Background
The 8th edition AJCC gastric cancer staging manual was refined using Japanese and Korean data from the International Gastric Cancer Association (IGCA). This study evaluated the eighth ...edition’s validity for U.S. populations.
Methods
National Cancer Database (NCDB) was used to obtain data on gastric cancer patients diagnosed from 2004 to 2008 who underwent surgery and to examine differences in stage grouping and survival between AJCC 7th and 8th editions. Discrimination of models derived from NCDB and IGCA data was compared.
Results
Of 12,041 patients, median age was 65, 57.6% were male, median lymph nodes retrieved was 2 (0–76), 30.9% underwent distal/partial gastrectomy, and 49.8% received no adjuvant treatment. The 8th edition differed in that T1–T3 disease was upstaged with N3b, T4aN3a was downstaged from IIIC to IIIB, and T4bN0 and T4aN2 were downstaged from IIIB to IIIA. These changes resulted in increased patients in IIIA (1436 in the 7th edition to 2310 in the 8th) and IIIB (1737–1896) and decreased in IIIC (2100–1067). This also resulted in lower median survival for IIIA (28.7–25.0 months), IIIB (19.6–17.4), IIIC (13.7–11.8). The concordance index for the 8th edition applied to NCDB data was 0.719 95% confidence interval (CI) 0.703–0.734), which is comparable to that for the 8th edition developed from IGCA data (0.775, 95% CI 0.770–0.780) and the 7th edition applied to NCDB data (0.720, 95% CI 0.704–0.735).
Conclusions
The 8th edition is valid for U.S. populations, showing clear separation of data with preservation of group order.
A
bstract
We consider a hybrid Monte Carlo algorithm which is applicable to lattice theories defined on Lefschetz thimbles. In the algorithm, any point (field configuration) on a thimble is ...parametrized uniquely by the flow-direction and the flow-time defined at a certain asymptotic region close to the critical point, and it is generated by solving the gradient flow equation downward. The associated complete set of tangent vectors is also generated in the same manner. Molecular dynamics is then formulated as a constrained dynamical system, where the equations of motion with Lagrange multipliers are solved by the second-order constraint-preserving symmetric integrator. The algorithm is tested in the λ
ϕ
4
model at finite density, by choosing the thimbles associated with the classical vacua for subcritical and supercritical values of chemical potential. For the lattice size
L
= 4, we find that the residual sign factors average to not less than 0.99 and are safely included by reweighting and that the results of the number density are consistent with those obtained by the complex Langevin simulations.
Abstract
Counterpropagating Alfvén waves are ubiquitously observed in many astrophysical environments, such as a star surface and a planetary foreshock. We discuss an efficient particle acceleration ...mechanism in two counterpropagating circularly polarized Alfvén waves. Phase transitions of particle behavior occur when wave amplitudes exceed two critical values. Above the critical amplitudes, the numerical simulation shows that any particles irreversibly gain relativistic energy within a short time regardless of their initial position and energy once the coherent waveform is formed. The accelerated particles have spatial coherence. Higher wave phase velocity requires smaller critical amplitudes, while the maximum attainable energy increases as the wavenumber and the frequency decrease. The results may be applicable in some astrophysical phenomena, as well as a future laboratory experiment using high-power lasers.
Background
The optimal surgical approach for treatment of oesophagogastric junction (OGJ) cancer is controversial. A randomized clinical trial (JCOG9502) comparing transhiatal (TH) and left ...thoracoabdominal (LTA) approaches was stopped after the first interim analysis owing to limited efficacy for LTA resections. Complete 10‐year follow‐up data are now available.
Methods
Patients with histologically proven adenocarcinoma of the OGJ or gastric cardia with oesophageal invasion of 3 cm or less were randomized to a TH or LTA approach. Both groups underwent total gastrectomy and splenectomy with D2 nodal dissection plus para‐aortic lymphadenectomy above the left renal vein. For LTA, a thorough mediastinal lymphadenectomy below the left inferior pulmonary vein was also mandatory. The primary endpoint was overall survival.
Results
A total of 167 patients (82 TH, 85 LTA) were enrolled. The 10‐year overall survival rate was 37 (95 per cent c.i. 26 to 47) per cent for the TH approach and 24 (15 to 34) per cent for the LTA technique (P = 0·060). The hazard ratio for death was 1·42 (0·98 to 2·05) for the LTA technique. Subgroup analysis based on the Siewert classification indicated non‐significant survival advantages in favour of the TH approach.
Conclusion
LTA resections should be avoided in the treatment of adenocarcinoma of the OGJ or gastric cardia. Registration number: NCT00149266 (https://www.clinicaltrials.gov).
No survival benefit from a more extensive operation
Planets form inside protostellar disks in a dead zone where the electrical resistivity of the gas is too high for magnetic forces to drive turbulence. We show that much of the dead zone nevertheless ...is active and flows toward the star while smooth, large-scale magnetic fields transfer the orbital angular momentum radially outward. Stellar X-ray and radionuclide ionization sustain a weak coupling of the dead zone gas to the magnetic fields, despite the rapid recombination of free charges on dust grains. Net radial magnetic fields are generated in the magnetorotational turbulence in the electrically conducting top and bottom surface layers of the disk, and reach the midplane by ohmlc diffusion. A toroidal component to the fields is produced near the midplane by the orbital shear. The process is similar to the magnetization of the solar tachocline. The result is a laminar, magnetically driven accretion flow in the region where the planets form.
