Epithelial ovarian cancer is the most common type of ovarian cancer. It can be easier to treat in the early stages, but as it progresses, it becomes much harder to fully cure.

Epithelial ovarian cancer makes up 85–90% of all ovarian cancers. Although it is common, it is difficult to detect in early stages and often reaches advanced stages before diagnosis.

There are several ways to treat epithelial ovarian cancer, depending on the stage and type a person has. This article will explain the types and how doctors treat them, as well as each type’s characteristics and survival rates.

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The ovaries are glands that produce eggs for reproduction. The protective outer layer of the ovaries is known as the germinal epithelium. Epithelial ovarian cancer occurs when cells in this area begin to multiply out of control, forming a tumor.

In the early stages of this cancer, a person may not experience any symptoms. But as tumors grow, they can cause damage to the body. In later stages, a person may notice pain and swelling in the pelvic area, as well as a frequent urge to urinate and trouble eating.

There are several subtypes of epithelial ovarian cancer:

  • serous
  • endometrioid
  • mucinous
  • clear cell
  • carcinosarcoma
  • malignant Brenner tumors

Serous

Serous is the most common type of epithelial ovarian cancer, making up 52% of diagnoses. It has two forms: high grade and low grade. A doctor determines the grade by looking at a tissue sample under a microscope and comparing it to healthy epithelial tissue. The more it looks like healthy tissue, the lower the grade.

Endometrioid

Endometrioid epithelial ovarian cancer makes up 10% of diagnoses. Doctors usually diagnose it early, so most diagnoses are low grade. It can have links to endometriosis.

Mucinous

Mucinous epithelial cancer makes up 6% of diagnoses. It can be difficult for doctors to diagnose. Doctors will typically check whether it started in the ovary or spread there from somewhere in the digestive system.

Clear cell

Clear cell epithelial cancer also makes up 6% of diagnoses. It can also relate to endometriosis, and doctors treat it in the same way as high grade serous cancer. However, chemotherapy treatment is usually less effective for this type than for other types.

Carcinosarcoma and malignant Brenner tumors

Carcinosarcoma is a type of cancer that has features of both carcinoma and sarcoma. Carcinoma is a cancer that forms in epithelial tissue, and sarcoma is a cancer that forms in bones and soft tissues. This type of cancer can form in the ovaries, although that is uncommon.

Brenner tumors are very rare. Only 2–3% of ovarian tumors are Brenner tumors, and only 1% of these are cancerous.

Any cancer can be more or less aggressive, case by case. But in general, doctors consider epithelial ovarian cancer to be aggressive. This is because high grade serous epithelial ovarian cancer is very aggressive and makes up the majority of cases.

Epithelial ovarian cancer is curable, but it depends largely on the stage at diagnosis. It can be hard for doctors to tell whether a person is in remission or whether the cancer is completely gone.

Remission occurs when cancer signs and symptoms either reduce or disappear. In partial remission, signs and symptoms partially reduce or disappear, while in complete remission, they disappear completely.

In contrast, “cured” means that a person’s cancer is gone and will never come back. If a person’s cancer stays in complete remission for 5 years or more, some doctors consider this an indication that the cancer is cured, as recurrence usually happens within 5 years. However, in rare cases, ovarian cancer can return after more than 5 years.

One way of measuring survival rates is with the 5-year relative survival rate, a measurement of the likelihood that a person with a type of cancer will live for the next 5 years in comparison to people of a similar age who do not have cancer.

For example, a 50% survival rate means that a person with that type of cancer is 50% as likely to survive the next 5 years as a person without that cancer.

The overall 5-year survival rate for all stages and subtypes of epithelial ovarian cancer is 50%.

In cases where the cancer is still localized, meaning it has not spread to other areas, the survival rate is 93%. If it has spread to the nearby region, the survival rate is 75%. If it has spread to distant areas, the rate is 31%.

These figures come from the years 2012 through 2018, so they may not reflect the most recent advances in cancer treatment, and they do not predict what will happen in each individual case. The outlook will vary for each person based on their unique situation.

The treatment for epithelial ovarian cancer can include surgery, chemotherapy, or targeted therapy.

Surgery

Surgery for epithelial ovarian cancer can have two goals: staging and debulking.

Staging

Surgical staging is when a doctor removes parts from the ovary and other areas to see how advanced the cancer is.

When staging epithelial ovarian cancer, a doctor will often remove the uterus, both ovaries, and both fallopian tubes. This means a person will no longer be able to become pregnant.

The surgeon may also remove the omentum, which is a fatty layer covering the abdomen, as well as certain lymph nodes in the pelvis and abdomen.

Doctors then test the tissues to see where the cancer has spread. Staging is important because different stages of cancer require different treatments. For example, low grade stage 1 ovarian cancer may not need any further treatment after surgery.

Debulking

Debulking is when a surgeon removes as much of a tumor as possible. Optimal debulking leaves behind no visible tumors, or no tumors bigger than 1 centimeter.

Debulking can significantly improve a person’s outlook. During the surgery, doctors may need to remove other body parts to remove the cancer. This could potentially include:

  • part of the intestines
  • part of the bladder
  • part of the stomach
  • part of the liver
  • part of the pancreas
  • the spleen
  • the gallbladder

Chemotherapy

Chemotherapy involves taking drugs to stop cancer cells from growing, either by killing them or by preventing them from dividing. There are two broad types: systemic and regional.

In systemic chemotherapy, the drugs enter a person’s bloodstream to reach cancer cells throughout the body. In regional chemotherapy, a doctor delivers the drugs into a specific part of the body.

Intraperitoneal chemotherapy is a type of regional chemotherapy for epithelial ovarian cancer. In this procedure, a doctor uses a thin tube to deliver the drugs into the peritoneal cavity, where the abdominal organs are.

Targeted therapy

Targeted therapy is a drug treatment that targets specific cancer cells.

One type of targeted therapy uses monoclonal antibodies. These are laboratory-grown immune system proteins that can detect cancer cells and signal for the immune system to attack them, or deliver anticancer substances directly to them.

Another type of targeted therapy uses poly polymerase inhibitors. These can stop DNA repair, which can kill cancer cells.

Epithelial ovarian cancer is the most common type of ovarian cancer, making up 85–90% of all cases.

Because people might not experience symptoms in the early stages, doctors may not detect the most common forms of epithelial ovarian cancer until the cancer has reached an advanced stage. At that point, it is difficult to cure entirely.

However, when people receive treatment in the early stages, the survival rates are high, and many people can go into remission. Additionally, new treatments, such as radiation therapy and immunotherapy, are currently in clinical trials and may improve survival rates in the future.