High-frequency spin torque oscillation in orthogonal magnetization disks with strong biquadratic magnetic coupling

In this study, we numerically investigate the spin transfer torque oscillation (STO) in a magnetic orthogonal configuration by introducing a strong biquadratic magnetic coupling. The orthogonal configuration consists of top and bottom layers with in-plane and perpendicular magnetic anisotropy sandwiching a nonmagnetic spacer. The advantage of an orthogonal configuration is the high efficiency of spin transfer torque leading a high STO frequency; however, maintaining the STO in a wide range of electric current is challenging. By introducing biquadratic magnetic coupling into the orthogonal structure of FePt/spacer/Co₉₀Fe₁₀, Ni₈₀Fe₂₀ or Ni, we were able to expand the electric current region in which the stable STO is realized, resulting in a relatively high STO frequency. For example, approximately 50 GHz can be achieved in an Ni layer at a current density of 5.5 × 10⁷ A/cm². In addition, we investigated two types of initial magnetic state: out-of-plane and in-plane magnetic saturation; this leads to a vortex and an in-plane magnetic domain structure after relaxation, respectively. The transient time before the stable STO was reduced to between 0.5 and 1.8 ns by changing the initial state from out-of-plane to in-plane.

Pimitespib in patients with advanced gastrointestinal stromal tumor (CHAPTER-GIST-301): a randomized, double-blind, placebo-controlled phase 3 trial

BACKGROUND

Prognosis of advanced gastrointestinal stromal tumors (GIST) refractory to tyrosine kinase inhibitors (TKIs) is poor. This randomized, placebo-controlled, phase 3 trial evaluated the efficacy and safety of pimitespib, a novel heat shock protein 90 inhibitor, in advanced GIST refractory to standard TKIs.

PATIENTS AND METHODS

Patients with histologically confirmed GIST refractory to imatinib, sunitinib, and regorafenib were randomized 2:1 to oral pimitespib 160 mg/day or placebo for five consecutive days per week in 21-day cycles. Following disease progression by blinded central radiological review (BCRR), crossover to open-label pimitespib was permitted. The primary endpoint was progression-free survival (PFS) by BCRR in the full analysis set. Secondary endpoints included overall survival (OS) adjusted using the rank preserving structural failure time method to reduce the expected confounding impact of crossover.

RESULTS

From Oct 31, 2018 to Apr 30, 2020, 86 patients were randomized to pimitespib (n=58) or placebo (n=28). Median PFS was 2.8 months (95% CI 1.6-2.9) with pimitespib versus 1.4 months (0.9-1.8) with placebo (hazard ratio [HR] 0.51 [95% CI 0.30-0.87]; one-sided p=0.006). Pimitespib showed an improvement in crossover-adjusted OS compared with placebo (HR 0.42 [0.21-0.85], one-sided p=0.007). Seventeen (60.7%) patients receiving placebo crossed-over to pimitespib; median PFS after crossover was 2.7 (95% CI 0.7-4.1) months. The most common (≥30%) treatment-related adverse events (AEs) with pimitespib were diarrhea (74.1%) and decreased appetite (31.0%); the most common (≥10%) grade ≥3 treatment-related AE was diarrhea (13.8%). Treatment-related AEs leading to pimitespib discontinuation occurred in 3 (5.2%) patients.

CONCLUSION

Pimitespib significantly improved PFS and crossover-adjusted OS compared with placebo and had an acceptable safety profile in patients with advanced GIST refractory to standard TKIs.

Multicenter prospective trial of total gastrectomy versus proximal gastrectomy for upper third cT1 gastric cancer

BACKGROUND

The appropriate surgical procedure for patients with upper third early gastric cancer is controversial. We compared total gastrectomy (TG) with proximal gastrectomy (PG) in this patient population.

METHODS

A multicenter, non-randomized trial was conducted, with patients treated with PG or TG. We compared short- and long-term outcomes between these procedures.

RESULTS

Between 2009 and 2014, we enrolled 254 patients from 22 institutions; data from 252 were included in the analysis. These 252 patients were assigned to either the PG (n = 159) or TG (n = 93) group. Percentage of body weight loss (%BWL) at 1 year after surgery, i.e., the primary endpoint, in the PG group was significantly less than that of the TG group (- 12.8% versus - 16.9%; p = 0.0001). For short-term outcomes, operation time was significantly shorter for PG than TG (252 min versus 303 min; p < 0.0001), but there were no group-dependent differences in blood loss and postoperative complications. For long-term outcomes, incidence of reflux esophagitis in the PG group was significantly higher than that of the TG group (14.5% versus 5.4%; p = 0.02), while there were no differences in the incidence of anastomotic stenosis between the two (5.7% versus 5.4%; p = 0.92). Overall patient survival rates were similar between the two groups (3-year survival rates: 96% versus 92% in the PG and TG groups, respectively; p = 0.49).

