Epithelial ovarian cancer represents 80% of all ovarian cancer. Due to its lack of symptoms, this disease is more often detected or diagnosed at an advanced stage (called stage III or IV) when the cancer has already spread into the body. Tumors present in secondary sites are called metastases. In addition, 30% of patients will develop ascites, a inflammatory abdominal liquid that often contain ovarian tumors.
Statistics and Survival Rates
Though ovarian Cancer accounts for about 3% of all cancer, it is the most gynecologic deadly cancer in women. In United States, ovarian cancer killed 15,520 women in 2007 and 21,000 deaths are predicted for 2008 while the number of new cases is around 21,600/year. In average the survival rate is below 50%. (source American Cancer Society).
Signs and Symptoms
Ovarian cancer is considered as an asymptomatic disease since the symptoms are not specific to the disease and may be also due to other illnesses. These symptoms are:
- Abdominal discomfort, swelling or pain
- Change in bowel habits and frequent urination
- Chronic indigestion, upset stomach
- Nausea
- Fatigue
- Menstruation disorder and vaginal bleeding
- Pain during intercourse
Classification of Epithelial Ovarian Cancer
Considering the morphologic, anatomic, and clinical differences between tumors three main classification parameters have emerged which are based on histological subtype, disease stage (I-IV) and tumor grade (0-3).
Staging
Four stages are used according to the volume and extend of tumor spread in the body. Stage strongly impacts the survival chance of patients.
- Stage I: tumors are limited to or both ovaries. The 5-yrs survival rate is ∼80%.
- Stage II: tumors are associated with pelvic extension. The 5-yrs survival rate is ∼60%.
- Stage III: tumors have spread outside the pelvis into the abdominal cavity. The 5-yrs survival rate is ∼15%.
- Stage IV: tumors may be present in liver and/or distant sites. The 5-yrs survival rate is ∼7%.
Grading
Four grades are used according to the degree differentiation of tumor cells. Grade also impacts the survival chance of patients.
- Borderline or grade 0: tumors are very well differentiated. The survival rate is 99%
- Grade 1: tumor cells are well differentiated. The 5 yrs-survival rate is ∼80%
- Grade 2: tumor cells are moderately differentiated. The 5-yrs survival rate is ∼50%
- Grade 3: tumor cells are poorly differentiate and more likely to spread. The 5-yrs survival rate is ∼20%
Histological Subtypes
There are 6 histological subtypes. The different histological subtypes are based on the particular shape of the tumoral cells. They are either Serous, mucinous, endometroid, Brenner, mixt and undifferentiated. The most common subtype is the serous subtype (60% of all subtype). The histological subtype also been reported to impact the survival rate of patients but with some discrepancies depending of the population analyzed.
Treatments
The standard treatment for ovarian cancer patients is surgery, called ovarectomy, during which ovaries are removed. This treatment is often followed by a radiation or platinum-based chemotherapy, although the disease often progresses even after surgery and becomes resistant to standard chemotherapy in less than 2 years.
For patients with high stage ovarian cancer, aggressive treatment, such as intraperitoneal chemotherapy, where the chemotherapeutic treatment is directly introduced in the peritoneal cavity, has been shown to be more effective and increases the survival rate compared to standard treatments. However such treatments are very toxic and should not be administrated routinely to patients, especially to those who are at less risk to relapse.
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