Male dogs more likely to develop this type of cancer

By Danny Halpin via SWNS

Male dogs are up to five times more likely than females to develop a contagious cancer on the nose or mouth, warns a new study.

Researchers think this is because they spend more time sniffing and licking female dogs’ genitalia than vice versa.

Canine Transmissible Venereal Tumour (CTVT) is an unusual cancer that is infectious and can spread when dogs come into contact. The living cancer cells physically jump from one animal to the other.

It usually affects dogs’ genitals and spreads through mating but it can also affect other areas like the nose, mouth and skin.

Study first author Dr. Andrea Strakova, a veterinarian from Cambridge University, said: “We found that a very significant proportion of the nose or mouth tumors of canine transmissible cancer were in male dogs.

“We think this is because male dogs may have a preference for sniffing or licking the female genitalia, compared to vice versa.

“The female genital tumors may also be more accessible for sniffing and licking, compared to the male genital tumors.”

For the study, published in the journal Veterinary Record, researchers reviewed a database of almost 2,000 cases of CTVT from around the world and found that only 32 CTVT tumors affected the nose or mouth. Of these, 27 cases were in male dogs.

CTVT is several thousand years old and comes from the cells of just one dog. The cancer survived by spreading to other dogs and it is now the oldest and most prolific cancer lineage known in nature, having spread through dogs worldwide.

It is mostly linked to countries with many stray dogs and so it isn’t common in the UK, although case numbers have risen in the past decade with imported dogs from abroad thought to be the cause.

Strakova said: “Although canine transmissible cancer can be diagnosed and treated fairly easily, veterinarians in the UK may not be familiar with the signs of the disease because it is very rare here.

“We think it’s important to consider CTVT as a possible diagnosis for oronasal tumors in dogs. Treatment is very effective, using single agent Vincristine chemotherapy, and the vast majority of dogs recover.”

The most common symptoms of the disease are sneezing, snoring, difficulty breathing, nasal deformation or bloody and other discharge from the nose or mouth.

Genital cases of CTVT are about the same for both genders of dogs.

Transmissible cancers can also be found in Tasmanian Devils and in a type of mollusk known as bivalves, like mussels and clams.

The researchers say that understanding this ancient cancer could assist the understanding of how human cancers work.