Rapid Detection of Free Cancer Cells in Intraoperative Peritoneal Lavage Using One-Step Nucleic Acid Amplification (OSNA) in Gastric Cancer Patients

Cytokeratin-19 (CK19) has been proven to be commonly expressed by cancer cells in a variety of solid tumors and may serve as a suitable marker of metastases in gastric cancer (GC). Since objective assessment of peritoneal lavage or fluid for free cancer cells (FCC) is essential for clinical decision making in patients with GC, it is important to develop a quantitative and reproducible method for such evaluation. We assessed the possible application of One-Step Nucleic Acid amplification (OSNA) assay as a rapid method for FCC detection in intraoperative peritoneal lavage or fluid of GC patients. Seventy-eight intraoperative peritoneal lavage or fluid samples were eligible for the analysis by conventional cytology and OSNA examination. The concentration of CK19 mRNA in intraoperative peritoneal lavage and fluid was compared with the conventional cytological assessment. CK19 mRNA concentration was detected by OSNA assay. For peritoneal lavage samples, sensitivity and specificity were 83.3% and 87.8%, respectively. In peritoneal fluid, significantly higher CK19 values were observed in patients with serosal infiltration (medians: 100 copies/µL vs. 415.7 copies/µL; p = 0.0335) and lymph node metastases (medians: 2.48 copies/µL vs. 334.8 copies/µL). OSNA assay turns out to be an objective, fast, and reproducible quantitative method of FCC assessment.

Free cancer cells in gastric cancer - methods of detection, clinical and prognostic importance (meta-analysis)

Gastric cancer (GC) is one of the most common malignant cancers worldwide. Intraperitoneal dissemination is the typical mechanism of the formation of metastases in GC. The diagnosis of the presence of intraperitoneal free cancer cells (IFCCs) is treated equally to the M (metastasis) category according to the 8^th edition of the TNM classification by the American Joint Committee on Cancer. IFCCs are cells which have detached from the primary tumour through exfoliation into the peritoneal cavity. The source of IFCCs may be iatrogenic due to improper surgical technique during resection of the tumour and may lead to intraperitoneal dissemination. Cytological examination of peritoneal lavage is considered as a gold standard in the confirmation of the presence of IFCCs; however, its sensitivity is very low. In order to increase the sensitivity and reliability of the examination, molecular biology techniques should be applied. In the case of detection of the presence of IFCCs in patients with GC, the patient should be qualified for chemotherapy, or possibly the use of hyperthermic intraperitoneal chemotherapy should be considered.

[Cytological diagnostics of intraoperative peritoneal washes in gastric cancer.]

Diagnosis of peritoneal microcanceromatosis is the most important task allowing to determine treatment strategy for patients with stomach cancer. Laparoscopy combined with peritoneal flushing and subsequent cytological examination should be performed to detect the peritoneal microcanceromatosis at the preoperative stage. The objective of this work was to improve cytological diagnostics of peritoneal washings using immunocytochemical techniques and the cell block method. The work was carried out on the basis of 276 surgical peritoneal washings in patients with stomach cancer who were on treatment in the department of high-tech surgery of the Moscow Clinical Scientific Centre of the State Budgetary Healthcare Institution named after Loginov A.S. from June 2016 to June 2018. As a result, the optimal panel of monoclonal antibodies (Ber-EP4, CEA, CK20) was chosen, which increased the sensitivity from 52% to 96% and the specificity of cytological diagnosis from 80% to 98%, and the overall accuracy of the method from 67% to 98%.

[Prevention of carcinomatosis in colon cancer]

Colorectal cancer (CRC) is one of the leading forms of cancer. In 2017, over 72,000 of Russian citizens have been diagnosed with CRC. Cancer stage IV was diagnosed in 18 149 of them. Peritoneal carcinomatosis (PC) is one of the forms of metastatic dissemination throughout the peritoneum. There no any unified and standardized approaches to the treatment or prevention of PC associated with CRC. Therefore, it is advisable to identify PC predictors in patients with colon cancer and prevention measures.