What is Peritoneal Cancer?
Peritoneal cancer is a type of cancer that develops in the lining of the abdominal cavity. This lining, called the serous membrane, covers and protects the organs in the belly. Peritoneal cancer can be either primary or secondary. Primary peritoneal cancer starts in this lining, while secondary peritoneal cancer is due to cancer cells that have spread from other parts of the body into the lining of the abdomen.
Specifically, primary peritoneal cancer can further be classified into different types based on how the cancer cells look under the microscope. Some of these types include extraovarian primary peritoneal carcinoma (EOPPC), papillary serous carcinoma of the peritoneum, and more. Other types of peritoneal cancer include malignant peritoneal mesothelioma, multicystic mesothelioma, and leiomyosarcomas, among others. Interestingly, EOPPC was first reported in 1959, and behaves similarly to a type of ovarian cancer, often involving the ovaries only minimally.
Secondary peritoneal cancer, also known as metastatic peritoneal cancer, commonly starts from cancers initially affecting the digestive organs and gynecological structures. This cancer can spread through various routes like the membrane lining the internal organs, the bloodstream, or lymph nodes.
Manifestations of peritoneal cancer are often subtle and could be mistaken for other conditions, leading to a delay in diagnosis. In general, primary peritoneal cancer is often detected when it has advanced, classifying it as stage III or IV. Similarly, metastatic peritoneal cancer is classified as stage IV, the most severe stage. Despite the late stages commonly associated with peritoneal cancer, treatments such as surgical removal and chemotherapy directly in the belly have been crucial for managing the disease. Advancements in understanding how the cancer spreads and progresses, along with technological innovations, have helped develop more effective treatments and techniques. Aiming for local control of the cancer in the lining and surrounding areas might help manage this advanced stage condition, especially when the disease has not spread extensively to other parts of the body.
What Causes Peritoneal Cancer?
Primary peritoneal cancer, or a type of cancer that starts in the lining of the abdominal cavity, often happens in women between ages 56 and 62. It’s closely related to a type of ovarian cancer. In rare cases, men can get this type of cancer too. Around 17.6% of the cases occur in people with changes in a gene called BRCA1. Therefore, if there’s a history of breast cancer in the family, doctors might consider the likelihood of this type of cancer.
Malignant peritoneal mesothelioma is a severe type of cancer frequently linked to asbestos exposure, and it usually occurs in men over the age of 60.
Disseminated peritoneal leiomyomatosis, on the other hand, is connected to higher levels of the hormone estrogen seen in women after menopause. Leiomyosarcoma, another type of cancer, is often associated with a condition called Li-Fraumeni syndrome, which also makes individuals prone to a type of eye cancer called retinoblastoma.
The desmoplastic small round cell tumor mostly affects teenagers with a median age of 19 and is more common in White people. This type of cancer is caused by a specific genetic change known as the [t(11;22)(p13;q12)] translocation.
Secondary peritoneal carcinomatosis, which is cancer that has spread to the lining of the abdominal cavity, often comes from tumors in various organs such as the stomach, colon, pancreas, gallbladder, appendix, breast, uterus, ovary, and lungs. When it comes to appendiceal (appendix) cancer, this spread is referred to as pseudomyxoma peritonei. This condition often responds well to treatment, and many patients live free of the disease for the rest of their lives.
However, cancer from the ovaries, stomach, and colon that has spread often has a higher chance of returning and can lead to more deaths. These three types of cancer are also the most common ones that spread to the peritoneum (lining of the abdominal cavity).
Risk Factors and Frequency for Peritoneal Cancer
Peritoneal tumors are a form of advanced cancer that are quite rare. Each year, due to this type of cancer, about 6.78 people per million are affected. Whites are usually more affected by this than Blacks. The most common variety of this kind of cancer is serous carcinoma of the peritoneum, which makes up about 10% of pelvic cancers. A less common, but very harmful type, is malignant mesothelioma. This mostly takes the form of pleural mesothelioma, but MPM is also quite prevalent, making up between 6% and 20% of all mesothelioma cases. This translates to about 600 to 800 new instances every year in the US. It’s important to note that about half of leiomyosarcomas, a kind of cancer, start in the retroperitoneum, which is an area at the back of the abdomen.
