Variations in survival and perioperative complications between hospitals based on data from two phase III clinical trials for oesophageal cancer

BACKGROUND

Variations in institutional practice may contribute to different outcomes of cancer treatment. The impact of interinstitutional heterogeneity on outcomes between hospitals after oesophagectomy has not been examined previously using data from surgical clinical trials.

METHODS

The data from two phase III trials for oesophageal cancer were used. Japan Clinical Oncology Group (JCOG) 9204 involved oesophagectomy (92-OP) versus oesophagectomy plus postoperative chemotherapy (92-POST), with accrual from 1992 to 1997. JCOG9907 involved postoperative chemotherapy (99-POST) versus preoperative chemotherapy (99-PRE), with accrual from 2000 to 2006. Hospitals contributing fewer than three patients were excluded. The influence of time and preoperative chemotherapy on interinstitutional heterogeneity related to postoperative complications and 5-year overall survival were evaluated by comparisons within and between these trial groups. Heterogeneity was estimated by a mixed-effects model after adjusting for age, sex, performance status, location of the primary tumour and clinical stage.

RESULTS

Twelve hospitals in 92-OP (114 patients), 13 in 92-POST (114), 19 in 99-POST (158) and 18 in 99-PRE (154) were eligible. There was considerable heterogeneity in predicted postoperative complications in both groups in JCOG9204 (median 31.3 (range 15.0-68.2) per cent), and in 99-PRE (35.2 (22.6-46.6) per cent) but not in 99-POST (27.7 (27.7-27.7) per cent) from JCOG9907. A similar pattern was seen for predicted overall survival (92-POST: 66.4 (range 64.1-68.9) per cent; 99-PRE: 55.9 (54.0-59.7) per cent; 99-POST: 44.4 (44.4-44.4) per cent).

CONCLUSION

Interinstitutional heterogeneity regarding complications and survival after oesophagectomy is a problem that merits wider consideration.

Clinicopathological significance of laminin-5γ2 chain expression in superficial esophageal cancer

The glycoprotein laminin 5γ2 chain (LN-5γ2) has recently become a focus of increased interest and investigation as a marker of invasion in gastrointestinal malignancies. We investigated the significance of LN-5γ2 expression as a prognostic factor in superficial esophageal cancer. The study population consisted of 87 patients who had undergone a transthoracic esophagectomy and three-field lymphadenectomy for the treatment of superficial esophageal cancer at Tokai University Hospital. Formalin-fixed, paraffin-embedded sections of the resected specimens were examined using immunohistochemical staining and hematoxylin and eosin staining to assess the correlations between the LN-5γ2 expression pattern and the clinicopathological factors (age, sex, T-factor, N-factor, ly-factor, v-factor, degree of differentiation, infiltrative growth pattern, tumor node metastasis classification of malignant tumors [TNM] stage, etc.) and the patient outcome. The expression pattern of LN-5γ2 was classified into an extracellular type (E type), characterized by the staining of extracellular matrix such as the basement membrane and the stroma (31 cases, 35.6%), and a cytoplasmic type (C type), characterized by the staining of the cytoplasm in the cancer cells (56 cases, 64.6%). The expression pattern was not correlated with any of the clinicopathological factors that were assessed. However, univariate analyses of the survival analysis data showed that the N-factor (P = 0.011), TNM stage (P = 0.011), and LN-5γ2 C type (P = 0.017) were prognostic factors. A multivariate analysis revealed that the N-factor (P = 0.049) and LN-5γ2 C type (P = 0.048) were prognostic factors. In the survival analysis, a univariate analysis of the 75 T1b cases also showed that the N-factor (P = 0.048), TNM stage (P = 0.048), and LN-5γ2 C type (P = 0.029) were prognostic factors, while a multivariate analysis showed that the LN-5γ2 C type (P = 0.035) was a prognostic factor. The C type expression of LN-5γ2, i.e. confined to the cytoplasm, was correlated with an unfavorable outcome among the patients with superficial esophageal cancer in the present series. Observation of the LN-5γ2 expression pattern may be useful for the diagnosis of highly malignant tumors.

