It’s Not all the Same: The Different Types of Ovarian Cancer

The most common type of ovarian cancer is epithelial, and that's what most people think of when they consider ovarian cancer. These cancers account for about 90 percent of all ovarian malignancies, and tend to affect women over age 50. Epithelial carcinomas arise from the surface layer of cells covering the uterus, and within this category there are subgroups, with serous tumors being the most common. This type of cancer is usually treated with a combination of surgery and chemotherapy, although hormone therapy may also be prescribed.

Another kind of epithelial ovarian cancer is called endometrioid.  "This is the same kind of cancer that can be in the lining of the uterus as well," says Dr. Lynn Parker, gynecologic oncologist with the Norton Cancer Institute in Louisville, Kentucky. This type of tumor can sometimes be associated with endometriosis, although most women with endometriosis do not have any malignancy.

A third type of epithelial ovarian cancer is called mucinous. "These cancers make mucous-like fluid. We think they come from the glands that are around the ovary," says Dr. Parker. Two other types of epithelial tumorsclear cell and undifferentiatedare fairly rare.

Epithelial ovarian cancers are usually treated with a combination of surgery and chemotherapy.

Beyond Epithelial

"The other big group we think about are called sex cord-stromal tumors. They come from the stroma, which is the supporting structure of the ovary," explains Dr. Parker. These tumors are much less common than epithelial tumors, accounting for only about  3 to 5 percent of all primary ovarian cancers. The majority of these tumors are diagnosed at an early stage, and can be treated with surgery alone.

There are several types of sex-cord stromal tumors, but the most common type is called a granulosa or theca cell tumor. Unlike epithelial tumors, these tumors usually develop in women in their 30s and 40s, though they can also be in older women or even young girls. "These tumors tend to make hormones," says Dr. Parker. "Granulosa cell tumors can make estrogen, and they can actually cause a uterine cancer by secreting a lot of estrogen."

When a woman has both a mass and bleeding, doctors consider the possibility of this type of tumor. In addition to estrogen, sex-cord stromal tumors also secrete a substance caused inhibin. Blood tests to detect high levels of estradiol or inhibin may help doctors to diagnose sex-cord stromal tumors.

Sex-cord stromal tumors are usually treated with surgery. "If a woman is young and wants to preserve fertility, we can manage that with fertility-sparing surgery and staging," says Dr. Parker. "And a lot of patients in that category have early stage disease, and don't need further treatment after surgery."

The Third Category

The third big group of ovarian cancer tumors is germ cell tumors, and they account for about 5 percent of all primary ovarian cancer diagnoses. These tumors arise in the ovarian cells that develop eggs. “And they tend to occur in younger girls and also women in their early twenties,” says Dr. Parker. Doctors can test women with suspected germ cell tumors for elevated levels of three different markers:

• alpha-fetoprotein (AFP)
• lactate dehydrogenase (LDH)
• human chorionic gonadotropin (hCG)

Most germ cell ovarian tumors are diagnosed early and treated with surgery. Chemotherapy isn’t generally necessary unless the cancer is diagnosed at a later stage. “And the cancer can usually be treated with fertility-sparing surgery,” says Dr. Parker, “meaning that if we have to take out one ovary we can leave the tube on that side, we can leave the tube and ovary on the other side, and we can leave the uterus in place so that it’s possible to have children after being treated for that type of cancer.”

Dr. Parker says it’s important for women and their doctors to know the type of ovarian cancer they’re dealing with for several reasons:

• It helps doctors know how best to treat the cancer, in terms of the type of surgery to do.
• When chemotherapy is recommended, the type of tumor helps determine which type of chemotherapy will work best.
• And it’s important for women to know what kind of tumor they have so they can learn about their genetic risk and that of other family members.

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