'Unusual' Cancer: Male Dogs More Susceptible To Nose, Mouth Tumors Than Females, Study Finds

Male dogs are much more likely to get a form of cancer in their nose and mouth than female dogs, a new study has found. This may be because of a habit that's more common in males.

Canine transmissible venereal tumor (CTVT) is an unusual type of cancer that affects dogs. It can spread through "direct transfer of living cancer cells" during mating, according to the authors of a new paper, published in the journal Veterinary Record.

While the cancer is often associated with tumors in the genital area, which affects both male and female dogs equally, there are instances when it manifests in areas such as the skin, nose and mouth, the University of Cambridge noted in a news release.

"Variation in the prevalence of oronasal CTVT between the sexes has not been systematically examined; however, there is reason to suspect that there might be sex-linked variation in risk," the researchers wrote.

For their study, the researchers looked at 1,916 records of dogs with "confirmed or suspected" CTVT. They found that 1,865 of them had "genital involvement" while 51 did not.

Among the dogs that did not have genital involvement, 32 were infected with oro-nasal CTVT. Interestingly, 27 of these dogs were males, meaning that the male dogs represented a whopping 84% of the oro-nasal CTVT cases.

"These findings suggest that male dogs are at four to five times greater risk of developing primary oro-nasal CTVT than females," the researchers wrote.

As for why this is the case, the researchers suspect it may have something to do with male dogs' habits.

"We think this is because male dogs may have a preference for sniffing or licking the female genitalia, compared to vice versa," said Dr. Andrea Strakova of the University of Cambridge, who was the study's first author. "The female genital tumors may also be more accessible for sniffing and licking, compared to the male genital tumors."

The researchers stressed the importance of considering CTVT as a possible diagnosis for dogs with oro-nasal tumors, "particularly male dogs." This is because even though the condition is rare and can actually be treated rather "easily," some veterinarians may not be familiar with it.

"Treatment is very effective, using single agent Vincristine chemotherapy, and the vast majority of dogs recover," added Strakova.