Purpose: Most studies have investigated the differences in postgastrectomy quality of life (QOL) based on the surgical procedure or reconstruction method adopted; only a few studies have compared QOL based on tumor location. This large-scale study aims to investigate the differences in QOL between patients with esophagogastric junction cancer (EGJC) and those with upper third gastric cancer (UGC) undergoing the same gastrectomy procedure to evaluate the impact of tumor location on postoperative QOL. Methods: The Postgastrectomy Syndrome Assessment Scale-45 (PGSAS-45) questionnaire was distributed in 70 institutions to 2,364 patients who underwent gastrectomy for EGJC or UGC.A total of 1,909 patients were eligible for the study, and 1,744 patients who underwent total gastrectomy (TG) or proximal gastrectomy (PG) were selected for the final analysis. These patients were divided into EGJC and UGC groups; thereafter, the PGSAS-45 main outcome measures (MOMs) were compared between the two groups for each type of gastrectomy. Results: Among the post-TG patients, only one MOM was significantly better in the UGC group than in the EGJC group. Conversely, among the post-PG patients, postoperative QOL was significantly better in 6 out of 19 MOMs in the UGC group than in the EGJC group. Conclusions Tumor location had a minimal effect on the postoperative QOL of post-TG patients, whereas among post-PG patients, there were definite differences in postoperative QOL between the two groups. It seems reasonable to conservatively estimate the benefits of PG in patients with EGJC compared to those in patients with UGC.

Objective: The placebo effect can enhance the response to treatment, even in the absence of pharmacological ingredients. One possible factor explaining the likelihood of the placebo effect in individuals is genetic polymorphisms in neurotransmitters. This study focused on gene polymorphisms in the catechol-O-methyltransferase (COMT) as an interindividual variable of the placebo effect.Design・Methods: All 120 participants were explained the effects of caffeine, including its ability to ameliorate drowsiness and increase concentration, and then given a placebo (lactose). The onset of the placebo effect was measured in terms of the degree of caffeine-reduced sleepiness using subjective indices of the Stanford Sleepiness Scale (SSS) and a feeling of drowsiness-Visual Analogue Scale (VAS). The mechanism of the placebo effect was objectively examined in terms of changes in cerebral blood flow in the prefrontal cortex of the brain. In addition, we investigated participants’ susceptibility to the placebo effect by examining genetic polymorphisms in COMT.Results: After taking the drug, sleepiness on the SSS and VAS was significantly improved (p＜0.001), although there was no change in prefrontal cortex activity. Among the 120 participants, 63 had a Val/Val-type polymorphism in COMT (52.5%), 45 had a Val/Met-type (37.5%), and 12 had a Met/Met-type (10.0%). There were no significant differences among COMT gene polymorphisms in the subjective measures of SSS and VAS. However, there was a tendency for the cerebral blood flow changes to be larger in the left hemisphere of the brain in individuals with the Met/Met type.Conclusion: There seems to be a relationship between prefrontal cortex activity and genetic polymorphisms. In particular, there may be a correlation between the expression of a placebo effect and COMT gene polymorphisms.