Primary Peritoneal Cancer: Know the Basics

CUREWomen's Cancers
Volume 1
Issue 1

Understand how the rare relative of ovarian cancer is diagnosed and treated.

Joanne Wilson was feeling less like herself — she was always tired, sometimes struggling just to get up in the morning, and packing on pounds. But she kept coming up with excuses to explain the problem: Then age 56, Wilson chalked up the weight gain to menopause. As for the fatigue — the retired legal secretary hadn’t had a break in quite a while. First she saw her mother-in-law through surgery, then she and her husband sold their house, and then she helped her sister-in-law when she had surgery. “I was exhausted,” Wilson says.

But then came a symptom Wilson couldn’t explain. “I realized I couldn’t eat that much — like my stomach had shrunk,” the 57-year-old recalls. “I could only eat about a half a cup of food at a time before I felt like I had just finished Thanksgiving dinner. But yet, I was still putting on weight.” She was constipated, too.

Out of town when the symptoms really started to bother her, Wilson went to an urgent care clinic. She was told she had Helicobacter pylori, a bacterial infection of the intestines, and to follow up with her primary care doctor. The next day, back home in Summerville, South Carolina, she visited her doctor of 27 years.

JOANNE WILSON began feeling full all the time and gaining weight, which can be signs of primary peritoneal cancer.

“From the moment he saw me, he said, he was concerned because there was something odd about my girth,” Wilson says. She was bloated throughout her torso, from the rib cage down. The doctor sent her for a computerized tomography (CT) scan right then. “The next morning, about 9:15, I got the call,” Wilson says. “He said, ‘I think you have cancer.’”

The CT scan revealed tumors on her liver and bladder, an enlarged right ovary and a thickened omentum — an apron of fat that hangs from the stomach and liver and wraps around the intestines. It’s part of the peritoneum, the lining of the abdomen that envelops most of the abdominal organs like plastic wrap. Caking, or thickening, of the omentum is a sign of a gynecologic cancer. Wilson’s longtime doctor referred her to a gynecologic oncologist.

Things moved quickly from there. The next day, Wilson had more than three liters of murky, brown fluid drained from her abdomen. After a few days, she got a call confirming that the spots on the CT scan were cancer, but its type and stage could be determined only by surgery to remove the tumors. A week later, Wilson had her omentum, ovaries and fallopian tubes removed. The tumors on her liver tumor and bladder were inoperable. Her diagnosis: stage 3C primary peritoneal cancer.


Wilson had never heard of peritoneal cancer. Like most women, she thought gynecologic cancers involved only the ovaries, uterus or cervix. Primary peritoneal cancer is a rare relative of ovarian cancer — in every 1 million people, fewer than seven cases occur.

It starts in the peritoneum — or at least that is where it is first identified. “Most of the time, it’s probably seeded from the ovaries or the fallopian tubes,” says Elizabeth Swisher, M.D., director of the breast and ovarian cancer prevention program at Seattle Cancer Care Alliance. “Or it could arise in endometriosis. It starts in the gyneco­logic tissues.”

Women may experience gastrointestinal symptoms, such as abdominal bloating, changes in bowel habits, feeling fuller sooner than usual when eating, bloating and consti­pation, more commonly than gynecologic symptoms.

Trying to distinguish ovarian, fallopian tube and peritoneal cancers from one another can be challenging. “Whether a cancer is called ovarian, fallopian tube or primary peritoneal (depends on) how much cancer is in the ovary or fallopian tubes,” Swisher says. “If it’s too little to be called ovarian or fallopian tube, it can be called primary peritoneal by default.”

Having chemotherapy to shrink the tumors as much as possible before operating can further muddy the waters. Tumors that started in the ovaries or fallopian tubes could be microscopic by the time surgery takes place, so the oncologist deems it peritoneal cancer.


Primary peritoneal cancer is most common in older women, particularly after menopause. The average age at diagnosis is 63. Risk factors also include reproductive history, such as never giving birth, having unexplained infertility or never taking birth control pills; using hormone replacement therapy; family history; and obesity.