CONCLUSIONS

Patients who underwent PG were better able to control weight loss without worsening the prognosis, relative to those in the TG group. Optimization of a reconstruction method to reduce reflux in PG patients will be important.

Reflux after esophagectomy with gastric conduit reconstruction in the posterior mediastinum for esophageal cancer: original questionnaire and EORTC QLQ-C30 survey

Reflux following an esophagectomy with gastric conduit reconstruction in the posterior mediastinum is a clinically significant problem. In this study, we investigated the frequency and impact of reflux on the quality of life (QOL) among 158 patients who underwent an esophagectomy for esophageal cancer using an original questionnaire and the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Version 3.0 (EORTC QLQ-C30). Reflux frequency was assessed using the original questionnaire. The number of patients who complained of reflux every day, two or three times a week, once a week, or less than once a week was 16 (10.1%), 21 (13.3%), 26 (16.5%), and 60 (38.0%), respectively. Out of 35 patients (22.2%) reported no reflux symptoms. Patients were divided into two groups: those with reflux ≥ once/week (63 patients) and those with low frequency of symptoms (95 patients). Time elapsed following surgery was the only factor to influence reflux frequency. Reflux frequency decreased within two years of surgery; however, the frequency plateaued after more than two years. QOL was assessed using the EORTC QLQ-C30. The ≥ once/week reflux group had a significantly lower global health status score than the low-frequency reflux group (59.6 ± 24.2 vs. 70.8 ± 20.7; P = 0.007). In addition, the ≥ once/week reflux group had a significantly lower social functioning score than the low-frequency reflux group (81.6 ± 24.1 vs. 88.4 ± 19.8; P = 0.035). Regarding symptoms, the ≥ once/week reflux group had significantly higher scores for fatigue, nausea, and vomiting, dyspnea and insomnia compared to the low-frequency reflux group (fatigue: 42.4 ± 21.9 vs. 28.9 ± 18.4, P < 0.001; nausea and vomiting: 17.3 ± 17.1 vs. 4.9 ± 10.6, P < 0. 001; dyspnea: 29.2 ± 26.0 vs. 21.7 ± 26.8, P = 0.043; insomnia: 22.2 ± 31.1 vs. 10.5 ± 21.7, P = 0.015). Thus, reflux after an esophagectomy was associated with a lower QOL.

Utility of initial induction chemotherapy with 5-fluorouracil, cisplatin, and docetaxel (DCF) for T4 esophageal cancer: a propensity score-matched analysis

Although no consensus is available on the treatment of esophageal squamous cell carcinoma (ESCC) invading adjacent organs (T4), establishing effective induction treatments is crucial to altering an unresectable status and achieving curative resection. Here, we evaluated the efficacy of chemotherapy using 5-fluorouracil, cisplatin, and docetaxel (DCF) as the initial induction treatment for T4 ESCC. Fifty patients without distant metastasis who underwent initial induction chemotherapy using DCF for T4 ESCC were propensity score-matched with 50 patients who underwent radiotherapy concurrent with cisplatin and 5-fluorouracil (CRT). In the DCF group, 24 (48.0%) patients underwent surgery, achieving a 64% clinical response rate compared to 72.0% for induction CRT. CRT was also performed in another 24 (48.0%) patients in the DCF group in whom surgical resection was not indicated. The DCF group had significantly higher overall resectability than the CRT group (78.0% vs. 48.0%, P = 0.0017). The esophageal perforation rate during induction treatments was significantly lower in the DCF group than the CRT group (4.0% vs. 18.0%, P = 0.0205). Prognosis was significantly better in the DCF group than the CRT group (5-year cancer-specific survival 42.1% vs. 22.2%, P = 0.0146). Thus, induction DCF chemotherapy in patients with T4 ESCC reduced esophageal perforation and increased overall resectability, leading to better survival than CRT alone. Therefore, DCF chemotherapy may be an effective and safe option for initial induction treatment of T4 ESCC.

Tissue Engineering of the Small Intestine by Acellular Collagen Sponge Scaffold Grafting

Tissue engineering of the small intestine will prove a great benefit to patients suffering from short bowel disease. However cell seeding in tissue engineering, such as fetal cell use, is accompanied by problems of ethical issues, rejection, and short supply. To overcome these problems, we carried out an experimental study on tissue engineering of the small intestine by acellular collagen sponge scaffold grafting. We resected the 5 cm long jejunum from beagle dogs and reconstructed it by acellular collagen sponge grafting with a silicon tube stent. The graft was covered with the omentum. At 1 month after operation, the silicon stent was removed endoscopically. Animals were sacrificed 1 and 4 months after operation, and were examined microscopically. Neo-intestinal regeneration was observed and the intestinal mucosa covered the luminal side of the regenerated intestine across the anastomosis. Thus, the small intestine was regenerated by tissue engineering technology using an acellular collagen sponge scaffold.

