Registry-derived stage (RD-Stage) for capturing cancer stage at diagnosis for endometrial cancer

BACKGROUND

Capture of cancer stage at diagnosis is important yet poorly reported by health services to population-based cancer registries. In this paper we describe current completeness of stage information for endometrial cancer available in Australian cancer registries; and develop and validate a set of rules to enable cancer registry medical coders to calculate stage using data available to them (registry-derived stage or 'RD-Stage').

METHODOLOGY

Rules for deriving RD-stage (Endometrial carcinoma) were developed using the American Joint Commission on Cancer (AJCC) TNM (tumour, nodes, metastasis) Staging System (8th Edition). An expert working group comprising cancer specialists responsible for delivering cancer care, epidemiologists and medical coders reviewed and endorsed the rules. Baseline completeness of data fields required to calculate RD-Stage, and calculation of the proportion of cases for whom an RD stage could be assigned, was assessed across each Australian jurisdiction. RD-Stage (Endometrial cancer) was calculated by Victorian Cancer Registry (VCR) medical coders and compared with clinical stage recorded by the patient's treating clinician and captured in the National Gynae-Oncology Registry (NGOR).

RESULTS

The necessary data completeness level for calculating RD-Stage (Endometrial carcinoma) across various Australian jurisdictions varied from 0 to 89%. Three jurisdictions captured degree of spread of cancer, rendering RD-Stage unable to be calculated. RD-Stage (Endometrial carcinoma) could not be derived for 64/485 (13%) cases and was not captured for 44/485 (9%) cases in NGOR. At stage category level (I, II, III, IV), there was concordance between RD-Stage and NGOR captured stage in 393/410 (96%) of cases (95.8%, Kendall's coefficient = 0.95).

CONCLUSION

A lack of consistency in data captured by, and data sources reporting to, population-based cancer registries meant that it was not possible to provide national endometrial carcinoma stage data at diagnosis. In a sample of Victorian cases, where surgical pathology was available, there was very good concordance between RD-Stage (Endometrial carcinoma) and clinician-recorded stage data available from NGOR. RD-Stage offers promise in capturing endometrial cancer stage at diagnosis for population epidemiological purposes when it is not provided by health services, but requires more extensive validation.

Impulsivity and Treatment Outcomes in Individuals with Cocaine Use Disorder: Examining the Gap between Interest and Adherence

Background: Impulsivity is implicated in the development and maintenance of Cocaine Use Disorder (CUD). Less work has examined impulsivity's role on interest in initiating treatment, treatment adherence, or treatment response. No pharmacotherapies are approved for CUD, so efforts to understand and bolster the effects of psychotherapy are important in guiding and refining treatment. The present study examined the impact of impulsivity on interest in treatment, treatment initiation, treatment adherence, and treatment outcomes in individuals with CUD. Methods: Following the completion of a larger study on impulsivity and CUD participants were offered 14 sessions of (12 weeks) Cognitive Behavioral Relapse Prevention (CBT-RP). Before starting treatment, participants completed seven self-report and four behavioral measures of impulsivity. Sixty-eight healthy adults (36% female) with CUD (aged 49.4 ± 7.9) expressed an interest in treatment. Results: Greater scores on several self-report measures of impulsivity, and fewer difficulties with delayed gratification were associated with increased interest in treatment in both males and females. 55 participants attended at least 1 treatment session, while 13 participants did attend a single session. Individuals who attended at least one treatment session scored lower on measures of lack of perseverance and procrastination. Still, measures of impulsivity did not reliably predict session attendance nor the frequency of cocaine-positive urine samples throughout treatment. Males attended nearly twice as many treatment sessions as females despite nonsignificant associations between impulsivity in males and the number of sessions attended. Conclusions: Greater impulsivity in individuals with CUD was associated with expressing an interest in treatment, but not treatment adherence or response.

Global survival trends for brain tumors, by histology: analysis of individual records for 556,237 adults diagnosed in 59 countries during 2000-2014 (CONCORD-3)

BACKGROUND

Survival is a key metric of the effectiveness of a health system in managing cancer. We set out to provide a comprehensive examination of worldwide variation and trends in survival from brain tumors in adults, by histology.

METHODS

We analyzed individual data for adults (15-99 years) diagnosed with a brain tumor (ICD-O-3 topography code C71) during 2000-2014, regardless of tumor behavior. Data underwent a 3-phase quality control as part of CONCORD-3. We estimated net survival for 11 histology groups, using the unbiased nonparametric Pohar Perme estimator.

