Towards the goal of r0 resection in locally advanced gastriccancer through the path of neoadjuvant chemotherapy e impact of tumour downstaging on survival in a single series.

Background: Long term survival after R0 resection in locally advanced gastric cancer (LAGC) remains poor, suggesting that a true curative treatment is seldom performed. Preoperative treatment protocols have been proven to be effective in LAGC by large-scale randomized trials; this theoretically happens through an increased control on both distant and loco-regional recurrencies. Aim of this study is the evaluation of the effects on the primary tumour, along with its lymphatic basin, induced by preoperative chemotherapy and the survival impact on a single series of locally advanced gastric carcinomas. Methods: 47 patients with LAGC, staged by laparoscopy, underwent D2-gastrectomy after preoperative chemotherapy. The effects of preoperative treatment were evaluated by a quantitative analysis , which determined the percentage of residual vital tumour cells in the surgical specimens, and by a qualitative analysis , which evaluated the achievement of 8 ABSTRACTStumour-downstaging (T/dwn) induced by any grade of pathologic response. T/dwn after preoperative chemotherapy was assessed comparing pre-treatment clinical and laparoscopic staging with post-operative pathologic staging. The c2 test was used to evaluate the significance of statistical differences among sub-groups. Survival was calculated by Kaplane Meier method and the prognostic significance of prognostic factors was determined by means of univariate analysis (log-rank test). Multivariate analysis was performed using the Cox proportional hazard model in backward stepwise regression. Results: "Quantitative analysis" of pathologic response was unable to show a clear prognostic significance. T/dwn was obtained in 25 out of 47 patients. T/dwn was associated with a smaller tumour diameter (34 mm. mean-diameter in T/dwn group versus 55 mm.mean-diameter in non-T/dwn group, p¼0.002) and a higher R0-resection rate (96% in T/dwn group versus 72% in no-T/dwn group, p¼0.04). Overall survival at 5 years was 55%. In those patients who benefited from a R0-resection (40/47 patients: R0-resection rate ¼ 85%) overall survival reached up to 63%. At univariate and multivariate analysis, R0-resection was found to be an independent prognostic factor (R1-2/R0: HR 6.250/1, p¼0.002). Conclusions: In this study, R0-resection was the most important prognostic factor for LAGC selected to be treated by preoperative chemotherapy. Patients who obtained T/dwn had a definitely better chance of cure, mainly through the achievement of a true R0-resection.