Presence of cancer cells in gastric lavage of gastric cancer patients as an indicator of advanced disease, predictor of tumour aggressive phenotype and independent prognostic factor for poor survival: The endoluminal metastatic pathway of gastric cancer and GL0/GL1 classification

Objective As of 2017, the pathobiology of gastric cancer (GC) is far from fully understood; consequently, new methods of basic and advanced research have been proposed and tested. The presence (GL1) vs absence (GL0) of malignant cells exfoliated in gastric lavage (GL) of GC patients was formerly evaluated with diagnostic intent but not for staging or prognostic assessment. We investigated this hitherto unreported application of cytopathology. Methods GL was preoperatively and prospectively collected from 80 GC patients and cytologically analysed. The results were compared with the classic clinicopathological features of GC and related to survival. The prognostic value of GL1 was assessed through univariate and multivariate analyses. Results GL1 was detected in 36 samples (45%) and correlated with advanced tumour depth (T3‐T4), lymphatic metastasis (N+), distant metastasis (M1) and lymphovascular invasion (LVI1; P=.0317, .0024, .003 and .0028, respectively). Overall survival (OS) was significantly shorter for GL1 (23 months) vs GL0 patients (42 months; P=.005) and GL1 vs GL0 T1 subjects (12.6 vs 47.8 months, P=.0029). Univariate analysis revealed that GL1, N+, M1, LVI1 and advanced stage were significantly associated with OS. Multivariate analysis assessed GL1 as the only independent prognostic factor for worse OS and progression‐free survival (P=.0013 and .0107). Conclusions In the present study, GL1 was correlated with advanced disease, aggressive tumour behaviour and poor prognosis. Although additional studies are needed to confirm these findings, the GL0/GL1 classification can be applied to GC patients to achieve higher accuracy in staging, prognostic stratification and treatment selection. We have investigated the presence of malignant cells in gastric lavage (GL1) of gastric cancer (GC) patients using cytopathologic analysis in order to find novel information on the pathobiology of this tumor. Our results showed that GL1 was associated with advanced disease, predicted aggressive tumor behavior and was a multivariate independent prognostic factor for poor overall survival and progression‐free survival. The clinical adoption of our test could ameliorate staging and treatment selection of GC patients.