Jamel S, et al. – This meta–analysis aimed to assess the value of peritoneal cytology as part of the staging of gastric cancer and survival prediction and to establish if positive cytology could be modified by neoadjuvant therapy, to improve prognosis. The researchers proposed that patients with initial positive cytology could have a good prognosis following neoadjuvant treatment if the cytology results changed to negative after treatment.

Methods

• Up to January 2016, the researchers performed an electronic literature search using Embase, Medline, Web of Science, and Cochrane library databases.
• They used the logarithm of the hazard ratio (HR) with 95% confidence intervals (CI) as the primary summary statistic.
• They used comparative studies, and the outcome measure was survival in three groups:
  • Positive vs. negative cytology at staging laparoscopy immediately preceding surgery
  • Effect of neoadjuvant therapy on cytology and survival
  • Positive cytology in the absence of macroscopic peritoneal disease was compared with obvious macroscopic peritoneal disease.

Results

• Pooled analysis revealed that positive cytology was correlated with significantly reduced overall survival (HR, 3.46; 95% CI, 2.77-4.31; P < 0.0001).
• Interestingly, negative cytology following neoadjuvant chemotherapy was correlated with significantly improved overall survival (HR, 0.42; 95% CI, 0.31-0.57; P < 0.0001).
• In this study, the absence of macroscopic peritoneal disease with positive cytology was correlated with significantly improved overall survival (HR, 0.64; 95% CI, 0.56-0.73; P < 0.0001).