Dosimetric sensitivity of leaf width on volumetric modulated arc therapy plan quality: an objective approach

BackgroundSeveral authors investigated a dosimetric impact of leaf width on radiotherapy plan quality subjectively, and concluded that thinner leaf-width multileaf collimators (MLC) are beneficial because of their better coverage of clinically relevant structures. Study aimed to investigate the dosimetric effect of MLC leaf width on volumetric modulated arc therapy plan quality by objective approach.Materials and methodsTwelve of each prostate and head-and-neck patients were planned for volumetric modulated arc therapy (VMAT) treatments for MLC leaf widths of 4 mm and 10 mm. Three different VMAT schemes single-arc, dual-arc and two combined independent single-arcs were optimized. Dose volume histogram and Isodose distribution were used for quantitative and qualitative comparison of the treatment plan, respectively. Dose-volume-indices of the planning target volume, organs at risk and number of delivered monitor units were compared. The 4 mm leaf width being reference over 10 mm and results were noted as statistically significant if p ≤ 0.05 using student t-test.ResultsAll VMAT schemes for both tumor sites showed a gain in target coverage, similar organs at risk doses and higher monitor units to be delivered, when changing leaf width from 10 mm to 4 mm. The p-values were significant for majority of head-and-neck dose indices.ConclusionThe thinner-leaf MLCs, owing to their better spatial resolution, result in an overall gain for target coverage, while maintaining permissible doses to the organs at risk.     

Dosimetric evaluation study of IMRT and VMAT techniques for prostate cancer based on different multileaf collimator designs

The hypofractionated radiotherapy modality was established to reduce treatment durations and enhance therapeutic efficiency, as compared to conventional fractionation treatment. However, this modality is challenging because of rigid dosimetric constraints. This study aimed to assess the impact of multi-leaf collimator (MLC) widths (10 mm and 5 mm) on plan quality during the treatment of prostate cancer. Additionally, this study aimed to investigate the impact of the MLC mode of energy on the Agility flattening filter (FF), MLC Agility-free flattening filter (FFF), and MLCi2 for patients receiving hypofractionated radiotherapy. Two radiotherapy techniques; Intensity Modulated Radiotherapy (IMRT) and Volumetric Modulated Arc Radiotherapy (VMAT), were used in this research. In the present study, computed tomography simulations of ten patients (six plans per patient) with localized prostate adenocarcinoma were analyzed. Various dosimetric parameters were assessed, including monitor units, treatment delivery times, conformity, and homogeneity indices. To evaluate the plan quality, dose-volume histograms (DVHs) were estimated for each technique. The results demonstrated that the determined dosimetric parameters of planning target volume (PTV)p (such as D mean, conformity, and homogeneity index) showed greater improvement with MLC Agility FF and MLC Agility FFF than with MLCi2. Additionally, the treatment delivery time was reduced in the MLC Agility FF (by 31%) and MLC Agility FFF (by 10.8%) groups compared to the MLCi2 group. It is concluded that for both the VMAT and IMRT techniques, the smaller width (5 mm) MLCs revealed better planning target volume coverage, improved the dosimetric parameters for PTV, reduced the treatment time, and met the constraints for OARs. It is therefore recommended to use 5 mm MLCs for hypofractionated prostate cancer treatment due to better target coverage and better protection of OARs.

     

Automatic VMAT planning for post-operative prostate cancer cases using particle swarm optimization: A proof of concept study

