Mucinous ovarian cancer is a rare subtype of epithelial ovarian cancer. Surgery is the best way to treat this type of cancer as it does not respond well to chemotherapy.

According to the American Cancer Society (ACS), mucinous ovarian cancer accounts for about 6% of ovarian carcinomas, the term doctors use for cancerous epithelial tumors.

Doctors categorize ovarian carcinomas by the type of cells that make up the tumor, which can be serous, clear cell, mucinous, or endometrioid. Serous carcinomas are the most common, according to the ACS.

This article provides a detailed look at mucinous ovarian cancer, including the symptoms a person may experience, the treatments available, and what getting a diagnosis can involve.

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Mucinous ovarian cancer is a rare form of ovarian cancer and is a subtype of epithelial ovarian cancer.

About 85–90% of malignant ovarian tumors involve epithelial ovarian cancer. Ovarian epithelial tissue covers the outside of the ovaries.

Learn more about the different types of tumors here.

Mucinous cancer cells produce thick mucus. Typically, this type of cell forms in the inner part of the cervix, stomach, and intestines.

The University of Chicago Medical Center explains that mucinous cancer cells are large and filled with fluid, and cells with a mucus coating mostly make up the tumors.

They may resemble cancerous cells that can grow in the gastrointestinal system, which can make determining whether a person’s mucinous ovarian cancer began in the ovaries or in a different area of the body difficult.

When cancer begins in one area of the body and spreads to another, it is known as metastatic cancer.

Research published in 2020 found that around 80% of mucinous ovarian cancer develops after cancer from a different primary site spreads to the ovary.

According to this research, 45% of mucinous carcinomas metastasized from the gastrointestinal tract, 20% began in the pancreas, 18% in the cervix and endometrium, and 8% in the breast.

However, mucinous cancer may also develop as a primary tumor in the ovary.

About 80% of primary tumors are at stage 1 of the disease when a person receives a diagnosis.

Learn more about the timing and stages of ovarian cancer here.

People with mucinous ovarian cancer may have a large mass on their ovary, which can produce the following symptoms:

A person may receive a diagnosis of mucinous ovarian cancer early on in the disease because of the fact that tumors can grow to be large and produce a wide range of symptoms.

A 2017 case report showed that early stage mucinous ovarian cancer can produce other noticeable symptoms, such as a nonproductive cough, shortness of breath, and joint pain.

In this case, the person had developed extensive blood clots that led to their diagnosis of mucinous ovarian cancer. However, the authors write that this case was a rare presentation of the disease.

Learn more about the early symptoms of ovarian cancer here.

Currently, the cause of mucinous ovarian cancer is not clear. According to research from 2020, the only risk factor that studies have identified is tobacco smoking.

Learn more about the negative health effects of smoking here.

A person may be at a higher risk of other forms of ovarian cancer due to the following factors:

However, according to research, these risk factors do not apply to mucinous ovarian cancer.

For instance, the ACS states that ovarian cancer is rare in females under the age of 40 and that more than half of all ovarian cancers occur in women aged 63 or older.

In contrast, women between the ages of 20 and 40 are more likely to develop mucinous ovarian cancer, according to 2019 research.

According to 2021 research, in 65–80% of cases, people receive a diagnosis of mucinous ovarian cancer in stage 1 of the disease.

British cancer charity Cancer Research UK writes that a person may need a pelvic exam as part of the diagnosis process. This can be external or internal.

A person may also need an ultrasound scan to build a detailed picture of their ovaries, cervix, and surrounding organs and tissue. This may be an abdominal ultrasound scan or a transvaginal scan. In some cases, a person will have both.

Blood tests, including CA-19, CA-125, and carcinoembryonic antigen (CEA) tests, can guide a person’s diagnosis. Doctors can also use them to predict a person’s outlook and see how well the cancer is responding to treatment.

A 2020 study found that elevated levels of cancer antigens CA19-9, CA-125, and CEA are useful in the diagnosis process to differentiate between benign, borderline, and malignant mucinous ovarian tumors.

A person will need to have a biopsy to definitively diagnose mucinous ovarian cancer. A doctor will usually do this during a person’s surgery. After this, a pathologist will analyze the sample under a microscope.

A person may also have an MRI scan. An MRI can show if a person’s mucinous ovarian cancer is a primary tumor or if it has spread from a different site in the body.

A person will typically have surgery to treat mucinous ovarian cancer.

The main aim of surgery to treat mucinous ovarian cancer is to remove all visible cancer or tumors larger than 1 centimeter (cm), which doctors term “optimally debulked.”

The ACS explains that people have a better outlook when a surgeon has optimally debulked the tumors compared with people who have larger tumors left after surgery. When a person still has some tumor remaining, doctors call it “suboptimally debulked.”

Although it can vary, a person may have surgery to remove their ovaries, cervix, uterus, and fallopian tubes. A person may also have surgery to remove the lymph nodes in the pelvis and abdomen to check if cancer has spread to those areas.

In some cases, a person will have their appendix removed, too. This is because mucinous ovarian cancer can spread to the appendix.

For people with early stage mucinous ovarian cancer, surgery may be the only treatment they need to have.

Those with advanced stage cancer may need additional treatment, such as platinum-based forms of chemotherapy.

However, according to 2020 and 2021 research, platinum-based chemotherapy is not an effective treatment for mucinous ovarian cancer. This may be because doctors designed this kind of chemotherapy to treat different types of ovarian cancer, and mucinous ovarian cancer has a different genomic structure.

The 2021 research says older studies found that the response rates of mucinous ovarian cancer to platinum-based chemotherapy were 12–35%, compared with 70% in high-grade serous carcinoma.

Learn more about what happens if chemotherapy is not working here.

A person’s outlook when living with mucinous ovarian cancer depends on which stage the disease has reached. Their outlook may improve if they receive a diagnosis in stage 1 of the disease.

The overall 5-year survival rate for early stages of the disease is 90%.

The survival rate refers to the proportion of people who are still alive for a length of time after receiving a particular diagnosis. For example, a 5-year survival rate of 50% means that 50% of people are still alive 5 years after receiving the diagnosis.

It is important to remember that these figures are estimates and relate to the results of previous studies or treatments. A person can consult a healthcare professional about how their condition is going to affect them.

How much of the tumor a surgeon has removed may influence a person’s outlook.

If a person receives a diagnosis in the later stages of the disease, their outlook can be worse. This may also be the case if a person has metastatic mucinous ovarian cancer.

A person may live for 12–30 months if they have advanced mucinous ovarian cancer.

Mucinous ovarian cancer is a rare type of ovarian cancer. A person may experience a wide range of symptoms, including pelvic and abdominal pain, bloating, and fatigue.

Typically, a person will need to have surgery to remove the tumor, which may involve removing the ovaries, cervix, and uterus. Research suggests that platinum-based chemotherapy that doctors use for other types of ovarian cancer is generally not as effective against mucinous ovarian cancer.

The outlook for people with mucinous ovarian cancer varies according to what stage of the disease a person receives a diagnosis at. Early diagnosis will improve the survival rate for this particular type of cancer.