Intercomparison of dose enhancement ratio and secondary electron spectra for gold nanoparticles irradiated by X-rays calculated using multiple Monte Carlo simulation codes

PURPOSE

Targeted radiation therapy has seen an increased interest in the past decade. In vitro and in vivo experiments showed enhanced radiation doses due to gold nanoparticles (GNPs) to tumors in mice and demonstrated a high potential for clinical application. However, finding a functionalized molecular formulation for actively targeting GNPs in tumor cells is challenging. Furthermore, the enhanced energy deposition by secondary electrons around GNPs, particularly by short-ranged Auger electrons is difficult to measure. Computational models, such as Monte Carlo (MC) radiation transport codes, have been used to estimate the physical quantities and effects of GNPs. However, as these codes differ from one to another, the reliability of physical and dosimetric quantities needs to be established at cellular and molecular levels, so that the subsequent biological effects can be assessed quantitatively.

METHODS

In this work, irradiation of single GNPs of 50 nm and 100 nm diameter by X-ray spectra generated by 50 and 100 peak kilovoltages was simulated for a defined geometry setup, by applying multiple MC codes in the EURADOS framework.

RESULTS

The mean dose enhancement ratio of the first 10 nm-thick water shell around a 100 nm GNP ranges from 400 for 100 kVp X-rays to 600 for 50 kVp X-rays with large uncertainty factors up to 2.3.

CONCLUSIONS

It is concluded that the absolute dose enhancement effects have large uncertainties and need an inter-code intercomparison for a high quality assurance; relative properties may be a better measure until more experimental data is available to constrain the models.

Screening E-Cadherin Germline Mutations in Italian Patients with Familial Diffuse Gastric Cancer: An Analysis in the District of Urbino, Region Marche, Central Italy

Aims & Background

Hereditary diffuse gastric cancer is a recently defined cancer syndrome caused by inactivating, heterozygous germline mutations in the E-cadherin gene (CDH1). To date, 16 truncating germline CDH1 mutations have been described in hereditary diffuse gastric cancer families in different ethnic groups, but so far, no investigation has been addressed to Italian patients. In the District of Urbino, Region Marche, Central Italy, gastric cancer is the most common tumor in men and it is the second in women after breast cancer. In this area, we investigated CDH1 mutations in patients who fulfilled the hereditary diffuse gastric cancer criteria.

Material and Methods

Consecutive patients with diffuse gastric cancer were considered eligible for the study. After pedigree analysis, patients who met the International Gastric Cancer Linkage Consortium criteria were studied for CDH1 mutations. After blood samples collection and DNA extraction, standard polymerase chain reaction and sequencing techniques were used for CDH1 analysis.

Results

In a study population of 98 patients with diffuse gastric cancer, 11 patients (11%) showed familial clustering and 3 of them met the International Gastric Cancer Linkage Consortium criteria for hereditary diffuse gastric cancer. None of the 3 patients showed inactivating germline mutation in CDH1.

Conclusions

According to recent studies, the frequency of CDH1 inactivating germline mutations in patients who fulfil the hereditary diffuse gastric cancer criteria may be lower than that reported in early investigations. The results of the present study in a population of Italian patients seem to confirm these data. It is likely that unidentified mutations in CDH1 or other involved genes contribute to diffuse gastric cancer susceptibility.

Cholestasis is the Main Determinant of Abnormal CA 19–9 Levels in Patients with Liver Cirrhosis

Background/Aims

Altered CA19–9 levels are commonly found in patients with liver cirrhosis though a clear explanation for this finding has not yet been given. The aim of this study was to investigate whether CA19–9 levels might be related to alterations in biochemical parameters and/or to functional impairment in cirrhotic patients with and without hepatocellular carcinoma. Methods: We studied 126 patients with liver cirrhosis, 60 of whom also had hepatocellular carcinoma. CA19–9 values were related to clinical, biochemical and functional parameters. In half of the patients CA19–9 levels were related to the monoethylglycinexylidide test, which is a dynamic liver function test.

