Peritoneal cancer is a rare malignancy that develops from the thin layer of epithelium lining the organs in the abdomen, known as the peritoneum. This lining is made up of the same kind of epithelial cells that cover the ovaries and line the fallopian tubes, and as such, cancers of the ovaries of fallopian tubes may spread to the peritoneum.
The peritoneum has an inner layer (visceral peritoneum) that lines the surface of the organs such as the bowel, the ovaries and the liver, and an external layer (parietal peritoneum) that lines the walls of the abdominal cavity and the pelvis. The peritoneal cavity lines the space between the two layers, and allows these layers to slide over each other when we move.
Peritoneal cancer is more common in women, and tends to be diagnosed over the age of 60. However, anyone can develop this disease.
Types of Peritoneal Cancer
There are two primary types of peritoneal cancers that are classified by where the cancer originally developed from:
- Primary peritoneal cancer (cancer originally develops in peritoneum).
- Peritoneal carcinomatosis (cancer originally develops elsewhere, such as the ovaries, fallopian tubes or abdomen, and spreads to the peritoneum).
Treatment
As peritoneal cancers develop from the same cells as ovarian and fallopian tube cancers, they are often staged and treated in the same manner. In most cases, peritoneal cancers are diagnosed at stage III/IV.
If peritoneal cancer is detected, it will be staged and graded based on size, metastasis, and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you.
Peritoneal cancers can be staged using the Federation of Gynecology and Obstetrics (FIGO) system from stage I to IV:
- Stage I: cancer cells are confined to one or both ovaries only. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby organs in the pelvis, such as the fallopian tubes, uterus, bladder and/or bowel. This is also known as localised cancer.
- Stage III: the cancer has become larger and has spread beyond the pelvis into the lining of the abdomen (peritoneum). Lymph nodessmall bean-shaped structures that filters harmful substances from lymph fluid are also often affected. This is also known as advancedat a late stage, far along or metastatic cancer.
- Stage IV: the cancer has spread to more distant organs, such as the lungs or the liver. This is also known as advanced or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Grade I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade-I tumours. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testinga procedure that analyses DNA to identify changes in genes, chromosomes and proteins, which can be used to analyse tumour DNA to help determine which treatment has the greatest chance of success, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. In particular, they may look for mutations in the hereditary breast cancer genes (BRCA1 and BRCA2), which can cause an increased risk in developing peritoneal cancer. They will then discuss the most appropriate treatment option for you.
Treatment is dependent on several factors, including fertility, type, stage of disease and overall health.
Treatment options for peritoneal cancers may include:
- Surgery, potentially including:
- Hysterectomycomplete or partial removal of the uterus.
- Bilateral salpingo-oophorectomy.
- Unilateral salpingo-oophorectomy.
- Lymphadenectomysurgical removal of lymph node(s).
- Peritonectomyremoval of the peritoneum.
- Chemotherapya cancer treatment that uses drugs to kill or slow the growth of cancer cells, while minimising damage to healthy cells.
- Targeted therapymedication that targets specific molecular features of cancer cells.
- Hormone therapymedication that alters the levels of certain hormones in the body, such as oestrogen and progesterone.
- Radiation therapya treatment that uses controlled doses of radiation to damage or kill cancer cells.
- Clinical trialsresearch studies performed to test new treatments, tests or procedures and evaluate their effectiveness on various diseases.
- Palliative carea variety of practices and exercises used to provide pain relief and improve quality of life without curing the disease.
Peritoneal Cancer Treatment and Fertility
Treatment for peritoneal cancer may make it difficult to become pregnant. If fertility is important to you, discuss your options with your doctor prior to the commencement of treatment.
Risk factors
While the cause of peritoneal cancer remains unknown, some of the following factors may increase the risk of developing the disease:
- Having ovarian cancer.
- Having a family history of ovarian, breast, uterine and/or bowel cancer.
- Having a mutation in the BRCA 1 and BRCA 2 genes.
Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.
Symptoms
Peritoneal cancer may appear asymptomatic in the early stages of disease. As the tumour progresses, some of the following symptoms may appear:
- An abdominal and/or pelvic mass.
- Pain, swelling and/or pressure in the abdomen, pelvis, lower legs and/or back.
- A feeling of abdominal fullness and/or heaviness.
- Changes in bathroom habits, potentially including:
- Constipation.
- Feeling of incomplete urination.
- Polyuriafrequent urination.
- Urgent urination.
- Changes in digestion, potentially including:
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- Feeling full quickly.
- Heartburn.
- Gas.
- Indigestion.
- Nausea and/or vomiting.
- Unexplainable weight loss/loss of appetite.
- Fatigue.
- Abnormal vaginal bleeding and/or discharge between periods or after menopause.
- Obstructions of the bowel or urinary tract.
Not everyone with the symptoms above will have cancer, but see your general practitioner (GP) if you are concerned.
Diagnosis
If your doctor suspects you have peritoneal cancer, they may order the following tests to confirm the diagnosis and refer you to a specialist for treatment:
- Physical examinationan examination of your current symptoms, affected area(s) and overall medical history.
- Pelvic examination.
- Imaging tests, potentially including:
- MRI (magnetic resonance imaging)a type of medical imaging that uses radiowaves, a strong magnet and computer technology to create detailed images of the body.
- CT (computed tomography) scana type of medical imaging that uses x-rays and computer technology to create detailed images of the body.
- Ultrasounda type of medical imaging that uses soundwaves to create detailed images of the body .
- Blood teststesting done to measure the levels of certain substances in the blood.
- Exploratory surgerya surgical procedure used for conditions that cannot be confirmed by scans and tests alone.
- Biopsyremoval of a section of tissue to analyse for cancer cells.
