Rapid hydrolysis of NO2 at High Ionic Strengths of Deliquesced Aerosol Particles.

Nitrogen dioxide (NO2) hydrolysis in deliquesced aerosol particles forms nitrous acid and nitrate and thus impacts air quality, climate, and the nitrogen cycle. Traditionally, it is considered to proceed far too slowly in the atmosphere. However, the significance of this process is highly uncertain because kinetic studies have only been made in dilute aqueous solutions but not under high ionic strength conditions of the aerosol particles. Here, we use laboratory experiments, air quality models, and field measurements to examine the effect of the ionic strength on the reaction kinetics of NO2 hydrolysis. We find that high ionic strengths (I) enhance the reaction rate constants (kI) by more than an order of magnitude compared to that at infinite dilution (kI=0), yielding log10(kI/kI=0) = 0.04I or rate enhancement factor = 100.04I. A state-of-the-art air quality model shows that the enhanced NO2 hydrolysis reduces the negative bias in the simulated concentrations of nitrous acid by 28% on average when compared to field observations over the North China Plain. Rapid NO2 hydrolysis also enhances the levels of nitrous acid in other polluted regions such as North India and further promotes atmospheric oxidation capacity. This study highlights the need to evaluate various reaction kinetics of atmospheric aerosols with high ionic strengths.

Improvement of the anthropogenic emission rate estimate in Ulaanbaatar, Mongolia, for 2020-21 winter.

Ulaanbaatar (UB), the fast-growing capital of Mongolia, is known for its world's worst level of particulate matter (PM) concentrations in winter. However, current anthropogenic emission inventories over the UB are based on data from more than fifteen years ago, and satellite observations are scarce because UB is in high latitudes. During the winter of 2020-21, the first period of the Fine Particle Research Initiative in East Asia considering the National Differences (FRIEND), several times higher concentrations of PM in UB compared to other urban sites in East Asia were observed but not reproduced with a chemical transport model mainly due to the underestimated anthropogenic emissions. Therefore, we devised a method for sequentially adjusting emissions based on the reactivity of PM precursors using ground observations. We scaled emission rates for the inert species (CO, elemental carbon (EC), and organic carbon (OC)) to reproduce their observed ambient concentrations, followed by SO2 to reproduce the concentration of SO42-, which was examined to have the least uncertainty based on the abundance of observed NH3, and finally NO and NH3 for NO3-, and NH4+. This improved estimation is compared to regional inventories for Asia and suggests more than an order of magnitude increase in anthropogenic emissions in UB. Using the improved emission inventory, we were able to successfully reproduce independent observation data on PM2.5 concentrations in UB in December 2021 from the U.S. Embassy. During the campaign period, we found more than 50% of the SO42-, NO3-, and NH4+ increased in UB due to the improvement could travel to Beijing, China (BJ), and about 20% of the SO42- could travel to Noto, Japan (NT), more than 3000 km away. Also, the anthropogenic emissions in UB can effectively increase OC, NO3-, and NH4+ concentrations in BJ when Gobi dust storms occur.

Solitary choroidal metastasis of distal cholangiocarcinoma: A case report.

Metastatic choroidal carcinoma is rare and generally has a poor prognosis. The present case report describes a case of choroidal metastasis from distal cholangiocarcinoma, which was successfully managed using stereotactic radiotherapy (SRT). A 67-year-old Japanese man underwent pancreaticoduodenectomy for distal cholangiocarcinoma. The pathological stage was T2N0M0 stage IIA, according to the Union for International Cancer Control 8th edition. After surgery, the patient received adjuvant chemotherapy with oral TS-1® for 1 month. A total of 2 months after surgery, the patient was readmitted to hospital due to decreased visual acuity. Fundoscopy revealed a macular hole in the right eye that accounted for the decreased visual acuity. Additionally, Goldmann three-mirror contact lens examination revealed a 4-mm choroidal mass with a yellowish color situated at a considerable distance from the optic nerve. Magnetic resonance imaging revealed an enhanced choroidal mass. Based on the findings of ophthalmologic examinations and the patient's history of cholangiocarcinoma, they were diagnosed with choroidal metastasis from distal cholangiocarcinoma. SRT was administered at a total dose of 40 Gy divided into 8 Gy fractions. A total of 1 year after SRT, the patient achieved complete remission without decreased visual acuity. The patient remains alive and in good health without recurrence, 4 years after the diagnosis of choroidal metastasis. To the best of our knowledge, this is the second reported case of intraocular metastasis from cholangiocarcinoma. In conclusion, SRT may provide an opportunity to control metastatic choroidal carcinoma without decreasing visual acuity.

