[Adjuvant therapy in gastric cancer]

In Western countries gastric cancer represents the third cause of death even if in the last twenty years the epidemiology of disease has changed. Surgery remains the treatment of choice and overall survival is still 7-15%. Survival data after curative resection are higher in Japan than in Western countries due to a substantial different surgical approach and "early" diagnosis. In both countries adjuvant treatment has been developed to increase the survival rate and different schedules and polipharmacological schemes have been tested. In Japanese trials a statistical significance in survival was observed with chemoimmunotherapy using chemotherapy as control arm. In Western countries data are not conclusive: most trial used surgery as control arm and sample size was not sufficient to show a significant difference between the two arms. The meta-analysis performed up to now have shown a trend of advantage in survival with adjuvant chemotherapy and many objections can be raised concerning the methodology of the same. In fact there are different types of meta-analyses according to whether they are based on the literature (MAL) or individual patient data (MAP or IPD meta-analysis). With an IPD meta-analysis a search is not only done in the literature for all relevant published trials, but also in the scientific community unpublished trials. For all trials, whether published or not, individual patient data on the endpoint of interest are obtained from the investigators. No meta-analysis performed up to now has adopted this methodology. Recently, combined therapy (CT/RT) has shown interesting results with an increase in DFS and OS. At the moment trials results are not sufficient to consider adjuvant chemotherapy the standard treatment: other large trials are required and a combined approach such as RT, IP chemotherapy, neoadjuvant plus adjuvant chemotherapy may be a future research possibility.