Results

In more than half the cases CA19–9 values were above the upper limit. Liver function worsening as assessed by Child-Pugh's score and monoethylglycinexylidide test did not seem to influence the alteration of the marker. By contrast, in univariate analysis CA19–9 correlated with aminotransferases, γ-glutamyltransferase and alkaline phosphatase. Multivariate analysis showed that besides alkaline phosphatase also the presence of hepatocellular carcinoma might influence the alteration of CA19–9, although the marker was of no use for the diagnosis of liver cancer in patients with altered though not diagnostic α-fetoprotein levels.

Conclusions

In our study we confirmed the correlation of CA19–9 levels with cholestasis and cytolysis parameters. Moreover, we found no association between CA19–9 levels and impaired liver function as assessed by means of the Child-Pugh's score and the monoethylglycinexylidide test, which is cholestasis-independent and explores liver metabolic and clearance activities. The cholestatic picture that characterizes liver cirrhosis might enhance the expression and passage of the marker from the bile to the blood. The addition of CA19–9 assessment is not useful for the diagnosis of hepatocellular carcinoma in patients with non-diagnostic levels of α-fetoprotein. Caution should therefore be used when evaluating CA19–9 in cirrhotic patients with cholestasis, since false positive results may occur.

Contribution of KRAS mutations and c.2369C > T (p.T790M) EGFR to acquired resistance to EGFR-TKIs in EGFR mutant NSCLC: a study on circulating tumor DNA

INTRODUCTION

KRAS oncogene mutations (MUTKRAS) drive resistance to EGFR inhibition by providing alternative signaling as demonstrated in colo-rectal cancer. In non-small cell lung cancer (NSCLC), the efficacy of treatment with EGFR tyrosine kinase inhibitors (EGFR-TKIs) depends on activating EGFR mutations (MUTEGFR). However, inhibition of EGFR may select resistant cells displaying alternative signaling, i.e., KRAS, or restoration of EGFR activity due to additional MUTEGFR, i.e., the c.2369C > T (p.T790MEGFR).

AIM

The aim of this study was to investigate the appearance of MUTKRAS during EGFR-TKI treatment and their contribution to drug resistance.

METHODS

This study used cell-free circulating tumor DNA (cftDNA) to evaluate the appearance of codon 12 MUTKRAS and p.T790MEGFR mutations in 33 advanced NSCLC patients progressing after an EGFR-TKI.

RESULTS

p.T790MEGFR was detected in 11 (33.3%) patients, MUTKRAS at codon 12 in 3 (9.1%) while both p.T790MEGFR and MUTKRAS codon 12 were found in 13 (39.4%) patients. Six patients (18.2%) were KRAS wild-type (WTKRAS) and negative for p.T790MEGFR. In 8 subjects paired tumor re-biopsy/plasma samples were available; the percent concordance of tissue/plasma was 62.5% for p.T790MEGFR and 37.5% for MUTKRAS. The analysis of time to progression (TTP) and overall survival (OS) in WTKRAS vs. MUTKRAS were not statistically different, even if there was a better survival with WTKRAS vs. MUTKRAS, i.e., TTP 14.4 vs. 11.4 months (p = 0.97) and OS 40.2 vs. 35.0 months (p = 0.56), respectively.

CONCLUSIONS

MUTKRAS could be an additional mechanism of escape from EGFR-TKI inhibition and cftDNA is a feasible approach to monitor the molecular development of drug resistance.

Prognostic impact of the cumulative dose and dose intensity of everolimus in patients with pancreatic neuroendocrine tumors

The aim of this work is to assess if cumulative dose (CD) and dose intensity (DI) of everolimus may affect survival of advanced pancreatic neuroendocrine tumors (PNETs) patients. One hundred and sixteen patients (62 males and 54 females, median age 55 years) with advanced PNETs were treated with everolimus for ≥3 months. According to a Receiver operating characteristics (ROC) analysis, patients were stratified into two groups, with CD ≤ 3000 mg (Group A; n = 68) and CD > 3000 mg (Group B; n = 48). The response rate and toxicity were comparable in the two groups. However, patients in group A experienced more dose modifications than patients in group B. Median OS was 24 months in Group A while in Group B it was not reached (HR: 26.9; 95% CI: 11.0-76.7; P < 0.0001). Patients who maintained a DI higher than 9 mg/day experienced a significantly longer OS and experienced a trend to higher response rate. Overall, our study results showed that both CD and DI of everolimus play a prognostic role for patients with advanced PNETs treated with everolimus. This should prompt efforts to continue everolimus administration in responsive patients up to at least 3000 mg despite delays or temporary interruptions.