Predictive significance of surgery-induced lymphopenia on the survival after curative resection for locally advanced gastric cancer: a retrospective cohort analysis.

BACKGROUND: Following the establishment of the anti-cancer effect of immune checkpoint inhibitors, lymphopenia has attracted attention as a parameter of preexisting cancer-related immune tolerance. Although the pretreatment absolute lymphocyte count (ALC) has been reported as a prognostic factor in gastric cancer patients, the impact of perioperative changes in the ALC remains unknown. The aim of the present study was to explore the relationship between surgery-induced lymphopenia and outcome. METHODS: Database entries for 584 patients who underwent curative resections for pathological Stage IB-III gastric cancer were reviewed. We retrospectively compared clinicopathological factors including pretreatment ALC (pre-ALC) and ALC at first visit after discharge (post-ALC) with the survival. The low ALC was defined as < 1000/µL. RESULTS: The ALC decreased significantly at 1 and 3 days after surgery and then recovered to the baseline value. A low pre-ALC (p < 0.001) and a low post-ALC (p < 0.001) were both correlated with a poor relapse-free survival (RFS). A multivariate analysis of RFS identified a low post-ALC (hazard ratio 1.875, 95% CI 1.156-3.402, p = 0.01), age, gender, BMI, T disease, N disease, severe vessel invasion, type of gastrectomy and postoperative morbidity as independent factors. The low post-ALC group had a poor RFS among patients with Stage II (p = 0.04) and Stage III (p = 0.04) disease, but not among patients with Stage IB disease (p = 0.13). Consistently, the overall survival (OS) rate was significantly lower among patients with a low post-ALC for all stage (p < 0.001), stage II (p = 0.02) and stage III (p = 0.01) disease, not for stage IB (p = 0.09). A low post-ALC was identified as an independent factor for predicting OS by multivariate analysis (hazard ratio: 2.275, 95% CI 1.373-3.769, p = 0.01). CONCLUSIONS: A decrease in post-ALC was correlated with both of RFS and OS after curative resection in patients with locally advanced gastric cancer. HIGHLIGHTS: Postoperative lymphopenia was a poor prognostic factor for gastric cancer.

Development of Quantitative Chemical Ionization Using Gas Chromatography/Mass Spectrometry and Gas Chromatography/Tandem Mass Spectrometry for Ambient Nitro- and Oxy-PAHs and Its Applications.

The concentration of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere has been continually monitored since their toxicity became known, whereas nitro-PAHs (NPAHs) and oxy-PAHs (OPAHs), which are derivatives of PAHs by primary emissions or secondary formations in the atmosphere, have gained attention more recently. In this study, a method for the quantification of 18 NPAH and OPAH congeners in the atmosphere based on combined applications of gas chromatography coupled with chemical ionization mass spectrometry is presented. A high sensitivity and selectivity for the quantification of individual NPAH and OPAH congeners without sample preparations from the extract of aerosol samples were achieved using negative chemical ionization (NCI/MS) or positive chemical ionization tandem mass spectrometry (PCI-MS/MS). This analytical method was validated and applied to the aerosol samples collected from three regions in Northeast Asia-namely, Noto, Seoul, and Ulaanbaatar-from 15 December 2020 to 17 January 2021. The ranges of the method detection limits (MDLs) of the NPAHs and OPAHs for the analytical method were from 0.272 to 3.494 pg/m3 and 0.977 to 13.345 pg/m3, respectively. Among the three regions, Ulaanbaatar had the highest total mean concentration of NPAHs and OPAHs at 313.803 ± 176.349 ng/m3. The contribution of individual NPAHs and OPAHs in the total concentration differed according to the regional emission characteristics. As a result of the aerosol samples when the developed method was applied, the concentrations of NPAHs and OPAHs were quantified in the ranges of 0.016~3.659 ng/m3 and 0.002~201.704 ng/m3, respectively. It was concluded that the method could be utilized for the quantification of NPAHs and OPAHs over a wide concentration range.

