Do dysplastic proximal resection margins predict the risk of anastomotic recurrence and overall survival in patients with esophageal squamous cell carcinoma?

Positive proximal resection margins are strongly associated with anastomotic recurrence in esophageal cancer. However, the prognostic significance of dysplastic proximal resection margins remains unclear. The aim of this study is to investigate whether the dysplastic proximal resection margin can predict anastomotic recurrence and overall survival in patients with esophageal squamous cell carcinoma. Between 2000 and 2014, patients with esophageal squamous cell carcinoma who received a nonpalliative resection and survived the perioperative period were included. Two expert pathologists independently reviewed the proximal resection margin status, which was classified as negative, dysplastic, or positive. The kappa statistic was used to test interobserver reliability. Anastomotic recurrence and overall survival served as the main outcome measures. The study cohort consisted of 469 patients (445 males and 27 females). There was an excellent interobserver agreement for negative (kappa = 0.88), dysplastic (kappa = 0.88), and positive (kappa = 1) proximal resection margins-which were identified in 418 (89.1%), 37 (7.9%), and 14 (3.0%) patients, respectively. After a median follow-up of 21.6 months, 30 (6.4%) patients developed an anastomotic recurrence. Compared with patients with negative proximal resection margins (24/418, 5.7%), the occurrence of anastomotic recurrence was more commonly observed in those with positive proximal resection margins (3/14, 21.4%, P = 0.017) but not in those with dysplastic proximal resection margins (3/37, 8.1%, P = 0.56). Multivariable Cox regression analysis identified positive proximal resection margins (hazard ratio: 5.93, P = 0.010) and advanced clinical stage (hazard ratio: 12.04, P = 0.023) as independent risk factors for anastomotic recurrence. Dysplastic proximal resection margins were not retained in the model as an independent predictor (hazard ratio: 1.38, P = 0.602). The 5-year overall survival rates of patients with negative (38.2%) and dysplastic margins (27.0%) were similar (P = 0.814), and significantly higher than that observed in those with positive proximal resection margins (9.5%, P = 0.015). In conclusion, dysplastic proximal resection margins can be identified in at least 7.9% of patients with esophageal squamous cell carcinoma, but neither they are associated with an increased risk of anastomotic recurrence nor they portend a poor overall survival.

Association between the thoroughness of the histopathological examination and survival in patients with esophageal squamous cell carcinoma who achieve pathological complete response after chemoradiotherapy.

The College of American Pathologists guidelines recommend examining at least four representative tumor blocks for determining pathological T stage in patients with primarily resected esophageal cancer. Whether the same pathological requirements are adequate in patients undergoing esophagectomy following neoadjuvant chemoradiotherapy (nCRT) remains unclear. We hypothesized that current examination protocols may underestimate the presence of microscopical residual disease after nCRT, potentially leading to under-staging. We retrospectively reviewed the records of patients with esophageal squamous cancer (ESCC) who were diagnosed as having pathological complete response (pCR) following nCRT. The thoroughness of the pathological examination in pCR patients was examined using (i) the number of blocks examined in suspicious tumor area (≤4 vs. >4), and (ii) the block quotient (calculated as the pretreatment tumor length divided by the number of blocks examined in suspicious tumor area). A total of 91 patients were enrolled. The mean number of blocks used to confirm pCR was 4.8 (range: 2-14). The 5-year overall survival (OS) and disease-free survival (DFS) in the entire cohort were 55% and 65%, respectively. Multivariate analyses identified the block quotient as the only independent predictor of OS and DFS. Receiver operating characteristic curve analysis indicated an optimal cutoff value of 1.4 for the block quotient. Among the patients who achieved pCR, the 5-year DFS differed significantly between subjects with a low (≤1.4) or high (>1.4) block quotient (76% vs. 47%, respectively, P = 0.03). The block quotient (calculated by the pretreatment tumor length divided by the number of blocks) - which reflects the meticulousness of the histopathological examination for confirming pCR - is associated with survival in ESCC patients.

The properties of BiSb nanoribbons from first-principles calculations.

The structural, electronic and magnetic properties of BiSb nanoribbons (BSNRs) with different widths and edge configurations are investigated via the first-principles pseudopotential method. It is found that the pristine BSNRs with armchair edges (ABSNRs) are semiconductors and the band gaps exhibit a width dependent odd-even oscillation. In contrast, the pristine BSNRs with zigzag edges (ZBSNRs) are found to be metallic. When all the edge atoms are passivated by hydrogen, both the ABSNRs and ZBSNRs become semiconducting and the corresponding band gaps decrease monotonically with the increasing width. If, however, the edge atoms are partially passivated, the ABSNRs can be either semiconducting or metallic. Moreover, local magnetism appears when all the edge Sb atoms are passivated and there are one or more unsaturated Bi atoms. Using the nonequilibrium Green's function (NEGF) approach, we find that all the investigated odd-numbered ABSNRs have almost the same peak value of the power factor around the Fermi level. This is not the case for the even-numbered ABSNRs, where the peaks are twice that of when they are n-type doped. Our calculations indicate that BSNRs can have a very high room temperature figure of merit (ZT value), which makes them very promising candidates for thermoelectric applications.

Theoretical study of alkali atom doped outside 4 angstroms carbon nanotubes.

Using first-principles calculations, we study the doping of alkali atoms on the outer surface of 4 angstroms single-walled carbon nanotubes. It is found that the exterior doping at the "center" site is more favorable than the interior doping along tube axis. The calculated binding energies show a strong chirality dependence, and the alkali atoms tend to be bound strongest with the (5, 0) tube. The change of band structure upon doping is studied and the charge transfer between tube and alkali atom is shown. Our calculations indicate that the Li storage capacity can be reached to a maximum of LiC2.5, which suggests that the 4 angstroms nanotube could be a plausible candidate for Li-ion battery applications.

Energetics of Stone-Wales defects in 4 A carbon nanotubes.

Density functional calculations have been performed to study the formation of Stone-Wales defects in 4 A single-wall carbon nanotubes, which were firstly synthesized inside the AFI zeolite template. The minimum energy paths from perfect tubes to defect-containing ones are calculated by the nudged elastic band method. It is found that the C--C bonds "along" the tube axis are more likely to be rotated than those bonds "around" the circumference. There is a marked chirality dependence of the formation barriers, which are found to be lower than that of graphite. Our results may raise a question on the origin of superconductivity observed in these 4 A tubes.

Electronic and electrochemical properties of Li-doped carbon nanotube-zeolite complex.

The electronic and electrochemical properties of Li-doped carbon nanotube-zeolite complex are studied by first-principles calculations. There are four possible sites for Li to be doped and the reactions are all exothermic. The corresponding energy band structures follow a rigid band picture and there are charge transfers from Li to the nanotube and/or zeolite. The Li capacity of the complex can be reached to 386 mAh g(-1) with only a slight increase in the cell volume, and the complex may be of good cyclic stability during the charge and discharge process. Moreover, a higher voltage of about 4 V can be obtained if the complex is used in an Li-ion battery.