Peritoneal cancer are a group of benign and malignant neoplasms of the serous membrane covering the internal organs and internal walls of the abdominal cavity. Malignant tumors can be both primary and secondary, but more often have a metastatic character. Benign neoplasms are asymptomatic or accompanied by signs of compression of nearby organs. Malignant tumors of the peritoneum are manifested by pain and ascites. The diagnosis is made on the basis of complaints, examination data, results of analysis for cancer markers, CT, laparoscopy, immunohistochemical and histological examination. Treatment – surgery, radiation therapy, chemotherapy.
Meaning
Peritoneal cancer are neoplasms of various origins localized in the visceral and parietal leaves of the peritoneum, small omentum, large omentum and mesentery of hollow organs. Benign and primary malignant neoplasms of the peritoneum are rarely diagnosed. Secondary tumors of the peritoneum are a more common pathology, they occur with oncological lesions of the abdominal cavity and retroperitoneal space, internal female and male genitalia. The prognosis for benign lesions is usually favorable, for malignant – unfavorable. The treatment is carried out by specialists in the field of oncology and abdominal surgery.
Classification
There are three main groups of peritoneal neoplasms:
- Benign tumors of the peritoneum (angiomas, neurofibromas, fibromas, lipomas, lymphangiomas)
- Primary malignant tumors of the peritoneum (mesothelioma)
- Secondary malignant tumors of the peritoneum that occur when malignant cells spread from another organ.
There are also mucus–forming neoplasms (pseudomyxomas), which some researchers consider as primary, and others as secondary tumors of the peritoneum of varying degrees of malignancy. In most cases, secondary peritoneal lesion develops as a result of aggressive local growth of neoplasms and implantation spread of cancer cells from organs located intraperitoneal, mesoperitoneal or extraperitoneal.
Tumors of the peritoneum resulting from implantation metastases can be detected in cancers of the stomach, small and large intestines, liver, pancreas, gallbladder, kidney, uterine body, cervix, ovaries, prostate, anterior abdominal wall, etc. Less often, there is a lymphogenic spread of metastases of chest tumors (for example, lung cancer) caused by retrograde movement of lymph along the lymphatic pathways.
Types
Benign tumors of the peritoneum
They are a very rare pathology. The causes of development are unknown. The disease can be asymptomatic for years. In some cases, tumors of the peritoneum reach huge sizes, without significantly affecting the patient’s condition. A case of removal of a lipoma of the omentum weighing 22 kilograms is described in the literature. With large nodes, an increase in the abdomen is detected. Sometimes benign tumors of the peritoneum cause compression of nearby organs. The pains are uncharacteristic. Ascites occurs extremely rarely. The diagnosis is determined by the results of laparoscopy. The indication for surgery is the compression effect of the neoplasm on neighboring organs.
Primary malignant tumors of the peritoneum
Mesotheliomas of the peritoneum are rare. They are usually found in men over 50 years of age. A risk factor is prolonged contact with asbestos. They are manifested by pain syndrome, weight loss and symptoms of compression of nearby organs. With sufficiently large tumors of the peritoneum, an asymmetric protrusion in the abdominal area may be detected. On palpation, single or multiple tumor-like formations of various sizes are detected.
The rapid progression of symptoms is characteristic. With compression of the portal vein, ascites develops. Due to the lack of specific signs, the diagnosis of malignant tumors of the peritoneum is difficult. Often, the diagnosis is made only after excision of the neoplasm and subsequent histological examination of the removed tissues. The prognosis is unfavorable. Radical removal is possible only with limited processes. In other cases, patients with peritoneal cancer die from cachexia or from complications caused by a violation of the functions of the abdominal organs.
Pseudomyxoma of the peritoneum
Occurs when an ovarian cystadenoma ruptures, a pseudomucinous cyst of the appendix or an intestinal diverticulum. Mucus-forming epithelial cells spread over the surface of the peritoneum and begin to produce a thick jelly-like liquid filling the abdominal cavity. Usually, the rate of development of this peritoneal tumor corresponds to a low degree of malignancy. The disease progresses for several years. Jelly-like liquid gradually causes fibrous tissue changes. The presence of mucus and tumor-like formation hinders the activity of internal organs.
Less often, peritoneal cancer of a high degree of malignancy are detected, capable of lymphogenic and hematogenous metastasis. In the absence of treatment, in all cases, a fatal outcome occurs. The cause of death of patients is intestinal obstruction, exhaustion and other complications. The presence of a mucus-forming tumor of the peritoneum is indicated by an increase in the size of the abdomen with a decrease in body weight, digestive disorders and jelly-like discharge from the navel.
