PetXmark is a liquid fiducial marker being developed to guide stereotactic radiosurgery treatment in pets with skin and subcutaneous cancers .
Cancer in pets
According to The Veterinary Cancer Society, an estimated 6 million dogs are diagnosed with cancer in the US every year. Cancer is the leading cause of death in 47% of dogs, especially dogs over age ten, and 32% of cats.
There are nearly 100 types of animal cancer. Cancer in pets can be found in the skin, bones, breast, head & neck, lymph system, abdomen and testicles. Approximately one-third of all tumors in dogs are skin tumors, and up to twenty percent of those are mast cell tumors. The most common location to find mast cell tumors is in the skin, followed by the spleen, liver, and bone marrow.
Approximately half of all skin tumors are found on the body, another forty percent on the limbs (most frequently the hind limbs), and the remainder on the head or neck.
Stereotactic radiosurgery for pets
Stereotactic radiosurgery, also known as SRS, is a noninvasive, nonsurgical treatment in which high doses of precisely focused radiation are delivered to destroy the tumor.
The pet is treated with a high dose of radiation that destroys tumor cells with minimal damage to nearby healthy tissue. This advanced form of radiation therapy is delivered in just 1-to-3 treatments, representing an 80-95% reduction in both treatment sessions and anesthetic events compared to traditional forms of radiation therapy. While SRS is widely accepted and available for treating cancer in people, this advanced technology has not been nearly as accessible to pets with cancer.
PetXmark guiding stereotactic radiosurgery
PetXmark is intended to guide stereotactic radiosurgery treatment of skin and subcutaneous cancers in pets. PetXmark is injected along the surgical incision and provide visibility of target in later medical imaging. Without PetXmark it is difficult to see the target and therefore not possible to provide the SRS treatment.
The traditional dogma in veterinary radiation therapy has held that SRS fractionation is not possible unless there is gross residual disease to target. In cases where patients have had their tumor resected down to microscopic residual disease, as in the case with most skin cancers, and where radiotherapy is considered necessary to achieve adequate local tumor control, the current recommendation would be to initiate a course of conventionally fractionated radiation therapy consisting of approx. 20 treatment fractions.
PetXmark is currently being tested in the clinic for guiding a single fraction treatment approach for skin and subcutaneous cancers. A successful outcome of this study would reduce the treatment visits for pet-owners from 20 to 1, minimizing the burden of radiotherapy in pets considerably.