Comparison of short-term outcomes between 2- and 3-field lymph node dissection for esophageal cancer

Although 3-field lymph node dissection (3-FLD) is often performed for thoracic esophageal squamous cell carcinoma (ESCC), the clinical effects of cervical lymph node dissection in addition to mediastinal and abdominal dissections on postoperative complications remain unclear. A total of 367 ESCC patients who underwent curative esophagectomy for thoracic esophageal cancer in our hospital from 2010 to 2015 were included in the study: 157 patients who underwent 2-field lymph node dissection (2-FLD) and 210 patients who underwent 3-FLD. Clinicopathological parameters and postoperative complications based on the Clavien-Dindo classification were compared between the two groups. We performed propensity score matching (PSM) analyses to compare the groups with well-balanced backgrounds. In terms of patient background, clinical T (p < 0.001), N (p < 0.001), and M (p = 0.002) stage of tumor was significantly more advanced; therefore, preoperative treatment was more frequently performed in the 3-FLD group than in the 2-FLD group (91.0% vs. 79.0%, P< 0.001). However, perioperative parameters including operation time, blood loss, and the number of dissected mediastinal and abdominal lymph nodes did not differ between the groups. In terms of postoperative complications, the occurrence rate of pneumonia increased significantly in patients with 3-FLD compared to 2-FLD (grade III or higher: 10.5% vs. 3.2%, P= 0.025). Although the duration of systemic inflammatory response syndrome (SIRS) was longer in the 3-FLD group than in the 2-FLD group (median 3 days vs. 2 days, P= 0.025), other postoperative parameters (including the highest level of postoperative serum C-reactive protein, intensive care unit stay, re-operation rate, and postoperative hospital stay) were similar between the groups. After PSM, the differences in the background between the groups disappeared. PSM analysis showed that there was no significant difference in each complication between the groups. The duration of SIRS tended to be longer in the 3-FLD group than in the 2-FLD group, but the difference was not significant. The field of lymphadenectomy negatively impacted the short-term outcome in ESCC patients in terms of pneumonia and inflammatory response. However, because the results of the PSM analyses indicate that the short-term outcome was similar between the two groups, 3-FLD could be as feasible as 2-FLD in ESCC patients.

Promoting Effect of Metal Compounds on Liver, Stomach, Kidney, Pancreas, and Skin Carcinogenesis

Systemic studies have been completed in Japan to detect those chemicals in the environment that act as promoters. Well-established two-stage models for liver, stomach, kidney, pancreas, and skin carcinogenesis were employed to detect the promoting effect of Zn Cl2, Cr Cl2, Cd Cl2, Ni Cl2, and Hg Cl2. As a result, Ni Cl2 was found to act as a promoter in renal carcinogenesis.

Comparative Studies on Lipid Peroxidation in the Kidney of Rats, Mice, and Hamsters and on the Effect of Cysteine, Glutathione, and Diethyl Maleate Treatment on Mortality and Nephrotoxicity After Administration of Potassium Bromate

As an index of lipid peroxidation (LPO), levels of thiobarbituric acid (TBA)-reactive substances were examined in the kidneys of male F344 rats, BDF1, CDF1, and B6C3F1 mice, and Syrian golden hamsters after a single intravenous (IV) administration of potassium bromate (KBrO3) at various doses. In the rats, LPO levels were significantly increased in both a dose-dependent and time-dependent manner. However, when the rats were given intraperitoneal (IP) injection of cysteine, the levels of LPO were not significantly different between KBrO3-treated animals and controls. In CDF1 mice, the slight increases in LPO levels observed were much weaker and not statistically significant. On the other hand, treatment of BDF1 and B6C3F1 mice or hamsters with KBrO3 resulted in decreased values as compared to controls. The effect of treatment with cysteine, glutathione (GSH), or diethyl maleate (DEM) on mortality was tested in male F344 rats given IV injection of KBrO3 at various doses. Significant reduction and elevation in the mortality were observed in rats treated with cysteine or GSH and DEM, respectively. Significant dose-dependent and time-dependent increases were observed in the levels of serum non-protein nitrogen (NPN), blood urea nitrogen (BUN), and creatinine, and absolute and relative weight of the kidneys in male F344 rats administered KBrO3 IV. Microscopically, the appearance of numerous eosinophilic droplets in the cytoplasm of proximal tubular epithelium of KBrO3-treated rats was noteworthy. All these changes were reduced and exacerbated by treatment with cysteine or GSH and DEM, respectively. The possibility of LPO formation in the kidney by active oxygen radicals generated by KBrO3 is suggested. A possible relationship between LPO levels in the kidney and species differences in the renal toxicity and carcinogenicity of KBrO3 is implicated.

