Different types of ovarian cancer are classified according to the type of cell from which they start.
Epithelial tumors: About 90 percent of ovarian cancers develop in the epithelium,
the thin layer of tissue that covers the ovaries. This form of ovarian cancer generally occurs in postmenopausal women.
Germ cell carcinoma tumors: Making up about five percent of ovarian cancer cases, this type begins in the cells that form eggs. While germ cell carcinoma can occur in women of any age, it tends to be found most often in women in their early 20s. Six main kinds of germ cell carcinoma exist, but the three most common types are: teratomas, dysgerminomas, and endodermal sinus tumors.
Stromal carcinoma tumors: Ovarian stromal carcinoma accounts for about five percent of ovarian cancer cases. It develops in the connective tissue cells that hold the ovary together and those that produce the female hormones estrogen and progesterone. The two most common types are granulosa cell tumors and sertoli-leydig cell tumors. Unlike with epithelial ovarian carcinoma, 70 percent of stromal carcinoma cases are diagnosed in Stage I.
Small cell carcinoma of the ovary: Small Cell Carcinoma of the Ovary (SCCO) is a rare, highly malignant tumor that affects mainly young women, with a median age at diagnosis of 24 years old. The subtypes of SCCO include pulmonary, neuro-endocrine and hypercalcemic.SCCO accounts for 0.1% of ovarian cancer cases. Approximately two-thirds of patients with SCCO have hypercalcemia. The symptoms are the same as other types of ovarian cancer.
Specific risk factors for ovarian cancer causes are not known, but risk factors that may increase your chances of getting ovarian cancer may include:
High fat diet
Never having children
Infertility, or not having children until late in life
Using infertility drugs but not becoming pregnant
Starting your periods at a young age, or going through menopause at an older than average age
Use of talcum powder on the genital area
Have an Eastern European (Ashkenazi) Jewish background.
Family history of ovarian cancer, breast cancer, or colon cancer
Peronal history of breast, uterine or colon cancer
Of these ovarian cancer risk factors, the most significant is a family history of ovarian cancer and /or breast cancer Having one close relative with ovarian cancer increases a woman's risk of developing ovarian cancer by nearly three times. Having additional family members with breast cancer, ovarian cancer or colon cancer increases the risk even further.
There are a number of factors that are associated with lowering the risk of ovarian cancer.
Use of birth control pills
Having multiple children
Having the ovaries removed (prophylactic oophorectomy)
For those women diagnosed with ovarian cancer limited to the ovary (stage I), over 90 percent will be alive at five years. This contrasts dramatically with approximately 25 percent for those women diagnosed with stage III and stage IV ovarian cancer.