► Effect of laser peening without coating on friction stir welded A6061-T6 joint. ► Compressive residual stress was imparted on the joint. ► Hardness on the stir zone was recovered in some degree. ► ...Fatigue strength was improved from 90 to 120MPa at 107 cycles. ► This strength was higher than that of unwelded base material.
The authors have applied laser peening without coating (LPwC) to fatigue specimens cut out from friction stir welded (FSWed) A6061-T6 aluminum alloy plates with a thickness of 3mm. Both crown and root sides of the specimens were peened by laser pulses with an energy of 60mJ and a peak power density of 2GW/cm2 from a frequency-doubled Nd:YAG laser. The effects on the fatigue properties were studied through plane bending fatigue tests with a stress ratio of R=−1. The results showed that the fatigue strength of unwelded specimens (base material; BM) was 110MPa at 107 cycles and LPwC enhanced the strength by 60MPa in spite of increase in surface roughness due to the direct irradiation of the laser pulses to the bare surface of the specimens. Meanwhile the fatigue strength of FSWed specimens was 90MPa and LPwC enhanced it by 30MPa to 120MPa. This increment is a half compared to that in the BM, however the fatigue strength of the FSWed specimens after LPwC was higher than that of the BM. The surface roughness, hardness and residual stress were assessed and characterized as well.
Background
The postoperative pancreatic fistula (POPF) rate for duct‐to‐mucosa and invagination anastomosis after pancreatoduodenectomy is still debated. The aim of this RCT was to investigate the ...POPF rate for duct‐to‐mucosa versus invagination pancreaticojejunostomy.
Methods
Patients were stratified by pancreatic texture and diameter of the main pancreatic duct and randomized to the duct‐to‐mucosa or invagination group. The primary endpoint was the rate of clinically relevant POPF (defined as grade B or C). Secondary endpoints were suture material cost for pancreaticojejunostomy, drain insertion duration and duration of postoperative hospital stay.
Results
Some 120 patients undergoing pancreatoduodenectomy were included following consent. Clinically relevant POPF developed in six of 59 patients (10 per cent) in the invagination group and in 14 of 61 patients (23 per cent) in the duct‐to‐mucosa group (P = 0·077). Duration of drain insertion (6 versus 7 days respectively; P = 0·027) and postoperative hospital stay (19 versus 24 days; P = 0·015) were shorter in the invagination group. Subgroup analysis for 61 patients with a soft pancreas revealed a lower rate of clinically relevant POPF in the invagination group (10 per cent versus 42 per cent in the duct‐to‐mucosa group; P = 0·010). Among 20 patients with a clinically relevant POPF, the six patients in the invagination group had a shorter duration of drain insertion (38·5 days versus 49 days for 14 patients in the duct‐to‐mucosa group; P = 0·028) and postoperative hospital stay (42 versus 54·5 days respectively; P = 0·028).
Conclusion
This study did not demonstrate a superiority of invagination over duct‐to‐mucosa pancreaticojejunostomy in the risk of POPF. However, in high‐risk patients with a soft pancreas, invagination may reduce the risk of clinically relevant POPF compared with duct‐to‐mucosa. Registration number: UMIN000005890 (http://www.umin.ac.jp).
No difference found
Background
It can be difficult to determine the transection line during totally laparoscopic surgery for early gastric cancer owing to lack of tactile feedback. This retrospective cohort study aimed ...to assess the role of intraoperative endoscopy in determining the resection margin in totally laparoscopic gastrectomy.
Methods
Consecutive patients with histologically confirmed gastric cancer who underwent laparoscopic gastrectomy between March 2012 and July 2015 were eligible. Preoperative placement of marking clips and intraoperative endoscopy were performed to determine the resection margin. Frozen‐section analyses were also performed to confirm the absence of cancer cells at the surgical margin. Success was defined as the proportion of specimens with all clips present and by the proportion of resections with a negative surgical margin following initial transection.
Results
Total laparoscopic gastrectomy with intraoperative endoscopy was performed in 522 patients; a total of 662 surgical margins were analysed. The overall success rate was 99·8 per cent (661 of 662 margins). The success rate of achieving a negative surgical margin during the initial transection was 98·9 per cent (550 of 556 margins).
Conclusion
Preoperative placement of marking clips and intraoperative endoscopy is helpful in the determination of a safe surgical margin in patients with gastric cancer who undergo laparoscopic gastrectomy.
Helpful
Background
Preoperative factors, including nutritional status, may have strong correlations with postoperative morbidities. The current study evaluated preoperative prealbumin concentrations as a ...predictor of postoperative complications after gastric surgery.
Methods
A retrospective study of 1798 patients who underwent gastrectomy for gastric adenocarcinoma was performed. Information was collected on basic patient characteristics, preoperative laboratory findings, and 30 day postoperative complications. The patients were divided into three groups based on prealbumin concentrations (≥22 mg/dL, <22 to ≥15 mg/dL, and <15 mg/dL) for analysis.
Results
The overall complication rate was 21.7 %, and the infection rate was 16 %. Subgroup analysis based on prealbumin concentrations showed that complication rates were markedly elevated with decreasing concentrations of prealbumin. Multivariate analysis using a logistic regression model showed that both overall and infectious complications were strongly associated with male gender, elevated C-reactive protein (CRP), and decreased prealbumin levels (
p
< 0.05). Even in patients with a CRP level higher than 0.1 mg/dL, male gender and low prealbumin concentrations (<15 mg/dL) were significantly correlated with overall and infectious morbidities (
p
< 0.05).
Conclusions
Preoperative prealbumin concentrations are useful predictors of short-term postoperative outcomes after gastrectomy.
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