Peritoneal Cytology and Management in Gastric Cancer

Peritoneal cytology is a pivotal component of staging in locally advanced gastric cancer, offering direct evidence of free tumour cells within the peritoneal cavity. Positive cytology (CY1) in the absence of macroscopic metastases signifies micrometastatic dissemination and is associated with markedly poorer prognosis. Emerging molecular and imaging techniques have enhanced the sensitivity of cytological assessment, enabling early detection of minimal residual disease. The integration of cytological status with genomic and transcriptomic biomarkers now informs tailored neoadjuvant and adjuvant strategies. Conversion from CY1 to negative cytology following systemic therapy correlates with improved survival and reduced peritoneal recurrence, thereby redefining the boundary between curative and palliative intent. Advances in personalised assays and rapid intraoperative detection promise more precise risk stratification, guiding decisions on gastrectomy, intraperitoneal chemotherapy and intensified surveillance.

Research from Nature Portfolio

An observational cohort evaluated postoperative chemotherapy in patients with positive peritoneal washing cytology but no visible peritoneal metastasis undergoing D2 gastrectomy. Among those receiving adjuvant chemotherapy, disease-free and overall survival were significantly prolonged compared with surgery alone, with hazard ratios exceeding threefold for recurrence and mortality. Conversion to cytology-negative status emerged as the strongest predictor of long-term benefit, underscoring the value of cytological response as a stratification tool. Despite improved outcomes, residual peritoneal relapse emphasises the need for enhanced local control strategies and optimisation of systemic regimens.

Peritoneal Cytology and Management in Gastric Cancer publication trend

The graph below shows the total number of articles in peritoneal cytology and management in gastric cancer across all publications each year (not limited to Nature Index journals).

Technical terms

Peritoneal Cytology: Microscopic examination of peritoneal lavage fluid to detect free gastric cancer cells.

Cytology-positive (CY1): Presence of malignant cells in peritoneal washings, indicating micrometastatic disease.

Neoadjuvant Chemotherapy: Systemic treatment administered before surgical resection to reduce tumour burden and eradicate occult metastases.

Stimulated Raman Molecular Cytology (SRMC): An optical imaging technique that combines chemical microscopy with machine learning to classify individual cells based on molecular composition.

Liquid Biopsy: Noninvasive analysis of circulating nucleic acids or cells in body fluids to detect tumour-derived biomarkers.

References

1. Accurate and Rapid Detection of Peritoneal Metastasis from Gastric Cancer by AI‐Assisted Stimulated Raman Molecular Cytology. Advanced Science (2023).
2. Transcriptomics-based liquid biopsy panel for early non-invasive identification of peritoneal recurrence and micrometastasis in locally advanced gastric cancer. Journal of Experimental & Clinical Cancer Research (2024).
3. Personalized analysis of minimal residual cancer cells in peritoneal lavage fluid predicts peritoneal dissemination of gastric cancer. Journal of Hematology & Oncology (2021).
4. Observational Study of Peritoneal Washing Cytology-Positive Gastric Cancer without Gross Peritoneal Metastasis in Patients who Underwent Radical D2 Gastrectomy. Scientific Reports (2020).
5. Gastric cancer with positive peritoneal cytology: survival benefit after induction chemotherapy and conversion to negative peritoneal cytology. World Journal of Surgical Oncology (2021).