A Vet's Guide to Testicular Cancer in Dogs: Diagnosis and Treatment

In this article, we’ll explore everything you need to know about testicular cancer in dogs, including its causes, clinical signs, diagnostic methods, treatment options, prevention tips, and more. By the end, you’ll have a comprehensive understanding to help keep your furry friend healthy.

A Quick Primer on Testicular Cancer In Dogs

Testicular cancer in dogs occurs when the cells within the testicles multiply uncontrollably, leading to the formation of tumors. It is one of the most common cancers in male dogs, particularly in older or unneutered dogs.

How common are canine testicular tumors and cancer?

Testicular cancer is particularly common in unneutered male dogs, with up to 27% of intact males developing one or more testicular tumors.

Among all canine cancers, testicular cancer accounts for approximately 4-7%, making it a significant concern for dog owners, especially those with unneutered pets.

While most canine testicular tumors are benign, there is a small chance they may become malignant and develop into a metastatic disease. In some cases, they spread to the bone marrow and other organs.

It’s important to note that most testicular tumors in dogs can appear unexpectedly, making it essential for pet parents to be informed about this condition.

Types of Aggressive Testicular Tumors and Cancer in Dogs

While most testicular cancers in dogs are malignant, they rarely spread to other organs (a process known as metastasis). The three most common types of testicular cancer in canines are seminoma, interstitial cell tumor, and Sertoli cell tumor.

Seminoma

Seminoma originates in germ cells, which produce sperm in males and are essential for genetic reproduction. This cancer typically affects older dogs, with cryptorchid dogs (those with undescended testicles) at higher risk.

Seminomas may appear as single or multiple tumors in one or both testicles, potentially causing feminization. While usually benign, rare cases of metastasis to other organs, such as the skin, have been reported.

Interstitial cell tumor

Compared to other testicular tumors, this condition arises from Leydig cells, which produce testosterone, and is the most common type in dogs.

Often discovered incidentally, it typically causes very few symptoms to none at all. Interstitial cell tumors can be challenging to distinguish from interstitial cell hyperplasia, a benign increase in tissue volume due to cell multiplication.

Sertoli cell tumor

Also known as sertolioma, this cancer arises from Sertoli cells in the seminiferous tubules of the testicles. These cells produce hormones like estrogen, which may cause feminization in dogs. Cryptorchid dogs are at higher risk.

Metastasis occurs in less than 15% of cases of malignant Sertoli cell tumors, and surgical removal is typically effective.

Key Clinical Signs of Canine Testicular Cancer

Ever wondered what testicular cancer looks like in dogs? It typically presents as one or more lumps in one or both testicles, though symptoms aren’t always obvious. Here are some clinical signs to watch for:

Testicular enlargement

Testicular enlargement is a common sign of testicular tumors, often noticeable during a veterinary exam. In some cases, the size difference between testicles can be significant. This enlargement may result from the tumor, local inflammation, or both.

Testicular discomfort and pain

Your dog may show discomfort or pain in the genital area, including limping, difficulty walking, excessive licking, or vocalization.

Behavioral changes

Dogs with testicular cancer may exhibit increased irritability or aggression. As regards intact male dogs, testicular tumors may be a possible explanation for this change in behavior.

Indicators of Feminization

These signs, often associated with seminoma and Sertoli cell tumors, may include:

• Enlarged Mammary glands
  
• Nipple elongation
  
• Penile and testicular atrophy
  
• Swelling or sagging of the foreskin
  
• Atrophy of the unaffected testicle
  
• Hair loss in specific areas
  
• Attracting males
  
• Squatting to urinate
  

What are the Stages of Testicular Cancer in Dogs?

Testicular cancer in dogs progresses through five stages:

• Stage 0: No clinical signs; abnormal cells are confined to the seminiferous tubules.
  
• Stage I: A palpable lump and slight swelling in one or both testicles; cancer remains within the testicle.
  
