Positive peritoneal cytology in patients with gastric cancer: natural history and outcome of 291 patients.

Abstract

Positive peritoneal cytology is a predictor of poor survival in patients with gastric cancer. Our aim is to more clearly define the natural history of this cohort. Review of a prospectively maintained gastric cancer database of patients who had diagnostic laparoscopy with peritoneal washings. Clinicopathologic and treatment-related variables were obtained. Univariate and multivariate analyses were performed for factors associated with disease-specific survival (DSS). From January 1993 to April 2009, a total of 1241 patients with gastric cancer underwent laparoscopy with peritoneal washings; 291 (23%) had positive cytology. There were 198 patients (68%) who had visible metastases discovered at laparoscopy (M1), and 93 patients (32%) were without gross evidence of advanced disease (M1 Cyt+). The median DSS for the entire cohort was 1 year; for M1, DSS was 0.8 years, and for M1 Cyt+, DSS was 1.3 years. At baseline, independent predictors of worse DSS were poor performance status, M1 disease, and diffuse tumors. Among the subset of patients with M1 Cyt + disease, performance status was the strongest independent predictor of DSS. A total of 48 of the 291 Cyt + patients had repeat staging laparoscopy after chemotherapy. Compared with patients who had persistently positive cytology (n = 21), those who converted to negative cytology (n = 27) had a significant improvement in DSS (2.5 years vs. 1.4 years, P = 0.0003). Patients with positive cytology as the only evidence of advanced disease exhibit a poor outcome; however, clearing of Cyt + disease by chemotherapy is associated with a statistically significant improvement in DSS. The role for gastrectomy in patients with positive peritoneal cytology remains uncertain.