RESULTS

The study included 556,237 adults. In 2010-2014, the global range in age-standardized 5-year net survival for the most common sub-types was broad: in the range 20%-38% for diffuse and anaplastic astrocytoma, from 4% to 17% for glioblastoma, and between 32% and 69% for oligodendroglioma. For patients with glioblastoma, the largest gains in survival occurred between 2000-2004 and 2005-2009. These improvements were more noticeable among adults diagnosed aged 40-70 years than among younger adults.

CONCLUSIONS

To the best of our knowledge, this study provides the largest account to date of global trends in population-based survival for brain tumors by histology in adults. We have highlighted remarkable gains in 5-year survival from glioblastoma since 2005, providing large-scale empirical evidence on the uptake of chemoradiation at population level. Worldwide, survival improvements have been extensive, but some countries still lag behind. Our findings may help clinicians involved in national and international tumor pathway boards to promote initiatives aimed at more extensive implementation of clinical guidelines.

Gabapentin increases the abuse liability of alcohol alone and in combination with oxycodone in participants with co-occurring opioid and alcohol use disorder

BACKGROUND

People who have co-occurring Alcohol Use Disorder (AUD) and Opioid Use Disorder (OUD) carry a higher risk of adverse outcomes, including drug overdose. Early clinical and preclinical studies suggested that gabapentin may be effective in treating both disorders. The present study was designed to assess the effects of gabapentin on the subjective and physiological effects of oxycodone (OXY) and alcohol (ALC), alone and in combination.

METHODS

During an 8-week, inpatient, within-subject, randomized, double-blind, placebo-controlled crossover study, non-treatment seeking participants (N = 13; 12 M/1F; 44.1 ± 3 years of age) with OUD and AUD were maintained on oral morphine (120 mg daily). Under gabapentin (1800 mg/day) and placebo (0 mg/day) maintenance, participants completed nine separate test sessions (three sessions per week) during which they received an oral solution containing 0, 15, or 30 mg/70 kg OXY in combination with 0, 0.5, or 0.75 g/kg ALC. During test sessions, subjective effects and physiological responses were assessed repeatedly on 100-mm visual analog scales (VAS). The primary outcome variable was the VAS rating of drug liking after receiving the drug challenge.

RESULTS

Alcohol alone (but not oxycodone alone) produced dose-related increases in several positive subjective responses, including drug liking. Gabapentin significantly increased drug liking when given in combination with ALC and OXY + ALC (p < 0.05). Gabapentin did not clinically compromise respiration or other vital functions.

CONCLUSIONS

Gabapentin may increase the abuse liability of ALC and OXY + ALC in those with co-occurring OUD and AUD.

(Dis)concordance of comorbidity data and cancer status across administrative datasets, medical charts, and self-reports

Background

Benchmarking outcomes across settings commonly requires risk-adjustment for co-morbidities that must be derived from extant sources that were designed for other purposes. A question arises as to the extent to which differing available sources for health data will be concordant when inferring the type and severity of co-morbidities, how close are these to the “truth”. We studied the level of concordance for same-patient comorbidity data extracted from administrative data (coded from International Classification of Diseases, Australian modification,10th edition [ICD-10 AM]), from the medical chart audit, and data self-reported by men with prostate cancer who had undergone a radical prostatectomy.

Methods

We included six hospitals (5 public and 1 private) contributing to the Prostate Cancer Outcomes Registry-Victoria (PCOR-Vic) in the study. Eligible patients from the PCOR-Vic underwent a radical prostatectomy between January 2017 and April 2018.Health Information Manager’s in each hospital, provided each patient’s associated administrative ICD-10 AM comorbidity codes. Medical charts were reviewed to extract comorbidity data. The self-reported comorbidity questionnaire (SCQ) was distributed through PCOR-Vic to eligible men.

Results

The percentage agreement between the administrative data, medical charts and self-reports ranged from 92 to 99% in the 122 patients from the 217 eligible participants who responded to the questionnaire. The presence of comorbidities showed a poor level of agreement between data sources.

Conclusion

Relying on a single data source to generate comorbidity indices for risk-modelling purposes may fail to capture the reality of a patient’s disease profile. There does not appear to be a ‘gold-standard’ data source for the collection of data on comorbidities.

