Primary peritoneal cancer is a rare cancer of the peritoneum, a layer of tissue lining the abdomen. People often don’t notice symptoms until the cancer has progressed. As a result, most people are diagnosed with peritoneal cancer at a later stage. The first treatments tend to be surgery followed by chemotherapy or targeted therapy.
The peritoneum also covers organs inside your abdomen, including the:
Your peritoneum is made of epithelial cells which protect surfaces of your body. The peritoneum also produces fluid that lets your organs move inside your abdomen.
Primary peritoneal cancer occurs when the cells within the peritoneum grow abnormally.
Healthcare providers classify peritoneal cancer based on where it first occurs:
Primary peritoneal cancer is very rare. Providers diagnose fewer than 7 in 1 million cases each year. But those numbers may be somewhat misleading. Researchers estimate that up to 15% of women diagnosed with advanced ovarian cancer may actually have peritoneal cancer.
Women have a higher risk of primary peritoneal cancer than men. Peritoneal cancer risk factors are similar to ovarian cancer and include:
Peritoneal cancer starts in a different place than ovarian cancer. Ovarian cancer usually starts inside the ovaries or in the cells at the far end of the fallopian tubes. Peritoneal cancer forms in the cells lining the inside of your abdomen and covering the organs contained within your abdomen.
People may easily confuse peritoneal and ovarian cancers. The same type of cells (epithelial) line the peritoneum and cover the ovaries. Both cancers spread along the internal lining of the abdomen, which often makes it difficult to detect where cancer started.
People diagnosed with peritoneal cancer are usually older than those diagnosed with ovarian cancer. The prognosis for peritoneal cancer is also worse than that of ovarian cancer.
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Researchers don’t know exactly why some people develop primary peritoneal cancer. People born with certain gene mutations (changes) have a higher risk of the disease.
As with ovarian cancer, people often don’t notice symptoms in the early stages of the disease. If they do, symptoms are often vague. Most people notice symptoms once cancer has advanced (grown).
If someone does have symptoms in the early stages, they may include:
As peritoneal cancer grows, additional symptoms may develop, including:
People with advanced peritoneal cancer may have the following complications:
Your healthcare provider will start with a history and physical exam and ask about any symptoms you’re experiencing. If your symptoms point to peritoneal cancer, you may have:
You may be referred to a genetic counselor to discuss genetic testing for certain conditions associated with an increased risk of peritoneal cancer if you have any of the following:
Since most people don’t develop symptoms in the early stages of primary peritoneal cancer, people are typically found to have stage 3 or 4 cancer once they are diagnosed.
Stage 3: Cancer has spread outside of the pelvis or to the lymph nodes located behind the abdomen.
Stage 4: Cancer has spread to organs outside of the abdomen such as the lungs, liver, spleen or to the tissue lining the lungs and chest.
Treatment for primary peritoneal cancer depends on:
Your provider will usually perform surgery as the first treatment. You may have a procedure called cytoreductive surgery. This surgery aims to remove as much cancer as possible. Research shows that outcomes are better when a gynecologic oncologist performs the surgery. These doctors specialize in treating conditions affecting female reproductive organs, including cancer.
Your surgeon may also remove the:
To stop cancer cells from spreading to other areas of the body, your treatment plan may also include:
You may have a lower risk of developing primary peritoneal cancer if you have ever:
Some people with a strong family history of ovarian cancer or BRCA gene mutations who have a higher risk of developing peritoneal cancer may choose to have their ovaries and fallopian tubes removed. While this procedure reduces the risk of developing peritoneal cancer, it doesn’t completely eliminate it.
Since providers usually don’t diagnose peritoneal cancer until a later stage, the prognosis is poor. Cancer often returns after treatment. But getting an earlier diagnosis can help improve outcomes.
About half of people with peritoneal, fallopian tube or ovarian cancer live five years or more after their diagnosis. Younger people tend to live longer, while older people tend to have a worse prognosis.
Survival rates may be higher if:
Several clinical trials are testing new ways to treat peritoneal cancer. New treatments include targeted therapies and immunotherapy. Immunotherapy works by stimulating your immune system to recognize and attack cancer cells within your body.
Your provider may suggest seeing a palliative medicine provider (a field of medical care that focuses on addressing and relieving symptoms of a serious illness) to help manage your symptoms from advanced peritoneal cancer. Your care may include:
Finding a support group of other people going through treatment can help you feel less alone. Family members can also find support groups to help them better understand what you’re going through.
A note from Cleveland Clinic
Primary peritoneal cancer is a rare type of cancer that occurs in the tissue lining the abdomen. People with peritoneal cancer often don’t experience symptoms until cancer has grown. So, many people are diagnosed with peritoneal cancer at later stages. Promising treatments such as HIPEC and targeted therapies, along with surgery, can improve outcomes. Clinical trials are also underway to discover additional treatment options that can increase survival rates.
Last reviewed by a Cleveland Clinic medical professional on 04/12/2022.
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