Peritoneal Cancer

21.03.2024

PERITONEAL CANCER DIAGNOSIS AND TREATMENT

Peritoneal cancer is cancer of the peritoneum, the thin membrane covering the abdominal cavity. Tumors in the peritoneum usually occur as a result of the spread of cancer of another organ into the peritoneum; Cancers of intra-abdominal organs, especially stomach, colon or ovarian cancer, often show peritoneal spread. Rarely, peritoneal cancer may begin primarily in the peritoneum. The importance of peritoneal cancer lies in the fact that it is often difficult to diagnose and treat in advanced stages. Because its symptoms are quite general, such as abdominal pain, bloating, weight loss and digestive problems, it can be difficult to diagnose. Treatment methods include surgery, chemotherapy and sometimes radiotherapy. New treatment approaches, especially methods such as hyperthermic intraperitoneal chemotherapy (HIPEC), are promising in the treatment of peritoneal cancer. This treatment involves the direct application of heated chemotherapeutic agents into the abdominal cavity during surgery. However, because peritoneal cancer is often diagnosed at an advanced stage, its prognosis is often difficult, and early diagnosis is especially important for this type of cancer.

WHAT ARE THE RISK FACTORS?

Peritoneal cancer usually occurs as a result of the spread of cancer in other organs, and therefore it is difficult to directly identify specific risk factors. However, some general factors that may increase the risk of peritoneal cancer include:

Presence of Other Types of Cancer: Cancers of intra-abdominal organs, especially stomach, colon, ovarian or pancreatic cancer, tend to spread to the peritoneum.

Genetic Predisposition and Family History: Some genetic syndromes and a family history of cancer may increase the risk of peritoneal cancer.

Age and Gender: Peritoneal cancer is generally more common in older ages and in women, especially in cases associated with ovarian cancer.

Chronic Inflammatory Conditions: Chronic inflammation, especially in the gastrointestinal tract, can increase the risk of developing cancer.

Exposure to Asbestos: Asbestos may increase the risk of a type of peritoneal cancer called mesothelioma.

Previous Abdominal Surgery or Radiation Therapy: Previous surgery or radiation therapy to the abdominal area may increase the risk of peritoneal cancer.

These factors are not absolute causes for the development of peritoneal cancer, but they can increase the risk. People with risk factors for peritoneal cancer are recommended to pay attention to changes in the abdominal area and have regular medical check-ups. Early diagnosis can significantly improve treatment options and outcomes.

Image 1: Peritoneal cancer occurs in the abdominal lining and can cause many complaints such as abdominal pain, constipation, and weight loss.

HOW DOES IT OCCUR?

Cancers in the peritoneum usually develop through the spread (metastasis) of primary cancers in the abdominal organs. Developmental mechanisms of peritoneal cancer include cancer cells adhering to the peritoneal surface, invading and growing there, forming new tumor colonies. Various molecular factors play a role in this process, such as cellular adhesion molecules, invasion-promoting enzymes, and changes in the tumor microenvironment. In addition, it is a common feature of this type of cancer that cancer cells released from the abdominal organs circulate and spread in the abdominal cavity through the peritoneal fluid and form new tumor foci. This spread of cancer cells is facilitated by the large surface area of ​​the peritoneum and can lead to tumors spreading over a large area on the peritoneum. Peritoneal cancer usually occurs in advanced stages and is therefore considered an aggressive and difficult to treat type of cancer. Understanding this type of cancer and developing effective treatment methods constitute an important area in cancer research.

WHAT ARE THE SYMPTOMS?

Peritoneal cancer may not show obvious or specific symptoms, so it can be difficult to diagnose. However, in later stages it may cause the following findings:

Abdominal Pain and Discomfort: There may be constant or intermittent pain or discomfort in the abdominal cavity.

Abdominal Bloating and Volume Increase: Bloating and enlargement may occur in the abdominal area due to fluid accumulation (ascites).

Digestive Problems: Digestive system problems such as loss of appetite, nausea, vomiting and digestive difficulties may occur.

Weight Loss: Unexplained weight loss and loss of appetite are common symptoms of peritoneal cancer.

Weakness and Fatigue: There may be a feeling of weakness and fatigue due to deterioration of general health and anemia.

Feeling of a Mass in the Abdomen: A mass may be felt in the abdomen due to tumor or fluid accumulation.

Change in Urinary and Bowel Habits: Symptoms such as frequent urination or change in bowel habits may be observed.

Stretching or Thickening in the Abdominal Wall: Abnormal stretching or thickening of the abdominal wall may occur.

Because peritoneal cancer is usually diagnosed at an advanced stage, the cancer may have already spread by the time these symptoms appear. Therefore, it is important to seek medical evaluation when such symptoms are noticed. Early diagnosis can increase treatment success and improve the patient's prognosis.

HOW IS IT DIAGNOSED?

The diagnosis of peritoneal cancer is usually made as a result of a series of medical tests and examinations. The first step begins with assessing the patient's symptoms and medical history. Doctors focus on symptoms such as abdominal pain, bloating, nausea, and perform a physical examination. Imaging tests, especially computed tomography (CT) and magnetic resonance imaging (MRI), are then used to see abnormalities in the peritoneal area. Additionally, the presence of cancer cells is confirmed by taking samples of the peritoneal membrane through a procedure called biopsy. Other tests may also be done to determine the stage of the cancer. The diagnostic process may vary depending on the specific condition of the patient and should occur under the supervision of an oncologist.

WHAT ARE THE PATHOLOGICAL TYPES?

Peritoneal cancer can have various pathological types. These types differ depending on the type of cell from which the cancer originates. Some pathological types of peritoneal cancer:

Epithelial Peritoneal Cancer: This is the most common type and arises from epithelial cells on the surface of the peritoneal membrane.