Promoting Effect of Metal Compounds on Rat Renal Tumorigenesis

Five metal compounds, zinc chloride (ZnCl2), mercury chloride (HgCl2), chromium chloride (CrCl3) hexahydrate, cadmium chloride (CdCl2) hemidihydrate, and nickel chloride (NiCl2) hexahydrate, were selected and tested for potential modifying influence on renal tumorigenesis. Six groups, each consisting of 15 male F344 rats, were given N-ethyl-N-hydroxyethylnitrosamine (EHEN) at a concentration of 500 ppm in their drinking water for the first 2 weeks as the initiation of carcinogenesis. Thereafter, the rats were treated orally for 25 weeks with ZnCl2, HgCl2, CrCl3, CdCl2, and NiCl2, respectively, at concentrations of 450, 40, 600, 100, and 600 ppm in the drinking water. The control group was given unsupplemented distilled water (DW) after EHEN initiation. Renal neoplastic lesions were classified histologically into dysplastic foci (DF) and renal cell tumors (RCT). As a result, statistically significant increases were found in the mean numbers of DF per cm2 in rats treated with the five metal compounds. On the other hand, the incidence of RCT was significantly higher only in rats treated with NiCl2. It is concluded that NiCl2 exerted a potential for promotion of renal tumorigenesis under the conditions of this study.

Lack of Promoting Effect of Sodium Chlorate and Potassium Chlorate in Two-Stage Rat Renal Carcinogenesis

Sodium chlorate (NaClO3) and potassium chlorate (KClO3), which are byproducts of water disinfection with chlorine dioxide (ClO2), were tested for potential promoting effect in two-stage rat renal carcinogenesis. Three groups of 15 male F344 rats each were given N-ethyl-N-hydroxyethylnitrosamine (EHEN) at the level of 0.05% for the first 2 weeks during the initiation phase. Thereafter, the rats were treated orally for 25 weeks with NaClO3 (1%), KClO3 (1%), or distilled water (DW). Three other groups (controls) were treated similarly, except that DW was given in the initiation phase. All animals survived for the duration of the experiment. Renal neoplastic lesions were classified histologically as dysplastic foci (DF) and renal cell tumors (RCT). The number of these lesions per unit area, in six sections from each kidney, was determined microscopically. There were no statistically significant differences in the incidences and in the mean number of DF and RCT of the kidney between compound-and DW-treated rats initiated with EHEN. It is concluded that NaClO3 and KClO3 show no promoting effect in rat renal carcinogenesis under the conditions of this study.

Development of Styrenic Copolymers for Improving Heat Resistance of Poly(methyl methacrylate)

Styrenic copolymers comprising styrene, methyl methacrylate, and maleic anhydride were developed to improve the heat-resistance property of poly(methyl methacrylate) (PMMA). The optical, thermal, and mechanical properties were examined for the blend specimens prepared by an injection-molding machine using melt-mixed samples. It was found that the copolymers, which were miscible with PMMA, increase the glass transition temperature and therefore the Vicat Softening temperature. Furthermore, the blends were completely transparent as similar to PMMA.

Inter-institutional heterogeneity in outcomes of chemotherapy for metastatic gastric cancer: correlative study in the JCOG9912 phase III trial

BACKGROUND

The standard chemotherapy regimen for gastric cancer has been established by several phase III trials. However, few studies have evaluated inter-institutional heterogeneity in randomised trials; such research may assure the generalisability of the results and also the reliability of the study group itself.

PATIENTS AND METHODS

The Japan Clinical Oncology Group (JCOG)9912 phase III trial compared irinotecan plus cisplatin and S-1 alone with fluorouracil alone for metastatic gastric cancer, and finally demonstrated the non-inferiority of S-1 alone with respect to overall survival (OS). Mixed effects models were used to evaluate outcomes of 658 patients from 22 hospitals. After adjustment for nine background factors, the heterogeneity in OS, progression-free survival (PFS), and incidences of grade 3-4 adverse events among hospitals was estimated. We also estimated the correlation between outcomes and either hospital volume or medical oncology clinical experience.

RESULTS

A large degree of heterogeneity in median OS was observed for fluorouracil alone (range, 8.3-13.3 months), while the difference in median PFS between hospitals was small (range, 2.4-3.4 months). Although some heterogeneity in the treatment effect of irinotecan plus cisplatin or S-1 alone was observed in OS and PFS, the HRs did not exceed 1.00 in any hospital for either regimen. There was minimal heterogeneity in the incidences of grade 3-4 adverse events. There was a trend towards correlation between greater medical oncology clinical experience and both better OS after fluorouracil alone and a lower HR for OS after irinotecan plus cisplatin, but it was not statistically significant.

CONCLUSIONS

Large inter-institutional heterogeneity was observed in OS, but not in PFS, after the standard regimen, but there was little heterogeneity in the treatment effects of irinotecan plus cisplatin or S-1 alone, indicating that the final results of the JCOG9912 trial can be generalised to the target population.

TRIAL REGISTRATION NUMBER

NCT00142350.

