Ovarian cancer usually begins on the surface of the ovary, the organ that produces eggs and female hormones.
There are several different types of ovarian cancer, named for the cells in the ovary where the cancer begins--epithelial, germ cell, and stromal cell. The majority of ovarian cancers are epithelial carcinoma, which begins on the surface of the ovary.
In the US, approximately 25,000 women will be diagnosed with ovarian cancer each year. Unfortunately, there are almost 15,000 deaths per year due to this disease. This is due to almost 70 percent of women with epithelial ovarian cancer are not diagnosed until the disease is in the advanced stages, having spread to the abdomen or beyond. However, there are new tools being explored to detect ovarian cancer early. When ovarian cancer is caught in the early stages, before it has spread beyond the ovary, more than 90 percent of women will survive beyond five years.
There are more than 30 different types of ovarian cancer, grouped into three categories by the type of cell where the malignancy begins.
- Epithelial: About 90 percent of ovarian cancers are epithelial ovarian carcinomas. In this type of cancer, the malignant tumor originates in the surface epithelial tissue, which is on the outside of the ovary. The risk of epithelial ovarian cancer increases with age, especially after the age of 50.
- Germ Cell: These tumors start from the cells that produce the individual eggs. Germ cell tumors are rare, accounting for 5 percent of all ovarian cancers. They usually occur in girls and women younger than 30 years of age. They are usually caught at an early stage and have high survival rates.
- Sex Cord Stromal: These tumors develop in the connective tissues that hold the ovary together and produce male or female hormones. Sex cord stromal tumors are relatively rare, accounting for 5 percent of all ovarian cancers, and are generally less aggressive than other ovarian tumors.
In the past, it was thought that ovarian cancer had no symptoms and was known as the “silent” killer. However, according to research conducted by Dr. Barbara Goff, professor and chair of the UW Division of Gynecologic Oncology and SCCA physician, early symptoms may be present in many women, but just missed or not noticed. There are early warning symptoms of ovarian cancer, according to Dr. Goff. But they often go unnoticed because they are often vague symptoms that people may experience off and on normally. Some of the symptoms include abdominal swelling, pain, bloating, a feeling of fullness even after a light meal, a change in bowel habits, frequent urination, and loss of appetite. You may also notice irregular bleeding, or bleeding with intercourse. “If these are new symptoms that persist for at least three weeks, you should talk to your doctor,” Dr. Goff says.
Annual gynecologic examinations may increase the likelihood that a doctor can find a pelvic mass or abdominal swelling, but finding a small ovarian tumor is very difficult.
If ovarian cancer is suspected, doctors may order additional screening tests, such as a transvaginal ultrasonography (a small probe inserted into the vagina to get as close to the ovaries as possible). Doctors may also order a CA-125 blood test, a tumor marker test which can detect most epithelial ovarian cancers.
Imaging tests, such as a computed tomography (CT) scan, which show cross-sectional pictures of the body, may be performed.
The risk of ovarian cancer increases with age, especially at around the age of menopause. A family history of ovarian cancer is the most important risk factor. A family history of breast cancer may also increase your risk. Other factors that may increase your risk include:
- A personal history of breast, endometrial, or colon cancer or Lynch syndrome
- A history of infertility, or the use of fertility drugs
- Ashkenazi Jewish heritage
- A mutation or abnormal change in the BRCA1 or BRCA2 gene (known as the breast-ovarian susceptibility gene).