Conversion surgery for stage IV gastric cancer: a multicenter retrospective study.

BACKGROUND: Recent improvements in systemic chemotherapy have provided an opportunity for patients with stage IV gastric cancer (GC) to undergo conversion surgery (CS). The aim of this study was to evaluate the long-term outcomes of patients who underwent CS and to elucidate the prognostic factors for CS in stage IV GC. METHODS: A total of 79 patients who underwent CS with the aim of R0 resection for stage IV GC at six institutions from January 2008 to July 2019 were enrolled. We retrospectively reviewed the clinicopathological data and prognosis. RESULTS: Of the 79 patients, 23 (31.1%) had initially resectable disease (IR) before chemotherapy, defined as positive for cancer on peritoneal cytology (CY1), resectable hepatic metastasis, or para-aortic lymph node No. 16a2/b1 metastasis. Of the 56 remaining patients with primary unresectable disease, 39 had peritoneal dissemination. R0 resection was accomplished in 63 patients (79.7%). The 3-year OS rates for patients with IR and unresectable disease were 78.3% and 44.5%, respectively. Multivariate analysis showed that IR (P = 0.014) and R0 (P = 0.014) were statistically significant independent prognostic factors for favorable OS. Among patients with peritoneal dissemination alone, OS was significantly better for patients with R0 resection than for patients with R1/2 resection, with the 3-year OS rates of 65.5% and 23.1%, respectively (P = 0.011). CONCLUSIONS: CS is a treatment option for selected patients with stage IV GC. Patients with IR and patients who achieve R0 resection may obtain a survival benefit from CS.

Long-range transport of airborne bacteria over East Asia: Asian dust events carry potentially nontuberculous Mycobacterium populations.

The nontuberculous mycobacterial pulmonary disease (NTM-PD) caused by Mycobacterium species has increased in prevalence all over the world. The distributions of NTM-PD are possibly determined by the westerly wind traveling at high altitudes over East Asia. However, the long-range transport of Mycobacterium species has not been demonstrated by analyzing the bacterial communities in aerosols such as desert mineral particles and anthropogenic pollutants transported by the westerly wind. Here, airborne bacterial compositions were investigated including Mycobacterium species in high-elevation aerosols, which were captured in the snow cover at 2,450 m altitude on Mt. Tateyama. This was further compared to the ground-level or high-altitude aerosols collected at six sampling sites distributed from Asian-dust source region (Tsogt-Ovoo) to downwind areas in East Asia (Asian continental cities; Erenhot, Beijing, Yongin, Japanese cities; Yonago, Suzu, Noto Peninsula). The cell concentrations and taxonomic diversities of airborne bacteria decreased from the Asian continent to the Japan area. Terrestrial bacterial populations belonging to Firmicutes and Actinobacteria showed higher relative abundance at high-elevation and Japanese cities. Additionally, Mycobacterium species captured in the snow cover on Mt. Tateyama increased in relative abundance in correspondence to the increase of black carbon concentrations. The relative abundance of Mycobacterium sequences was higher in the aerosol samples of Asian continental cities and Japanese cities than in the desert area. Presumably, anthropogenic pollution over East Asia carries potential Mycobacterium species, which induce NTM-PD, thereby impacting upon the public health.

Role of Dust and Iron Solubility in Sulfate Formation during the Long-Range Transport in East Asia Evidenced by 17O-Excess Signatures.