Impact of number of [(18)F]fluorodeoxyglucose-PET-positive lymph nodes on survival of patients receiving neoadjuvant chemotherapy and surgery for oesophageal cancer

BACKGROUND

[(18) F]fluorodeoxyglucose (FDG)-PET has been used to evaluate the response of primary tumours to neoadjuvant therapy for oesophageal cancer. The clinical significance of the number of PET-positive nodes before and after therapy has not been investigated previously.

METHODS

[(18) F]FDG-PET was performed before and 2-3 weeks after completion of neoadjuvant chemotherapy to identify the number of PET-positive nodes, and these numbers were assessed in relation to metabolic changes in the primary tumour.

RESULTS

Of 302 patients in total, 90 had no PET-positive nodes, 83 had one, 59 had two and 70 patients had three or more positive nodes before therapy. After treatment, the numbers were: none in 207 patients, one in 59, two in 20 and three or more in 16 patients. The number of PET-positive nodes after treatment was influenced by both the number of PET-positive nodes before therapy and the response to preoperative therapy, and correlated with the number of metastatic lymph nodes. Overall survival was longer in patients who had no PET-positive nodes after treatment than in those who had one or more. Multivariable analysis identified the numbers of PET-positive nodes before and after chemotherapy as independent prognostic factors, together with clinical response, tumour depth and lymph node involvement.

CONCLUSION

The number of PET-positive nodes after treatment correlated with survival in patients with oesophageal cancer who underwent neoadjuvant chemotherapy.

Ten-year follow-up results of a randomized clinical trial comparing left thoracoabdominal and abdominal transhiatal approaches to total gastrectomy for adenocarcinoma of the oesophagogastric junction or gastric cardia

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

Monitoring gastric cancer progression with circulating tumour DNA

Background:

Circulating tumour DNA (ctDNA) is an emerging candidate biomarker for malignancies and may be useful for monitoring the disease status of gastric cancer.

Methods:

We performed targeted deep sequencing of plasma cell-free DNA (cfDNA) by massively parallel sequencing in patients with tumours harbouring TP53 mutations. The quantitative values of TP53-ctDNA during the clinical course were compared with the tumour status.

Results:

Three out of ten patients with TP53 mutations in primary tumours showed detectable TP53 mutation levels in preoperative cfDNA. Although the cfDNA concentrations were not always reflective of the disease course, the ctDNA fraction correlated with the disease status.

Conclusions:

ctDNA may serve as a useful biomarker to monitor gastric cancer progression and residual disease.

Relevance of [18F]fluorodeoxyglucose positron emission tomography-positive lymph nodes after neoadjuvant chemotherapy for squamous cell oesophageal cancer

Background

Several studies have examined the clinical significance of metabolic response in primary tumours by [18F]fluorodeoxyglucose positron emission tomography (18F-FDG-PET) in patients with oesophageal cancer who undergo neoadjuvant therapy. The relevance of the metabolic response in lymph nodes is unclear.

Methods

Consecutive patients with oesophageal cancer who underwent neoadjuvant chemotherapy followed by surgery were studied. 18F-FDG-PET was performed before and 2–3 weeks after completion of neoadjuvant chemotherapy, assessing FDG uptake in primary tumours and lymph nodes considered to be metastatic.

Results

Before therapy, 156 (73·9 per cent) of 211 patients had PET-positive nodes, of whom 89 (57.1 per cent) had no evidence of metabolic activity in these lymph nodes following chemotherapy. There was a significant relationship between post-treatment lymph node status assessed by FDG-PET and numbers of pathologically confirmed metastatic lymph nodes. Patients with post-treatment PET-positive nodes had shorter survival than those without (5-year survival rate 25 versus 62·6 per cent; P &lt; 0·001). There was no difference in survival between patients with PET-positive nodes before but not after therapy and patients who had PET-negative nodes throughout (5-year survival rate 59 versus 71 per cent respectively; P = 0·207). Multivariable analysis identified post-treatment nodal status assessed by FDG-PET and tumour depth as independent prognostic factors.

Conclusion

Identification of PET-positive lymph nodes after completion of chemotherapy is a predictor of poor prognosis of patients with oesophageal cancer scheduled for surgery. FDG-PET lymph node status after neoadjuvant chemotherapy is more important than that before chemotherapy.

High expression of Lin28 is associated with tumour aggressiveness and poor prognosis of patients in oesophagus cancer

BACKGROUND

Lin28 is a negative regulator of the tumour suppressor microRNA, let-7, suggesting its role in tumourigenesis. However, the clinical significance of Lin28 expression in oesophageal cancer has not been elucidated.

METHODS

Lin28 and Lin28B expression was examined by immunohistochemistry in 161 tissues from patients with oesophageal cancer who had undergone curative surgery. The relationship between the expressions of Lin28 and Lin28B and various clinicopathological factors was examined. In vitro assays were conducted to determine the role of Lin28 in aggressiveness of oesophageal cancers using oesophageal cancer cell line.

