What is the Peritoneum and what is Peritoneal Cancer?
The peritoneum is the lining of epithelial cells present inside the wall of the abdomen.(1) Peritoneal cancer is a form of rare cancer that develops in the peritoneum.(2,3,4) The peritoneum is responsible for protecting and covering the organs present in the abdomen, including your:
The peritoneum also manufactures a lubricating fluid that helps these organs in the abdomen move easily inside.(5)
Peritoneal cancer should not be confused with stomach or intestinal cancer. It is also not the same as cancers that have spread to reach the peritoneum. Peritoneal cancer begins in the peritoneum itself and is thereby known as primary peritoneal cancer.(6)
Most of the time, the symptoms of peritoneal cancer remain undetected in the early stages. This type of cancer is typically diagnosed only at an advanced stage.
However, this does not mean that every case of peritoneal cancer is the same. Not only is every case different, but the treatment and outlook for each case of peritoneal cancer also vary from person to person. Nevertheless, in spite of being diagnosed at a late stage, recent development and newer treatments have improved the survival rates of those with peritoneal cancer.
There is often a lot of confusion between peritoneal cancer and ovarian cancers. This is because peritoneal cancer looks and behaves very much like ovarian cancer since the surface of the ovaries is also made up of epithelial cells, similar to the peritoneum. This is also the reason why peritoneal and ovarian cancer causes identical symptoms. Even doctors treat both these cancers in the same method.(7)
However, despite the similarities between both cancers, you can still have peritoneal cancer if your ovaries are removed. Peritoneal cancer can develop anywhere in the abdominal cavity, and it can also affect the surface of the organs contained inside the peritoneum.
Types of Peritoneal Cancer : Primary and Secondary Peritoneal Cancer
Diagnosing your cancer as primary or secondary peritoneal cancer refers to the area where cancer started and is not a measure of the severity of the cancer.(8)
Primary Peritoneal Cancer
This type of peritoneal cancer begins in the peritoneum itself. It generally affects only women and is very rarely seen in men. Primary peritoneal cancer is closely related to ovarian cancer, and the treatment and outlook are also more or less similar.
Some people may be affected by a rare type of primary peritoneal cancer, known as peritoneal malignant mesothelioma.(9)
Secondary Peritoneal Cancer
Secondary peritoneal cancer begins in another organ within the abdomen itself, and then spreads or metastasizes to the peritoneum.(10) It is possible for secondary peritoneal cancer to start in the following organs:
- Fallopian tubes
- Small bowel
This type of cancer affects both men and women and is more common than primary peritoneal cancer. According to doctors’ estimates, nearly 15 to 20 percent of people with colorectal cancer go on to develop metastases in their peritoneum. Additionally, 10 to 15 percent of those with stomach cancer will develop metastases in the peritoneum.(11)
Once cancer metastasizes from the original site of cancer, the new site will also have the same type of cancerous cells that are present in the original site.
What are the Symptoms of Peritoneal Cancer?
As mentioned above, the symptoms of peritoneal cancer are usually not felt before the cancer reaches an advanced stage. The symptoms also depend on the type of peritoneal cancer you have and the stage of the cancer. During the early stages, there are unlikely to be any symptoms. In some cases, even in the advanced stages, peritoneal cancer does not present any symptoms.
Early-stage symptoms of peritoneal cancer can be quite vague and could also be caused by other medical conditions. Some of the common symptoms of peritoneal cancer include:
- Enlarged abdomen
- Abdominal pain or bloating
- Nausea and/or vomiting
- Feeling of pressure in the pelvis or abdomen
- Feeling full after eating just a little bit of food
- Loss of appetite
- Urinary or bowel changes
- Weight gain or weight loss
- Back pain
- Vaginal discharge
As the peritoneal cancer advances, sometimes a watery fluid can start to accumulate within the abdomen. This is known as ascites, and this condition can cause:(12)
Some of the symptoms of advanced stage peritoneal cancer may include:
- Stomach pain
- Inability to eat or drink
- Complete urinary or bowel blockage
What are the Stages of Peritoneal Cancer?
After diagnosis, peritoneal cancer is first staged according to its position, size, and the initial place from where it began. At the same time, it is given a grade, which allows doctors to estimate how quickly it is able to metastasize or spread.
Staging of Primary Peritoneal Cancer
Staging for primary peritoneal cancer is done in the same manner used for ovarian cancer as the two cancers are very similar. However, primary peritoneal cancer is almost always classed as stage 3 or stage 4 cancer, while ovarian cancer has two prior stages as well.(13,14)
Stage 3 of primary peritoneal cancer is further divided into three more stages. These are:
Stage 3A: By this stage, the cancer has already spread to the lymph nodes present outside the peritoneum. This means that the cancer cells have already spread to the peritoneum surface and outside the pelvis.
Stage 3B: The cancer at this stage has spread to the peritoneum outside the pelvis. The cancer in the peritoneum is sized at 2 centimeters (cm) or smaller. It is also likely to have spread to the lymph nodes outside the peritoneum.
Stage 3C: By this stage, the cancer has grown larger than 2 centimeters and has spread to the peritoneum outside the pelvis. It has also spread to the lymph nodes or the surface of the spleen or the liver.