Inherited genetic mutations that increase the risk of ovarian cancer, such as BRCA1 and BRCA2, raise the risk of peritoneal cancer, too. Certain genetic conditions, such as Lynch syndrome and Li-Fraumeni syndrome, also increase the likelihood of developing the disease.

Removing the ovaries and fallopian tubes can reduce but not completely eliminate a patient’s chance of developing the disease. After removal of the ovaries, women who have BRCA1 or BRCA2 mutations “still have a lifetime risk, about 1 or 2 percent, of getting peritoneal cancer,” says Jocelyn Chapman, M.D., a gynecologic oncologist and surgeon at University of California, San Francisco, Health. “We’ve all seen cases of it. A woman will have her ovaries and fallopian tubes out, then in her 60s or 70s, she develops peritoneal cancer.”

However, removing these organs can bring on side effects, such as early menopause, reduced sexual function and infertility. Researchers involved in the ongoing Women Choosing Surgical Prevention (WISP) Trial, which is taking place at seven sites around the country, are examining whether women at high genetic risk of ovarian, fallopian and peritoneal cancers can better their odds by first removing the fallopian tubes, then delaying removal of the ovaries until they choose. The doctors leading the study recommend removal of the ovaries by age 40 for women with a BRCA1 mutation, by 45 for BRCA2 mutation carriers and by menopause for women with mutations in other ovarian cancer genes.

“The standard surgery is removing the ovaries and fallopian tubes, and we know that saves lives,” Swisher says. “But many of these cancers do arise in the fallopian tubes, so women want to know whether they can just remove the fallopian tubes so (that) they won’t have to go into menopause.”

Common risk factors aside, any woman can get primary peritoneal cancer, as Amanda Sobhani learned. At 26 years old, the nutritionist in Malta, New York, was in a car accident and never felt quite right afterward. Finally, abdominal pain, which she thought might be related to the accident, prompted her to go to urgent care. The doctor thought her symptoms suggested a ruptured cyst and told her to follow up with her gynecologist, who subsequently referred her to a gynecologic oncologist after an ultra­sound revealed what looked like many cysts. That startled Sobhani, but she knew she didn’t have risk factors for a gynecologic cancer — no family history and her mother had been tested for relevant gene mutations following a pancreatic cancer diagnosis.

Still, Sobhani, like Wilson, had the classic symptoms. “My stomach was getting kind of big,” Sobhani, now 27, recalls. “I was bloated. And every time I ate — even just five or six crackers — I felt full.”

Unfortunately, because this type of cancer is so rare, doctors don’t always recognize the signs. In a small study conducted in India, researchers discovered that in countries where tuberculosis is more prevalent primary peritoneal cancer was first diagnosed as abdominal tuberculosis.

“If a woman is having some of these symptoms, it’s reasonable to think about getting a second opinion,” says Barbara Goff, M.D., chair of the Department of Obstetrics and Gynecology at the University of Washington School of Medicine in Seattle. “Way too often, patients don’t get second opinions, but if you don’t feel you’re getting the diagnostic work-up that you should, that’s when you want to be seeking a second opinion.” That’s true even if the first opinion is cancer, she adds: “It’s important to get more than one opinion when someone’s telling you that you have a serious illness.”


A doctor may perform a pelvic exam to feel for tumors or enlarged organs, but small tumors and microscopic cells could sneak by undetected. “Pelvic exams are pretty bad at (picking up these cancers),” Chapman says. “It doesn’t take a very large tumor on the ovary to slough off cells and spread to the peritoneal cavity. Before there’s even a mass that’s palpable on an exam or visible on a scan, you could already have disease floating around in the abdomen.”

Primary peritoneal cancer may elevate blood levels of the protein cancer antigen (CA) 125, but not always. “My CA 125 was normal,” Sobhani says, “yet I had cancer in other places in my body.” Elevated CA 125 levels can also be a sign of other conditions, such as endometriosis, fibroids, pregnancy and pelvic inflammatory disease. A blood test for elevated levels of another protein, human epididymis secretory protein 4 (HE4), may better predict the presence of ovarian and peritoneal cancer, but it’s also not a perfect test. “Multiple clinical trials have demon­strated that (protein) tests are not really effective for early screening,” Chapman says.

