Epithelial ovarian cancer — the most common ovarian cancer — develops in tissue surrounding your ovaries. It includes fallopian tube cancer and primary peritoneal cancer. High-grade serous ovarian cancer (HGSOC) occurs most often and tends to spread before detection. Debulking surgery removes ovarian cancer tumors.
Epithelial ovarian cancer is the most common type of ovarian cancer. This cancer develops in the epithelial tissue, a thin lining that covers the outside of an ovary.
Cancer may also form in the lining of a fallopian tube. Or it can begin in the peritoneum, the tissue that covers your abdominal organs.
Medical experts consider fallopian tube cancers and primary peritoneal cancers to be epithelial ovarian cancers. The diseases share many similarities, including treatments.
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Ovarian cancer refers to a group of cancers that begin in your ovaries. These organs are part of the female reproductive system. Most females have two ovaries that produce eggs and hormones. From your ovaries, eggs travel through your fallopian tubes to your uterus.
Ovarian cancer is the second most common cancer that affects the female reproductive system (gynecological cancer). Uterine (endometrial) cancer is the most common. A female has a 1 in 78 lifetime risk of getting ovarian cancer.
In 2021, more than 21,400 people learned they had ovarian cancer. Epithelial ovarian cancer accounts for more than 9 in 10 of these cases. More than half of epithelial ovarian cancer cases affect people over 65.
About 3 out of 4 epithelial ovarian cancers are high-grade serous ovarian carcinomas (HGSOC). Cancer cells that are high-grade grow and spread faster than those that are low-grade.
Experts believe HGSOC grows slowly at first. It starts in your fallopian tubes. It may take up to six and a half years to reach your ovaries.
Once the cancer is in your ovaries, it spreads quickly. The cancer often affects your peritoneum and other parts of your body. Nearly 70% of HGSOCs are stage 3 or 4 at the time of diagnosis. This means the cancer has spread outside of the original tumor and is now metastatic cancer.
Less common types of epithelial ovarian cancers include:
Most cancers, including epithelial ovarian cancers, develop for no known reason. Research now suggests that many ovarian cancers actually start in cells at the end of the fallopian tubes. Then, they spread to the ovaries.
More than half of ovarian cancer diagnoses occur in people over 65 who have gone through menopause.
Certain factors may increase your risk of ovarian cancer, such as:
Epithelial ovarian cancer rarely causes symptoms in its early stage. Symptoms become more noticeable as the disease progresses. As it spreads into your peritoneum (tissue that covers your abdominal organs), fluid accumulates in your abdomen (ascites).
You may also experience:
Less common symptoms include:
There aren’t any screening tests to detect ovarian cancer early. You might have tests only if you have symptoms or are high risk. Your healthcare provider may start by performing a pelvic exam to check for unusual growths or enlarged organs.
You might have a CA-125 blood test to check for elevated levels of a protein called cancer antigen 125 (CA-125). High levels may mean you need more testing.
These imaging tests help detect ovarian cancer:
You may also undergo a laparoscopy. This less invasive procedure lets your surgeon view your reproductive organs. Your healthcare provider may take tissue samples of a tumor to biopsy for cancer cells. A biopsy is the only way to definitively diagnose ovarian cancer.
Cancer staging helps healthcare providers track a cancer’s growth. It tells your healthcare provider if the cancer has spread and affects treatment decisions. The same tests that diagnose cancer can determine the cancer stage.
There are four stages of ovarian cancer. Some stages have sub-stages. A higher stage number reflects a more advanced cancer. Ovarian cancer stages include:
Surgeons perform debulking surgery, which removes as much of the tumor as possible, followed by chemotherapy. Most people are initially cured, but the majority will get it again later.
People with early-stage cancer may choose to remove only the diseased ovary and fallopian tube.
People with advanced cancers often undergo debulking surgery to remove:
Depending on the cancer type, you may get one or more of these treatments after surgery:
Certain surgical procedures may also lower cancer risk. Surgery to prevent cancer is called prophylactic surgery. This involves the removal of your fallopian tubes and ovaries with or without a hysterectomy. This is considered in people who are at high risk due to family history (like those who have a BRCA mutation or Lynch syndrome). However, experts advise taking these actions only if medically necessary. Removing your ovaries can bring on early menopause, which has its own effects on your body.
These procedures don’t completely eliminate cancer risk. Some people may already have undetected cancer when surgery takes place.
People with BRCA gene mutations can still get primary peritoneal cancer after removal of their fallopian tubes and ovaries. Ask your healthcare provider if you should have a BRCA test to find out if you have the BRCA gene.
More than 13,000 people die from ovarian cancer every year. It’s the fifth leading cause of cancer deaths among people assigned female at birth (AFAB). But promising new treatments are under development in clinical trials. And researchers are making progress in detecting the disease earlier.
When epithelial ovarian cancer is detected before it spreads, the five-year survival rate is more than 90%. This number drops to about 30% when the cancer has spread (metastasized).
Many factors affect a cancer prognosis, including:
Call your healthcare provider if you experience:
You may want to ask your healthcare provider:
HGSOC (high-grade serous ovarian cancer) is a very aggressive ovarian cancer. The cancer grows slowly in your fallopian tubes at first. But it then spreads rapidly once it reaches your ovaries. Unfortunately, most people with HGSOC have advanced (metastatic) ovarian cancer by the time they get a diagnosis.
Yes. In fact, most epithelial ovarian tumors aren’t cancerous. Some tumors are borderline tumors or atypical proliferating tumors. They used to be known as low malignant potential tumors.
In borderline tumors, abnormal cells grow into the epithelial tissue but not your ovary’s supporting tissue (stroma). These cells usually stay in your ovary and rarely become cancer. When cancer occurs, 3 out of 4 cases are stage 1 (confined to your ovary and more treatable). These tumors tend to affect younger people.
A note from Cleveland Clinic
Epithelial ovarian cancer is the most common ovarian cancer. It includes fallopian tube cancer and primary peritoneal cancer. Ovarian cancers rarely cause symptoms in the early stages. The disease often spreads undetected by the time of diagnosis. This is especially true for HGSOC, the most common epithelial cancer. If you’re at high risk for ovarian cancer, ask your healthcare provider if preventive (prophylactic) measures are right for you.
Last reviewed by a Cleveland Clinic medical professional on 01/03/2022.
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