Animals – Sun-induced skin cancers a risk

As New Zealanders, we all know to slip, slop and slap to protect ourselves from the dangers of sun exposure, but did you know excessive sun can cause problems in our pets, too? In the last few weeks, our clinic vets have had to conduct surgery to remove skin cancers in two cats, one sheep and one cow, so now seems a timely point to discuss two types of skin cancers we see that are considered solar-induced.

Squamous Cell Carcinomas (SCC) are the most commonly seen skin cancers and appear as little raised lumps or scabs that are readily traumatised and bleed. In cats, they occur on the hairless areas of the ears and the nose. Unfortunately, white haired cats are much more prone to developing SCC because they lack the pigment in these areas that would otherwise provide some protection from UVB rays. If you have a white cat, regularly look and feel for the development of little non-healing scabs along the ear margins or nose and have them checked by your vet promptly. SCCs do not generally spread to other regions of the body, but they are locally invasive and grow rapidly. Early detection means treatment can be relatively simple – freezing the cancer off with little distortion to the tissue, but if left too long it can require complete ear resections to remove. Large SCCs on the nose leave us little option for treatment, other that some fairly radical surgery.

Skin-associated hemangiomas are a tumour of the blood vessel walls that are also considered sun-induced. Although these are usually benign, there is a closely associated form (hemangiosarcomas) that are much nastier and spread within organs in the body. Hemangiomas have the appearance of single or multiple small, flat, red or purple discolorations of the sparsely haired, light skinned areas of the body that grow into large nodules that ulcerate and bleed. We generally see these tumours on the bellies and chest of short and thin coated dog breeds such as staffies and bulldogs, but it can occur in any dog (or cat). If you have a dog that loves to spend its days sunbathing belly-up, I’d recommend some precautions to minimise the chances of hemangiomas developing. Either limit the sunbathing to the non-sunburn times of the day, apply a pet-safe sunscreen with the same regularity as you would for yourself on the beach, or fit a ‘sun-suit’ on your dog. An oversized t-shirt with some extra leg-holes cut in will do a decent job to protect your dog’s belly from the sun, too.