Neoplasic cells search in peritoneal washing of Gastric Cancer patients: cytological and molecular analysis

• Grant number: 23/04835-1
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: March 01, 2024
• End date: February 28, 2026
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Ulysses Ribeiro Júnior
• Grantee: Gabriel da Silva Kawakami
• Host Institution: Instituto do Câncer do Estado de São Paulo Octavio Frias de Oliveira (ICESP). Coordenadoria de Serviços de Saúde (CSS). Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil

Abstract

Gastric cancer (GC) continues to be a significant cause of mortality, with the peritoneum being the primary site of metastasis in advanced disease, and the most frequent pattern of recurrence after curative-intent surgery. The evaluation of peritoneal lavage (PL) is important for determining the management and survival of patients. However, the sensitivity of conventional cytological examinations in detecting tumor cells in PL is limited (50~67%), with approximately 32.25% of patients, despite macroscopic carcinomatosis, having negative lavage (false-negative). Therefore, the search for techniques that can improve assessment is important to ensure the ideal staging for patients with advanced disease. As an alternative to conventional Papanicolaou staining cytology, genetic detection based on qRT-PCR of epithelial or malignant cells in peritoneal fluid emerges, along with the detection of extracellular vesicles that serve as important mediators of cellular communication. Especially in patients with advanced GC, such techniques could refine cytological assessment at the time of diagnostic laparoscopy to complement staging, assisting in defining the ideal therapeutic approach. Thus, this present study aims to investigate the presence of free tumor cells (FTCs) through cytology and analysis of extracellular vesicles in samples of PL and blood obtained from GC patients using molecular techniques and compare the results with conventional cytology in detecting neoplastic cells. The association of findings with other clinicopathological parameters and patient prognosis will also be evaluated. (AU)