RESULTS

Lin28 and Lin28B were overexpressed in oesophageal cancer cells compared with non-cancerous epithelial cells, especially in the invasive front. High expression of Lin28 and Lin28B correlated significantly with lymph node metastasis and poor prognosis. High expression of Lin28B expression correlated significantly with low expression of let-7. Multivariate analysis also identified Lin28B expression as an independent prognostic factor. In vitro assays showed that the proliferative and invasive activities were significantly reduced in Lin28B-knockdown cells, compared with control cells.

CONCLUSION

High expression of Lin28 is associated with poor prognosis and high tumour aggressiveness in oesophageal cancer and these effects are mediated through increased proliferation and invasiveness of oesophageal cancer cells.

Prospective randomized trial of preoperative enteral immunonutrition followed by elective total gastrectomy for gastric cancer

BACKGROUND

Perioperative enteral immunonutrition is thought to reduce postoperative morbidity in patients undergoing major gastrointestinal surgery. This study assessed the clinical effects of preoperative enteral immunonutrition in well nourished patients with gastric cancer undergoing total gastrectomy.

METHODS

Well nourished patients with primary gastric cancer, fit for total gastrectomy, were randomized to either a control group with regular diet, or an immunonutrition group that received regular diet supplemented with 1000 ml/day of immunonutrients for 5 consecutive days before surgery. The primary endpoint was the incidence of surgical-site infection (SSI). Secondary endpoints were rates of infectious complications, overall postoperative morbidity and C-reactive protein (CRP) levels on 3-4 days after surgery.

RESULTS

Of 244 randomized patients, 117 were allocated to the control group and 127 received immunonutrition. SSIs occurred in 27 patients in the immunonutrition group and 23 patients in the control group (risk ratio (RR) 1.09, 95 per cent confidence interval 0.66 to 1.78). Infectious complications were observed in 30 patients in the immunonutrition group and 27 in the control group (RR 1.11, 0.59 to 2.08). The overall postoperative morbidity rate was 30.8 and 26.1 per cent respectively (RR 1.18, 0.78 to 1.78). The median CRP value was 11.8 mg/dl in the immunonutrition group and 9.2 mg/dl in the control group (P = 0.113).

CONCLUSION

Five-day preoperative enteral immunonutrition failed to demonstrate any clear advantage in terms of early clinical outcomes or modification of the systemic acute-phase response in well nourished patients with gastric cancer undergoing elective total gastrectomy.

REGISTRATION NUMBER

ID 000000648 (University Hospital Medical Information Network (UMIN) database).

Overexpression of PFTK1 predicts resistance to chemotherapy in patients with oesophageal squamous cell carcinoma

Background:

Recently, PFTK1 was identified as a member of the cyclin-dependent kinase family; however, its expression and clinical significance in oesophageal squamous cell carcinoma (ESCC) have not been evaluated.

Methods:

PFTK1 expression was initially examined by expression microarray in 77 ESCC patients. Using independent samples of 223 patients, PFTK1 expression was evaluated immunohistochemically to assess the relationship between expression and various clinicopathological parameters. The association between PFTK1 and the response to chemotherapy was also investigated in pretreatment samples of 85 patients who received chemotherapy as first treatment.

Results:

Significant upregulation of PFTK1 expression was noted in ESCC compared with normal epithelium. PFTK1 expression was positive in 51.6% (115 out of 223) of the tumours, but did not correlate with any clinicopathological parameter. The 5-year overall survival rate was poorer in patients positive for PFTK1 (43.6%) than those with negative expression (66.2%, P<0.001). Uni- and multivariate analyses identified PFTK1 as an independent marker of prognosis (RR=2.428, 95% CI=1.615–3.711, P<0.001). Out of 85 biopsy samples, 40 (47.1%) tumours showed PFTK1-positive expression, and the response rate to chemotherapy was significantly lower than PFTK1-negative tumours (27.9% vs 72.1%, P<0.001).

Conclusion:

PFTK1 is not only useful as a prognostic marker, but also as a predictor of the response to chemotherapy.

Phase II trial of preoperative S-1 plus cisplatin followed by surgery for initially unresectable locally advanced gastric cancer

BACKGROUND

The aim of this study was to evaluate the efficacy and feasibility of preoperative chemotherapy with S-1 plus cisplatin in patients with initially unresectable locally advanced gastric cancer.

METHODS

We enrolled patients with initially unresectable locally advanced gastric cancer because of severe lymph node metastases or invasion of adjacent structures. Preoperative chemotherapy consisted of S-1 at 80 mg/m(2) divided in two daily doses for 21 days and cisplatin at 60 mg/m(2) intravenously on day 8, repeated every 35 days. If a tumor decreased in size, patients received 1 or 2 more courses. Surgery involved radical resection with D2 lymphadenectomy.

