Prevalence
Up to 7% of all canine cancers. Most common in middle-aged to older Golden Retrievers (lifetime risk ~1 in 5), German Shepherds, Labradors.
Who gets it
Older large-breed dogs. Goldens have a uniquely high lifetime incidence — a current focus of the Morris Animal Foundation Golden Retriever Lifetime Study.
Symptoms to watch for
- Sudden collapse, pale gums, weakness (rupture of splenic mass)
- Lethargy, decreased appetite
- Distended abdomen
- Exercise intolerance, irregular heartbeat (cardiac form)
- Bruising or skin nodules (cutaneous form, often more indolent)
How it's diagnosed
- Abdominal ultrasound + chest radiographs
- Echocardiogram if cardiac form suspected
- Splenectomy with histopathology — required for definitive diagnosis
- Staging CT (chest + abdomen) to assess metastasis
- Optional: liquid biopsy (Nu.Q canine cancer test) for early detection
Prognosis ranges
Splenic HSA: surgery alone median 1–3 months; surgery + doxorubicin median 5–7 months. Cardiac HSA: poorer, often weeks. Cutaneous (dermal-only) form has much better prognosis (often >2 years with surgery).
Treatment landscape
Recurrent mutations in this cancer
Frequencies from canine clinico-genomic cohorts. SciRouter Oncology auto-checks every mutation in your dog's report against the OncoKB-aligned database for matched targeted therapies.
Questions to ask your vet
- Is this splenic, cardiac, or cutaneous? Does it matter for prognosis?
- What did the staging CT show?
- What's the realistic survival window with vs without chemo?
- Are we considering metronomic or conventional chemo?
- What are the warning signs of a bleeding event at home?
- Is the FidoCure HSA cohort study still enrolling for analysis?
Quality-of-life notes
Many HSA dogs feel quite normal until the day they collapse. Owners should be educated on bleeding signs (pale gums, lethargy, distended belly) so they can act quickly.