Peritoneal metastasis is the term for when cancer spreads within the peritoneal cavity, and this is the most common form of malignancy found in this area. It’s common for this to happen in ovarian cancer cases, being present in about 75% of instances when the disease is found. Studies show that in 55% of cases, it happens at the same time as the primary tumor, and in 45% of cases, it happens later during follow-up for non-gynecological tumors.
Colorectal tumors show signs of spreading within the peritoneum in about 5% to 10% of cases when they are first diagnosed. However, this number increases to 20% to 50% over time. With gastric cancers, spread to the peritoneum is seen in about 14% of cases at first detection. It’s also important to mention that in about 9% of cases, the spread of cancer to the peritoneum comes from sites outside the abdomen. The most common of these sites are the breasts (40.8% of cases), lungs (25.6% of cases), and in cases of melanoma (9.3%).
Signs and Symptoms of Peritoneal Cancer
Peritoneal cancer, which affects the thin layer of tissue that lines the abdomen, can cause a variety of vague symptoms. These symptoms may include abdominal bloating, distension, nausea, loss of appetite, weight loss, fatigue, constipation, and abdominal or back pain. Notably, many patients list abdominal distension (swelling) and pain as their primary concerns. A protruding abdominal mass and excessive bodily fluid in the abdomen, known as ascites, are additional common signs of this cancer. Almost 85% of patients show these non-specific abdominal symptoms and ascites.
Moreover, swollen lymph nodes related to the tumor can create noticeable masses in certain areas of the body and, in some instances, can obstruct the large vein carrying blood from the upper part of the body called the superior vena cava. This latter condition is mainly seen in Malignant Peritoneal Mesothelioma (MPM). Some patients with Desmoplastic Small Round Cell Tumor (DSRCT) may find that they vomit blood.
The condition’s symptoms can vary greatly depending on where the secondary metastatic deposits occur, and their size. When primary or secondary tumor growth causes pressure effects, this can lead to a sudden, severe problem known as “acute abdomen”, which is a medical emergency. This is often the result of mechanical intestinal obstruction. A bowel obstruction is common in about 20% of colorectal cancer cases. Also, excess fluid in the abdomen may be found in several types of cancer, with studies suggesting that it is present in 43% of pancreatic cancer cases.
During a medical examination, healthcare providers may observe abdominal distension, feel noticeable abdominal masses, detect tenderness, or note the dull sound produced by an accumulation of fluid during the percussion test. Depending on cancer’s reach and involvement, other signs such as malnutrition, anemia, or jaundice may also be present. However, the indications of peritoneal cancer can vary widely and can be affected by factors like the tumor’s location, size, and how aggressive it is. Therefore, thorough evaluations, including imaging studies and laboratory tests, are necessary to accurately diagnose and stage the disease.
Testing for Peritoneal Cancer
To diagnose peritoneal cancer – a type of cancer that forms on the thin tissue layer lining the abdomen – doctors use a mix of lab tests, imaging tests, and sometimes more invasive procedures. When combined with information from a patient’s medical history and physical examination, these tests can help determine if a person has peritoneal cancer.
Lab tests might include a complete blood count, a comprehensive metabolic panel, and tests for enzymes such as amylase and lipase. They also often look at coagulation studies, urinalysis, serum albumin, and blood typing. At the same time, your doctor might test for certain tumor markers, which are substances produced by cancer cells or other cells in the body in response to cancer. However, these markers can also be elevated in other cancers, or even noncancerous conditions, so they aren’t a definitive way to diagnose peritoneal cancer.
Imaging studies help doctors spot and categorize any peritoneal masses, assess how far a tumor might have spread, and check for metastatic disease (cancer that has spread to other parts of the body). They use different types of scans such as ultrasound, CT (computed tomography), and MRI (magnetic resonance imaging) for this.
