Tongue Cancer in Dogs: What to Know

Tongue tumors are uncommon in dogs, but most are cancer (Cray, 2023). In a study of 1,196 tongue lesions in dogs, 54% were tumors, and 64% of those tumors were malignant. The malignant types included melanoma, squamous cell carcinoma, hemangiosarcoma, and fibrosarcoma (Dennis et al., 2006). Squamous cell carcinoma is the most common tongue tumor (Cray, 2023).

Many owners first notice a lump on the tongue. Other signs can include drooling, bad breath, trouble eating or swallowing, discharge from the mouth, and weight loss (Cray, 2023).

Surgery to remove the tumor and part of the tongue is the main treatment. In a study of 97 dogs treated surgically, median survival was 483 days overall, 216 days for squamous cell carcinoma, and 241 days for melanoma. Dogs whose tumors were smaller than 2 cm at diagnosis lived significantly longer (Culp et al., 2013). Finding a tongue lump early really does matter.

Key points

• About half of tongue lesions in dogs are tumors, and about two-thirds of those are malignant (Dennis et al., 2006).
• Squamous cell carcinoma and melanoma are the most common malignant tongue tumors (Cray, 2023; Culp et al., 2013).
• Tumors smaller than 2 cm at diagnosis were linked to significantly longer survival (Culp et al., 2013).
• Complete removal of the tumor, with clean margins, was linked to longer survival in another study (Syrcle et al., 2008).
• Tumors toward the back of the tongue have a higher potential to spread (Cray, 2023).
• Benign tongue tumors carried a median survival of more than 1,607 days, compared with 286 days for malignant ones (Syrcle et al., 2008).

Detailed explanation

What tongue lesions are

Not every bump on a dog's tongue is cancer. In the large study of 1,196 tongue lesions, 46% weren't tumors at all (Dennis et al., 2006). Among the tumors, benign types included squamous papillomas, plasma cell tumors, and granular cell tumors, while malignant types included melanoma, squamous cell carcinoma, hemangiosarcoma, and fibrosarcoma (Dennis et al., 2006).

Because you can't tell these apart by looking, any persistent tongue lump needs a biopsy. Our guide to reading a pathology report can help when the results come back.

Which dogs are at risk

Breed patterns differ by tumor type (Dennis et al., 2006):

• Melanoma: large breeds, especially Chow Chows and Chinese Shar-Peis
• Squamous cell carcinoma: females of all breeds, and Poodles, Labrador Retrievers, and Samoyeds
• Hemangiosarcoma: Border Collies
• Fibrosarcoma: Golden Retrievers
• Plasma cell tumors (usually benign): small breeds, especially Cocker Spaniels

If your dog is one of these breeds, include the tongue when you check your dog's mouth. Our article on cancer in Labrador dogs covers other risks for Labs.

Signs to watch for

Many dogs with mouth tumors are brought in because the owner noticed a mass (Cray, 2023). Other signs of oral tumors can include (Cray, 2023):

• Drooling more than usual
• Bad breath
• Trouble eating or swallowing
• Discharge from the mouth
• Weight loss

If your dog's breath has changed, our article on why dog cancer can smell bad explains the link, and if eating has become a struggle, see why a dog with cancer won't eat. Our page on squamous cell carcinoma in the mouth covers oral tumors more broadly.

The main types of tongue cancer

Squamous cell carcinoma. This is the most common tongue tumor in dogs (Cray, 2023). In the 97-dog surgical study, it made up 32% of cases, with a median survival of 216 days after surgery (Culp et al., 2013). See our squamous cell carcinoma in dogs hub.

Melanoma. Melanoma made up 30% of cases in the surgical study, with a median survival of 241 days (Culp et al., 2013). Our melanoma in dogs hub explains this cancer in more depth.

Other tumors. Hemangiosarcoma, fibrosarcoma, and benign tumors such as plasma cell tumors and granular cell tumors also occur on the tongue (Dennis et al., 2006).

Treatment: surgery on the tongue

Surgery is the main treatment. Depending on the tumor's size and location, surgeons may remove the tumor with a margin of tissue (marginal excision) or remove a larger portion of the tongue (partial or subtotal glossectomy). In the 97-dog study, 38% of dogs had a marginal excision, 59% a subtotal glossectomy, and 3% a near-total glossectomy, and surgical complications were rare (Culp et al., 2013).

A partial glossectomy can be considered for tumors on one side or toward the front of the tongue. Tumors in the middle of the tongue or on both sides are harder to remove, and radiation is an alternative for them (Cray, 2023).

After tongue surgery, short-term effects reported in one study included drooling and the wound reopening, while long-term effects were limited to minor changes in eating and drinking (Syrcle et al., 2008). Our article on recovery after cancer surgery covers general aftercare.

Outlook

In the surgical study, the tumor came back in 28% of dogs and spread elsewhere in 19% (Culp et al., 2013). Tumors toward the back of the tongue, and those involving the tonsils, have a higher potential to spread (Cray, 2023).

Size at diagnosis made a significant difference. Dogs whose tumors were 2 cm or larger at diagnosis had shorter survival than dogs with smaller tumors (Culp et al., 2013). In a separate study of 42 dogs, smaller tumors were more likely to be removed completely and less likely to recur, and complete margins were linked to longer survival (Syrcle et al., 2008). That same study found a median survival of more than 1,607 days for benign tongue tumors compared with 286 days for malignant ones (Syrcle et al., 2008).

Because margins matter so much, it's worth understanding what your pathology report says about them. Our article on whether clear margins mean your dog is in the clear walks through it. Tongue surgery and radiation planning can be complex, so asking about a referral to a veterinary oncologist is reasonable.

When to contact a veterinarian

Book an appointment soon if your dog has:

• Any lump, swelling, or discolored area on the tongue
• Drooling, bad breath, or bleeding from the mouth that's new or getting worse
• Trouble eating, chewing, or swallowing
• Weight loss without an obvious reason

Call the same day if your dog can't eat or drink, is bleeding from the mouth and it won't stop, or has trouble breathing.

Questions to ask your veterinarian

• Can we biopsy this tongue lump to find out what it is?
• How large is it, and where on the tongue is it?
• Should we check the lymph nodes and take chest X-rays first?
• How much of the tongue would need to be removed?
• Is radiation an option if surgery isn't?
• How will my dog eat and drink after surgery?
• What's the chance the tumor comes back, and how will we monitor for it?

Sources

Cray, M. (2023, September). Surgical options for oral tumors. MSPCA-Angell. https://www.mspca.org/wp-content/uploads/2023/12/Cray_Surgical-Options-for-Oral-Tumors.pdf

Culp, W. T. N., Ehrhart, N., Withrow, S. J., Rebhun, R. B., Boston, S., Buracco, P., Reiter, A. M., Schallberger, S. P., Aldridge, C. F., Kent, M. S., Mayhew, P. D., & Brown, D. C. (2013). Results of surgical excision and evaluation of factors associated with survival time in dogs with lingual neoplasia: 97 cases (1995-2008). Journal of the American Veterinary Medical Association, 242(10), 1392-1397.

Dennis, M. M., Ehrhart, N., Duncan, C. G., Barnes, A. B., & Ehrhart, E. J. (2006). Frequency of and risk factors associated with lingual lesions in dogs: 1,196 cases (1995-2004). Journal of the American Veterinary Medical Association, 228(10), 1533-1537. 

Syrcle, J. A.(2008). Retrospective evaluation of lingual tumors in 42 dogs: 1999-2005. Journal of the American Animal Hospital Association, 44(6), 308-319.