Ovarian Cancer

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Ovarian cancer is the fifth leading cause of cancer deaths among U.S. women and has the highest mortality of any of the gynecologic cancers. The lifetime risk of dying from ovarian cancer is 1.1%. According to the U.S. Cancer Statistics: 2004 Incidence and Mortality report, 20,095 women in the U.S. learned they had ovarian cancer in 2004. About 6,600 women are diagnosed with ovarian cancer in the UK each year, around 1,500 in Australia and 2,300 in Canada. The death rate for this disease has not changed much in the last 50 years.
Unfortunately, almost 70 percent of women with the common epithelial ovarian cancer are not diagnosed until the disease is advanced in stage - i.e., has spread to the upper abdomen (stage III) or beyond (stage IV). The overall 5-year survival rate is at least 75% if the cancer is confined to the ovaries and decreases to 17% in women diagnosed with distant metastases. Symptoms usually do not become apparent until the tumor compresses or invades adjacent structures, ascites develops, or metastases become clinically evident. As a result, two thirds of women with ovarian cancer have advanced (Stage III or IV) disease at the time of diagnosis. Carcinoma of the ovary is most common in women over age 60. Other important risk factors include low parity and a family history of ovarian cancer. Less than 0.1% of women are affected by hereditary ovarian cancer syndrome, but these women may face a 40% lifetime risk of developing ovarian cancer.
There are many types of tumors that can start in the ovaries. Some are benign, or noncancerous, and the patient can be cured by surgically removing one ovary or the part of the ovary containing the tumor. Some are malignant or cancerous.The treatment options and the outcome for the patient depend on the type of ovarian cancer and how far it has spread before it is diagnosed.
Ovarian tumors are named according to the type of cells the tumor started from and whether the tumor is benign or cancerous.
The three main types of ovarian tumors are:

Epithelial tumors

Epithelial ovarian tumors develop from the cells that cover the outer surface of the ovary. Most epithelial ovarian tumors are benign. There are several types of benign epithelial tumors, including serous adenomas, mucinous adenomas, and Brenner tumors. Cancerous epithelial tumors are carcinomas. These are the most common and most deadly of all types of ovarian cancers. There are some ovarian epithelial tumors whose appearance under the microscope does not clearly identify them as cancerous; these are called borderline tumors or tumors of low malignant potential (LMP tumors). Epithelial ovarian carcinomas (EOC's) account for 85 to 90 percent of all cancers of the ovaries. This group of cancers are commonly referred to as "ovarian cancer".
The cells that make up EOC have several forms that can be recognized under the microscope. They are known as serous, mucinous, endometrioid, and clear cell types. Undifferentiated EOC's lack distinguishing features of any of these four subtypes and tend to grow and spread more quickly.
In addition to their classification by cell type, EOC's are given a grade and stage. The grade is on a scale of 1, 2, or 3. Grade 1 EOC more closely resembles normal tissue and tends to have a better prognosis than Grade 3 EOC, which looks less like normal tissue and usually implies a worse outlook than Grade 1 EOC.
The stage of the tumor can be ascertained during surgery, when it can be determined how far the tumor has spread from where it started in the ovary.