ObjectiveTo investigate the potential of Particle Swarm Optimization (PSO) for fully automatic VMAT radiotherapy (RT) treatment planning.Material and MethodsIn PSO a solution space of planning constraints is searched for the best possible RT plan in an iterative, statistical method, optimizing a population of candidate solutions. To identify the best candidate solution and for final evaluation a plan quality score (PQS), based on dose volume histogram (DVH) parameters, was introduced.Automatic PSO-based RT planning was used for N = 10 postoperative prostate cancer cases, retrospectively taken from our clinical database, with a prescribed dose of EUD = 66 Gy in addition to two constraints for rectum and one for bladder. Resulting PSO-based plans were compared dosimetrically to manually generated VMAT plans.ResultsPSO successfully proposed treatment plans comparable to manually optimized ones in 9/10 cases. The median (range) PTV EUD was 65.4 Gy (64.7–66.0) for manual and 65.3 Gy (62.5–65.5) for PSO plans, respectively. However PSO plans achieved significantly lower doses in rectum D_2% 67.0 Gy (66.5–67.5) vs. 66.1 Gy (64.7–66.5, p = 0.016). All other evaluated parameters (PTV D_98% and D_2%, rectum V_40Gy and V_60Gy, bladder D_2% and V_60Gy) were comparable in both plans. Manual plans had lower PQS compared to PSO plans with −0.82 (−16.43–1.08) vs. 0.91 (−5.98–6.25).ConclusionPSO allows for fully automatic generation of VMAT plans with plan quality comparable to manually optimized plans. However, before clinical implementation further research is needed concerning further adaptation of PSO-specific parameters and the refinement of the PQS.     

Comparison of dosimetric variation between prostate IMRT and VMAT due to patient's weight loss: Patient and phantom study

Aim

This study compared the dosimetric impact between prostate IMRT and VMAT due to patient''s weight loss.

Background

Dosimetric variation due to change of patient''s body contour is difficult to predict in prostate IMRT and VMAT, since a large number of small and irregular segmental fields is used in the delivery.

Materials and methods

Five patients with prostate volumes ranging from 32.0 to 86.5 cm³ and a heterogeneous pelvis phantom were used for prostate IMRT and VMAT plans using the same set of dose–volume constraints. Doses in IMRT and VMAT plans were recalculated with the patient''s and phantom''s body contour reduced by 0.5–2 cm to mimic size reduction. Dose coverage/criteria of the PTV and CTV and critical organs (rectum, bladder and femoral heads) were compared between IMRT and VMAT.

Results

In IMRT plans, increases of the D99% for the PTV and CTV were equal to 4.0 ± 0.1% per cm of reduced depth, which were higher than those in VMAT plans (2.7 ± 0.24% per cm). Moreover, increases of the D30% of the rectum and bladder per reduced depth in IMRT plans (4.0 ± 0.2% per cm and 3.5 ± 0.5% per cm) were higher than those of VMAT (2.2 ± 0.2% per cm and 2.0 ± 0.6% per cm). This was also true for the increase of the D5% for the right femoral head in a patient or phantom with size reduction due to weight loss.

Conclusions

VMAT would be preferred to IMRT in prostate radiotherapy, when a patient has potential to suffer from weight loss during the treatment.     

A study on the correlation between plan complexity and gamma index analysis in patient specific quality assurance of volumetric modulated arc therapy

Aim

To evaluate the new Octavius 4D system for patient specific quality assurance and to study the correlation between plan complexity and gamma index analysis in patient specific quality assurance of VMAT using the Octavius 4D system.

Background

McNiven (2010) proposed a study to evaluate the utility of a complexity metric, the Modulation Complexity Score, to evaluate the relationship of the metric with deliverability in IMRT.

Materials and methods

Evaluation of the Octavius 4D system was carried out by gamma evaluation of user defined MLC created patterns and AAPM TG 119 benchmark plans. The relationship between plan complexity expressed as Modulation Complexity Score (MCS) and the gamma index analysis was established by a planar and volumetric gamma analysis of 106 clinically approved VMAT patient plans of different sites.

Results

Average volumetric 3D global gamma evaluation (3 mm/3%) results for the evaluation plans was 97.41% for 6 MV X-rays and 98.30% for 15 MV X-rays. Average MCS values for the head and neck, pelvic and thoracic plans were 0.2224, 0.3615 and 0.1874. Average volumetric 3D global gamma analysis (3 mm/3%) results for the head and neck, pelvic and thoracic VMAT plans were 95.45%, 97.51% and 96.98%, respectively. Out of 90 correlation analyses between the MCS and gamma passing rate, only 3 had the r value greater than 0.5.

