Free peritoneal tumour cells are an independent prognostic factor in curatively resected stage IB gastric carcinoma.
Several studies have shown that the cytological detection of free peritoneal tumour cells (FPTCs) in patients with gastric cancer indicates the presence of metastatic disease. The immunocytochemical detection of FPTCs, especially in early-stage tumours, has not been examined comprehensively. Peritoneal lavage was performed in 351 patients before curative resection of a gastric carcinoma between 1987 and 2001, and an adequate sample was obtained from 346 patients. FPTCs were detected immunocytochemically using Ber-EP4 antibody. Median follow-up time was 70 months. FPTCs were detected in the lavage fluid of 74 patients (21.4 per cent) and correlated with increasing pathological tumour depth (pT) and lymph node (pN) status (P < 0.001). The 5-year overall survival of patients with FPTCs was significantly worse than that of patients without FPTCs (35 versus 71.9 per cent; P < 0.001). FPTCs were present in 14 (8.5 per cent) of 164 patients with stage IA or IB tumours. Although the detection of FPTCs had no prognostic significance for stage IA tumours, the presence of FPTCs in those with stage IB tumours was associated with a worse prognosis (P < 0.001). Multivariate analysis identified the presence of FPTCs as an independent prognostic factor in the whole cohort and in the stage IB subgroup. Detection of FPTCs is associated with poor prognosis even in patients with early-stage gastric cancer and should be used for risk-group stratification.