NanOx, a new model to predict cell survival in the context of particle therapy

Particle therapy is increasingly attractive for the treatment of tumors and the number of facilities offering it is rising worldwide. Due to the well-known enhanced effectiveness of ions, it is of utmost importance to plan treatments with great care to ensure tumor killing and healthy tissues sparing. Hence, the accurate quantification of the relative biological effectiveness (RBE) of ions, used in the calculation of the biological dose, is critical. Nevertheless, the RBE is a complex function of many parameters and its determination requires modeling. The approaches currently used have allowed particle therapy to thrive, but still show some shortcomings. We present herein a short description of a new theoretical framework, NanOx, to calculate cell survival in the context of particle therapy. It gathers principles from existing approaches, while addressing some of their weaknesses. NanOx is a multiscale model that takes the stochastic nature of radiation at nanometric and micrometric scales fully into account, integrating also the chemical aspects of radiation-matter interaction. The latter are included in the model by means of a chemical specific energy, determined from the production of reactive chemical species induced by irradiation. Such a production represents the accumulation of oxidative stress and sublethal damage in the cell, potentially generating non-local lethal events in NanOx. The complementary local lethal events occur in a very localized region and can, alone, lead to cell death. Both these classes of events contribute to cell death. The comparison between experimental data and model predictions for the V79 cell line show a good agreement. In particular, the dependence of the typical shoulders of cell survival curves on linear energy transfer are well described, but also the effectiveness of different ions, including the overkill effect. These results required the adjustment of a number of parameters compatible with the application of the model in a clinical scenario thereby showing the potential of NanOx. Said parameters are discussed in detail in this paper.

Monte Carlo comparison of x-ray and proton CT for range calculations of proton therapy beams

Proton computed tomography (CT) has been described as a solution for imaging the proton stopping power of patient tissues, therefore reducing the uncertainty of the conversion of x-ray CT images to relative stopping power (RSP) maps and its associated margins. This study aimed to investigate this assertion under the assumption of ideal detection systems. We have developed a Monte Carlo framework to assess proton CT performances for the main steps of a proton therapy treatment planning, i.e. proton or x-ray CT imaging, conversion to RSP maps based on the calibration of a tissue phantom, and proton dose simulations. Irradiations of a computational phantom with pencil beams were simulated on various anatomical sites and the proton range was assessed on the reference, the proton CT-based and the x-ray CT-based material maps. Errors on the tissue's RSP reconstructed from proton CT were found to be significantly smaller and less dependent on the tissue distribution. The imaging dose was also found to be much more uniform and conformal to the primary beam. The mean absolute deviation for range calculations based on x-ray CT varies from 0.18 to 2.01 mm depending on the localization, while it is smaller than 0.1 mm for proton CT. Under the assumption of a perfect detection system, proton range predictions based on proton CT are therefore both more accurate and more uniform than those based on x-ray CT.

Assessment of the 7th edition of the AJCC classification and a proposal of a new classification in patients with gastric cancer undergoing D2 gastrectomy

4084

Background: Studies on Asian, US, and German patients have moved some criticisms on the validity of the 7th edition of the AJCC classification to discriminate outcome of gastric cancer stages. We investigated the effect of this AJCC classification in a high-quality surgical populations of patients receiving D2 lymphadenectomy. Methods: From the prospective database at San Salvatore Hospital, Pesaro, we identified 515 patientswith gastroesophageal junction (Siewert II and III) or stomach adenocarcinoma who underwent gastrectomy with curative intent from 1998 to 2010. Lymphadenectomy extended to the 3rd level 12p/b nodes (D2/D3) was performed in all patients. Overall survival (OS) probabilities, calculated from the date of surgery to the date of death, from any cause, were estimated using the Kaplan-Meier method and compared using the log-rank test. Results: 58% of patients were male,median age was 73 years (range 36-96). Median number of examined lymph nodes was 32 (range, 1-89), and only 8.9% of patients had less than 15 examined lymph nodes; 96 patients received adjuvant chemo- or chemoradiotherapy. As shown in the table, we proposed a revised staging system (Pesaro Staging System, PSS), which performs better than the 7th edition of AJCC classification in terms of survival differences between stages. Conclusions: This study confirms once again that the 7th edition of the AJCC classification does not discriminate adequately the outcome from stage to stage. In a European population of patients undergoing gastrectomy plus at least D2 lymphadenectomy, the revised staging system, PSS, better defines patient prognosis. [Table: see text]