Conclusions

The Octavius 4D system is a suitable device for patient specific pretreatment QA. Global and local gamma analysis results showed a weak correlation with the MCS.     

Mortality and incidence of new primary cancers in men with prostate cancer: A Danish population-based cohort study

Background: Prostate cancer (PC) survivors may have an increased risk of new primary cancers (NPCs) due to shared risk factors or PC-directed treatments. Methods: Using Danish registries, we conducted a cohort study of men with (n = 30,220) and without PC (n = 151,100) (comparators), matched 1:5 on age and PC diagnosis/index date. We computed incidence rates of NPCs per 10,000 person years (PY) and associated 95% confidence intervals (CI), and used Cox proportional hazards regression to compute hazard ratios (HRs) and 95%CI, adjusting for comorbidities. In order to obviate any impact of shorter survival among prostate cancer patients, we censored comparator patients when the matched prostate cancer patient died or was censored. Results: Follow-up spanned 113,487 PY and 462,982 PY in the PC and comparison cohorts, respectively. 65% of the cohorts were aged >70 years at diagnosis. Among PC patients, 51% had distant/unspecified stage, and 63% had surgery as primary treatment. The PC cohort had lower incidence of NPCs than their comparators. The adjusted HR of NPC among men with PC versus the comparators was 0.84 (95%CI = 0.80, 0.88). Lowest HRs were among older men, those with distant stage, and were particularly evident for cancers of the brain, liver, pancreas, respiratory, upper gastrointestinal, and urinary systems. Conclusions: We find no evidence of an increased risk of NPCs among men with PC. The deficit of NPCs among men with PC may be a true effect but is more likely due to lower levels of risk factors (e.g., smoking) in PC patients versus comparators, clinical consideration of cancers at new organs as metastases rather than new primaries, or under-recording/under-reporting of NPCs among PC patients.     

The effect of scatter correction and radius of rotation on semiquantitative measurements in SPECT 123I-FP-CIT imaging. A phantom study

PurposeThe high energy emissions of ¹²³I and the suboptimal radius of rotation affect the semiquantitative measurements performed during ¹²³I-FP-CIT tomographic imaging. An in-house extra low cost striatum phantom with brain and striatum compartments was constructed and was used to study the effects of Triple Energy Window scatter correction (TEW-SC) and radius of rotation on the Specific Binding Ratio (SBR) measurements.Materials and methodsThe phantom compartments were filled with radioactive ¹²³I solutions with varying concentrations, in a series of experiments. Tomographic images were acquired at six different radii of rotation, with and without TEW-SC and the SBRs were calculated using appropriate regions of interest, as in clinical imaging.ResultsSBRs decreased with increasing radius of rotation in both non-SC and TEW-SC images, the decrease being more pronounced in the latter. The application of TEW-SC increases SBR values by 40% on average. A maximum %Recovery of 42.7% of the true SBR value was achieved in the non-SC images, which increased to 64.6% after TEW-SC. Appropriate correction factors (CF) were calculated in order to make the SBR values independent on the radius of rotation, which could be used to correct SBR values obtained from tomographic acquisitions with suboptimal radius of rotation.ConclusionThe use of appropriate CF can provide more consistent SBR values and a more meaningful comparison between SBRs calculated from images acquired at different radii of rotation.     