RESULTS

Between December 2000 and December 2007, 27 patients were enrolled on the study. No CR was obtained, but PR was seen in 17 cases, and the response rate was 63.0%. Thirteen patients (48.1%) had R0 resections. There were no treatment related deaths. The median overall survival time (MST) and the 3-year overall survival (OS) of all patients were 31.4 months and 31.0%, respectively. Among the 13 patients who underwent curative resection, the median disease-free survival (DFS) and the 3-year DFS were 17.4 months and 23.1%, respectively. The MST and the 3-year OS were 50.1 months and 53.8%, respectively. The most common site of initial recurrence after the R0 resection was the para-aortic lymph nodes.

CONCLUSIONS

Preoperative S-1 plus cisplatin can be safely delivered to patients undergoing radical gastrectomy. This regimen is promising as neoadjuvant chemotherapy for resectable gastric cancer. For initially unresectable locally advanced gastric cancer, new trials using more effective regimens along with extended lymph node dissection are necessary.

A randomized controlled phase III trial to evaluate the effect of preoperative enteral immunonutrition on the surgical site infection after total gastrectomy (OGSG0507)

74

Background: To investigate the effect of preoperative enteral immunonutrion on the incidence of surgical site infection (SSI) after total gastrectomy for gastric cancer, we conducted a prospective randomized controlled trial.

Methods: Eligibility criteria included: (1) histologically proven adenocarcinoma of stomach, (2) scheduled total gastrectomy, (3) aged less than 80 years, (4) not malnourished, (5) possible to ingest liquid diet, (6) written informed consent. Eligible patients (pts) wereassigned to the immunonutrition (I) group or the control (C) group. In the C group pts freely accessed to regular diet until surgery. In the I group, pts were supplemented with 1,000 ml/day of immunonutrient enriched with arginine, omega-3 fatty acids and RNA (Impact) in addition to the regular diet for 5 days before surgery. The primary endpoint was the incidence of SSI and the secondary endpoints were other infectious complications and serum CRP level on POD 3 or 4.

Results: From 02/2004 to 12/2009, 240 gastric cancer patients (pts) who underwent gastric surgery were enrolled. 125 pts assigned to the I group and 115 pts assigned to the C group. Age, sex, body weight, serum albumin and general nutritional status were well balanced between the two groups. 223 pts underwent total gastrectomy, 6 pts proximal gastrectomy, 4 pts distal gastrectomy, and 7 pts simple laparotomy. In terms of tumor status, there were no significant difference between the groups in histological type, T stage, and lymph node metastasis. 104 of 125 pts assigned to the I group tolerated a daily intake 1,000 ml of Impact for 5 days. The incidence of SSI was 26 (20.8%) in the I group and 24 (20.9%) in the C group (R.R: 1.00, 95% C.I: 0.61-1.63). Postoperative morbidity was 36 (28.8%) in the I group and 30 (26.1%) in the C group. There was no difference in days of hospital stay after surgery between the groups.

Conclusions: The oral administration of immunonutrient for 5 days before surgery did not contributed to the reduction of infectious complications after total gastrectomy in gastric cancer pts.

No significant financial relationships to disclose.

Randomized controlled trial of omental bursectomy for resectable cT2-3 gastric cancer

72

Background: Omental bursectomy, a traditional surgical procedure to dissect the peritoneal lining covering the pancreas and the anterior plane of the transverse mesocolon, has often been performed against resectable gastric cancer. We have conducted a multi- institutional randomized controlled trial to elucidate the safety and usefulness of this procedure.

Methods: Patients with cT2 or cT3 gastric adenocarcinoma were intraoperatively randomized to radical gastrectomy plus D2 lymphadenectomy either with or without bursectomy. The primary endpoint was overall survival (OS). The planned sample size was 464, with an alpha error of 0.05 and statistical power of 80% to detect a 10% margin of non-inferiority for the non-bursectomy group. The first interim analysis was conducted on Sep 2008, and we decided the preliminary data release according to Korn's proposal (J Clin Oncol. 2005).

Results: Between Jul 2002 and Jan 2007, a total of 210 patients were randomized to either the bursectomy group or the non-bursectomy group. Background characteristics were well balanced. Intraoperative blood loss was greater in the bursectomy group than in the non-bursectomy group (median, 475 mL vs. 350 mL, p=0.047), while other surgical factors did not vary significantly. The overall morbidity rate was 14%, the same between two groups. The hospital mortality rate was 0.95%; one patient per group. In the first interim analysis, the 3-year OS were 86% in bursectomy group and 79% in non-bursectomy group, and the hazard ratio was 1.55 (95% CI: 0.84-2.84). The non-bursectomy group had more patients with peritoneal recurrences than the bursectomy group (14% vs. 8%).

Conclusions: Experienced surgeons could safely perform a D2 gastrectomy with an additional bursectomy. First interim analysis suggested the survival advantage of omental bursectomy for cT2-3 gastric cancer patients. Final analysis will be conducted in 2012.

