Ovarian Cancer In Dogs – Symptoms & Treatments

Cancer of the ovaries (ovarian carcinoma) is rare in dogs. Ovarian tumors are malignant growths in the surface cells of ovaries, which are the female sex glands where eggs are formed. The ovarian tumor can be classified depending on its cell origin. They are skin/tissue (epithelial) tumors, sperm and ova (germ) tumors, and sex cord-stromal (SCST) cell tumors. Of all canine ovarian tumors, SCST and epithelial tumors together account for 80-90%.

Mesenchymal tumors (mesodermal-derived precursor cells that develop into cartiolage, bone, blood vessels, connective tissues, etc), fibromas, and teratomas (or teratocarcinoma) have also been reported.

Ovarian carcinomas are the most common type of ovarian tumor. About 20-30% of cases of Ovarian tumors also spread to nearby organs (metastasizing) and some are capable of producing hormones.

Since ovaries are seedbeds for tumors, it is very important to differentiate between benign and malignant lesions. Benign conditions like ovarian cysts and para ovarian (or para tubal) cysts symptoms are often misdiagnosed to be ovarian cancer. Ovarian cysts which usually develop within the ovary are sacs or packets filled with fluids and are often confused with a neoplastic disease. On the other hand, Para ovarian cysts originate from the genital ridges (mesonephric tubules) and usually dissolve on their own.

Moreover, there have been reports of ovarian metastasis in cases of pancreatic, mammary, intestinal, carcinoma, and lymphoma.

• Hormonal Dysfunction
• Malignant Ascites (carcinogenic fluid inside the abdomen).
• In the case of Thoracic Metastasis - Pleural Effusions.
• Aplastic Pancytopenia (Bone marrow aplasia - RBC’s not developing correctly).
• Lack of a “going into heat” period.
• Overproduction of steroid hormones (estrogen, progesterone).
• Persistent Estrus
• Sanguineous discharge in the vulva / Vulvar Enlargement.
• Hyperadrenocorticism
• Alopecia
• Excessive infiltration of endometrium cells.
• Other female dogs giving too much attention (higher testosterone levels may make the dog impart male dog traits).
• Uncomfortable with being touched or petted.

• Intracavitary Chemotherapy of Cisplastin - A high dose of chemotherapy is injected into the tumor, but the rest of the body receives only a very low dose and it is used to control malignant effusions.
• Oophorectomy - Surgical removal of the ovary/ovaries (an alternative to ovariohysterectomy).
• Ovariohysterectomy - Ovaries and Uterus are removed.

As with any disease, the prognosis is dependent on the extent of the disease, its location, and the treatment chosen.

More importantly, follow the instructions given to you by your veterinarian. Follow up with thoracic and abdominal radiographs once in 2 months if any metastasis is indicated or monitor for recurrence.

Discuss home treatments with your vet to ensure there won’t mess with other medications.

The only way of prevention is by having your pet spayed (removal of ovaries) and this completely prevents the chance of this happening.

Spaying also prevents uterine infections, and accidental pregnancy and decreases the chances of mammary cancer by over 50%.

German Shepherd, Boxer, Yorkshire Terrier, Poodle, German Shorthaired Pointer, German Wirehaired Pointer, Boston Terrier

1. Risk factors:

• Mostly Idiopathic
• Old Age
• Intact Dogs
• Overweight or Obese
• Hereditary

2. Types:

Epithelial Cell Tumors:

• The most common type of canine ovarian neoplasm (40%-50%).
• Epithelial cell Tumors can be divided into cystadenomas, papillary adenomas, papillary adenocarcinomas, and undifferentiated carcinomas.
• ‘Undifferentiated’ means when we are unable to conclude the type of embryonic cell cancer developed from.

Germ Cell Tumors:

• Germ cell tumors originate from the primordial germ (egg) cells of the ovary (5 to 12% ).
• Germ cells are classified into teratomas, teratocarcinoma, and dysgerminomas.
• The metastatic proportion of teratomas and teratocarcinoma is 30%.
• The common sites of metastasis may include various lungs, bones, abdominal sites, and anterior mediastinum.

Sex Cord Stromal Tumors (SCST):

• SCST subtypes are Sertoli-Leydig cell tumors, granulosa cell tumors, leuteomas, and thecomas.
• Of all canine ovarian malignancies, Granulosa cell tumors account for 50% and have 20 - 25% metastatic potential.
• The sites of metastatic potential include lungs, liver, pancreas, and sublumbar lymph nodes.
• Peritoneal carcinomatosis (affecting the peritoneum- a thin layer of tissue that lines the abdomen) is also reported.

3. Morbidity:

Epithelial tumor's peak incidence in dogs is between 4 to 12 years.

Germ cell tumors (such as Teratomas) have been reported in dogs between 20 months to 10 years.

Sex cord-stromal cell tumors are reported in dogs between 14 months - 12 years.

4. Stages:

Stage I: The least advanced stage of ovarian cancer. Cancer is present in one or both ovaries.

Stage II: Tumor has reached organs close to the ovaries (uterus, fallopian tubes, or both).

Stage III: Cancer has spread to the stomach lining and nearby lymph nodes.

Stage IV: The most advanced stage. Cancer has metastasized to distant organs such as the lungs and liver.

5. Grading:

Grade 1: Cancer is well-differentiated. They are less likely to spread or recur.

Grade 2: Moderately differentiated.

Grade 3: Looks more unusual. Cancer is poorly differentiated. They are more likely to spread or recur.

6. Mortality:

The asymptomatic nature, no apparent symptoms during the growth of the tumor or delayed onset of symptoms, and lack of proper screening results in the high mortality rate of ovarian cancer.

7. Diagnosis:

• Baseline Tests - Complete blood count (CBC), biochemical profile, and urinalysis.
• Abdominal radiographs (X-rays) and thoracic radiographs.
• Abdominal Ultrasound
• Cytology (evaluation of cells) - To check the presence of abdominal or thoracic fluid.
• Microscopic evaluation and Biopsy are necessary for a definitive diagnosis.

8. Prognosis:

Stage I and II dogs can have a good prognosis. The five-year survival rate for stage I and II cancer is approximately 70%. After the removal of tumors, the survival rate is estimated at four to six years.

When all types of ovarian cancer take together almost 3 in 4 dogs' the survival rate is at least 1 year after diagnosis.

Contact your vet right away, if you notice any of the following:

• Lack of a “going into heat” period / Persistent estrus.
• Sanguineous discharge in the Vulva / Vulvar Enlargement.
• Other female dogs giving too much attention (higher testosterone levels may make the dog impart male dog traits).

The ratio would be:

35 to 50 percent protein + less than 25 percent carbs + 25 to 35 percent fat (including omega-3 fatty acids).

Some of the most popular food items include:

• Fresh, Organic Meats, either raw or cooked.
• Chicken
• Fish
• Organ Meat
• Broccoli
• Dark-green, Leafy Vegetables like Spinach.
• Eggs
• Antioxidant Berries
• Omega 3 fatty acid foods (Sardines, Mackerel, Herring etc).

For dogs with ovarian cancer, the long-term prognosis is generally poor, regardless of treatment. Dogs can have an improved quality of life for a period of time with proper treatment.