Deep learning dose prediction for IMRT of esophageal cancer: The effect of data quality and quantity on model performance

PurposeTo investigate the effect of data quality and quantity on the performance of deep learning (DL) models, for dose prediction of intensity-modulated radiotherapy (IMRT) of esophageal cancer.Material and methodsTwo databases were used: a variable database (VarDB) with 56 clinical cases extracted retrospectively, including user-dependent variability in delineation and planning, different machines and beam configurations; and a homogenized database (HomDB), created to reduce this variability by re-contouring and re-planning all patients with a fixed class-solution protocol.Experiment 1 analysed the user-dependent variability, using 26 patients planned with the same machine and beam setup (E26-VarDB versus E26-HomDB). Experiment 2 increased the training set by groups of 10 patients (E16, E26, E36, E46, and E56) for both databases.Model evaluation metrics were the mean absolute error (MAE) for selected dose-volume metrics and the global MAE for all body voxels.ResultsFor Experiment 1, E26-HomDB reduced the MAE for the considered dose-volume metrics compared to E26-VarDB (e.g. reduction of 0.2 Gy for D95-PTV, 1.2 Gy for Dmean-heart or 3.3% for V5-lungs). For Experiment 2, increasing the database size slightly improved performance for HomDB models (e.g. decrease in global MAE of 0.13 Gy for E56-HomDB versus E26-HomDB), but increased the error for the VarDB models (e.g. increase in global MAE of 0.20 Gy for E56-VarDB versus E26-VarDB).ConclusionA small database may suffice to obtain good DL prediction performance, provided that homogenous training data is used. Data variability reduces the performance of DL models, which is further pronounced when increasing the training set.     

高密度中心城区蓝绿空间冷岛效应及其影响因素——以北京五环路以内地区为例

蓝绿空间作为城市绿色基础设施的重要组成部分,对促进城市热环境健康、改善局地微气候具有重要作用。利用Landsat 8遥感影像、土地利用等数据,基于辐射传输方程算法、K均值聚类算法、相关性分析等方法,量化了典型的高密度中心城区--北京五环快速路以内地区的1199块1hm²以上的蓝绿空间冷岛效应的表征指标,并分析与蓝绿空间规模、形状复杂度、景观组成、环境组成、植被覆盖等要素的相关关系,还根据蓝绿空间的不同降温特性进行分类,探讨每类蓝绿空间在缓解高密度中心城区热岛效应中的独特作用、优势与机制。结果表明：（1）蓝绿空间的规模、形状复杂度、景观组成等景观要素与冷岛效应的关系显著,如总面积、绿地面积和水体面积与降温幅度、降温范围、降温服务呈显著正相关,与降温效率和降温速率呈显著负相关;周长与降温范围、降温服务呈显著正相关,与降温效率和速率呈显著负相关;周长面积比与降温幅度和降温服务呈显著负相关,与降温效率和蓝绿空间自身温度呈显著正相关,而形状指数则与降温范围和降温服务呈显著正相关。（2）蓝绿空间的环境要素与冷岛效应也存在相关关系。蓝绿空间之间会产生冷岛效应的协同与促进现象,蓝绿空间降温范围内的其他蓝绿空间的总面积与该蓝绿空间的降温幅度、降温范围、降温服务和辐射距离呈显著正相关,与蓝绿空间自身温度呈显著负相关。（3）蓝绿空间的总面积、水体面积、周长与降温幅度之间,周长面积比与降温效率之间存在阈值,为节约土地资源、保证降温效果,建议不应过多超过阈值。（4）基于蓝绿空间在降温幅度、效率、辐射距离等方面的差异,将蓝绿空间划分为4类。高密度中心城区蓝绿空间规划建设应充分评估区域降温需求,了解蓝绿空间降温现状,合理配置具有不同降温特性和优势的蓝绿空间,在土地和资金有限的情况下,充分发挥各类蓝绿空间的冷岛效应。本研究有助于政府和规划师摸清当前蓝绿空间冷岛效应的现状、问题和发展潜力,对理论和实践具有一定参考意义。     

Chaperone-like effect of ceftriaxone on HEWL aggregation: A spectroscopic and computational study

Background

Lysozyme is a widely distributed enzyme present in a variety of tissue and body fluids. Human and hen egg white lysozyme are used as validated model to study protein folding and stability and to understand protein misfolding and aggregation. We recently found that ceftriaxone, a β-lactam antibiotic able to overcome the blood-brain barrier, successfully eliminated the cellular toxic effects of misfolded proteins as Glial Fibrillary Acidic Protein (GFAP) and α-synuclein. To further understand the anti-amyloidogenic properties of ceftriaxone, we studied its activity towards lysozyme aggregation with the aim to investigate a possible chaperone-like activity of this molecule.

