Cancer: Testicular

Cancer Quicklinks


Testicular cancer is differentiated by the cells involved (called sertoli, germ and leyding cells) and the behavior of the cancer (called intact, lobar tumor, diffused deeper into the testicles or metastasis/fast spreading to other organs).There is another form of testicular cancer in dogs that can be spread during copulation (intercourse).

Testicles may appear as being enlarged, descended or when touched (palpatated) being nodular (small mass of tissues or cells). Aged and intact dogs are more susceptible to testicular cancer. Dogs may show signs of hyperestrogenism (excessive female hormone) along with swelling on the testicles and surrounding abdominal region. Symptoms associated with hyperestrogenism include thrombosis (clots circulating in blood), lameness and slight paralysis of the hind quarter (less frequent).

An initial diagnosis is made based on the history of the dog, age, signs and symptoms. A definite diagnosis may require a biopsy (tissue test) along with series of laboratory tests.

Treatment is mostly dependent upon form of cancer and the cells involved. Surgical resection and chemotherapy is usually effective, but in most cases a surgical castration is highly recommended.

The prognosis for those dogs receiving a surgical castration is excellent and the recurrence rate is very low. Metastasis or spreading of the cancer may occur, but is less frequent due to the anatomical and gravitational position of testicles.


Three types of canine testicular cancer may exist. These three types are associated with three different types of cells. Cancer may appear as:

Cell types include:

1. Sertoli Cell Tumor: Sertoli cells are responsible for the nurturing of the testicles. These tumors may also involve the supporting leyding cells, too.

2. Germinoma: Germ cells in the testicles are called “Seminoma”. It may be benign (not cancer, slow growing) or malignant (fast growing) in nature and usually spreads to the lymph nodes of the inguinal (groin) region.

3. Sertoli: Also known as a Leyding Cell Tumor. Sertoli & leyding cells in combination may develop a less common form of cancer, called a sertoli – leyding cell tumors.

Another form of cancer, which may affect the testicles in dogs, is called “Canine Transmissible Venereal Tumor” or infectious sarcoma. It is transmitted via copulation, and if malignant, it may affect the testicles.


Initial signs of canine testicular cancer is swelling at the testicles, scrotal area (pouch containing the testicles) and swelling extended to the abdominal region.

Cryptorchid (un descended testis) in dogs are more susceptible to canine testicular cancer. Hyperestrogenism (producing too much of the hormone estrogen) may be due to testicular cancer and more specifically due to a sertoli cell tumor. This testicular hormonal disturbance is more common in the dogs affected by cancer.

On palpation (handling during examination), the testicles will appear enlarged and pulpy. The prostate gland will also appears as enlarged and swollen. Metastasis is more common in sertoli cell tumors and cancer may spread to the surrounding scrotal area, abdomen and lymph nodes. Dogs affected with a transmissible venereal tumor may have a cauliflower like nodular generation at the penis and prepuce (penis covering).


Diagnosis is usually based upon the history, signs and physical examination. For a confirmatory and differential diagnosis a biopsy is usually required. Dogs having hyperestrogenism along with other signs such as swelling, nodular appearance and enlarged testes may be suspected for testicular cancer.

Abdominal, chest X – Rays and radiography usually help in determining the metastasis activity of cancer and the severity of cancerous cell activity.


Castration of affected dogs is the most effective way to treat canine testicular cancer. It is highly recommended that a surgical castration technique be used that results in a confirmed blood supply blockage and in complete eradication of cancerous cells.

There is a homeopathic supplement available that may provide your dog with additional support. C-Caps Formula is made specifically to help the immune system of dogs and is a good source for additional research.


The prognosis for dogs affected by testicular cancer is usually very good. Castration has emerged as most effective way to treat testicular cancer, and thereby improves the prognosis for this condition.