Gastric cancer represents one of the most severe cancers with poor overall survival. Despite the availability of published data on the efficacy of adjuvant treatment, the actual percentage of treated patients remains low. The toxicity of radiotherapy or chemotherapy regimens differ and clinicians need accessible tools in order to better select candidates for adjuvant treatment. In this review, we present published data from clinical trials and cancer registries that might be useful for properly balancing the efficacy and toxicity of adjuvant treatment in gastric cancer patients who underwent surgery with curative intent.