• Stage II: Cancer spreads to surrounding tissues (epididymis, spermatic cord), causing significant swelling, pain, lethargy, and reduced activity.
  
• Stage III: Cancer reaches regional lymph nodes (groin), causing swollen nodes, reduced appetite, weight loss, and general sickness, but no distant metastasis.
  
• Stage IV: Rare metastasis to distant organs or tissues.
  

Early-stage testicular cancer in dogs clinical signs

Early-stage testicular cancer often shows subtle or no signs. Mild enlargement of the affected testicle may be noticeable, along with increased sensitivity causing slight discomfort or pain.

What Causes Testicular Cancer in Dogs?

The exact causes of cancer, including testicular cancer, remain unknown, but several risk factors increase susceptibility:

• Age: Most common in older unneutered male dogs over 10 years, though it can occur in younger dogs.
  
• Cryptorchidism: Dogs with undescended testicles are at higher risk, often developing cancer after age 6.
  
• Breed: Certain breeds, such as Norwegian Elkhounds, Afghan Hounds, Shetland Sheepdogs, and Siberian Huskies, are more prone, while mixed breeds, Dachshunds, Toy Poodles, Rottweilers, and Miniature Schnauzers are less susceptible.
  
• Environmental factors: Exposure to secondhand smoke increases risk of cancer.
  

Does testicular cancer spread fast in dogs?

Testicular cancer in dogs spreads slowly, with low metastasis rates (6-20%). It typically spreads to regional lymph nodes but, in aggressive cases, may metastasize to the liver, lungs, heart, skin, or kidneys.

How is Dog Testicular Cancer Diagnosed?

Diagnosing testicular cancer in dogs involves several steps to confirm the tumor and plan treatment. The main steps include:

Clinical examination

Your veterinarian will perform a physical exam, including palpating the testicles to check for changes in size, shape, structure, or lumps.

Diagnostic imaging

This stage involves diagnostic imaging such as abdominal and testicular ultrasounds, X-rays, CT scans, and MRIs to detect tumors or metastases.

• Testicular ultrasound identifies internal structures and lumps in the testicles.
  
• Abdominal ultrasound is particularly useful for cryptorchid males to locate testicles in the abdomen or inguinal canal.
  
• Abdominal ultrasound and X-rays also help assess potential metastases.
  

Laboratory tests

Your veterinarian may recommend a complete blood panel, including a CBC and biochemical profile, to assess organ function and check for anemia. Hormone level tests may also be suggested to detect excess estrogen.

Fine Needle Aspiration (FNA) and biopsy

These tests help confirm a diagnosis of testicular cancer:

• FNA (Fine Needle Aspiration): A sample of tumor cells is collected with a fine needle and examined under a microscope. If inconclusive, a biopsy is required.
  
• Biopsy: The affected testicle is surgically removed and analyzed in a histopathology lab for a definitive diagnosis.
  

Both tests identify the type of cancer (Sertoli cell tumor, seminoma, or interstitial cell tumor).

How is Testicular Cancer in Dogs Treated?

Conventionally treating testicular cancer in dogs typically involves surgery, sometimes combined with adjuvant therapies. Key treatment methods include:

Surgical Removal

Orchiectomy, the surgical removal of the affected testicle, is the most effective treatment for testicular tumors. It eliminates the cancer source, prevents hormonal effects like feminization, and reduces the risk of recurrence or spread. For cases involving both testicles, a bilateral orchiectomy is performed.

This surgical procedure is performed under general anesthesia, with the testicles removed through an incision in the scrotum or abdomen, depending on their location. Like any surgery, it carries some risks:

• Anesthetic reaction: Side effects from anesthesia can range from mild to severe.
  
• Infections: Incision site infections may occur without proper hygiene or if the dog licks excessively. Antibiotics and wound care help prevent this.
  
