Experimental Canine Cancer Treatment May Be Successful in Humans

Researchers are beginning to make progress treating oral melanoma in canines, which may translate to beneficial therapies for humans. This combination treatment that targets melanoma cells is now being explored in clinical trials.

The investigators first explored treating mouse models with cancer through nanoparticle hyperthermia, where non-toxic iron oxide nanoparticles are injected into tumors, before applying a non-toxic magnetic field to excite the nanoparticles, according to a press release from the Dartmouth-Hitchcock Norris Cotton Cancer Center.

The Dartmouth investigators found that the cancer cells were killed through the heat, and this method also stimulated the immune system to target these cells.

Building on this process, the team next explored whether these findings could be used to advance standard cancer treatments, such as radiation.

A technique called hypofractionated radiation, which involves fewer but larger doses, could cut down treatment times while remaining effective. Even though hypofractionated radiation can kill cancer cells and improve immune response, adding more immune stimulation techniques was deemed necessary, according to the press release.

After the strategy was successful in mouse models, the researchers tested this treatment in 2 canines with naturally occurring cancers, and would have been administered standard treatment.

“Dogs have been shown to develop the same types and have the same cancer incidences as humans,” said researcher P. Jack Hoopes, DVM, PhD. “They are also exposed to the same carcinogenic environmental elements that humans are, such as second-hand smoke and pesticides, which makes them highly translatable to humans and valuable participants in cancer research”

In the first case, the investigators treated a Schnauzer referred by her veterinarian due to recurrent cancer. The canine was successfully treated with radiation and magnetic nanoparticle hyperthermia, but a secondary carcinoma was developed on a toe pad, according to the release.

Typically, the canine’s entire leg would be amputated, but the researchers treated the tumor with a combination of hypofractionated radiation, magnetic nanoparticle hyperthermia, and immunogenic plant virus nanoparticles. The treatment killed the cancer cells, and the canine was in remission with a functional foot.

In the second case, the team tested all 3 treatments in a canine named Clancey, who was diagnosed with aggressive oral melanoma.

The standard treatment would remove part of the canine’s jaw, followed by daily radiation, and a melanoma vaccine with limited efficacy. The total cost for the treatment would have been more than $30,000, the canine’s owner reported.

In the study, the canine received 6 localized radiation treatments, 2 nanoparticle heating treatments, and 2 injections of the immunogenic viral-like particle into the treatment. The investigators noticed a swollen lymph node, which typically indicated metastasis, but was a collection of immune cells.

“The enlarged lymph node was produced as a result of the combined radiation and injected nanoparticle therapies, which we believe stimulated Clancey’s immune system to kill off residual cancerous cells,” Dr Hoopes said.

The canine has remained in remission for 14 months, and has been eating and acting normally since treatment, according to the release.

The investigators believe these findings suggest this treatment approach may be successful in humans. They are continuing their studies through sequencing human and canine cancers to determine if similarities exist.

The researchers plan to further collaborate with the veterinary community to make this a possibility. Not only will this lead to improved care for canine patients, but it may also help human patients with cancer in the future, the press release concluded.