If your dog suddenly collapses, has pale gums, a swelling belly or fast breathing, treat it as an emergency and go to a vet now.
Our note: This advice is ours. The study reports signs at diagnosis but gives no owner advice.
→ Emergency Signs in Dogs: When to Go Now, Not Tomorrow
In UK vet records from 2019, 381 of 788 dogs diagnosed with haemangiosarcoma, 48.3%, did not survive the day of diagnosis (Taylor et al., PLoS One 2025). Across all dogs, the median survival was 9 days.
While the outlook was poor overall, it varied a great deal with where the tumour was. Dogs with a tumour in the skin lived a median of 119 days. The authors also ask whether the tumour’s grim reputation is itself shortening lives.
→ A Mass on the Spleen: Why “Two-Thirds Are Cancer” Is Out of Date
1. The study
The dogs. Researchers used VetCompass, a database of anonymised UK primary-care records, covering 2.2 million dogs. They found 788 new cases in 2019. The median age at diagnosis was 10.6 years.
Where the tumours were. The spleen was most common (62.1%), then the liver (25.1%) and the skin (18.5%). Some dogs had more than one site.
Funding. An animal health charity funded the work. One author works for that charity, and the charity’s grant funds two others.
2. How long dogs lived
| Tumour site | Median survival from diagnosis |
|---|---|
| Any site | 9 days |
| Spleen | 4 days |
| Heart | 0 days |
| Liver | 0 days |
| Skin | 119 days |
One year on. About 12% of all dogs were alive a year after diagnosis. For skin tumours it was 35%.
Confirmed cases lived longer. Only about a third of dogs had a tissue sample confirm the diagnosis. In those dogs, median survival was 105 days.
Most deaths were euthanasia. Where the records said how a dog died, 92.3% were put to sleep.
Our note: The authors suggest sicker dogs were less likely to have a biopsy, which could explain why confirmed cases lived longer. We haven’t checked this.
3. What the authors think is going on
A self-fulfilling prophecy? The authors write that a common view of “extremely poor prognosis” may lead to frequent euthanasia at diagnosis. They say this could create “a self-fulfilling prophecy and short survival times.”
Sick on arrival. They also note that many dogs arrived with severe signs, and few had chemotherapy (5.3%). About a third had surgery, most often removal of the spleen.
What helped, after day one. Among dogs that lived at least a day, skin tumours and any surgery were linked to a lower risk of death. Bigger tumours were linked to a higher risk.
Our note: The study links referral to fewer deaths on day one, but that doesn’t show referral caused it. You can ask your vet about referral or a biopsy.
→ How to Know When It’s Time to Say Goodbye
4. What the study can’t tell you
Not every case was confirmed. Two-thirds of dogs had no biopsy. Some may have had a different, or benign, condition.
Stage wasn’t recorded. Tumour spread was noted in only about a fifth of records, so stage couldn’t be analysed.
Some figures don’t add up. The paper says dogs that had surgery or medical treatment were “more than 25 times more likely to die on day of diagnosis”. That runs against its other findings and reads as a reversed result. It also gives 146 skin cases in one place and 162 in another.
Our note: We describe the reversed odds ratio as printed. Check the published version if you need the exact figure.
5. What we could not verify
| Commonly said | What we found |
|---|---|
| “Haemangiosarcoma is always fatal within days” | Not always. Median survival was 9 days overall, but 119 days for skin tumours. |
| “Surgery doesn’t help” | Not shown. Surgery was linked to lower risk after day one, though this isn’t proof. |
| “Every bleeding spleen is haemangiosarcoma” | No. The authors note that not all bleeding spleens are malignant. |
Sources
- Taylor C, Barry GJ, O’Neill DG, Guillén A, Price PP, Labadie J, Brodbelt DC. Survival time and prognostic factors in dogs clinically diagnosed with haemangiosarcoma in UK first opinion practice. PLoS One 2025: VetCompass study, 2019, 788 dogs. Funded by an animal health charity that employs one author
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