Numerical models have been developed to elucidate air pollution caused by sulfate aerosols (SO42-). However, typical models generally underestimate SO42-, and oxidation processes have not been validated. This study improves the modeling of SO42- formation processes using the mass-independent oxygen isotopic composition [17O-excess; Δ17O(SO42-)], which reflects pathways from sulfur dioxide (SO2) to SO42-, at the background site in Japan throughout 2015. The standard setting in the Community Multiscale Air Quality (CMAQ) model captured SO42- concentration, whereas Δ17O(SO42-) was underestimated, suggesting that oxidation processes were not correctly represented. The dust inline calculation improved Δ17O(SO42-) because dust-derived increases in cloud-water pH promoted acidity-driven SO42- production, but Δ17O(SO42-) was still overestimated during winter as a result. Increasing solubilities of the transition-metal ions, such as iron, which are a highly uncertain modeling parameter, decreased the overestimated Δ17O(SO42-) in winter. Thus, dust and high metal solubility are essential factors for SO42- formation in the region downstream of China. It was estimated that the remaining mismatch of Δ17O(SO42-) between the observation and model can be explained by the proposed SO42- formation mechanisms in Chinese pollution. These accurately modeled SO42- formation mechanisms validated by Δ17O(SO42-) will contribute to emission regulation strategies required for better air quality and precise climate change predictions over East Asia.

Simple modifications of conventional esophagogastrostomy after proximal gastrectomy adequately reduces the postoperative reflux esophagitis: a retrospective analysis of posterolateral fundoplication.

PURPOSE: While proximal gastrectomy is being performed increasingly frequently for the treatment of gastric cancer, a standard reconstruction method to obtain optimal postoperative quality of life (QOL) still remains to be established. We modified the original esophagogastrostomy technique by introducing an additional posterolateral fundoplication (PLF) technique to minimize the risk of reflux esophagitis in patients undergoing proximal gastrectomy. The aim of this study was to clarify the clinical benefit of PLF. METHODS: A retrospective analysis of the database was conducted to evaluate the effects of PLF. The data were compared between 44 patients in whom PLF was performed (PLF group) and 17 patients in whom conventional esophagogastrostomy without PLF was performed (C group). A number of incidence of postoperative reflux esophagitis and symptoms were assessed by findings of endoscopic examination and the PGSAS-45 questionnaire, respectively. RESULTS: The incidence of grade B or worse esophagitis after surgery was significantly lower in the PLF group than in the C group (0% vs. 58.8%, P < 0.01). The score for the esophageal reflux subscale, as the main outcome measure of PGSAS-45, was significantly better in the PLF group (PLF: 1.5 vs C: 2.4, P < 0.01). Cohen's d value was 1.75, which suggested a rather large effect size. Postoperative benign anastomotic stricture was encountered in 10 cases (22.7%) of the PLF group and 4 cases (23.5%) of the C group, all of whom were successfully treated by brief endoscopic mechanical dilatation. CONCLUSION: PLF is an expedient procedure for reconstruction after proximal gastrectomy.

Intracorporeal hand-sewn anastomosis following pylorus-preserving gastrectomy: surgical technique and short-term surgical outcome.

BACKGROUND: Although several procedures for mechanical anastomosis have recently been reported, intracorporeal manually hand-sewn anastomosis for totally laparoscopic pylorus-preserving gastrectomy (TLPPG) is considered technically difficult. Here, we report a new technique for laparoscopic reconstruction using hand-sewn sutures. METHODS: Together with a proper lymphadenectomy, the stomach was detached and resected using separate two-layer incisions, similar to the original laparotomy method. An approximately 5-cm antral cuff was left in place. The essential concept of this new method was to align the anastomotic site by rotating each clamped gastric stump. This allowed us to perform a secure, hand-sewn, two-layer anastomosis successfully. The short-term surgical outcome after TLPPG was retrospectively compared with that for patients who underwent a conventional laparoscopy-assisted procedure (LAPPG). RESULTS: Of the 20 consecutive patients who underwent pylorus-preserving gastrectomy in our department between 2014 and 2021, the first 8 patients and the subsequent 12 patients underwent LAPPG and TLPPG, respectively. The operation time was significantly longer in the TLPPG group (median, 302 vs. 269 min). The morbidity was comparable (8.3% in TLPPG vs. 12.5% in LAPPG). Postoperative delayed gastric emptying was only observed in one patient in the LAPPG group. TLPPG reduced the cost of the operation by reducing the number of linear stapler cartridges required. CONCLUSION: A purely hand-sewn gastrogastrostomy is safe, feasible, and cost-effective, and it omits the need for a mini-laparotomy in the upper abdomen.

