PRIMARY PERITONEAL CANCER (PPC)
Cancer occurs when cells in an area of the body grow in an abnormal way. Primary peritoneal cancer (PPC) is a relatively rare cancer that develops most commonly in women. PPC is a close relative of epithelial ovarian cancer, which is the most common type of malignancy that affects the ovaries. The cause of primary peritoneal cancer is unknown, but it is important for women to know that it is possible to have primary peritoneal cancer even if their ovaries have been removed.
The abdominal cavity and the entire surface of all the organs in the abdomen are covered in a cellophane-like, glistening, moist sheet of tissue called the peritoneum. It not only protects the abdominal organs, it also supports and prevents them from sticking to each other and allows them to move smoothly within the abdomen. The cells of the peritoneal lining develop from the same type of cell that lines the surface of the ovary and fallopian tube for that matter. Certain cells in the peritoneum can undergo transformation into cancerous cells, and when this occurs, the result is primary peritoneal cancer. It can occur anywhere in the abdominal cavity and affect the surface of any organ contained within it. It differs from ovarian cancer because the ovaries in PPC are usually only minimally affected with cancer.
Fallopian tube cancer
The fallopian tubes are a pair of floppy tube-like structures that originate at the top (fundus) of the uterus where they communicate with the endometrial cavity and course away from the uterus, on either side, towards the ovaries where they “flop” over the ovaries with their finger-like (fimbriated) end. Cancers of the fallopian tube are also relatively rare and very closely related to cancers of the ovary and PPC. They share many commonalities and emerging data is even suggesting that many of the previously felt to be ovarian cancers may indeed have been Fallopian Tube Cancer (FTC).
Although the clinical presentation of FTC is very similar to ovarian cancer and PPC, there are some differences. Cancers of the fallopian tube arise within the inside (lumen) of the fallopian tube and typically cause it to swell like a sausage. The involvement of the ovary is secondary, but it is usually so extensive that one cannot tell whether it began on the ovary and spread to the fallopian tube, or vice versa. Because of that, many fallopian tube cancers may have been classified as ovarian cancers. As the fallopian tube swells with cancer, it produces fluid, similar to ascites, that can “leak” back into the uterus and lead to a watery vaginal discharge, the classic presentation of FTC when associated with an adnexal mass.
PPC and FTC symptoms
Unfortunately, because of the vague nature of the signs, PPC and FTC are usually diagnosed in advanced stages of disease, when achieving a cure is difficult.
The typical symptoms of both are more commonly gastrointestinal rather than gynecologic in nature, and include:
- Abdominal bloating
- Changes in bowel habits
- Early feeling of fullness after eating
- Bloating and when severe, nausea and vomiting may result
Occasionally, patients can present with a blockage of the intestines related to tumor on or next to the bowels. Vaginal bleeding is infrequently seen in patients with PPC, but may be a little more common in patients with FTC.
Medical evaluation and diagnosis
Both PTC and FTC are usually diagnosed when a woman sees her doctor complaining of abdominal swelling and bloating. As described above, the symptoms of either cancer are more commonly gastrointestinal than gynecologic in nature. These symptoms are related to the accumulation of fluid, also known as ascites, that commonly occurs with either cancer. Gastrointestinal symptoms also occur because seedlings of tumor often line the peritoneal surface (the outer lining) of the intestines, a process called carcinomatosis. The omentum, an apron of fatty tissue that hangs down from the colon and stomach, often contains bulky tumor, described as omental caking. Although omental cakes can be detected on a physical exam, they frequently are subtle and difficult to detect. When a woman is found to have fluid in the abdomen (ascites), the usual first step toward a diagnosis is a CT scan. This is a special type of x-ray test that allows doctors to assess the entire abdomen and pelvis. Omental caking and ascites, as well as other tumor growths, are commonly seen, and point toward the diagnosis of PPC, FTC or ovarian cancer. Other cancers can cause these findings, thus, further tests are needed and are usually focused around ruling out other more common cancers, such as colon and breast cancer.
Frequently, the evaluation of ascites begins with a procedure known as a paracentesis, whereby fluid is removed from the abdomen using a needle. The fluid is examined under the microscope, looking for the presence of cancerous cells. Unfortunately, this procedure is not without risks as the process of performing a paracentesis can actually “seed” the abdominal wall with cancer cells. Therefore, it is important to seek the advice of a gynecologic oncologist when considering this procedure as it may not be necessary given that most patients with these findings will undergo surgery regardless of the results. However, it may be helpful in the patient who is either not a surgical candidate, or in one suspected of having ascites for reasons other than cancer, such as liver or heart disease. Sometimes fluid is even drawn off because of patient discomfort until surgery or chemotherapy can be scheduled.
There are several blood tests that are frequently performed when either PPC or FTC is suspected. The most common of which is the CA 125 blood test. CA 125 is a chemical that is made by tumor cells and is usually elevated in patients with PPC and FTC. Unfortunately, it can also be elevated in a variety of benign conditions, as well as other cancers, and thus an elevated CA 125 blood test does not mean the patient has a cancer. More recently a newer blood test, HE4, can also be used as it is less likely elevated than CA 125 in benign conditions. You can read more about CA 125 with our brochure, CA 125 Levels: Your Guide.
The actual diagnosis of PPC or FTC is often not completely certain until a woman undergoes surgery. This is because the clinical presentation of either disease is so similar to that of epithelial ovarian cancer. PPC, FTC and ovarian cancer appear identical under the microscope. It is the pattern of tumor distribution and organ involvement in the abdominal cavity that indicates the origin of the primary cancer. Patients with FTC usually have gross involvement of the fallopian tubes with lesser involvement of the ovaries. Patients with PPC are usually found to have normal ovaries, or only superficial involvement of the ovaries, at the time of pre-surgical imaging tests or at time of surgery. However, the diagnosis can occasionally remain uncertain even following surgery.
Surgical staging of cancers is performed in order to fully assess the extent of disease. This allows for decisions to be made regarding additional therapy, which is usually in the form of chemotherapy. Surgical staging generally involves removal of all visible disease, as well as removal of the ovaries, fallopian tubes and uterus. It can also include removal of the omentum, lymph nodes and other organs depending on the surgical findings.
While there is no formal agreed-upon staging system for PPC, because it is so similar to ovarian cancer with respect to treatment, tumor state is typically assigned using guidelines established for ovarian cancer.
Stages I through IV describe how far the tumor has spread. Nearly all patients diagnosed will have Stage III or higher because warning signs are typically few until the cancer is widespread. Patients with PPC or FTC may have fluid around the lungs, known as a pleural effusion. If an effusion is present, some fluid may be removed in order to look for tumor cells. If tumor cells are found in this fluid, the patient has Stage IV disease.
PPC and FTC treatment side effects
Both PPC and FTC are treated in the same way as ovarian cancer is treated. They are most often treated with surgery and chemotherapy—only rarely is radiation therapy used. Your specific treatment plan will depend on several factors, including:
- Stage and grade of the cancer
- Size and location of the cancer
- Your age and general health
All treatments for either cancer have side effects. Most side effects can be managed or avoided. Treatments may affect unexpected parts of your life, including your function at work, home, intimate relationships and deeply personal thoughts and feelings.
Before beginning treatment, it is important to learn about the possible side effects and talk with your treatment team members about your feelings or concerns. They can prepare you for what to expect and tell you which side effects should be reported to them immediately. They can also help you find ways to manage the side effects you experience.