Ovarian cancer

Types of ovarian cancer

There are different types of ovarian cancer, classified according to the cell from which they start.

Epithelial ovarian cancer

This is the most common type (approximately 90%) of ovarian cancer. It starts in the cells that cover the lining (or epithelium) of the fallopian tube or the ovary. There are distinct sub-types of epithelial ovarian cancer and research suggests that they should be treated as different types of cancer rather than as one disease.

Serous tumours: Serous cancer can be either high grade or low grade. High-grade serous epithelial ovarian cancer is the most common sub-type and accounts for up to 70% of all ovarian cancer cases. The majority of high-grade serous ovarian cancer has recently been found to originate in the fallopian tube, not the ovary. Approximately 1/4 of Canadian women with this type of ovarian cancer have an inherited abnormality in their BRCA1/2 genes. Low-grade serous epithelial ovarian cancer is the least common type of ovarian cancer, and as such, knowledge of this type of ovarian cancer is very limited.
Clear cell carcinoma: This is the 2nd most common type of ovarian cancer affecting approximately 10-13% of women diagnosed with ovarian cancer. This type is often associated with endometriosis.
Endometroid tumours: This is the third most common type of ovarian cancer and is believed to arise from endometriosis.
Mucinous tumours: This affects approximately 4% of women diagnosed with ovarian cancer.
Undifferentiated or unclassified: These are ovarian cancers in which it is not possible to tell where the tumour cells originated because the cells are quite undeveloped.
Borderline ovarian tumours: These tumours are less likely to be malignant. They usually affect younger women, have a better cure rate than other types of tumours and are treated only with surgery.

Germ cell ovarian cancer

Some 5-10% of ovarian cancer cases are germ cell tumours and start from germ cells (cells from which eggs are formed) within the ovaries. They can occur in women at any age, but tend to affect woman in their twenties.

The sub-types are:

dysgerminoma
endodermal sinus tumours
embryonal carcinoma, immature teratoma, choriocarcinoma, polyembryomas, and mixed germ cell tumours

Stromal cell cancer

This type of cancer accounts for less than 5% of all incidents of ovarian cancer and begins in the cells that hold the ovaries together. These cells may produce female hormones. These tumours generally occur in younger women under 50 years old.

A common symptom is known as virilism, which can include:

infrequent menstrual periods
menstrual periods after menopause
appearance of facial hair
a hoarse voice