Development of spray-drying-based surface-enhanced Raman spectroscopy.

We report a spray-drying method to fabricate silver nanoparticle (AgNP) aggregates for application in surface-enhanced Raman spectroscopy (SERS). A custom-built system was used to fabricate AgNP aggregates of four sizes, 48, 86, 151, and 218 nm, from drying droplets containing AgNPs atomized from an AgNP suspension. Sample solutions of Rhodamine B (RhB) at 10-6, 10-8, and 10-10 M concentrations were dropped onto the AgNP aggregates as probe molecules to examine the enhancement of the Raman signals of the RhB. The ordering of the analytical enhancement factors (AEFs) by aggregate size at a 10-6 M RhB was 86 nm > 218 nm > 151 nm > 48 nm. When RhB concentrations are below 10-8 M, the 86 and 151 nm AgNP aggregates show clear RhB peaks. The AEFs of the 86 nm AgNP aggregates were the highest in all four aggregates and higher than those of the 218-nm aggregates, although the 218-nm aggregates had more hot spots where Raman enhancement occurred. This finding was attributable to the deformation and damping of the electron cloud in the highly aggregated AgNPs, reducing the sensitivity for Raman enhancement. When RhB was premixed with the AgNP suspension prior to atomization, the AEFs at 10-8 M RhB rose ~ 100-fold compared to those in the earlier experiments (the post-dropping route). This significant enhancement was probably caused by the increased opportunity for the trapping of the probe molecules in the hot spots.

Impacts of SNPs on adverse events and trough concentration of imatinib in patients with gastrointestinal stromal tumors.

Although imatinib has dramatically improved the outcomes of patients with gastrointestinal stromal tumor (GIST), marked inter-individual differences in its efficacy and toxicity have been observed. Extensive pharmacogenetic studies in Caucasian and Asian populations have demonstrated that several genetic polymorphisms are involved in these differences; however, no studies have focused on Japanese patients with GIST. This study aimed to evaluate the impacts of genetic polymorphisms of drug metabolizing enzymes and transporters on the incidence of adverse events and trough plasma concentrations (Ctroughs) of imatinib in Japanese patients with GIST. Of 35 candidate SNPs genotyped from 65 patients, ABCG2 421C>A was significantly associated with increased incidence rates of grade 2 or higher rash. When relationships between the genotypes and Ctroughs were examined in a subgroup of 38 patients from whom plasma was available, 5 SNPs were associated with significant trends toward increased or decreased dose-adjusted Ctroughs. Of them, SLCO1B3 334T>G and SLCO1A2 -1032G>A made significant contributions to the individual variability of Ctrough by multivariate regression analysis. Genetic variations in ABCG2, SLCO1B3, and SLCO1A2 may play important roles in the safety and pharmacokinetics of imatinib in Japanese patients with GIST, although a replication study is necessary for validation.

First X-ray Spectroscopic Observations of Atmospheric Titanium Species: Size Dependence and the Emission Source.

Titanium dioxide (TiO2) in mineral dust is considered as one of the driving forces of photocatalytic reaction at the aerosol surface in the atmosphere. As a precursor of mineral dust, soil contains ilmenite (FeTiO3) and titanite (CaSiTiO5), which have lower photochemical reactivities than TiO2. However, Ti species other than TiO2 in aerosol particles are not well recognized due to the lack of observation in ambient samples. In this study, Ti species in size-fractionated aerosol samples collected in the Noto Peninsula, Japan, were determined by macroscopic and semi-microscopic X-ray absorption fine structure spectroscopy. Regardless of aerosol particle size, Ti species were primarily composed of rutile, anatase, ilmenite, and titanite. Semi-microscopic Ti speciation showed that Ti-poor spots associated with mineral dust were composed of a mixture of rutile, anatase, ilmenite, and titanite, and Ti-rich spots were primarily composed of TiO2 (rutile or anatase) derived from authigenic minerals or anthropogenic materials. Thus, the Ti species in aerosol particles, especially mineral dust, were not composed solely of TiO2 polymorphs. Therefore, the photochemical reactivities of Ti in aerosol particles may be overestimated when laboratory experiments or model studies employ TiO2 as the representative Ti species.