More recent research explores the viability of DNA blood tests to detect the presence of cancer cells. “As cancer cells grow, they also die, and their abnormal DNA winds up in your bloodstream,” Chapman says. “Detecting mutated tumor DNA or other genomic changes in the blood is probably where the new findings and possibilities for early detection lie.”

Depending on the size of the tumors, ultrasounds, CT scans or MRIs could pick them up. Researchers are searching for techniques, such as new dyes, that would make even the smallest tumors visible in radiologic imaging. “Then you can potentially move the needle in terms of imaging techniques for early detection, but most of those are in very early trial,” Chapman says.

Ultimately, surgery is required to definitively diagnose and stage the cancer. Nearly all patients who receive a diagnosis will have stage 3 or higher, because warning signs are typically few until the cancer is wide­spread, according to the Foundation for Women’s Cancer. In stage 3 — which is broken down into 3A, B or C — the cancer has spread outside the pelvis to other parts of the abdomen and/or nearby lymph nodes. Both Sobhani and Wilson were stage 3C. Sobhani’s peritoneal cancer had reached her appendix and colon; Wilson’s was in her ovaries and fallopian tubes and on her liver and bladder. In stage 4, cancer has spread beyond the abdominal cavity, potentially including fluid around the lungs and lymph nodes in the groin.

AMANDA SOBHANI recommends attempting small feats, such as making the bed or taking a short walk, to help with physical and mental health.


Women with primary peritoneal cancer usually have a combination of surgery and chemotherapy, just as they would for ovarian cancer. They might receive neoadjuvant therapy — chemotherapy prior to surgery — to shrink the tumors before removal.

Sobhani’s gynecologic oncologist removed a tumor from her peritoneum, near her uterus, and also took out her appendix and a section of her colon. “They removed everything they could see,” Sobhani says. “But the doctor says there are likely microscopic cancer cells, so I have to go through chemotherapy to — hopefully — kill them.”

She finished chemotherapy in early February, and although she usually felt tired and sick in the days following, getting active as soon as possible was an impor­tant part of her self-care. “I slept for the first few days after treatment,” Sonhani says, “but if you can at least make the bed or walk outside for 15 minutes, it’s really good for your physical and mental well-being.”

Wilson says that her doctor felt it would be more dangerous to remove the tumors from the surface of her liver and bladder than to leave them. “The hope was that chemotherapy (after surgery) would shrink them, and it did,” she says.

Chemotherapy after surgery is standard, and women may receive it as an oral medication, through IV infusion or an infusion directly into the abdominal cavity. “After surgery and chemotherapy,” Swisher says, “most women will go into remission, but recurrence rates remain high even though the initial response is good.”

That’s something Wilson understands well. Six weeks after she finished treatment, her CA 125 was back to normal and a CT scan showed no evidence of remaining disease. Nine months later, however, she experienced that uncomfortable full feeling again. This time she knew what it meant. A new CT scan found fluid in her abdomen and a two-inch tumor.

“It blew my mind! Eight weeks earlier, the CT scan was clear,” she says. Wilson resumed chemotherapy in January. After three rounds, her CA 125 was back to normal and her tumor was gone. “No hair once in a while, chronic constipation and neuropathy are small trade-offs to still be alive,” she says.

Researchers continue to explore how to reduce the high recurrence rates of ovarian, fallopian and peritoneal cancers. Hyperthermic intraperitoneal, or heated, chemotherapy, to which cancer cells are believed to be more sensitive, deliv­ered directly into the abdominal cavity after surgery might reduce recurrence. Other clinical trials include radiation, immunotherapy and vaccines as ways to treat or prevent recurrence of ovarian and peritoneal cancers.

Wilson doesn’t let the prospect of recurrence cloud her outlook. She sees peritoneal cancer as a condition that she may have to manage for the rest of her life. “It’s chronic— it’s not always a death sentence,” she says. “There are women who have lived 10, 15 years, some without a recurrence, some with. You get through.”

Sobhani shares that attitude: “I think the expectation is that I will have a recurrence at some point, but my doctor says he expects me to live a long life.”

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