面向生态修复的自然资源资产评估与应用研究——以广州市为例

生态修复是国土空间治理的重要内容。做好生态受损、功能退化地区的辨识并因地施策,是科学编制国土空间规划、实施生态修复重大工程的优先任务。基于自然资源资产评估方法,探索提出一种面向生态保护与修复规划的应用路径。在自然资源资产理念与方法评估辨析基础上,以广州为例,构建在地化的自然资源实物核算、生态系统服务功能价值评估框架,开展生态修复空间辨识,提出空间规划应对策略。主要研究结论：(1)2009年广州市自然资源资产总值约8334亿元,2019年为12025亿元;(2)自然资源资产价值总体呈上升趋势;剔除价格上涨因素后,调节与支持服务价值有所下降,生态保护与修复工作仍待强化;(3)提出自然资源资产评估在国土空间规划生态重要性地区识别、生态空间主导功能分区、生态治理重点研判等规划应用。最后,就如何提高自然资源资产评估的合理性与准确性,自然资源资产评估方法在不同层次国土空间生态修复规划中的适应性,如何基于自然资产评估推动生态修复规划实施等方面进行了讨论。     

基于生态系统服务功能和生态敏感性的生态空间划定研究——以南宁市为例

生态空间管制是我国国土空间管制的重要内容。针对目前国内对生态空间认知有差异,对其划定技术方法还处于探索阶段的情况下,以生态系统服务功能和生态敏感性技术评价方法为手段,以广西壮族自治区南宁市为研究对象,开展了基于生态系统服务功能重要性和生态敏感性的生态空间划定方法的探索研究。结果表明:(1)研究区域内主导的生态系统服务功能主要为生物多样性维护功能和水土保持功能,其次为水源涵养功能。生态系统综合服务功能重要性类型以一般重要为主,约占研究区总面积的42.32%。(2)研究区生态敏感性以水土流失敏感性为主,其次为石漠化敏感类型。生态环境综合敏感类型以敏感为主,约占总面积的85.44%。(3)研究区内初步划定生态空间总面积约9325.27 km~2,占研究区总面积的42.19%,占研究区内生态用地面积的76.59%。土地利用类型以林地为主,约占生态空间面积的83.65%。划定的生态空间范围涵盖了绝大部分生态用地。本研究在一定程度上丰富了生态空间的内涵,可为进一步理解和划定生态空间提供参考与借鉴。     

The effect of uphill and downhill walking on gait parameters: A self-paced treadmill study

It has been shown that gait parameters vary systematically with the slope of the surface when walking uphill (UH) or downhill (DH) (Andriacchi et al., 1977; Crowe et al., 1996; Kawamura et al., 1991; Kirtley et al., 1985; McIntosh et al., 2006; Sun et al., 1996). However, gait trials performed on inclined surfaces have been subject to certain technical limitations including using fixed speed treadmills (TMs) or, alternatively, sampling only a few gait cycles on inclined ramps. Further, prior work has not analyzed upper body kinematics. This study aims to investigate effects of slope on gait parameters using a self-paced TM (SPTM) which facilitates more natural walking, including measuring upper body kinematics and gait coordination parameters.Gait of 11 young healthy participants was sampled during walking in steady state speed. Measurements were made at slopes of +10°, 0° and −10°. Force plates and a motion capture system were used to reconstruct twenty spatiotemporal gait parameters. For validation, previously described parameters were compared with the literature, and novel parameters measuring upper body kinematics and bilateral gait coordination were also analyzed.Results showed that most lower and upper body gait parameters were affected by walking slope angle. Specifically, UH walking had a higher impact on gait kinematics than DH walking. However, gait coordination parameters were not affected by walking slope, suggesting that gait asymmetry, left-right coordination and gait variability are robust characteristics of walking. The findings of the study are discussed in reference to a potential combined effect of slope and gait speed. Follow-up studies are needed to explore the relative effects of each of these factors.     