"Prostate cancer is far more hidden…": Perceptions of stigma, social isolation and help-seeking among men with prostate cancer

The purpose of this study was to provide in-depth insight into men's experiences of prostate cancer, specifically: perceived stigma and self-blame, social isolation, unmet need and help-seeking. A qualitative descriptive approach was used. Semi-structured interviews were undertaken with 20 men diagnosed with prostate cancer, and thematic analysis was undertaken. Some participants perceived a stigma associated with prostate cancer and cancer in general, which sometimes acted as a barrier to disclosure. Self-blame and internalisation of cause was not a prominent issue. Participants' descriptions of emotional distress, social isolation and anxiety demonstrated the impact of prostate cancer. Social isolation was most commonly reported as a physical consequence of treatment and/or side effects. Participants felt both support and ongoing care were limited at post-treatment. Most did not seek or receive help for emotional or psychosocial problems from a formal source due to anticipated awkwardness, autonomous coping, not burdening others, unwanted sympathy and retaining privacy. Prostate cancer can cause considerable emotional and social burden for some men, and many are unlikely to seek or receive help. Men, and their support networks, require active encouragement throughout diagnosis, treatment and follow-up to overcome barriers and access additional support, particularly for sexual, emotional and psychosocial issues.

Oncological outcomes in an Australian cohort according to the new prostate cancer grading groupings

Background

A new 5-tiered grading grouping system has recently been endorsed for reporting of prostate cancer (PCa) grade to better reflect escalating risk of progression and cancer death. While several validations of the new grade groupings have been undertaken, most have involved centralised pathological review by specialist urological pathologists.

Methods

Participants included 4268 men with non-metastatic PCa diagnosed between 2006 and 2013 from the multi-institutional South Australia Prostate Cancer Clinical Outcomes Collaborative registry. PCa-specific survival and biochemical recurrence-free survival were compared across the five grade groups using multivariable competing risk regression.

Results

For the entire cohort, risk of PCa death increased with increasing grade groups (at biopsy) Adjusted subdistribution-hazard ratios [sHR] and 95% confidence intervals [95%CI] were: 2.2 (1.5–3.6); 2.5 (1.6–4.2); 4.1 (2.6–6.7) and 8.7 (4.5–14.0) for grade groups II (pattern 3 + 4), III (pattern 4 + 3), IV (total score 8) and V (total score 9–10) respectively, relative to grade group I (total score < =6). Clear gradients in risk of PCa death were observed for radical prostatectomy (RP), but were less clear for those who had radiotherapy (RT) with curative intent and those who were managed conservatively. Likewise, risk of biochemical recurrence increased across grade groups, with a strong and clear gradient for men undergoing RP [sHR (95%CI): 2.0 (1.4–2.8); 3.8 (2.9–5.9); 5.3 (3.5–8.0); 11.2 (6.5–19.2) for grade groups II, III, IV and V respectively, relative to grade group I], and a less clear gradient for men undergoing RT.

Conclusion

In general, the new five-tiered grade groupings distinguished PCa survival and recurrence outcomes for men with PCa. The absence of a clear gradient for RT may be due to heterogeneity in this patient group.

Initial evidence that blood-borne microvesicles are biomarkers for recurrence and survival in newly diagnosed glioblastoma patients

The purpose of this pilot study was to determine whether blood-borne microvesicles from newly diagnosed glioblastoma patients could be used as biomarkers. We collected 2.8 mL blood from 16 post-operative patients at the time that they were being simulated for chemoradiation therapy (radiation with concurrent temozolomide). Two additional samples were collected during chemoradiation therapy and a final sample was collected at the end of chemoradiation therapy. Patients continued with the therapy suggested by their physicians, based on tumor conference consensus and were followed for recurrence and overall survival. Microvesicles were isolated using serial centrifugation and stained for surface markers (Annexin V for phosphotidyl serine, CD41 for platelets, anti-EGFR for tumor cells, and CD235 for red blood cells). Flow cytometry analysis was performed. Our findings provide initial evidence that increases in Annexin V positive microvesicle levels during chemoradiation therapy are associated with earlier recurrence and shorter overall survival in newly diagnosed glioblastoma patients. The effect is dramatic, with over a four-fold increase in the hazard ratio for an individual at the 75th versus the 25th percentile. Moreover the pattern of Annexin V positive microvesicles remain significant after adjustment for confounding clinical variables that have previously been shown to be prognostic for recurrence and survival. Inclusion of neutrophil levels at the start of chemoradiation therapy in the model yielded the largest attenuation of the observed association. Further studies will be needed to verify and further investigate the association between these two entities.

