Do dogs get skin cancer? What is melanoma in dogs?
Vet Oncologist Viewpoint
Dogs do get Melanoma. The veterinary oncology community has done a fair amount of research on melanoma, in association with the human oncology community. What we found is that melanomas in dogs are a good model for a specific type of melanoma that people get - what are called mucosal melanomas. In people, these mucosal melanomas can occur in the mouth, on the bottom of the feet, or in the GI tract. The melanomas that dogs get, whether on their toes, mouth, or skin, are similar. But the typical skin melanomas found in people are not like melanomas in dogs, as they have a specific genetic abnormality that dog melanomas don't have.
So yes, melanomas are common in both people and animals, but the sub-types are often quite different.
So, if dogs get skin cancer, is that a different cancer than melanoma?
Dogs do get melanomas of the skin, but again it's not the same genetic type as the melanomas of the skin in people. Dogs can also get skin cancer in terms of basal cell tumors or squamous cell carcinoma. The most common skin tumors in dogs are often benign. So, just because your dog gets a skin tumor, does not mean it's malignant. If possible, all tumors should be biopsied to find out what type of cancer your dog has, if any.
One Health Chief Veterinary Officer
Melanoma in Dogs
Melanomas are typically cancerous tumors of the skin and mucous membranes.
When melanomas are of the feet and lips, the disease often evolves differently than when it occurs on the skin or in the mouth. Tumors in fur/hair-covered-skin areas are generally benign (although there are exceptions). Tumors on the nail bed and mouth are most often malignant, with the vast majority of oral melanomas being malignant. Oral tumors also often recur more quickly than other types of melanoma after the first round of treatment.
During examination and treatment, a vet will likely assess lymph node health, to understand whether the melanoma has spread to other organs in a dog. Oral melanomas are likely to spread to lymph nodes (usually causing the lymph nodes to swell) and other parts of the body.
Although a biopsy (analysis of a small sample of tumor cells) is required to definitively diagnose the disease, a senior dog with an oral tumor, or a dog with a pigmented lesion can has a high likelihood of having the disease, and pet parents and vets should try to move forward quickly with treatment.
FidoCure can help create a personalized treatment approach for dogs with melanoma.
Skin cancers and lesions in dogs
Fur cover and dark pigmentation are usually effective at protecting dogs from sun damage and its negative consequences, like developing sun-damage-induced skin cancer. Some dogs might be at higher risk, however, if they have bare patches of light skin, live in regions with higher levels of UV radiation, live exclusively outdoors, and or enjoy activities like sunbathing.
Another common type of cancer affecting the skin is called mast cell tumors, which isn't necessarily linked to sun exposure.
The following conditions are sun-related cancers or related lesions that might affect our canine companions:
SUNBURNS AND ACTINIC KERATOSIS
Dogs can be sunburned, and like humans, the severity of the burn is related to length and intensity of sun exposure. Areas that might be at risk include the nose, or anywhere with hair loss and light skin color. Australian shepherds, for example, are considered at risk for nasal sunburn. Repeated damage can also lead to a condition called actinic keratosis, which may represent a pre-cancerous condition. It is caused when UV damage to skin cells results in gene mutations in the cells. These mutations can lead to more mutated cells being produced. At first the lesions resemble symptoms of sunburn, but the skin eventually becomes crusted, thickened, or firm. Multiple studies have documented a close association between actinic keratosis and squamous cell carcinoma (SCC) (described below).
Multiple forms of hemangioma (HA) have been reported in dogs, but here we will focus on UV-light-induced HA. Chronic sun damage is a key cause of HA on dogs' skin, with a strong clinical association between sun exposure and tumor development on the skin.
Usually this disease causes multiple tumors to be present on the skin. The disease develops first with small, flat, purple discolorations, but in time the lesions enlarge and possibly redden. Larger lesions can ulcerate and bleed. These tumors rarely metastasize, however, so preventing excessive bleeding and secondary infections, in addition to seeking treatment, is key to the health of a dog suffering from this form of HA.
UV-light-induced Hemangiosarcoma (HSA)might evolve from sun-induced HA, or most often, progresses from actinic keratoses. As with HA, sun-induced HSAs are typically on the surface of the skin, and often develop into multiple tumors. These tumors may be dark red to purple. Prognosis is significantly better for sun-induced HSA than for deeper and non–sun-induced versions of HSA, since sun-induced HSA is less likely to spread to other areas of the body.
For dogs suffering from many different forms of HSA, FidoCure has been an especially effective treatment option - learn more about HSA and FidoCure here.
SQUAMOUS CELL CARCINOMA (SCC)
Squamous cell carcinoma (SCC) is associated with actinic keratosis, as described above. It is worth noting that in humans, more than 80% of SCCs on the skin are believed to be associated with actinic keratosis. In addition to areas of sun damage, SCC can also develop in areas of chronic inflammation, injury, and viral infection. Non–sun-induced tumors can develop in different breeds and at different body locations than the sun damage-induced disease. Fortunately, UV-light-induced SCC rarely spreads to other parts of the body, unlike other types of SCC.
While non–UV-light-induced SCCs will often evolve as single tumors, this form of SCC may quickly form multiple tumors. Similar to the other lesions, severe bleeding and infection should be addressed and prevented during treatment.