For instance, an abdominal ultrasound is often the first imaging test used for suspected peritoneal cancer. While it is not as sensitive as CT or MRI, an ultrasound can detect the build-up of fluid in the abdomen (ascites), liver metastases, and intraabdominal masses. It cannot, though, catch very small malignant granules (under 2 cm).
CT scans, which use a series of X-ray images to create detailed images of the body, are often the primary imaging test for peritoneal cancer. They’re particularly good at detecting smaller peritoneal lesions. When CT scans are used alongside a contrast agent – a special dye that helps doctors see the structures inside the body more clearly – they can help spot ascites and identify smaller peritoneal deposits.
On the other hand, MRI scans use strong magnetic fields and radio waves to form detailed images of body structures. They’re particularly good for detecting smaller tumors, specifically those less than 1 cm in size. If a CT scan or MRI isn’t enough to detect small peritoneal implants, a PET-CT scan can be used. This type of scan involves injecting a small quantity of a radioactive sugar into your body, which the cancer cells absorb. These cells show up brighter on the scan.
However, sometimes non-cancerous lesions can look like cancer on these tests, so more invasive techniques might be needed to confirm the diagnosis. These procedures typically involve taking a biopsy, or small sample of tissue, to examine under a microscope.
For example, your doctor might take a sample of ascitic fluid – fluid that builds up in the abdomen. They do this using a procedure known as paracentesis. By analyzing this fluid, doctors can identify the presence of cancer cells, count the cells, and check the protein levels.
Lastly, doctors might use laparoscopy – a procedure that involves surgically inserting a small camera into the abdomen – to get a closer look at the peritoneum. This lets them take targeted samples for testing, can help calculate the spread of cancer across the abdomen, and is a useful way to avoid unnecessary surgeries or chemo treatments.
All of these tests help to diagnose peritoneal cancer and guide treatment decisions. However, it’s important to remember that cancer can often exist without showing symptoms, which is why early detection is crucial. This, in turn, can help to improve patient outcomes and survivability rates.
Treatment Options for Peritoneal Cancer
A multi-faceted approach called multimodal therapy is the best way to treat peritoneal cancer. This method combines surgery, chemotherapy, and targeted therapies. It has been shown to significantly improve survival rates, often up to 60 months, compared to the 4 to 12 months of traditional treatments.
The treatment options for peritoneal cancer include:
Cytoreductive Surgery: This involves removing all visible tumors from the layers of the peritoneum, a smooth, clear membrane that separates the digestion area from your other organs in your abdomen. The goal is to leave no tumor larger than 2.5 mm. The procedure can also employ various tools to remove growths and stop bleeding. It is important to select patients very carefully for this surgery as it can increase the risks of other health problems.
Certain factors, like the spread of the cancer and the patient’s overall health, help us determine if this type of surgery is a good fit. For example, it may not be the best approach if the cancer has spread to key areas in the abdomen or if there are multiple cancers outside of the abdomen.
The effectivity of this surgery is evaluated through a scoring system called ‘completeness of cytoreduction’ score (CCR). It categorizes the extent of any remaining disease. Although, this type of surgery could lead to post-surgical complications like blood clots, infections at the surgical site, leaks in the digestive system, abnormal connections between organs (fistulas), and prolonged intensive care stays. Hence, a meticulous surgical technique and careful patient selection are crucial.
Hypothermic Intraperitoneal Chemotherapy (HIPEC): This treatment involves introducing potent chemotherapy drugs into the area of the abdomen after surgery for approximately 2 hours, at a temperature higher than the body’s normal temperature (around 108 °F or 41-43 °C). This heat enhances the drug’s absorption and ensures better distribution within the peritoneal cavity aiming to kill off remaining cancer cells. This method concentrates the chemotherapy in the area where it’s needed most, reducing the exposure of the rest of the body to the drugs.
Common side effects of HIPEC may include decreased white blood cell count (neutropenia), unintended bowel holes (perforations), electrolyte imbalances, acute kidney failure, and bleeding disorders.