HtrA1, a potential predictor of response to cisplatin-based combination chemotherapy in gastric cancer

AIMS

HtrA1 is a member of the HtrA (high-temperature requirement factor A) family of serine proteases. HtrA1 plays a protective role in various malignancies due to its tumour suppressive properties. The aim of this study was to determine HtrA1 expression as a predictor of chemoresponse in patients with advanced gastric cancer.

METHODS AND RESULTS

HtrA1 expression was determined by immunohistochemistry on specimens of primary gastric cancer from 80 patients treated consecutively with cisplatin-based combination chemotherapy. Response to chemotherapy was assessed according to Response Evaluation Criteria in Solid Tumours (RECIST) criteria. Our population consisted of males/females [51/29; median age 64 years (range 32-82)]. A complete or partial response was observed in 71.4% [95% confidence interval (CI) 54.7-88.2], 66.7% (95% CI 47.8-85.5) and 28.6% (95 CI 11.8-45.3) of tumours showing high, medium and low HtrA1 expression, respectively. A statistically significant association between HtrA1 expression and the clinical response was observed (P = 0.002). The median overall survival for patients with high/medium expression was 17 months compared to 9.5 months for patients with low HtrA1 expression (P = 0.037).

CONCLUSIONS

Identification of HtrA1 in gastric cancer prior to chemotherapy indicates that levels of HtrA1 could be used to predict response to platinum-based combination therapies. Further assessment of HtrA1 expression is highly warranted in large, prospective studies.

Real-time monitoring of the Bragg-peak position in ion therapy by means of single photon detection

For real-time monitoring of the longitudinal position of the Bragg-peak during an ion therapy treatment, a novel non-invasive technique has been recently proposed that exploits the detection of prompt gamma-rays issued from nuclear fragmentation. Two series of experiments have been performed at the GANIL and GSI facilities with 95 and 305 MeV/u (12)C(6+) ion beams stopped in PMMA and water phantoms. In both experiments, a clear correlation was obtained between the carbon ion range and the prompt photon profile. Additionally, an extensive study has been performed to investigate whether a prompt neutron component may be correlated with the carbon ion range. No such correlation was found. The present paper demonstrates that a collimated set-up can be used to detect single photons by means of time-of-flight measurements, at those high energies typical for ion therapy. Moreover, the applicability of the technique both at cyclotron and at synchrotron facilities is shown. It is concluded that the detected photon count rates provide sufficiently high statistics to allow real-time control of the longitudinal position of the Bragg-peak under clinical conditions.

Second-line chemotherapy for patients with advanced gastric cancer: who may benefit?

No established second-line chemotherapy is available for patients with advanced gastric cancer failing to respond or progressing to first-line chemotherapy. However, 20–40% of these patients commonly receive second-line chemotherapy. We evaluated the influence of clinico-pathologic factors on the survival of 175 advanced gastric cancer patients, who received second-line chemotherapy at three oncology departments. Univariate and multivariate analyses found five factors which were independently associated with poor overall survival: performance status 2 (hazard ratio (HR), 1.79; 95% CI, 1.16–2.77; P=0.008), haemoglobin ⩽11.5 g l⁻¹ (HR, 1.48; 95% CI, 1.06–2.05; P=0.019), CEA level >50 ng ml⁻¹ (HR, 1.86; 95% CI, 1.21–2.88; P=0.004), the presence of greater than or equal to three metastatic sites of disease (HR, 1.72; 95% CI, 1.16–2.53; P=0.006), and time-to-progression under first-line chemotherapy ⩽6 months (HR, 1.97; 95% CI, 1.39–2.80; P<0.0001). A prognostic index was constructed dividing patients into low- (no risk factor), intermediate- (one to two risk factors), or high- (three to five risk factors) risk groups, and median survival times for each group were 12.7 months, 7.1 months, and 3.3 months, respectively (P<0.001). In the absence of data deriving from randomised trials, this analysis suggests that some easily available clinical factors may help to select patients with advanced gastric cancer who could derive more benefit from second-line chemotherapy.

