Monday, June 2, 2014

Strontium 90 – An old modality brings new treatment options to the VCC

Recently the Veterinary Cancer Center added to their armamentarium in the fight against  cancer with a Strontium-90 superficial probe. A Strontium -90 probe is a radioactive probe that can be placed against a tumor to deliver high doses of radiation.  The benefit of this probe is that it emits very low energy radiation, so the radiation only penetrates 2-4 mm into the patient (about the thickness of two quarters).  This means that for small, superficial tumors we can deliver a very large dose to the tumor and surrounding skin, with little to no risk of long term side effects.  Most patients develop a scab in the area after treatment, which resolves over 4-6 weeks, then the area will remain hairless.  Significant long-term side effects are very rare.
Strontium – 90 probes have been used to treat small superficial tumors, including mast cell tumors in cats, solar induced squamous cell carcinomas in cats, small mast cell tumors in some dogs like pugs.  It may be beneficial in palliative treatment of squamous cell carcinoma under the tongue in cats.  It is great for treating pets with multiple tumors, because each treatment is usually less than ten minutes, and requires only a short anesthesia.  For pets with multiple tumors it allows us to treat all of their tumors in one, shorter anesthesia.  Also, it can be very helpful for treating eyelid tumors or corneal tumors, which are often very difficult to remove with surgery.
If your pet has a small tumor and you think they may be a candidate for strontium therapy contact your local veterinarian to see if the tumor might be treated with this option.

Image 1 – Close up of the strontium probe.  The radioactive Strontium is in the small metal cylinder at the tip and this is what is placed against the patient’s tumor.
Image 2 typical appearance of the local site after strontium – 90 treatment.  Hair loss and depigmentation are usually the only side effects that occur long term