• Pain and discomfort: Common post-surgery, these can be managed with prescribed pain medications to keep your dog comfortable
  

Chemotherapy

If the cancer has spread, systemic treatment called chemotherapy may be recommended alongside surgery to target cancer cells throughout the body.

Radiotherapy

Radiation therapy is rarely used for testicular cancer in dogs but may be an option for aggressive or metastatic tumors, especially when surgery isn’t feasible. It is generally recommended for seminomas.

After treatment, regular veterinary check-ups are essential to monitor for recurrence or metastasis.

In Sertoli cell tumors, hormonal symptoms like feminization typically resolve after neutering, though severe cases may require hormone therapy to restore balance.

How Long Can a Dog Live with Testicular Cancer?

Survival time for dogs with testicular cancer depends on factors like cancer type, metastasis, overall health, and treatment.

• Untreated dogs typically survive up to a year.
  
• Dogs with metastases treated with chemotherapy may live a few months to over two years.
  
• Dogs without metastases who undergo surgery can live for many years.
  

Can Testicular Cancer in Dogs Be Treated Naturally?

If your dog has testicular cancer, homeopathic products can complement conventional treatments by strengthening the immune system and supporting recovery. While not a substitute for standard care, they can enhance overall well-being when used together.

Zumalka's PIPTOPET is designed to support your pet during testicular tumors and cancer in dogs

PIPTOPET is a natural product that helps dogs fight testicular cancer and recover. Its key ingredient, Fomitopsis betulina (birch polypore), is known for its numerous health benefits, including:

• Anti-inflammatory properties
  
• Immune system support
  
• Antiviral and antibacterial effects
  
• Antioxidant properties
  
• Antitumoral activity
  

PIPTOPET enhances your dog’s immune system, supports natural healing, and improves quality of life, making it an excellent supplement for dogs with testicular cancer.

Boosting immune system health and overall wellness with the PIPTOPET Optimal Kit

PIPTOPET can be used as part of an Optimal Kit, which includes additional remedies to enhance its effects:

• TONICPET #4: Enhances quality of life by delivering oxygen throughout the body, supporting immune response.
  
• TONICPET #5: Encourages healthy circulation for proper body system function.
  
• TONICPET #7: Boosts oxygen circulation and strengthens the immune system to fight cancer effectively.
  
• TONICPET #10: Balances body pH, discouraging tumor growth by creating an environment less favorable for cancer cells.
  

Combining these natural remedies can significantly boost your dog’s immune system.

Moreover, CBD oil (cannabidiol) is another natural product that can help dogs fight testicular cancer. Studies show it promotes cancer cell death (apoptosis) and reduces cell viability.

Can You Prevent Testicular Cancer in Dogs?

There are no other methods of preventing testicular cancer in dogs other than early neutering. Metastatic seminoma and other types of testicular tumors and cancer are quite common

Removing the testicles completely eliminates the risk of developing testicular tumors. It is recommended to neuter your dog at a young age, before sexual maturity.

In the case of cryptorchid dogs, which are more at risk of developing testicular cancer, early neutering is ideal. The advantages and disadvantages of this procedure should be discussed with your veterinarian.

Regular checkups can help diagnose testicular cancer in its early stages. Therefore, take your dog to the vet for regular checkups. Consulting a pet homeopathy expert can also help you explore natural treatment options.

About the author

Dr. Iuliana Mihai, DVM, MSc, PhD

Iuliana Mihai, DVM, MSc, PhD, is a Bucharest-based veterinary expert specializing in internal medicine and oncology.

Her work has been published in reputable publications such as Veterinary Medicine Journal, Catster.com, Dogster.com, Hepper.com, Meowiz.com, Springnaturals.com, Petkeen.com, and Wilderharrier.com.

She is a malpractice and negligence veterinary consultant and a graduate of The University of Agronomic Sciences and Veterinary Medicine and The Romanian Academy.

Read the complete profile of Dr. Iuliana Mihai, DVM, MSc, PhD (Veterinarian) here.