Peritoneal Cancer - Information and Specialists

Peritoneal cancer (peritoneal carcinomatosis) refers to the spread of malignant cells to the lining of the abdominal organs (the peritoneum). In most cases, these are tumor cells.

In most cases of peritoneal cancer, the tumor cells are metastases from another tumor in the abdominal cavity. Very rarely do they originate from a tumor of the peritoneum itself.

The extent of the tumor cell involvement and its spread can vary greatly and influence the prognosis and course of the disease. For example, the involvement may be limited to a few nodules in specific areas of the peritoneum (limited peritoneal carcinomatosis).

This most often affects areas within the abdominal cavity where there is little movement of the internal organs. The small intestine is one of the most mobile structures, while the large intestine is relatively less mobile. Areas with low motility (ability to move actively) are found, for example, in the cecal region or in the Douglas pouch.

The prognosis for limited peritoneal carcinomatosis is better than that for diffuse peritoneal carcinomatosis. However, the latter is more common. Typically, larger tumor nodules are scattered throughout the peritoneum and on the surfaces of adjacent organ structures (diffuse peritoneal carcinomatosis).

The peritoneum is a thin membrane that encloses most of the organs in the abdominal cavity.

The abdominal cavity contains:

• Intestines
• Liver, and
• Stomach

The peritoneum produces a fluid called peritoneal fluid. This fluid acts as a lubricating layer between the organs and allows them to move easily relative to one another.

For example, during digestion, the loops of the intestines move against one another to transport food. Peritoneal fluid also forms in cases of liver damage and inflammation.

Nerves run through the peritoneum. Inflammation can therefore cause severe pain. The abdominal muscles tense up to protect the abdomen. This reaction is called defensive tension and is the body’s warning sign that something is wrong inside the abdomen.

The peritoneum is a smooth membrane that lines the inside of the abdominal cavity @ sakurra /AdobeStock

The tumor-related condition may originate in the peritoneum itself (primary peritoneal carcinoma, peritoneal mesothelioma). In most cases, peritoneal cancer is the result of a malignant tumor in another organ within the abdominal cavity.

In these cases, the malignant cells spread into and across the peritoneum. Doctors refer to this as secondary peritoneal carcinoma because the malignant cells originate from other tissues.

However, secondary peritoneal carcinoma is always a sign of advanced cancer in the organ of origin. Stomach cancer and pancreatic cancer, in particular, tend to lead to peritoneal carcinomatosis, as do ovarian tumors.

Ascites facilitates the spread of tumors among the individual organs. The tumor cells can spread very easily through the serous layer.

Almost every type of tumor that occurs in the abdominal cavity in any way eventually affects the peritoneum and forms secondary tumors (metastases) there. However, this is already a sign of advanced tumor growth and usually indicates a poor prognosis.

A rare tumor entity that can also lead to peritoneal cancer is pseudomyxoma peritonei. This is a tumor that produces large amounts of mucous-like material. The tumor cells migrate from the cecum into the peritoneum.

Even though it is a benign tumor, its course is comparable to that of a slowly growing malignant tumor. In the advanced stage, the entire peritoneum is filled with gelatinous tissue and tumor masses.

Since peritoneal cancer is usually caused by an advanced tumor in an abdominal organ, symptoms depend on the affected organ.

Typical symptoms of stomach cancer include:

• Nausea
• Loss of appetite, and
• Stomach pain
• Symptoms of tumors in the small intestine are more likely to include:
• Diarrhea
• Constipation
• Intestinal obstruction

Involvement of the peritoneum tends to lead to atypical symptoms, which are less likely to prompt a visit to the doctor. These can initially be treated with home remedies.

The progressive spread of tumor cells leads to displacement of adjacent abdominal organs, resulting in functional impairment.