The diagnosis is established on the basis of CT, laparoscopy, histological and immunohistochemical examination. Positron emission tomography can be used for malignant tumors of the peritoneum. With a benign variant of the disease, this study is uninformative. The tactics of treatment of peritoneal cancer are determined individually. In some cases, surgical excision of the affected areas in combination with intraperitoneal intracavitary chemotherapy is possible. With the timely start of treatment, the prognosis is quite favorable, especially for low–grade peritoneal cancer.
Single secondary malignant tumors of the peritoneum
The lesion occurs when malignant tumors germinate, located in organs partially or completely covered with the peritoneum. The appearance of tumors of the peritoneum is accompanied by an increase in pain syndrome and deterioration of the patient’s condition. Palpation of the abdomen may reveal tumor-like formations. With the disintegration of the focus in the hollow organ (stomach, intestines), the phenomena of perforated peritonitis are observed. In some cases, the primary tumor simultaneously sprouts the wall of the hollow organ, the leaves of the peritoneum and the anterior abdominal wall. When the resulting conglomerate disintegrates, a phlegmon of soft tissues occurs.
Tumors of the peritoneum are diagnosed on the basis of anamnesis (there is a malignant neoplasm of an organ covered with the peritoneum), clinical manifestations, abdominal ultrasound data and other studies. With a limited process, radical excision of the primary tumor together with the affected area of the peritoneum is possible. In the presence of distant metastases, symptomatic therapy is performed. Patients with tumors of the peritoneum are prescribed painkillers, with the accumulation of fluid in the abdominal cavity, laparocentesis is performed, etc. The prognosis depends on the prevalence of the process.
Peritoneal carcinomatosis
Malignant cells entering the abdominal cavity spread rapidly through the peritoneum and form multiple small foci. At the time of diagnosis of stomach cancer, peritoneal carcinomatosis is detected in 30-40% of patients. In ovarian cancer, secondary tumors of the peritoneum are found in 70% of patients. Pathology is accompanied by the appearance of profuse effusion in the abdominal cavity. Patients are exhausted, weakness, fatigue, stool disorders, nausea and vomiting are detected. Large tumors of the peritoneum can be palpated through the abdominal wall.
There are three degrees of carcinomatosis: local (one lesion zone is detected), with the defeat of several sites (lesions alternate with areas of unchanged peritoneum) and widespread (multiple secondary tumors of the peritoneum are detected). With an undiagnosed primary tumor and multiple nodes of the peritoneum, clinical diagnosis in some cases presents difficulties due to the similarity with the picture of tuberculous peritonitis. In favor of secondary tumors of the peritoneum, the hemorrhagic nature of the effusion and the rapid recurrence of ascites after laparocentesis indicate.
The diagnosis is established taking into account anamnesis, clinical manifestations, ultrasound data of the abdominal cavity, MSCT of the abdominal cavity with contrast, cytology of ascitic fluid obtained during laparocentesis, and histological examination of a sample of peritoneal tumor tissue taken during laparoscopy. As an additional diagnostic technique, a test for cancer markers can be used, which allows more accurately determining the prognosis, timely detecting relapses and evaluating the effectiveness of therapy.
If it is possible to completely remove the primary neoplasm and tumors of the peritoneum, radical operations are performed. Depending on the location of the primary focus, peritonectomy is performed in combination with colectomy, gastric resection or gastrectomy, pangisterectomy and other surgical interventions. Due to the danger of contamination of the abdominal cavity with cancer cells and the possible presence of visually undetectable tumors of the peritoneum during surgery or after its completion, intraperitoneal hyperthermic chemotherapy is performed. The procedure allows for a powerful local effect on cancer cells with minimal toxic effect of chemotherapy drugs on the patient’s body.
Despite the use of new treatment methods, the prognosis for disseminated secondary tumors of the peritoneum remains unfavorable. Carcinomatosis is one of the main causes of death of patients with oncological lesions of the abdominal cavity and pelvis. The average survival rate of patients with stomach cancer in combination with peritoneal cancer is about 5 months. Relapses after radical surgical interventions for secondary neoplasms of the peritoneum occur in 34% of patients. Specialists continue to search for new, more effective methods of treating secondary tumors of the peritoneum. New chemotherapy drugs, immunochemotherapy, radioimmunotherapy, gene antisense therapy, photodynamic therapy and other techniques are used.