Fission time measurements: a new probe into superheavy element stability

Reaction mechanism analyses performed with a 4pi detector for the systems 208Pb + Ge, 238U + Ni and 238U + Ge, combined with analyses of the associated reaction time distributions, provide us with evidence for nuclei with Z=120 and 124 living longer than 10(-18) s and arising from highly excited compound nuclei. By contrast, the neutron deficient nuclei with Z=114 possibly formed in 208Pb + Ge reactions have shorter lifetimes, close to or below the sensitivity limit of the experiment.

Characteristics of the patients referred to a Hypertension Unit between 1989 and 2003

The level of blood pressure, the type of antihypertensive treatment and the prevalence of resistant hypertension at the first examination were evaluated in 6254 patients referred to a hospital Hypertension Unit from 1989 to 2003. From 1989-1993 to 1999-2003, we observed a reduced prevalence of grade 2 and grade 3 hypertension, and an increase in the prevalence of grade 1 hypertension, the proportion of treated subjects, the average number of antihypertensive drugs per patient and the prevalence of resistant hypertension.

Pharmacogenetic profiling in patients with advanced colorectal cancer treated with first-line FOLFIRI chemotherapy

The primary end point of the study was the analysis of associations between polymorphisms with putative influence on 5-fluorouracil/irinotecan activity and progression-free survival (PFS) of patients with advanced colorectal cancer treated with first-line FOLFIRI chemotherapy. Peripheral blood samples from 146 prospectively enrolled patients were used for genotyping polymorphisms in thymidylate synthase (TS), methylenetetrahydrofolate reductase (MTHFR), excision repair cross-complementation group-1 (ERCC 1) xeroderma pigmentosum group-D (XPD), X-ray cross-complementing-1 (XRCC 1), X-ray cross-complementing-3 (XRCC 3) and uridine diphosphate-glucuronosyltransferases-A1 (UGT1 A1). TS 3'-UTR 6+/6+ and XRCC3-241 C/C genotypes were associated with adverse PFS. Hazard ratio for PFS achieved 2.89 (95% confidence interval=1.56-5.80; P=0.002) in 30 patients (20%) with both risk genotypes. Risk for Grade III-IV neutropenia was significantly associated with UGT1A1*28 7/7 genotype. These promising findings deserve further investigations and their validation in independent prospective studies.

Accuracy of the blood pressure measurement

Blood pressure measurement is the cornerstone for the diagnosis, the treatment and the research on arterial hypertension, and all of the decisions about one of these single aspects may be dramatically influenced by the accuracy of the measurement. Over the past 20 years or so, the accuracy of the conventional Riva-Rocci/Korotkoff technique of blood pressure measurement has been questioned and efforts have been made to improve the technique with automated devices. In the same period, recognition of the phenomenon of white coat hypertension, whereby some individuals with an apparent increase in blood pressure have normal, or reduced, blood pressures when measurement is repeated away from the medical environment, has focused attention on methods of measurement that provide profiles of blood pressure behavior rather than relying on isolated measurements under circumstances that may in themselves influence the level of blood pressure recorded. These methodologies have included repeated measurements of blood pressure using the traditional technique, self-measurement of blood pressure in the home or work place, and ambulatory blood pressure measurement using innovative automated devices. The purpose of this review to serve as a source of practical information about the commonly used methods for blood pressure measurement: the traditional Riva-Rocci method and the automated methods.

Noninvasive ratio indexes to evaluate fibrosis staging in chronic hepatitis C: role of platelet count/spleen diameter ratio index

OBJECTIVES

Noninvasive evaluation of fibrosis is an on-going effort in the management of chronic hepatitis C. This study was planned to noninvasively evaluate fibrosis staging.

DESIGN

We evaluated the biochemical, functional [aminopyrine breath test (ABT)] and ultrasonographic variables of 75 chronic hepatitis C patients.