This results in:

• Urinary retention due to narrowing of the ureters
• Impaired bowel function (subileus) up to
• complete bowel obstructions (subileus and ileus) as well as
• the accumulation of fluid in the abdomen (ascites)

Impairment of the gastrointestinal tract is often accompanied by the following symptoms:

• Nausea
• Feeling of fullness
• Loss of appetite and
• Nausea

Doctors often do not detect peritoneal cancer until the primary tumor is surgically removed. Since further imaging tests (computed tomography (CT) or magnetic resonance imaging (MRI)) are performed, peritoneal cancer is often suspected beforehand.

However, CT or MRI scans only provide definitive results once the cancer has already spread extensively within the abdominal cavity.

A laparoscopy is considered the most reliable method for detecting peritoneal cancer. During this procedure, the doctor inserts a special endoscope into the abdominal cavity through a small incision in the skin.

This endoscope is equipped with a light source and a camera, allowing doctors to view the inside of the abdominal cavity and the abdominal organs on a monitor.

If abnormalities are found, doctors can and should take tissue samples at the same time. They then send these samples for histological examination, which confirms or rules out the suspected diagnosis.

Laparoscopy is suitable for diagnosing peritoneal cancer @ Iryna /AdobeStock

If only a small portion of the peritoneum is affected by tumor cells, doctors can, ideally, remove that portion completely.

Since doctors often don’t detect peritoneal cancer until a late stage, it is considered difficult to treat and is often no longer curable.

If a cure is no longer possible, doctors can only initiate palliative care. This is intended to improve the patient’s quality of life without directly treating the tumor itself.

Life expectancy is significantly reduced in such cases. The primary goal of all therapeutic measures is to improve the patient’s remaining quality of life.

Palliative care includes:

• Pain management
• Nutritional therapy
• Chemotherapy
• Surgical tumor reduction
• Creation of a colostomy

Pain Management

Pain management is generally possible with pills and/or pain patches and serves to improve quality of life. In some cases, pain can only be controlled with IV infusions. In such cases, pain catheters are used.

Special catheters (known as port catheters) are implanted under the skin. This allows for pain management even outside the hospital. As a result, patients can spend the remainder of their lives at home with their loved ones.

A pain catheter is a thin plastic tube through which the patient receives pain medication @ Gecko Studio /AdobeStock

Nutritional Therapy

In some cases, patients with incurable cancer are no longer able to consume sufficient food and fluids. It is not uncommon for them to lose their appetite, which is a typical sign of malignant diseases. 

On the other hand, cancer is also associated with increased energy requirements, which often leads to deficiency symptoms and weight loss. 

Nutritional infusion therapy can help in these cases and can also be administered via a port catheter. In addition, the patient receives important minerals and vitamins through this method.

Chemotherapy

Chemotherapy can be curative or palliative. Curative means that a cure is, in principle, possible.

The goal of palliative therapy is to improve quality of life by reducing tumor size or slowing tumor growth. 

Since all chemotherapy has side effects, doctors should carefully consider whether to administer palliative chemotherapy. 

Ideally, palliative chemotherapy can extend life expectancy. However, the side effects often lead to a deterioration in quality of life.

Surgical Tumor Reduction

The removal of tumor tissue from the peritoneum involves:

•  Removal of the primary tumor 

In many cases, removal of directly connected organs (spleen, gallbladder, diaphragm, and portions of the intestine)

The patient must be informed of this prior to surgery and provide written consent. Curative chemotherapy may still be necessary afterward if it cannot be confirmed with certainty that the tumor was completely removed. 

This is because, although surgeons can remove all visible tumors during surgery, individual, invisible tumor cells may remain.

• Creation of a colostomy

Sometimes the patient also receives a colostomy. This may be necessary temporarily to relieve pressure on the healthy intestine. 

This is especially true when doctors have removed parts of the bowel and sutured the remaining ends together.

In such cases, creating a colostomy beforehand can relieve pressure on the intestinal suture. This, in turn, reduces the risk of the suture tearing.