Gastric Cancer Prognosis and Treatment: New Findings on Peritoneal Lavage Cytology

Strategic Insights -

Researchers at Hiroshima University have published a new study on the prognosis and treatment of gastric cancer, specifically in cases where peritoneal lavage cytology is positive (CY1). The study, published in the World Journal of Gastrointestinal Oncology, analyzed data from 13 institutions over a 5-year period (2015-2019) and included 82 patients who underwent gastrectomy with CY1.

According to the study, diffuse-type histology and the absence of postoperative chemotherapy were identified as independent poor prognostic factors. The 5-year survival rate was significantly higher for patients who received a combination of fluoropyrimidine and docetaxel/oxaliplatin (82.4%) compared to those who received S-1 monotherapy or a cisplatin-based regimen (21.8%). The study also found that chemotherapy regimen was an independent prognostic factor, with a hazard ratio of 5.47 (P = 0.004).

Key Takeaways:

  • Peritoneal lavage cytology-positive gastric cancer has a poor prognosis, with a median overall survival of 22.8 months.
  • Diffuse-type histology and the absence of postoperative chemotherapy are independent poor prognostic factors.
  • Combination therapy with oxaliplatin or docetaxel may enhance treatment intensity and improve survival outcomes after gastrectomy.
  • The 5-year survival rate was significantly higher for patients who received a combination of fluoropyrimidine and docetaxel/oxaliplatin (82.4%) compared to those who received S-1 monotherapy or a cisplatin-based regimen (21.8%).
  • Chemotherapy regimen was an independent prognostic factor, with a hazard ratio of 5.47 (P = 0.004).
  • The average relative dose intensity of the fluoropyrimidine + docetaxel/oxaliplatin group was 82.1%, with significantly more patients achieving a relative dose intensity of 80% compared to the S-1 monotherapy or cisplatin-based group (P = 0.001).

Statistics:

  • Median overall survival: 22.8 months
  • 5-year survival rate: 82.4% (fluoropyrimidine + docetaxel/oxaliplatin), 21.8% (S-1 monotherapy or cisplatin-based regimen)
  • Hazard ratio for chemotherapy regimen: 5.47 (P = 0.004)
  • Average relative dose intensity: 82.1% (fluoropyrimidine + docetaxel/oxaliplatin), 70.5% (S-1 monotherapy or cisplatin-based regimen)
  • Number of patients: 82

Sources:

  • World Journal of Gastrointestinal Oncology, "Prognostic Factors and Efficacy of Postoperative Chemotherapy In Patients With Gastric Cancer With Positive Peritoneal Cytology After Gastrectomy," 2025;17(9)
  • Hiroshima University, Graduate School of Biomedical and Health Sciences, Dept Perioperat & Crit Care Management
  • Kazuaki Tanabe, Hiroshima University, Graduate School of Biomedical and Health Sciences, Dept Perioperat & Crit Care Management
  • NewsRx, "Study Findings on Gastric Cancer Are Outlined in Reports from Hiroshima University," Cancer Weekly, October 14, 2025; p 5524.