Integrating GIS and expert judgment in a multi-criteria analysis to map and develop a habitat suitability index: A case study of large mammals on the Malayan Peninsula

Many habitat patches in tropical landscapes have become less suitable for wildlife due to an increase in anthropogenic disturbances. An index of habitat suitability based on the ecological factors that collectively determine the suitability of an organism's habitat is important for conservation planning. However, a widely accepted and comprehensive multi-criteria habitat suitability index for umbrella species is still lacking, particularly in areas where information related to the biology and ecology of the species of interest is not available. Therefore we develop preliminary habitat maps and measure the degree of habitat suitability for large mammals, focusing on four umbrella species in the State of Selangor, Peninsular Malaysia: Panthera tigris jacksoni (Malayan tiger), Tapirus indicus (Malayan tapir), Helarctos malayanus malayanus (Malayan sun bear), and Rusa unicolor cambojensis (sambar deer). The former two are endangered and the latter two are vulnerable according to the IUCN Red List. The suitability of habitat patches for each species was measured across the entire study area as well as in nine wildlife protected areas by integrating GIS data and expert opinion. Expert opinions were used as the source of information regarding the stresses faced by the species because there was insufficient information available from ground surveys.We developed an index and maps of habitat suitability for each species, which were then integrated to represent a combined index (ranging from 0 to 27) and spatially explicit maps of the area's habitat suitability for large mammals. The average large mammal habitat suitability index value of the State of Selangor (9) indicates that many habitat patches have become unsuitable for such species. Of the nine wildlife protected areas, Fraser's Hill (22), Sungai Dusun (22), and Bukit Kutu (21) are very suitable; Klang Gate (20) and Templers Park (17) are suitable; and the remaining four are unsuitable for large mammals. We assume that this preliminary habitat suitability index and mapping are useful for conservation planning of wildlife habitats at both landscape and regional scales, as well as providing an initial foundation for revision by future research with significant new information.     

Impact of seminal and serum zinc on semen quality and hormonal status: A population-based cohort study of Russian young men

BackgroundTrace elements are important factors in human reproductive health. Among them, special attention is paid to zinc, which is an essential trace element and is necessary for the normal functioning of the male reproductive system and the process of spermatogenesis. The aim of the study was to investigate the association between seminal and serum zinc concentrations and semen quality and reproductive hormone levels in population of Russian young men.MethodsThe study population consisted of 626 young Russian men (median age 22.5 years), recruited from the general population, regardless of their fertility status. Each participant provided semen and blood sample, information about his lifestyle and ethnicity. Semen quality (sperm concentration, motility and morphology), reproductive hormone levels (testosterone, estradiol, LH, FSH and inhibin B), and serum and seminal zinc concentrations were evaluated. The semen samples were analyzed according to the WHO laboratory manual (WHO, 2010). Serum hormones were measured by enzyme immunoassay, zinc concentrations were determined using spectrophotometry and direct colorimetry without deproteinization.ResultsZinc was present in the seminal plasma in a significantly higher concentration than in the blood serum (median serum Zn concentration was 23.6 μmol/L vs seminal Zn concentration 1571.8 μmol/L). The seminal zinc concentration was positively related to the total sperm count, sperm concentration, progressive motility and normal morphology (Spearman’s test: 0.221; 0.286; 0.269; 0.183, respectively, p < 0.001), while the serum Zn concentration was negatively related to serum testosterone and estradiol levels (r = −0.249 and r = −0.096, respectively, p < 0.001−0.05). It was found that the seminal Zn content in men with normal semen quality was higher compared to men with lowered semen quality (means: 6.37 and 5.03 μmol/ejaculate, respectively, p < 0.001). Similarly, the semen volume, total sperm count, sperm concentration, progressive motility, normal morphology and the serum testosterone level in men with the seminal Zn deficiency were lower than in men with the normal seminal Zn content.ConclusionBased on the results of our population-based study, seminal Zn levels were closely associated with semen parameters in young men, so Zn deficiency may be an important risk factor for lowered semen quality. Seminal Zn determinations should be considered as a useful tool in addition to other parameters in assessing male fertility.     