Germ Cell Peritoneal Cancer: This type originates from germ cells and can metastasize to the peritoneum.

Mesenchymal Peritoneal Cancer: It is a rare type of peritoneal cancer arising from mesenchymal cells. It often resembles soft tissue sarcomas.

Lymphoma: Although lymphoma types originating from the lymph nodes in the peritoneal area are rare, they can be considered peritoneal cancer.

The pathological type of peritoneal cancer may have an impact on treatment options and prognosis. Therefore, it is important to determine the correct pathological type during the diagnosis and treatment process. An appropriate treatment plan is created by an oncologist based on the patient's medical history, symptoms and pathological type. There are receptors and molecular markers that are important in the treatment of peritoneal cancer. Chief among these markers is CA-125, this blood test is used to monitor peritoneal cancer and evaluate treatment response. In addition, factors such as HER2 (Human Epidermal Growth Factor Receptor 2) positivity, hormonal receptors (ER and PR), MSI (Microsatellite Instability) and MMR (Mismatch Repair) status, p53 mutations and PD-L1 expression are also taken into account in treatment planning. These molecular markers help us better understand the biological characteristics of a patient's cancer and personalize treatment. However, which markers to test and which treatment options to use should be determined by specialist doctors, taking into account the patient's specific situation and medical history.

Image 2: In peritoneal cancer, fluid accumulation in the abdomen may occur. Fluid in the abdomen can be drained using the paracentesis method.

HOW IS TUMOR STAGING DONE?

Staging of peritoneal cancer is a process used to determine the extent and progression of cancer. This staging process is important in determining the patient's treatment options and predicting prognosis. Staging of peritoneal cancer is done as follows:

Stage I: At this stage, the cancer is limited to tissues on or near the surface of the peritoneal membrane. It is usually found in a single area.

Stage II: The cancer has spread to more areas of the peritoneal lining or organs, but is still confined to the abdomen.

Stage III: At this stage, the cancer has spread further within the abdomen and may have spread to surrounding organs or lymph nodes.

Stage IV: At this most advanced stage, the cancer has metastasized to organs outside the abdomen or to other parts of the body.

Staging of peritoneal cancer is usually done by imaging tests (computed tomography, magnetic resonance imaging, ultrasound) and biopsies taken during surgery. Staging results are used to determine the patient's treatment plan and prognosis. It is important to perform this staging to develop a customized treatment approach for each patient.

HOW IS TREATMENT DONE ACCORDING TO STAGES?

Peritoneal cancer treatment may vary depending on the stage and type of cancer and the patient's general health condition. Here is a general treatment approach according to the stages of peritoneal cancer:

Stage 0 and Stage I: Among the treatment options, surgical intervention plays a key role. This surgery involves removing the tumor and trying to control the cancer. Adjuvant treatments such as chemotherapy or radiotherapy may also be considered after surgery, but are determined individually for each patient.

Stage II and Stage III: Treatment usually involves surgery, although surgery may be applied to a more widespread area. Adjuvant treatments such as chemotherapy or radiotherapy may be more commonly used after surgery. If cancer has spread to lymph nodes or other organs, additional treatments targeted to these areas may be required.

Stage IV: Treatment generally focuses on palliative treatments, with surgery playing a limited role. Palliative treatments are used to control symptoms and improve quality of life. Systemic treatments such as chemotherapy, targeted therapies, and immunotherapy are frequently used. Pain management, nutritional support and psychosocial support are important to improve the patient's quality of life.

Peritoneal cancer treatment is customized for each patient and is determined by taking into account the patient's health status, age, biological characteristics of the tumor and other factors. The treatment plan is created by an oncologist based on the individual needs of the patient.

Image 3: In some cancers that develop in the abdominal lining, chemotherapy may be given in the abdomen.

WHAT ARE THE SYSTEMIC DRUGS USED IN TREATMENT?

Some chemotherapies, hormonal drugs, smart drug therapies and immunotherapies used in the treatment of peritoneal cancer may include:

Chemotherapy drugs:

Platinum-based chemotherapy: Platinum-containing drugs such as carboplatin or cisplatin are usually used.

Pemetrexed: It is a chemotherapy drug used in the treatment of peritoneal cancer.

Paclitaxel or docetaxel: These drugs can treat cancer cells by stopping them from growing.

Smart Drug Therapies:

Bevacizumab: This drug is used to treat peritoneal cancer by preventing the tumor's vessels from growing.

Olaparib: It is a PARP inhibitor that can be used in patients with BRCA gene mutations.

Immunotherapies: Immunotherapy is a newer approach to treating peritoneal cancer and is used specifically for patients with certain molecular markers.

Pembrolizumab: This drug can be used as immunotherapy in patients with positive PD-L1 expression.

Nivolumab: It is an immunotherapy option for patients with positive PD-L1 expression.

The treatment plan is determined depending on the specific condition of the patient, the characteristics and stage of the tumor. Therefore, peritoneal cancer treatment should be carefully evaluated by a specialist doctor and planned individually.

HOW SHOULD FOLLOW-UP BE CARRIED OUT AFTER RECOVERY?

Follow-up after peritoneal cancer treatment is important to monitor the patient's health and evaluate any recurrence or response to treatment. A follow-up program usually includes the following elements: regular doctor exams, blood tests (such as CA-125 levels), imaging studies (computed tomography or magnetic resonance imaging), and monitoring of symptoms. Frequency of follow-up may vary depending on the patient's stage, response to treatment, and other individual factors. Follow-up is important to detect possible relapses or complications early and improve the patient's quality of life. Patients should monitor their follow-up plans regularly and stay in touch with their physicians.