Stage 4 of primary peritoneum cancer indicates that cancer has spread to other organs as well. This stage is also divided into two further stages:
Stage 4A: At this stage, the cancer cells are already found in the fluid that accumulates around the lungs.
Stage 4B: The cancer has already spread to tissues and organs outside of the abdominal cavity, including the liver, lungs, or the lymph nodes present in the groin.
Staging of Secondary Peritoneal Cancer
The staging of this type of peritoneal cancer is done based on the initial cancer site. When any type of primary cancer spreads to the peritoneum, it is classified as stage 4 of the primary cancer.(15)
Treatment of Peritoneal Cancer
Once you are diagnosed with peritoneal cancer, your oncologist will sit with you to discuss a potential treatment plan. Treatment for primary peritoneal cancer is very much similar to that of ovarian and stomach cancers.
For treating both primary and secondary peritoneal cancer, the treatment depends on the size and location of the tumor and your overall health. Treatment for secondary peritoneal cancer also takes into consideration the status or severity of the primary cancer and how your body is responding to that treatment.(16)
Surgery is usually the very first step of treating peritoneal cancer, with your surgeon removing as much of the cancerous tissue as possible. Sometimes, there might be a need to also remove:
- The uterus
- Ovaries and fallopian tubes
- A layer of fatty tissue located near the ovaries
- Any abnormal-looking tissue within the abdominal area will also be removed for testing.
Chemotherapy and radiation therapy may be used before the surgery for shrinking the tumor and in preparation for the operation. These procedures may also be used after the surgery to kill any remaining cancerous cells.
The outlook for people with either primary or secondary peritoneal cancer has improved dramatically in the last decades owing to the advances in treatment for this type of cancer. However, the overall outlook remains poor because this rare type of cancer usually does not get diagnosed until it has already reached an advanced stage. There is also a high risk of peritoneal cancer returning after treatment.
While the symptoms of peritoneal cancer are challenging to detect, but if you notice any type of general symptoms that tend to persist, then it is necessary to bring it to your doctor’s attention at the earliest. Remember that an early diagnosis can help you get a better outcome.
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- Clement, P.B., 1994. Diseases of the peritoneum. In Blaustein’s pathology of the female genital tract (pp. 647-703). Springer, New York, NY.
- FROMM, G.L., Gershenson, D.M. and SUVA, E.G., 1990. Papillary serous carcinoma of the peritoneum. Obstetrics & Gynecology, 75(1), pp.89-95.
- Bell, D.A. and Scully, R.E., 1990. Serous borderline tumors of the peritoneum. The American journal of surgical pathology, 14(3), pp.230-239.
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- Burger, R.A., Brady, M.F., Bookman, M.A., Walker, J.L., Homesley, H.D., Fowler, J., Monk, B.J., Greer, B.E., Boente, M. and Liang, S.X., 2010. Phase III trial of bevacizumab (BEV) in the primary treatment of advanced epithelial ovarian cancer (EOC), primary peritoneal cancer (PPC), or fallopian tube cancer (FTC): A Gynecologic Oncology Group study. Journal of Clinical Oncology, 28(18_suppl), pp.LBA1-LBA1.
- Makhija, S., Amler, L.C., Glenn, D., Ueland, F.R., Gold, M.A., Dizon, D.S., Paton, V., Lin, C.Y., Januario, T., Ng, K. and Strauss, A., 2010.
- Clinical activity of gemcitabine plus pertuzumab in platinum-resistant ovarian cancer, fallopian tube cancer, or primary peritoneal cancer. Journal of Clinical Oncology, 28(7), pp.1215-1223.
- Cancer.osu.edu. 2020. [online] Available at: <https://cancer.osu.edu/for-patients-and-caregivers/learn-about-cancers-and-treatments/cancers-conditions-and-treatment/cancer-types/peritoneal-cancer> [Accessed 15 July 2020].
- Loggie, B.W., 2001. Malignant peritoneal mesothelioma. Current treatment options in oncology, 2(5), pp.395-399.
- Desai, J.P. and Moustarah, F., 2019. Cancer, Peritoneal Metastasis. In StatPearls [Internet]. StatPearls Publishing.
- Pott, D., 2020. [online] Gesundheitsindustrie-bw.de. Available at: <https://www.gesundheitsindustrie-bw.de/en/article/news/peritoneal-cancer-long-term-survival-with-good-quality-of-life/> [Accessed 15 July 2020].
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- Prat, J. and FIGO Committee on Gynecologic Oncology, 2014. Staging classification for cancer of the ovary, fallopian tube, and peritoneum. International Journal of Gynecology & Obstetrics, 124(1), pp.1-5.
- Zeppernick, F. and Meinhold-Heerlein, I., 2014. The new FIGO staging system for ovarian, fallopian tube, and primary peritoneal cancer. Archives of gynecology and obstetrics, 290(5), pp.839-842.
- Castro-Mesta, J.F., González-Guerrero, J.F., Barrios-Sánchez, P. and Villarreal-Cavazos, G., 2016. Bases and foundations of the treatment of peritoneal carcinomatosis. Medicina universitaria, 18(71), pp.98-104.
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