HIPEC can also be administered laparoscopically (using small incisions). This method has proven effective, particularly for managing a fluid buildup (refractory malignant ascites). The laparoscopic procedure offers several advantages such as allowing chemotherapy drugs to penetrate deeper, and it’s associated with significantly lower risks and mortality rates compared to open surgery.
However, the laparoscopic method could result in higher recurrence rates of the cancer. Despite the potential risks, HIPEC remains a valuable option for selected peritoneal cancer patients, offering the potential for improved outcomes and quality of life.
Early Postoperative Intraperitoneal Chemotherapy (EPIC): This form of treatment is kick-started on the first day following surgery and continuously given for 5 to 7 days. It involves introducing solutions containing chemotherapy drugs into the area of the abdomen where the concentrations of cancer cells remain highest.
When compared to HIPEC, EPIC might be better due to increased drug contact time with the affected area. But, the patient’s specific conditions and potential risks must be considered when choosing the most suitable approach for peritoneal cancer treatment.
Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC): This novel approach makes minimal invasive delivery of chemotherapy possible, especially for patients who can’t undergo the combined surgery and HIPEC treatment method. PIPAC is also used to alleviate symptoms and improve the quality of life. However, PIPAC is not suitable for everyone, especially patients in the early stages of the disease or those experiencing recurrence after extensive surgery.
The multi-faceted treatment approach, which is called the Bidirectional/Neoadjuvant Intraperitoneal and Systemic Chemotherapy (BIPSC/NIPS), involves several steps that address different aspects of the disease. This involves administering chemotherapy both systemically and directly into the peritoneal cavity to target cancer cells both within the stomach and any potential peritoneal spread. Following this, patients undergo extensive surgery to rid of remaining tumor lesions. This combines systemic chemotherapy, surgery, HIPEC, and EPIC to manage gastric cancer (and potentially other peritoneal cancers).
What else can Peritoneal Cancer be?
When doctors are trying to diagnose peritoneal cancer, they should also consider the possibility of other conditions that share similar symptoms. These might include:
- Peritoneal lymphomatosis
- Peritoneal tuberculosis
- Granulomatous peritonitis from histoplasmosis
- Peritoneal melanosis
- Gliomatosis peritonei
- Desmoid tumor
- Solitary fibrous tumor
- Carcinoid tumor
- Actinomycosis
- Splenosis implants
- Endometriosis
- Foreign body reaction
Such a diagnosis process is crucial as it helps doctors ensure they are treating the correct disease.
What to expect with Peritoneal Cancer
Peritoneal cancer is a deadly disease with a difficult prognosis, regardless of whether it starts in the peritoneum, a thin tissue that lines the abdomen, or spreads there from another location. Primary peritoneal cancer, which originates in the peritoneum, is often discovered in its advanced stage (stage IV), and patients usually live for about 11 to 17 months after diagnosis. Secondary peritoneal cancer, where the cancer spreads to the peritoneum from elsewhere, tends to have a median survival time of roughly 6 months, but it can vary based on the cancer’s stage of progression. Survival rates can also be influenced by where the primary tumor is located. For instance, if the primary tumor is in the pancreas, the prognosis tends to be very poor, with a median survival time of about 2.9 months. Tumors in the stomach and colon typically lead to median survival times of 6.5 and 6.9 months, respectively. The presence of ascites (a buildup of fluid in the abdomen) and spread of cancer to the liver can further decrease survival rates.
When it comes to peritoneal cancer developing due to abnormal cells in the ovaries, factors affecting prognosis include the patient’s age, the cancer’s stage, the patient’s overall health, and the size of the remaining tumor after cytoreductive surgery (CRS), which is surgery to reduce the size of tumor. Studies have shown that patient’s overall health and the size of remaining tumor are significant predictors of the prognosis.
