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NCCN Guidelines for Patients



Ovarian Cancer, Version 1.2017


Ovarian cancer

Cancer cells

Cancer cells make new cells that aren’t needed

and don’t die quickly when old or damaged. Over

time, cancer cells grow and divide enough to form

a mass called a tumor. The first tumor formed by

the overgrowth of cancer cells is called the primary


Types of ovarian cancer

The ovaries are made up of three main types of cells:

epithelial cells, stromal cells, and germ cells. Cancer

can start in each type of cell. Thus, there is more

than one type of ovarian cancer.

Most ovarian cancers start in the epithelial cells.

This is called epithelial ovarian cancer. Epithelial

cells form the outer layer of tissue around the

ovary. This layer of tissue is called the epithelium.

See Figure 3.

About 90 out of 100 ovarian cancers

are epithelial ovarian cancer. Because it is the most

common type, it is often simply referred to as ovarian


Borderline epithelial tumors [LMP (






otential] also start in the epithelial cells. It is a rare

type of epithelial ovarian cancer. LMP tumors don’t

grow into the supporting tissue of the ovary. The

tumor cells may spread and grow on the surface of

nearby organs and tissues. But, they almost never

grow into (invade) tissue the way fully cancerous

cells do.

This guideline also discusses other LCOH (








istopathologies) including

carcinosarcomas (MMMTs [








umors) of the ovary, clear cell carcinomas,

mucinous carcinomas, low-grade (grade 1) serous

carcinomas/endometrioid epithelial carcinomas,

malignant sex cord-stromal tumors, and malignant

germ cell tumors.

It is helpful to understand that the terms carcinoma

and malignant both refer to cancer when used in the

names of the LCOH. The term carcinoma means

cancer that starts in the cells that form glands or the

lining or organs. Malignant is also used in the names

and also means cancer.

Cancer cells

Cancer cells act differently than normal cells in three

key ways. First, cancer cells grow without control.

Unlike normal cells, cancer cells make new cells that

aren’t needed and don’t die when they should. The

cancer cells build up to form a primary tumor.

Second, cancer cells can grow into (invade) other

tissues. This is called invasion. Normal cells don’t

do this. Over time, the primary tumor can grow large

and invade tissues outside the ovary. Ovarian cancer

often invades the fallopian tubes and uterus.

Third, cancer cells don’t stay in one place as they

should. Unlike normal cells, cancer cells can spread

to other parts of the body. This process is called

metastasis. Ovarian cancer cells can break off

(shed) from the primary tumor to form new tumors

on the surface of nearby organs and tissues. These

are called “implants” or “seeds.” Implants that grow

into supporting tissues of nearby organs are called

invasive implants.

Cancer cells can also spread through blood or lymph

vessels. Lymph is a clear fluid that gives cells water

and food. It also has white blood cells that help fight

germs. It travels in small tubes (vessels) to lymph

nodes. Lymph nodes are small groups of disease-

fighting cells that remove germs from lymph. Lymph

vessels and nodes are found all over the body.


Figure 4.