Woman with ovarian cancer looking in the mirror.
Getty Images/Klaus Vedfelt

Ovarian cancer starts in the ovaries. The ovaries are female reproductive organs that produce eggs and hormones. The National Cancer Institute estimates there will be 19,880 new diagnoses of ovarian cancer in the United States in 2022.

There are several types of ovarian cancer. The most common is epithelial ovarian cancer, which develops when cancer begins on the surface of the ovaries.

This type of ovarian cancer is called mucinous ovarian cancer. It happens when tumors on the ovaries contain cells that produce mucus.

In this article, we will discuss mucinous ovarian cancer, its symptoms, and how it is diagnosed and treated.

Mucinous ovarian cancer (MOC) is a kind of epithelial ovarian cancer. This type of cancer begins in the cells that line the surface of the ovary. According to the American Cancer Society, 85% to 90% of ovarian cancers are epithelial.

Overall, MOC is rare. In fact, it only makes up about 6% of epithelial ovarian cancers.

mucus is a thick, protective substance that is found in the gastrointestinal, Urogenital, and respiratory systems. There are ovarian tumors filled with this fluid.

The primary or metastatic origin is what MOC can be.

  • Primary: Primary MOC begins in an ovary. According to research, this happens when healthy cells transform into cancerous cells over time.
  • Metastatic: Metastatic MOC happens because cancer that started somewhere else in the body, like the gastrointestinal (GI) tract, spread to an ovary.

Doctors are often challenged to distinguish between the two origins.

“Most of the MOCs are heterogeneous. This means tumors can contain a mixture of different types of cells. There are cells that look abnormal but aren’t yet cancer.”

There are tumors that can get large. The average size of a mucinous ovarian tumor is 18 centimeters. That is between the size of a cantaloupe and a basketball.

Primary tumors affect one ovary. Metastatic ovarian tumors can affect both.

The symptoms of MOC are similar to other ovarian cancers. Common symptoms can include:

Other possible symptoms can be.

Ovarian cancer symptoms are similar to other conditions that affect the abdomen or the pelvis. Symptoms are important to look out for.

  • Get worse over time.
  • Continue to stay around.
  • It happen more often.
  • They are more severe than usual.

People who get MOC are typically younger than those who develop other types of ovarian cancer. For example, according to a 2019 research article, the average age of diagnosis for MOC is 45 years.

According to a 2020 review, MOC also doesn’t have the same types of risk factors as other types of ovarian cancer. Right now, smoking is the only risk factor associated with this type of cancer.

The diagnostic process begins with a doctor getting your medical history and performing a physical exam. They will ask about your symptoms, when they began, and how long you’ve had them. They’ll also do a pelvic exam to feel for a mass in the area of the ovaries.

Your doctor will order additional tests if ovarian cancer is suspected. These can include:

  • Imaging tests: Imaging tests can help your doctor get a look at what’s going on in your body. Some of the types of imaging tests that may be used to diagnose ovarian cancer are:
  • Blood tests: These tests involve collecting a sample of blood from a vein in your arm and can include:
    • metabolic panel, which assesses liver and kidney function as well as other factors associated with overall health
  • Upper GI endoscopy or colonoscopy: Because MOC may originate from cancers in the GI tract, your doctor may use an upper GI endoscopy or a colonoscopy to look for a primary tumor.
  • Biopsy: A tissue sample, or biopsy, is needed to make the diagnosis of ovarian cancer. This sample is collected from the tumor and is examined in a laboratory.

A tumor can be characterized by a biopsy to see if they are consistent with the MOC. If cancer started in the ovary or another location, this includes looking at various markers.

Ovarian cancers, including MOC, are often treated with surgery. Many times, MOC is diagnosed in its earlier stages, so surgery may be the only treatment needed.

The extent of the surgery depends on how far the cancer has spread. Ovarian cancer surgery can involve removal of some or all of the following.

  • Either one or both of the ovaries.
  • One or both fallopian tubes.
  • The uterus.
  • The uterus.
  • There are lymph nodes nearby.
  • A fold of tissue in the abdomen is called the omentum.

“Pursuant to the doctor’s order, you may be asked to wash your abdominal area to see if the cancer has spread. The procedure uses a saltwater solution. The solution is removed to check for cancer cells.”

Because MOC can arise from cancers in the GI tract, appendectomy may be recommended as a part of surgery for these cancers. This is the surgical removal of the appendix.

For more advanced MOC, platinum-based chemotherapy may be recommended after surgery. However, MOC isn’t very responsive to chemotherapy.

Other treatment options for MOC may be available in the future. As a 2020 study notes, these cancers can be well suited for targeted therapy drugs.

“Ovarian cancer symptoms don’t start until they’ve spread. They are typically diagnosed at more advanced stages.”

This is not the case with MOC. Symptoms can begin to occur earlier because of the large size of the tumors. The result is a quicker diagnosis.

According to a 2020 review, 80% of MOCs are stage 1 at diagnosis. Researchers note early stage MOC has an overall relative 5-year survival rate of over 90%.

A small 2016 study further illustrates this point. Researchers compared overall survival of primary MOC with overall survival of primary serous cancer, the most common type of ovarian cancer. The relative 5-year survival rate of people with MOC was 100% compared with 58% in those with serous cancer.

The outlook for people with advanced or metastatic MOC is not nearly as good. In these cases, life expectancy generally ranges between 12 and 30 months. A 2015 study found that just 11% of people with these types of cancer survive for longer than 5 years.

Ovarian cancer is a rare type. It causes tumors that are mucus-forming. These tumors can be very large. When another type of cancer spreads, MOC can begin in the ovary.

Most MOC cases are diagnosed in the early stages because the tumors grow so large. The outlook is usually excellent when this happens. The advanced or metastatic MOC has a worse outlook.

The symptoms of MOC include abdominal pain, bloating, and a lump on one side of the abdomen. If these symptoms persist, occur frequently, or become severe, talk to a doctor.