Skip to main content

What is ovarian cancer?

Ovarian cancer includes cancers that start in the ovaries, fallopian tubes, and the lining of the abdomen (peritoneum). Doctors use imaging tests and look at the tissues to tell where cancer started. Cancer that starts in those three areas behave similarly and are treated similarily, so they are grouped together as ovarian cancer. 

Normal, healthy cells grow, divide and die in a controlled process. Cancer cells are different because they:

  • Grow out of control and divide into new abnormal cells 
  • Outlive normal cells
  • Lead to the growth of a tumor 
  • Can spread (metastasize) to other parts of the body

Cancer is named for the body part where it starts, even if it spreads to other body parts later. Gynecologic cancers are cancers that start in the female reproductive organs. Ovarian cancer is a gynecologic cancer that starts in the ovaries. Ovarian cancer has many different types, which can be broken down into different subtypes. The main types include:

  • Epithelial ovarian cancers 
  • Germ ovarian cancers
  • Stromal cell ovarian cancers 

When ovarian cancer is diagnosed, your doctor will try to determine if it has spread throughout the body and how far. This is called staging. Ovarian cancer stages are numbered 1 to 4. Stages may also be written as I, II, III, and IV. Each stage can be broken down into smaller substages that provide more detail about the cancer. 

Besides ovarian cancer, other gynecologic cancers include:

  • Cervical cancer: Cancer that starts in the cervix, which connects the vagina to the upper part of the uterus. Cervical cancer is the only gynecologic cancer that can be screened for to try and prevent. 
  • Uterine cancer: Cancer that starts in the uterus (womb). The uterus is a pear-shaped organ in a woman’s pelvis. The uterus is where the baby grows during pregnancy.
  • Vaginal cancer: Cancer that starts in the vagina. The vagina is also called the birth canal. It is a hollow, tube-like channel that a baby goes through when it is born.  
  • Vulvar cancer: Cancer that forms in the vulva, the outer part of the female genital organs. The vulva includes the opening of the vagina, outer lips (labia majora), and inner lips (labia minora), and clitoris.

Where are your ovaries located?

The ovaries are two small, almond-shaped organs in the pelvis, which is the lower area between the hips. They are located on either side of the uterus. The ovaries store eggs and produce the female hormones estrogen and progesterone.  

An ovary is made up of three cells:

  • Epithelial cells cover the surface of the ovary. They also line the fallopian tubes.
  • Germ cells are the reproductive cells of the ovaries. They are also called egg cells or oocytes. 
  • Stromal cells make up certain types of connective tissue. They produce estrogen and progesterone. 

The most common type of ovarian cancer starts in the epithelial cells. This accounts for about 85% to 90% of ovarian cancers. Germ cell and stromal cell cancer are less common.

What causes ovarian cancer?

The exact cause of ovarian cancer is unknown. There are many ideas about what causes the disease. Ovarian cancer starts when the DNA in ovarian cells mutates (changes). DNA contains instructions that tell a cell what to do. When DNA mutates, it tells the cells to grow and multiply quickly. This creates a mass of cancer cells that continue to grow while healthy cells die. 

A small number of ovarian cancers occur in those who have inherited mutations linked to an increased risk. These include mutations in the BRCA1 and BRCA2 genes. These genes usually protect you from getting certain cancers. Mutations in these genes prevent them from working properly. You are more likely to get certain cancers if you inherit these mutations.

Acquired mutations are gene mutations that occur during a person’s life. The cause of most acquired mutations is currently unknown. But most ovarian cancers have several acquired mutations, including TP53, PTEN, and PALB2. 

Although there is no known way to prevent ovarian cancer, there are certain things that can reduce your risk, including:

  • Pregnancy 
  • Birth control pills
  • Tubal ligation 
  • Hysterectomy

How is ovarian cancer diagnosed?

There is no early detection test or effective screening tool for ovarian cancer. Surgery is the only way to make a clear diagnosis. Your doctor may perform a biopsy to remove tissues from a tumor. A pathologist will look at the tissues to determine if it is cancer. 

If you have signs or symptoms of ovarian cancer, there are tests that can help in getting a diagnosis. These include:

  • Pelvic exam: This exam checks for an enlarged ovary or signs of fluid in the abdomen. The doctor examines the uterus, vagina, ovaries, bladder and rectum for any unusual changes such as a mass. 
  • Transvaginal ultrasound: This examination uses a small instrument placed in the vagina to look at the ovaries and uterus. It is used for people with ovaries who have an increased risk for ovarian cancer or those with an abnormal pelvic exam.
  • CA-125 blood test: This measures the level of CA-125, a protein found in higher levels in people with ovarian or fallopian tube cancer. It is important to know that CA-125 levels may increase due to other health conditions, not just ovarian cancer. 

What is the prognosis for ovarian cancer?

No two people with ovarian cancer are alike, and outcomes can vary depending on many factors. Survival rates can provide an idea of how many people are still alive for a certain period of time after being diagnosed or starting treatment. They are usually given for a five-year period. Survival rates are estimates and not predictions. 

Historically, the five-year survival rate for ovarian cancer diagnosed in stage I has been cited as over 95%. But survival rates vary based on the type of ovarian cancer. Some ovarian cancers are more aggressive than others, regardless of the stage. Recent clinical trials have found that some women diagnosed in late stages have a positive prognosis. There may be something about their particular cancer that is less aggressive than others. Experts are still conducting research to understand why that is.

About the National Ovarian Cancer Coalition

For over three decades, the National Ovarian Cancer Coalition (NOCC) has been the leading advocacy organization for people with ovarian cancer. From our humble beginnings as a grassroots effort, we have grown into an important national voice in the fight against this disease. We support the quality of life of ovarian cancer survivors and their caregivers. We are here for you no matter where you are in your ovarian cancer journey. We provide you with the programs, resources, and direct support services that help you thrive—not just survive—with an ovarian cancer diagnosis.

Related Topics


Get information about the tests that are available for making a diagnosis when ovarian cancer is suspected. 

Who's at risk?

Understand the risk factors of ovarian cancer and learn what to do if you or someone you love are at an increased risk.

Signs and symptoms

Knowing what to look for is important, especially if you’re at increased risk; the signs and symptoms of ovarian cancer are often vague or mimic other ailments.  

Make a donation

Contact us

Find a support group