Your dog is suspected of having a disease called splenic haemangiosarcoma (HSA). It is a form of cancer. This disease occurs in older dogs, often larger breeds, and can be insidious or dramatic in its presentation. The growth, or tumour, occurs in the spleen quite commonly because it is a growth of blood vessels, and the spleen is largely made up of this tissue. However, because there are blood vessels throughout the body, the tumour can occur anywhere

There are a number of important steps to be taken in dealing with this disease

Firstly, it is important for us to assess where in the body the cancer is present. Abdominal ultrasound is the best way of assessing the abdomen, both to look at the spleen itself, but also to check the rest of the abdomen, particularly the liver and lymph nodes, for signs of disease spread. We also will recommend ultrasound examination of the heart, as up to 10- 25% of dogs with a splenic HSA will also have a tumour growing on the heart itself. Chest X-rays will allow us to look for secondary spread (known as metastasis) into the lungs. A blood count and metabolic function tests are also vital in assessing a patient’s ability to cope with the planned treatment.

Surgical removal of the spleen is usually the next step. This has a twofold role, both in removing the primary disease, and also in confirming the identity of the tumour. This confirmation is vital, as around 1/3 of splenic tumours are the less aggressive haemangioma or another benign process, and these cases carry a much brighter outlook and usually require no further treatment. Of the remaining 2/3, around 60-70% of these are HSA, the other 30-40% being other malignant (cancerous) diseases. Often the patient presents with a bleeding tumour, so removal of the whole organ also allows us to control further blood loss (dogs can cope very well without a spleen.)

If a malignant disease is confirmed, then chemotherapy is likely to be recommended to improve the outlook for the patient. Chemotherapy can significantly extend the life expectancy of a dog with HSA (or other splenic cancers), and protocols have been designed to avoid the side-effects commonly associated with chemotherapy in humans. The most commonly used protocol (and the one we recommend) uses a single drug called doxorubicin, injected every 3 weeks, for 4-5 cycles. Careful monitoring of the patient’s blood is important during treatment with any chemotherapy, so blood counts are checked before each treatment, and also when the blood count is likely to be at its lowest, to ensure the dog does not become sick. (Other multi-drug protocols are available if response is poor, but the possibility of side effects does increase as more drugs are used.

Following successful treatment, patients will be regularly monitored for any signs of recurrence of disease, involving a thorough physical examination at 1, 3, 6 and 12 months after treatment.

The outlook for dogs undergoing no treatment (ie no surgery to remove the spleen) is very poor: these dogs are very sick, and will usually die quickly without treatment.

Dogs undergoing surgery alone, where the disease is confirmed as HSA, live for an average of around 2-3 months beyond their diagnosis.

Dogs undergoing chemotherapy follow-up treatment after surgery live for an average of 6 – 9 months beyond their diagnosis, i.e. 50% of dogs live beyond this time.

Dogs with a tumour around their heart will often respond well to chemotherapy, although the best treatment is surgical removal: this clearly is a much greater task than removing a spleen. If an owner wished to proceed with this treatment, referral to a specialist surgeon would be recommended.

Dogs with metastasis to other organs (such as liver, lungs and brain) do not do as well, but can also respond favourably to chemotherapy.

In summary:

  • Splenic tumours are more often than not cancerous
  • Removal of the tumour is usually the core of the treatment, but in cases of HSA, combination with chemotherapy gives the best outlook
  • Full assessment of the patient before surgery allows an owner the chance to decide if they wish to go ahead with treatment, particularly if large scale spread has already occurred, decreasing our chances of a successful outcome
  • Chemotherapy is significantly helpful in prolonging the quality of life of these patients.

If you have any questions, please contact your local Vets4Pets practice.

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