Calculating source contributions to urban atmospheric polycyclic aromatic hydrocarbons and nitropolycyclic aromatic hydrocarbons using 1-nitropyrene and pyrene: An application to an Asian dust event.

A method to calculate source contributions to atmospheric polycyclic aromatic hydrocarbons (PAHs) and their nitrated congeners (NPAHs) is proposed, using pyrene (Pyr) and 1-nitropyrene (1-NP), as respective representatives of PAHs and NPAHs. This is based on the known increases in NPAH to PAH ratios as combustion temperatures increase. The fractions of 1-NP and Pyr from high temperature combustion sources in total 1-NP and Pyr are respectively calculated as a (0 < a <1) and b (0 < b < 1). By using atmospheric concentrations of Pyr and 1-NP obtained at monitoring sites, contributions of high and low temperature combustion sources were calculated. Using this method, the contributions of automobiles and coal combustion facilities/industries to atmospheric Pyr and 1-NP concentrations were calculated for atmospheric samples collected in Kanazawa, Japan during a seasonal Asian dust event. The results show that Pyr was almost entirely emitted from industries in China and transported long-range to Japan. By contrast, 1-NP was emitted primarily from automobiles in Kanazawa and its surrounding areas, with a small amount of 1-NP possibly transported from China. The proposed method can provide greater clarity on source identification compared to the typically used PAH isomer pairs.

Efficacy and safety of ramucirumab plus paclitaxel therapy for advanced gastric cancer patients treated previously with docetaxel-containing chemotherapy.

BACKGROUND: Ramucirumab (RAM) plus paclitaxel (PTX) therapy has shown promising results as a standard second-line treatment for advanced gastric cancer patients. Recently, combined docetaxel (DOC) plus S-1 (DS) therapy could be regarded as the new standard adjuvant chemotherapy for patients with curatively resected stage III gastric cancer. However, the efficacy and safety of RAM plus PTX therapy in patients treated previously with DOC-containing therapy remains unclear. METHODS: This study assessed the clinical outcomes of RAM plus PTX therapy in advanced gastric cancer patients with or without a previous history of treatment with a DOC-containing regimen. RESULTS: In a series of 107 consecutive patients enrolled for this study, the median PFS and OS were 4.2 and 6.2 months, respectively. Fifty-five patients had a history of prior therapy with DOC and 52 did not. There was no significant difference between with and without DOC groups in the ORR (22.2% vs. 23.5%), PFS (4.2 vs. 5.3 months), or OS (7.2 vs. 6.4 months). In a comparison taking into account the interval from the DOC-containing therapy to the RAM plus PTX therapy, the number of treatment courses was significantly smaller and the PFS significantly shorter in the patient group with an interval of ≤ 6 months (median, 2 vs 4.5 courses, P = 0.033; 3.4 months vs. 5.1 months, P = 0.043). CONCLUSIONS: RAM plus PTX therapy in patients with advanced gastric cancer is effective even in patients who have previously received DOC-containing chemotherapy, especially if the interval is > 6 months.

Comparative Analysis of PM2.5-Bound Polycyclic Aromatic Hydrocarbons (PAHs), Nitro-PAHs (NPAHs), and Water-Soluble Inorganic Ions (WSIIs) at Two Background Sites in Japan.

