Adenocarcinoma in Dogs

Glands are tissues in the body that produce specific secretions such as hormones and digestive juices. Adenocarcinomas can develop in any type of glandular tissue, which creates a wide spectrum of severity in symptoms and prognosis.

Adenocarcinomas may grow rapidly and become large. The surface of the tumor may darken, become rough, or break open and bleed. Redness, swelling, and discharge may develop.

Adenocarcinomas vary in severity and risk factors depending on localization and staging of the tumor. They have the potential to spread and cause damage to the affected organs. Early intervention and rapid treatment are the most effective ways to increase the chance of a better prognosis.

The symptoms vary depending on the location of the tumor.

Sometimes an adenocarcinoma is a “functional” tumor, resulting in excessive production of the substance secreted by the gland. In canine thyroid adenocarcinoma, for example, symptoms of hyperthyroidism like weight loss and increased appetite develop as a result of unregulated thyroid hormone production.

Certain types are more common in specific breeds and suggest a genetic risk factor. Some types have specific risk factors, for example mammary adenocarcinoma is more prevalent in unspayed females and those that are spayed after their first heat. Adenocarcinomas of the anal glands and the prostate, however, occur in dogs regardless of sex or reproductive status.

Most of the time no specific cause for adenocarcinoma formation can be identified. As with all forms of cancer, both environmental and genetic factors are likely.

Symptoms vary depending on the location of the tumor and are generally nonspecific in early stages of development.

Some types of adenocarcinoma, like those on the anal glands, mammary tissue, or around the eye, may be suspected based on the appearance of a lump. Biopsy is necessary to confirm the diagnosis. Adenocarcinomas affecting tissue inside the body are less straightforward to diagnose, so a number of tests are necessary to identify them:

• Diagnostic imaging
• Bloodwork
• Urinalysis
• Biopsy

Treatment varies depending on the location of the adenocarcinoma but includes;

• Surgery
• Chemotherapy
• Radiation
• Palliative care
• Symptom management
• Pain management

Prognosis depends on the localization, size, spread, and stage of the tumor. The prognosis can range from fair to very poor and there is a chance of remission or metastasis with most treatments.

Since the cause of adenocarcinoma is unknown, it is not possible to prevent. Spaying female dogs before their first heat decreases the likelihood for mammary adenocarcinoma, and eliminates the possibility for ovarian carcinoma. Neutering male dogs eliminates the possibility of adenocarcinoma of the testicle. Adenocarcinoma is not contagious.

Adenocarcinoma is one of the most common types of canine cancer.

• Surgery
• Chemotherapy
• Radiation
• Palliative care