No significant financial relationships to disclose.

Functional outcomes after extended surgery for gastric cancer

BACKGROUND

Extended gastrectomy with para-aortic nodal dissection (PAND) or thorough dissection of mediastinal nodes using a left thoracoabdominal (LTA) approach is an alternative to D2 lymphadenectomy, with variable postoperative results.

METHODS

Two randomized controlled trials have been conducted to compare D2 lymphadenectomy alone (263 patients) versus D2 lymphadenectomy plus PAND (260), and the abdominal-transhiatal (TH) approach (82) versus the LTA approach (85), in patients with gastric cancer. Prospectively registered secondary endpoints bodyweight, symptom scores and respiratory function were evaluated in the present study.

RESULTS

Bodyweight was comparable after D2 and D2 plus PAND, but higher after TH than after LTA procedures at 1 and 3 years. At 1- and 3-year follow-up symptom scores were comparable between D2 and D2 plus PAND. A LTA approach resulted in significantly worse scores than a TH approach in terms of meal volume, return to work, incisional pain and dyspnoea up to 1 year. The decrease in vital capacity was significantly greater after LTA than TH procedures up to 6 months.

CONCLUSION

Bodyweight and postoperative symptoms were not affected by adding PAND to a D2 procedure. A LTA approach aggravated weight loss, symptoms and respiratory functions compared with a TH approach.

The impact of ischemic stress on the quality of isolated pancreatic islets

BACKGROUND

Although the ischemic stress of donated organs has been shown to have strong negative effects on islet recovery, the impact on islet quality remains uncertain. In the present study, therefore, we examined the influence of ischemic stress on the expression of inflammatory mediators among isolated islets.

MATERIALS AND METHODS

Islets were isolated from adult porcine pancreata subjected to 16-hour cold ischemia time (CIT) in addition to 40-minute warm ischemia time (WIT). We evaluated the islet yield, islet loss during the first 24 hours in culture, adenosine diphosphate (ADP)/adenosine triphosphate (ATP) ratio, ATP/DNA ratio, glucose-stimulated respiratory activity, in vivo bioassay, and the expression of inflammatory mediators (tissue factor [TF], [MCP-1], macrophage migration inhibitory factor) on the isolated islets. We also analyzed ATP/DNA ratios of the exocrine tissues during isolation procedures.

RESULTS

The islet yield, survival rate during culture, and glucose-stimulated respiratory activity were significantly lower in cases of 16-hour CIT plus 40-minute WIT compared with the control group (P < .0001, .0006, and .002, respectively). In contrast, ADP/ATP ratio as well as TF and MCP-1 expressions on the isolated islets were higher among the ischemic group (P = .005, .16, and .005, respectively). During isolation procedures, the ATP/DNA of the exocrine tissues was extremely lower in the ischemic compared to the control group (P < .0001). Notably, however, both ATP/DNA and ADP/ATP ratio of isolated islets were well preserved even in the ischemic group (P = .45 and .40).

DISCUSSION

These data suggest that ischemic stress during the preservation period negatively affects the energy status of exocrine tissues. Destruction of the exocrine tissues, in combination with warm ischemic stress during the isolation procedures, subsequently decreases isolated islet activity, inducing the expression of inflammatory mediators.

Role of multidrug resistance protein 2 (MRP2) in chemoresistance and clinical outcome in oesophageal squamous cell carcinoma

BACKGROUND

Although multidrug resistance protein 2 (MRP2) confers chemoresistance in some cancer types, its implication on oesophageal squamous cell carcinoma (ESCC) remains unclear.

METHODS

We evaluated MRP2 expression by immunohistochemistry and RT-PCR using 81 resected specimens from ESCC patients who did or did not receive neo-adjuvant chemotherapy (NACT), including 5-fluorouracil, doxorubicin, and cisplatin (CDDP). Correlation between MRP2 expression and response to chemotherapy was also examined in 42 pre-therapeutic biopsy samples and eight ESCC cell lines.

RESULTS

MRP2-positive immunostaining was more frequently observed in ESCCs with NACT than in those without NACT (27.3 vs 5.4%). The MRP2-positive patients showed poorer prognosis than MRP2-negative patients (5-year survival rate, 25.6 vs 55.7%). Concordantly, ESCC with NACT showed 2.1-fold higher mRNA expression of MRP2 than those without NACT (P=0.0350). In pre-therapeutic biopsy samples of patients with NACT, non-responders showed 2.9-fold higher mRNA expression of MRP2 than responders (P=0.0035). Among the panel of ESCC cell lines, TE14 showed the highest MRP2 mRNA expression along with the strongest resistance to CDDP. Inhibition of MRP2 expression by small-interfering RNA reduced chemoresistance to CDDP.

CONCLUSION

Our data suggested that MRP2 is one of molecules, which regulate the sensitivity to chemotherapy including CDDP in advanced ESCC patients.