Long-term survival after gastrectomy for cancer in randomized, controlled oncological trials: comparison between West and East.

BACKGROUND: The presence of mixed evidence about the value of lymphadenectomy in gastric cancer surgery coupled with the difference in patients' demographics and tumor stage between the West and East have doubted the needs to standardize surgical techniques in Western clinical practice. The purpose of this study was to compare survival rates between the West and East following gastrectomy in randomized, controlled, oncological trials with appropriate adjustment for confounding variables.
METHODS: Systematic search revealed 25 trials that have randomization into surgery and chemotherapy versus surgery alone between 1995 and 2012 (n = 7 (East) and n = 18 (West)). End points were 5-year survival and cancer recurrence.
RESULTS: There was association between gastrectomy performed in the East and improved 5-year survival (pooled odds ratio (OR) 4.83; 95 % confidence interval (CI) 3.27-7.12) and reduced cancer recurrence (pooled OR 0.33; 95 % CI 0.2-0.54). Association of improved 5-year survival with surgery in the East remained when meta-regression adjusted for the effect of age, sex, chemotherapy, tumor depth and nodal status, and gastrectomy type. Association of reduced cancer recurrence also persisted with meta-regression adjusting for age, chemotherapy, nodal status, and gastrectomy type. However, when adjustment for the percentage of patients with tumor depth T1 or 2 was made statistical significance was lost.
CONCLUSIONS: This analysis shows association between gastrectomy performed in Eastern countries and improved survival. The known difference in surgical techniques between the East and the West is one potential unexamined variable that may be responsible in part for such discrepancy in outcomes.