Daily PM2.5 (particulate matter with aerodynamic diameter ≤2.5 µm) samples were simultaneously collected at two background sites (Wajima Air Monitoring Station (WAMS) and Fukue-Jima Atmosphere and Aerosol Monitoring Station (FAMS)) in Japan in the East Asian winter and summer monsoon periods of 2017 and 2019, to compare the characteristics of air pollutants among different regions and to determine the possible variation during the long-range transport process. Polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), and water-soluble inorganic ions (WSIIs) were analyzed. Despite the PM2.5 concentrations at FAMS (8.90-78.5 µg/m3) being higher than those at WAMS (2.33-21.2 µg/m3) in the winter monsoon period, the average concentrations of ∑PAHs, ∑NPAHs, and ∑WSIIs were similar between the two sites. Diagnostic ratios indicated PAHs mainly originated from traffic emissions and mostly aged, whereas NPAHs were mostly secondarily formed during long-range transport. WSIIs at WAMS were mainly formed via the combustion process and secondary reactions, whereas those at FAMS mainly originated from sea salt and dust. Backward trajectories revealed the air masses could not only come from Asian continental coastal regions but also distant landlocked areas in the winter monsoon period, whereas most came from the ocean in the summer monsoon period. These findings can provide basic data for the establishment of prediction models of transboundary air pollutants in East Asia.

Billroth-I vs Roux-en-Y after distal gastrectomy: A comparison of long-term nutritional status and survival rates from a large-scale multicenter cohort study.

BACKGROUND: The optimal standard reconstruction procedure after distal gastrectomy is controversial. No large-scale persuasive clinical studies from long-term perspectives on this topic have yet been conducted. STUDY DESIGN: This retrospective multicenter study analyzed a database of 2510 consecutive patients with clinical stage I gastric cancer who underwent distal gastrectomy followed by Billroth-I (B-I) or Roux-en-Y (R-Y) anastomosis from 2006 to 2012. After adjusting for 30 potential confounding factors using propensity score matching, we compared the body weight loss and other nutritional status for 5 years as primary outcomes between the two groups. We also investigated surgical outcomes, endoscopic findings, and long-term survival rates as secondary outcomes. RESULTS: After matching the inclusion criteria, 940 patients (470 in each group) were enrolled. There was no marked difference in the body weight loss and other nutritional indicators. The incidence of grade ≥3 postoperative complications (Clavien-Dindo classification) or the incidence of gallstone formation was not markedly different between the two groups. The postoperative hospital stay after surgery was significantly longer, and the readmission rate was significantly higher in the R-Y group than in the B-I group. An endoscopic examination revealed no trends regarding the incidence and severity of gastritis or residual food in the remnant stomach. The 5-year overall survival rate was 92.6% in the B-I group and 91.8% in the R-Y group, with no significant difference (P = .379, log-rank test). CONCLUSIONS: Roux-en-Y reconstruction may be nearly equal to Billroth-I with regard to the long-term nutritional perspectives.

Incidence of Multiple Metachronous Gastric Cancers After Pyloric-Preserving Gastrectomy.

AIM: Pylorus-preserving gastrectomy (PPG) is widely used for early gastric cancer located in the middle third of the stomach. The minimization of the extent of gastrectomy may increase the risk of metachronous multiple gastric cancer (MGC). We report the findings of a study that was conducted to evaluate the prevalence of MGC after PPG. METHODS: The clinical data of 533 patients who underwent PPG for gastric cancer between 1993 and 2018 were reviewed. The clinicopathological characteristics at the time of the primary treatment that were predictive of the development of MGC were explored. The median (range) observation period was 112.4 (8.1-290.7) months. RESULTS: Metachronous MGC was diagnosed in 33 of the 533 patients. The cumulative 5-year and 10-year event rates were 3.3% and 6.2%, respectively. The patient gender, presence/absence of synchronous MGC and the macroscopic type of the primary gastric cancer were significantly associated with the risk of development of metachronous MGC. Multivariate analysis identified the presence of synchronous MGC (hazard ratio [HR]: 4.828, 95% confidence interval [CI]; 1.611-12.30, p = 0.004) and Type 0-IIa primary gastric cancer (HR 2.810, 95% CI; 1.113-7.090, p = 0.029) as independent factors associated with the risk of development of MGC. All the patients could be treated by surgical or endoscopic resection for the metachronous MGC. Recurrence was observed in one patient. CONCLUSIONS: There was quite a few incidence of development of metachronous MGC after PPG. Nevertheless, PPG remains reasonable treatment option, if adequate postoperative surveillance can be ensured.