Probe of the solar magnetic field using the "cosmic-ray shadow" of the sun

We report on a clear solar-cycle variation of the Sun’s shadow in the 10 TeV cosmic-ray flux observed by the Tibet air shower array during a full solar cycle from 1996 to 2009. In order to clarify the physical implications of the observed solar cycle variation, we develop numerical simulations of the Sun’s shadow, using the potential field source surface model and the current sheet source surface (CSSS) model for the coronal magnetic field. We find that the intensity deficit in the simulated Sun’s shadow is very sensitive to the coronal magnetic field structure, and the observed variation of the Sun’s shadow is better reproduced by the CSSS model. This is the first successful attempt to evaluate the coronal magnetic field models by using the Sun’s shadow observed in the TeV cosmic-ray flux.

The characteristics of muscle fiber types of longissimus thoracis muscle and their influences on the quantity and quality of meat from Japanese Black steers

Forty-four Japanese Black fattening steers from four groups, produced in four districts and consisting of differing genetic backgrounds were slaughtered to examine the characteristic differences in muscle fiber types at the 6th thoracic vertebra of the M. longissimus thoracis (LT). The influence of percentage, diameter, and relative area of each muscle fiber type on the carcass characteristics and some quantity and quality traits of beef taken from LT, were also investigated. Significant differences in the characteristics of the muscle fiber types were observed among the four groups, except for muscle fiber diameter in the αR fiber, and the relative area of each αW fiber. For all steers, the average percentages and diameters of each muscle fiber type, βR, αR and αW were 26.8, 18.5 and 54.7% and 51.4, 50.6 and 52.4 μm, respectively. The relative area of each fiber type was similar to those of muscle fiber composition. αR Fiber content had significant negative correlations with marbling score (p<0.05), intramuscular fat content (p<0.05) and ultimate pH value (p<0.05). Significant correlations between the diameter of each fiber type, and the quantity or quality traits of the meat were not found, with the exception of red fiber types (βR and αR) and meat color a(∗) values (p<0.05) which were positively correlated.

SU-E-T-497: Study of Restricted Mass Stopping Power Ratio in Small Electron Tube Fields

PURPOSE

Electron tubes with small radii are useful to treat narrow regions which cannot accommodate normal electron applicators. In small electron fields, it is not trivial to estimate restricted mass stopping power ratio (MSR), which is needed to evaluate dose from ion chamber measurement. We studied MSRs in small electron tube fields using the Monte Carlo simulation.

METHODS

Electron tubes with radii, 3 and 2.5 cm, were used in this study. Nominal electron energies were 6 and 9 MeV. There were two types of tubes. One has a normal cut but the other has a 45-degree cut. For the normal cut tube, percent depth dose (PDD) in water was evaluated along the center of axis (CAX) of a beam. For the 45-degree cut tube, PDD was evaluated along the vertical line from the intersection of the CAX and the phantom surface with 45-degree gantry angle. The MSRs and mean electron energies were calculated using the Monte Carlo simulation.

RESULTS

We found good agreement between the measured and calculated PDDs. The changes of mean energies from those in the 10×10 cm² field at the depth of maximum dose (dmax) were very small for the normal cut electron tubes. For the 45-degree cut tubes, the changes of mean energies at dmax were less than 1 MeV. The MSRs in the normal cut tube fields were almost the same as those in the 10×10 cm² field at the corresponding depths. The MSRs for the 45-degree cut tubes deviated from those in the 10×10 cm² by about 1% (1.5 % at most).

CONCLUSIONS

We evaluated the mean energies and MSRs in small electron tube fields. The deviations of them from the values in the 10×10 cm² were small. The maximum difference of MSR was 1.5% in 45-degree cut tube fields. This work was supported by KAKENHI (23791449), Japan Society for the Promotion of Science, and Cancer Professional Training Plan, The Ministry of Education, Culture, Sports, Science and Technology, Japan.