Malignant Peritoneal Tumors - Introduction.

This article provides an introduction to peritoneal tumors, which are the subject of a series of review papers published in Issue 5 (2019) of Klinicka onkologie. Many malignant peritoneal tumors are characterized by production of mucinous and gelatinous masses, multiple peritoneal disability, so-called peritoneal carcinomatosis, and various grades of malignancy depending on their origin, staging, and histological type. Malignant peritoneal tumors are rare and their clinical symptomatology is nonspecific and varies according to the extent of disability. Diagnosis, particularly in the initial asymptomatic stages, is very complicated and often impossible, and tumors are often diagnosed by chance during other operations. Malignant peritoneal tumors were regarded as incurable and lethal for a long time; however, this view has changed over the past three decades. The Sugarbaker method, a combination of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy, was introduced in the 1990s. Postoperative cytostatic lavage is usually performed in specific cases. Classifications for the extent of disease and completeness of cytoreduction were established. Studies repeatedly confirmed the efficacy of this treatment for peritoneal malignancy. The combination of an aggressive surgical approach and intraperitoneal chemotherapy not only enhances quality of life, but also prolongs progression-free survival and overall survival in selected patients. Specialized centers for treatment of peritoneal malignancy were established based on results from the Czech Republic and around the world. These centers provide complex care, including specific surgical interventions and follow-up, for selected patients with primary and secondary peritoneal malignancy.

Therapy and Prophylaxis of Peritoneal Metastases from Colorectal Cancer.

Stage IV colorectal cancer is associated with high mortality, and the prognosis is significantly worse for patients have peritoneal metastases. Peritoneal carcinomatosis from colorectal cancer was considered incurable with an infaust prognosis. Median survival of untreated patients is about 6 months and palliative systemic chemotherapy can prolonge this time up to 20 months. Patients with this disease were previously only surgically treated if they had severe clinical symptoms or complications. This view has changed dramatically over the past 15 years. Aggressive cytoreductive surgery in combination with intraperitoneal chemotherapy may prolong median survival for more than 40 months in selected patients. The Peritoneal Surface Oncology Group International (PSOGI), the international authority on the treatment of peritoneal tumors, recommends cytoreduction with intraperitoneal chemotherapy as the standard of care for selected patients with moderate-to-small volume peritoneal metastases secondary to colorectal cancer. Macroscopic cytoreduction appears to be essential; however, the role of hyperthermic intraperitoneal chemotherapy and the optimal chemotherapeutic agent for intraperitoneal lavage to treat peritoneal metastases from colorectal cancer remain unclear. The results of ongoing and future clinical trials are eagerly awaited.

GAPPS - Gastric Adenocarcinoma and Proximal Polyposis of the Stomach Syndrome in 8 Families Tested at Masaryk Memorial Cancer Institute - Prevention and Prophylactic Gastrectomies.

Gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) is a rare variant of familial adenomatous polyposis. It is an autosomal-dominant cancer-predisposition syndrome with massive polyposis of the stomach and a significant risk of gastric adenocarcinoma. Li et al., 2016, described point mutations in the Ying Yang 1 binding site of the APC gene 1B promoter associated with GAPPS syndrome. The first GAPPS syndrome in a Czech family was described in 2016. At Masaryk Memorial Cancer Institute, GAPPS syndrome was diagnosed in eight families using Sanger sequencing. In all families, one mutation in promoter 1B of APC gene NM_001127511: c.-191T>C was detected. This mutation was not found in any patient with multiple colon polyposis without a detected classic mutation in the APC gene. In total, 24 carriers of this mutation in promoter 1B of the APC gene were detected. Out of those 24 carriers, 20 had massive gastric polyposis with more than 100 fundic glandular polyps diagnosed between the age of 22 and 65, 5 had already died of adenocarcinoma of the stomach (at the ages of 29, 40, 59, 60 and 64, respectively) and another woman was treated at the age of 29. Two female carriers do not yet have polyposis of the stomach at the ages of 31 and 65, respectively; one female carrier has incipient polyposis at the age of 58. A male carrier does not have any clinical symptoms, gastroscopy was not indicated because of his age. Prophylactic total gastrectomy with D2 lymphadenectomy has already been performed 6 times at Masaryk Memorial Cancer Institute, in 5 cases without adenocarcinoma at the ages of 27, 34, 44, 51 and 66, respectively; in one female carrier adenocarcinoma of the stomach was detected in a histology specimen. Two prophylactic gastrectomies with D1 lymphadenectomy were performed at University Hospital Brno at the ages of 42 and 50, respectively. In the Czech Republic point mutation c.-191T>C (rs879253783) in the 1B promoter of the APC gene is a frequent cause of gastric polyposis with a high risk of gastric adenocarcinoma, even at a young age. Positively tested individuals are recommended to high-risk oncology clinic. A necessary part of the discussion with the patient is information about a preventive gastrectomy.