The prognosis for Mesothelioma, a type of cancer affecting the peritoneum, depends on the histological subtype of the disease, meaning how the cancer cells appear under the microscope. For instance, patients with the epithelioid subtype have a better prognosis compared to those with the biphasic subtype. One study found that patients with the epithelioid subtype had a median survival time of 55 months, while it was only 13 months for those with the biphasic subtype. Other factors such as the depth of cancer invasion, CCR score (which is a measure of how completely the cancers were removed), and the inflammation in the surrounding tissues can also impact the prognosis. Desmoplastic small round cell tumor (DSRCT), another type of peritoneal cancer, generally has a poor prognosis. The survival rate over five years ranges from 15% to 30%. Factors such as the presence of tumors outside the abdomen and the effectiveness of surgery and radiation therapy can influence survival outcomes.
Leiomyosarcoma, a rare type of cancer that begins in the smooth muscle tissue, has a prognosis affected by the tumor’s stage and size. The 5-year survival rate for this type of cancer is 64%. For secondary peritoneal cancer originating from tumors in the gastrointestinal tract, factors such as the microscopic appearance of the tumor, the cancer stage, and the CCR score can influence the prognosis. For peritoneal cancer that originates from ovarian cancer, tumors that are low-grade, small, and effectively treated with chemotherapy followed by complete CCR have better outcomes. The PCI score, which is a measure of how widespread the tumors are inside the abdomen, is considered the best indicator for survival. Understanding these factors can help guide treatment decisions and provide patients with a realistic expectation about their prognosis and survival outcomes.
Preventing Peritoneal Cancer
Peritoneal cancer, a type of cancer that develops in the tissue lining your stomach, often comes from other primary cancers spreading to it. This makes it important to avoid things that increase your risk for these primary cancers, since it could also reduce your chances of peritoneal cancer. To avoid primary cancers like ovarian cancer, cancer of the gastrointestinal tract (your digestive system), or cancers in the mesothelium (a thin layer covering most of your organs), you could live a healthier lifestyle. Ways to do this include maintaining a diet with plenty of fruits and vegetables, exercising regularly, staying away from tobacco, limiting how much alcohol you drink, and keeping away from harmful environmental substances like asbestos.
Understanding the factors that put you at risk for peritoneal cancer can also help you detect and manage the disease earlier. To be more specific, you might have a higher risk if you or a family member has had cancer before, if you’re genetically more susceptible to getting cancer (such as having BRCA mutations for ovarian cancer), if you’ve been exposed to harmful substances, if you have chronic inflammation like inflammatory bowel diseases, or if you have certain hereditary syndromes like Lynch syndrome. You should be aware of early warning signs of peritoneal cancer, like pain or discomfort in your stomach, bloating, changing bowel habits, unexplained weight loss, loss of appetite, feeling tired, and the buildup of fluid in your abdomen (ascites). If any of these symptoms continue or worry you, report them straight away to your healthcare provider to get a diagnosis and treatment as soon as possible.
Even though there’s no specific screening test for peritoneal cancer in the general population, if you’re at a higher risk because of your genetics or past medical history, you might have a personalized monitoring plan. It’s crucial that you follow recommended screening guidelines and regular check-ins with your healthcare provider to catch any changes that could be suspicious. If you have a family history that suggests you might have hereditary cancer syndromes, such as BRCA mutations associated with ovarian cancer, genetic counseling and testing can provide useful information about your risk of cancer. Your healthcare provider should educate you about the availability and benefits of genetic counseling and testing, so you can make informed decisions about your healthcare and chances of risk reduction.
Those that are diagnosed with peritoneal cancer and their caregivers should be encouraged to connect with advocacy organizations and support groups. These resources offer important information, emotional support, and practical help during the journey with cancer. This aids patients in dealing with the difficulties that come along with the diagnosis, treatment, and surviving cancer. In conclusion, medical professionals can help reduce peritoneal cancer and improve patient results, by educating patients on this disease in a comprehensive way that ranges from preventing it, detecting it early, being aware of the risks, recognizing symptoms, screening, genetic counseling and testing, and psychological support. By giving individuals the knowledge and resources, they are equipping them mentally and physically to handle peritoneal cancer.
