What is it? Canceromatosis

Peritoneal canceromatosis is the appearance of tumor nodules on the peritoneum, the primary source of which is malignant neoplasms.

About the Disease

Peritoneal canceromatosis is one type of metastasis of malignant processes. This pathway of spreading tumor cells is particularly common in ovarian cancer, carcinoma of the gastrointestinal tract organs (stomach, intestines, pancreas). Less frequently, canceromatosis may result from the dissemination of malignant cells from the bronchopulmonary system, breast, and melanoma (skin tumor originating from melanocytes). The spread of the process throughout the peritoneum is usually classified as stage 4 of the disease, significantly worsening the prognosis, thus requiring early treatment.

The routes of dissemination of cancer cells towards the peritoneum can be various. In some cases, they spread with the flow of lymphatic fluid, while in others, they spread through implantation. Pathogenetically, interepithelial slit contacts on the peritoneum are also attributed a role, which may occur in cancers of the pelvic organs. Peritoneal canceromatosis should be distinguished from myxoma. Canceromatosis is always a secondary process, while myxoma is a primary malignant tumor originating from the mesothelium, which constitutes the peritoneum.

The symptoms of peritoneal canceromatosis are nonspecific, which complicates the timely diagnosis of the pathological process. Detecting this process at an early stage can only be achieved through dynamic monitoring of oncology patients.

Currently, the treatment of peritoneal canceromatosis involves a comprehensive approach. For maximum destruction of tumor cells, their surgical removal (cytoreduction surgery) is performed in combination with intraperitoneal administration of chemotherapeutic agents. This treatment is applicable to patients without severe comorbidities. In case comorbidities are present, systemic cytostatic therapy may be used as an alternative.


From a prognostic perspective, it is important for the physician to determine the extent of tumor nodules spread throughout the peritoneum. For standardization, in 1996, Sugarbaker proposed using the Peritoneal Cancer Index (PCI). To calculate this parameter, the peritoneal sheet is divided into 13 regions. In each of these segments, the diameter of the tumor nodule is determined (taking into account the largest one), based on which it is assigned a value from 0 to 3 points. Then all 13 parameters are summed up. The higher the final score (the maximum value can be 39), the more widespread the process.

Symptoms of Peritoneal Canceromatosis

The disease often progresses for a long time without specific manifestations. However, nonspecific signs such as abdominal distension, nausea, frequent loose stools, abdominal pain, and weight loss should be considered. When such symptoms occur, it is mandatory to exclude the possibility of peritoneal tumor involvement. The development of bowel obstruction is particularly serious.

In most cases, canceromatosis is accompanied by the appearance of ascitic fluid in the abdominal cavity, indicating a relatively long existence of the pathological process. Normally, there should be no more than 20 ml of transudate between the parietal and visceral layers of the peritoneum. An increase in this volume can be observed in both tumor and non-tumor diseases (e.g., peritonitis). The mechanisms of development of cancerous ascites can vary: mechanical obstruction of lymphatic vessels by pathological cells, increased permeability of the vascular wall due to the influence of growth factors and cytokines.

The development of ascites in the context of malignant tumors is considered an unfavorable prognostic sign. Ascitic fluid creates conditions for the spread of tumor cells and forms an optimal microenvironment for them, thereby contributing to the progression of the malignant process.


To date, the exact mechanisms of peritoneal metastasis are not established. It is believed that this process depends, on one hand, on the anatomy of the organ and physical factors, and on the other hand, on the ability of primary tumor cells to adapt to a different environment (microenvironment).

True peritoneal canceromatosis is always a secondary process that can develop with tumors of almost any localization. The appearance of a seeding nodule on the peritoneum undergoes several stages sequentially: a small group of malignant cells separates from the primary neoplasm, destroys the interstices (intercellular space), penetrates into the blood or lymphatic vessels and settles there temporarily, reaches distant organs where it implants.

In peritoneal transudate, tumor cells move freely, especially under the influence of intestinal peristalsis and diaphragmatic movements. As a result, they find themselves in the most favorable conditions and can penetrate not only into the peritoneum but also into the omentum. When the lymphatic collectors of the peritoneum are blocked, ascites appears, creating even better conditions for malignant implantation. The appearance of tumor cells stimulates an inflammatory reaction, which increases vascular permeability and thus contributes to more pronounced plasma exudation. Ascites progresses, creating a better microenvironment for implantation, and the disease progresses more aggressively.

Diagnosis of Peritoneal Canceromatosis

The diagnosis of peritoneal canceromatosis is based on visualization (laboratory markers are not informative). The main visualization methods include:

  • Ultrasound scanning;
  • Computed tomography (CT);
  • Magnetic resonance imaging (MRI);
  • Positron emission tomography/computed tomography (PET/CT).

Ultrasound allows for the accurate detection of ascites, but may not always help visualize canceromatous areas. CT can be informative in identifying tumor nodules on the peritoneum with a diameter of more than 1 cm. MRI and PET/CT are almost equally informative, especially when used to detect peritoneal metastases in patients with ovarian, stomach, or intestinal tumors. However, artifact overlay due to intestinal peristalsis is possible. The combination of magnetic resonance and computed tomography provides a more complete picture than CT alone. This emphasizes that establishing an accurate diagnosis of peritoneal tumor involvement is a complex task that requires an individualized approach.

Undoubtedly, the most accurate information can be obtained through direct examination of the peritoneum. In this regard, diagnostic laparoscopy (3 punctures) is more acceptable than laparotomy (1 long incision) since it causes minimal damage to the peritoneum. This means that the likelihood of secondary inflammation is minimal, and therefore, conditions for the dissemination of cancer cells are worse. Diagnostic laparoscopy also allows for a prognostic assessment of the possibility of performing surgery for peritoneal canceromatosis – cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS and HIPEC).

Treatment of Peritoneal Canceromatosis

When peritoneal canceromatosis develops, the patient’s overall condition is assessed, and conditions for surgery are determined.
Conservative treatment
Conservative treatment in the form of systemic administration of chemotherapy drugs may be acceptable only in cases of severe comorbidities in the patient.

Surgical treatment – surgery for peritoneal canceromatosis
Significant progress in the treatment of microscopic tumor nodules has been achieved after achieving adequate complete cytoreduction (CRS) – macroscopic removal of visible tumor nodules in combination with hyperthermic intraperitoneal chemotherapy (HIPEC). The therapeutic efficacy between different cytotoxic drugs and hyperthermia begins at a temperature of 39°C. This synergy is more pronounced the higher the temperature. However, some cytotoxic drugs lose their beneficial effects at temperatures above 43°C and increase their toxic effects on the intestines. Hyperthermia up to 43°C has no effect on the frequency of complications. There are several levels of hyperthermia used for this method. In most cases, a hyperthermic intraperitoneal chemotherapy regimen at a temperature of 41°C – 43°C is chosen, and only in exceptional cases, soft or hard hyperthermic perfusion regimens may be indicated.
Hyperthermic intraperitoneal chemotherapy (HIPEC) can be performed by open or closed methods.

  • Open method involves laparotomy. A cytostatic is introduced into the abdominal cavity through an incision, and an assistant continuously mixes it to achieve uniform distribution in the abdominal cavity.
  • Closed method. Before the drug is administered, the abdominal cavity is sutured, which allows maintaining a relatively constant temperature and preventing leakage of the chemotherapeutic agent.

Prevention is aimed at timely treatment of the malignant process.