RESULTS

Clinical [body mass index (BMI)], biochemical [aspartate aminotransferase (AST), alanine aminotransferase (ALT) and platelets (PLT)] and ratio indexes, together with the ABT, showed a higher relationship with fibrosis: initial (score<or=2) versus evident (score>2) fibrosis: BMI (24+/-2 vs. 26+/-2, P=0.0007), AST (56+/-36 vs. 88+/-65, P=0.0159), ALT (92+/-54 vs. 139+/-108, P=0.0290), PLT (220+/-64 vs. 173+/-61, P=0.0007), PLT/spleen diameter ratio (PLT/SPD) (2133+/-786 vs. 1540+/-681, P=0.0003), AST/platelet count ratio index (APRI) (0.80+/-0.87 vs. 1.51+/-1.47, P=0.0010), ABT%d/h30 min (10.8+/-4.5 vs. 7.6+/-3.8, P=0.0007), ABT%d/cum120 min (8.9+/-3.3 vs. 6.5+/-3.1, P=0.0007). Considering the differences between fibrosis score 2 and 3 patients, BMI, ABT and PLT/SPD ratio proved to be statistically significant. Multivariate stepwise analysis (with and without BMI) identified two models for distinguishing between initial and evident fibrosis: Model 1: -0.569+(BMIx0.107)+(APRIx0.169)-(PLT/SPDx0.304), and Model 2: 2.376+( APRIx0.152)-(ABTd/h30x0.043)-(PLT/SPDx0.249). These models showed concordance in identifying or ruling out evident fibrosis in 76% and 78.7% of the patients respectively. The PLT/SPD ratio also showed 78.7% concordance with the histological score.

CONCLUSION

These results suggest that noninvasive evaluation of fibrosis in chronic hepatitis C may be considered an effective tool thanks to the use of an inexpensive, reproducible ratio index.

[Role of aldosterone in the metabolic syndrome]

The purpose of this review is to summarize the current knowledge regarding metabolic syndrome prevalence and features in primary aldosteronism. We will also discuss the link between aldosterone and the different metabolic changes typical of the metabolic syndrome. Hypertensive patients have a high prevalence of obesity, dyslipidemia and hyperglycaemia. These are risk factors for the metabolic syndrome, and are associated with an increased cardiovascular risk profile. In particular, insulin resistance seems to be the major alteration in patients affected by primary aldosteronism. We will then describe the experimental and clinical evidences of the role of aldosterone in the pathogenesis of insulin resistance. Higher rates of cardiovascular events have been recently reported in primary aldosteronism: they could be partly due to the increased prevalence of the metabolic syndrome in this disorder.

Weekly oxaliplatin, 5-fluorouracil and folinic acid (OXALF) as first-line chemotherapy for elderly patients with advanced gastric cancer: results of a phase II trial

BACKGROUND

Elderly patients have been often excluded from or underrepresented in the study populations of combination chemotherapy trials. The primary end point of this study was to determine the response rate and the toxicity of the weekly oxaliplatin, 5-fluorouracil and folinic acid (OXALF) regimen in elderly patients with advanced gastric cancer. The secondary objective was to measure the time to disease progression and the survival time.

METHODS

Chemotherapy-naive patients with advanced gastric cancer aged 70 or older were considered eligible for study entry. Patients received weekly oxaliplatin 40 mg/m2, fluorouracil 500 mg/m2 and folinic acid 250 mg/m2. All drugs were given intravenously on a day-1 schedule.

RESULTS

A total of 42 elderly patients were enrolled. Median age was 73 years and all patients had metastatic disease. The response rate according to RECIST criteria was 45.2% (95% CIs: 30%-56%) with two complete responses, 17 partial responses, 13 stable diseases and 10 progressions, for an overall tumor rate control of 76.2% (32 patients). Toxicity was generally mild and only three patients discontinued treatment because of treatment related adverse events. The most common treatment-related grade 3/4 adverse events were fatigue (7.1%), diarrhoea (4.8%), mucositis (2.4%), neurotoxicity (2.4%) and neutropenia (4.8%). The median response duration was 5.3 months (95% CIs: 2.13 - 7.34), the median time to disease progression was 5.0 months (95% CIs: 3.75 - 6.25) and the median survival time was 9.0 months (95% CIs: 6.18 - 11.82).

CONCLUSION

OXALF represents an active and well-tolerated treatment modality for elderly patients with locally advanced and metastatic gastric cancer.