Helpful grandmothers in rural Ethiopia: A study of the effect of kin on child survival and growth

Kin selection and parental investment theories state that, in highly social species, such as humans, individuals can increase their inclusive fitness by extending support to their relatives. Here, we document patterns of kin support in a rural Ethiopian community, where postmarital residence practices provide differential access to relatives. Using demographic, anthropometric, and behavioral data collected from four villages we are able to (a) identify the effects of the presence of kin on child mortality and growth patterns and (b) provide detailed information on the role of relatives within the household.

Mortality analyses indicate that grandmothers had a positive effect on child survival. Anthropometric data reveal that maternal grandmothers had a particularly beneficial effect on child height, but paternal grandmothers less so. Time allocation data suggest that grandmothers continued to visit their daughters' households, irrespective of postmarital residence, where they relieved their daughters of heavy domestic tasks rather than helping with direct grandchild care. Matrilocal postmarital residence was associated with improved child survival, although children in matrilocal households were actually smaller. This may be due to wealth effects, increased competition between siblings, or higher survival of smaller infants in matrilocal households.     

Probabilities of dying from cancer and other causes in French cancer patients based on an unbiased estimator of net survival: A study of five common cancers

BackgroundNet survival is the survival that would be observed if cancer were the only possible cause of death. Although it is an important epidemiological tool allowing temporal or geographical comparisons, it cannot inform on the “crude” probability of death of cancer patients; i.e., when taking into account other possible causes of deaths.MethodsIn this work, we provide estimates of the crude probabilities of death from cancer and from other causes as well as the probability of being alive up to ten years after cancer diagnosis according to the age and year of diagnosis. Based on a flexible excess hazard model providing unbiased estimates of net survival, our methodology avoids the pitfalls associated with the use of the cause of death. We used data from FRANCIM, the French network of cancer registries, and studied five common cancer sites: head and neck, breast, prostate, lung, and colorectal cancers.ResultsFor breast, prostate, and colorectal cancers, the impact of the other causes on the total probability of death increased with the age at diagnosis whereas it remained negligible for lung and head and neck cancers whatever the age. For breast, prostate, and colorectal cancer, the more recently was the cancer diagnosed, the less was the probability of death from cancer.ConclusionThe crude probability of death is an intuitive concept that may prove particularly useful in choosing an appropriate treatment, or refining the indication of a screening strategy by allowing the clinician to estimate the proportion of cancer patients who will die specifically from cancer.     

In vitro effect of fungal cyclodepsipeptides on leukemic cells: study of destruxins A, B and E.

The activities of three mycotoxins isolated from the hyphomycete Metarhizium anisopliae: destruxin A, B, and E (DA, DB and DE) are described and compared in vitro on leukemic cells. Their antitumor effect was investigated by flow cytometry on growth, cell viability and cell cycle perturbation 48 h after destruxin exposure. Against P388 leukemic cells, DE displayed greater antiproliferative activity than DA and DB. The minimum concentration required to inhibit 50% of cell proliferation is 0.33 microgram/ml for DE, 11.7 micrograms/ml for DA and 9.4 micrograms/ml for DB. Cell cycle modifications were only observed with DE at 50 and 10 micrograms/ml and consisted in an accumulation of the cells in G0/1 phase. DA and DB did not modify the number of cells in G0/1 of the cell cycle. Nevertheless a decrease in the number of cells in G2+M phase was induced by the three destruxins.