Optimizing hypoxia detection and treatment strategies

Clinical studies using Eppendorf needle sensors have invariably documented the resistance of hypoxic human tumors to therapy. These studies first documented the need for individual patient measurement of hypoxia, as hypoxia varied from tumor to tumor. Furthermore, hypoxia in sarcomas and cervical cancer leads to distant metastasis or local or regional spread, respectively. For various reasons, the field has moved away from direct needle sensor oxygen measurements to indirect assays (hypoxia-inducible factor-related changes and bioreductive metabolism) and the latter can be imaged noninvasively. Many of hypoxia's detrimental therapeutic effects are reversible in mice but little treatment improvement in hypoxic human tumors has been seen. The question is why? What factors cause human tumors to be refractory to antihypoxia strategies? We suggest the primary cause to be the complexity of hypoxia formation and its characteristics. Three basic types of hypoxia exist, encompassing various diffusional (distance from perfused vessel), temporal (on or off cycling), and perfusional (blood flow efficiency) limitations. Surprisingly, there is no current information on their relative prevalence in human tumors and even animal models. This is important because different hypoxia subtypes are predicted to require different diagnostic and therapeutic approaches, but the implications of this remain unknown. Even more challenging, no agreement exists for the best way to measure hypoxia. Some results even suggest that hypoxia is unlikely to be targetable therapeutically. In this review, the authors revisit various critical aspects of this field that are sometimes forgotten or misrepresented in the recent literature. As most current noninvasive imaging studies involve PET-isotope-labeled 2-nitroimidazoles, we emphasize key findings made in our studies using 2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)acetamide (EF5) and F-18-labeled EF5. These show the importance of differentiating hypoxia subtypes, optimizing drug pharmacology, ensuring drug and isotope stability, identifying key biochemical and physiological variables in tumors, and suggesting therapeutic strategies that are most likely to succeed.

Need for a roadmap for development of a coordinated national registry programme

Clinical quality registries are an overlooked and under-funded arm of clinical research in Australia. Registries are databases for patients with a particular disease, or who undergo a procedure, or use a health resource. Registries, where properly funded and universally adopted, have provided substantial benefits to the quality of healthcare and, in some cases, have had demonstrable effect in reducing costs. There is a lack of a coordinated programme for both funding and development of registries in Australia. A coordinated effort is required to address key gaps in registry coverage and ensure registries comply with appropriate technical and operating principles, and target areas where registries can add value to the health system. This will ensure that Australia is competitive with its international peers in this dynamic environment.

Improved Methods to Generate Spheroid Cultures from Tumor Cells, Tumor Cells & Fibroblasts or Tumor-Fragments: Microenvironment, Microvesicles and MiRNA

Diagnostic and prognostic indicators are key components to achieve the goal of personalized cancer therapy. Two distinct approaches to this goal include predicting response by genetic analysis and direct testing of possible therapies using cultures derived from biopsy specimens. Optimally, the latter method requires a rapid assessment, but growing xenograft tumors or developing patient-derived cell lines can involve a great deal of time and expense. Furthermore, tumor cells have much different responses when grown in 2D versus 3D tissue environments. Using a modification of existing methods, we show that it is possible to make tumor-fragment (TF) spheroids in only 2–3 days. TF spheroids appear to closely model characteristics of the original tumor and may be used to assess critical therapy-modulating features of the microenvironment such as hypoxia. A similar method allows the reproducible development of spheroids from mixed tumor cells and fibroblasts (mixed-cell spheroids). Prior literature reports have shown highly variable development and properties of mixed-cell spheroids and this has hampered the detailed study of how individual tumor-cell components interact. In this study, we illustrate this approach and describe similarities and differences using two tumor models (U87 glioma and SQ20B squamous-cell carcinoma) with supporting data from additional cell lines. We show that U87 and SQ20B spheroids predict a key microenvironmental factor in tumors (hypoxia) and that SQ20B cells and spheroids generate similar numbers of microvesicles. We also present pilot data for miRNA expression under conditions of cells, tumors, and TF spheroids.

Mechanisms of blood flow and hypoxia production in rat 9L-epigastric tumors

Classical descriptions of tumor physiology suggest two origins for tumor hypoxia; steady-state (diffusion-limited) hypoxia and cycling (perfusion-modulated) hypoxia. Both origins, primarily studied and characterized in murine models, predict relatively small, isolated foci or thin shells of hypoxic tissue interspersed with contrasting oxic tissue. These foci or shells would not be expected to scale with overall tumor size since the oxygen diffusion distance (determined by oxygen permeability and tissue oxygen consumption rate) is not known to vary dramatically from tumor to tumor. We have identified much larger (macroscopic) regions of hypoxia in rat gliosarcoma tumors and in larger human tumors (notably sarcomas and high-grade glial tumors), as indicated by biochemical binding of the hypoxia marker, EF5. Thus, we considered an alternative cause of tumor hypoxia related to a phenomenon first observed in window-chamber tumor models: namely longitudinal arteriole gradients. Although longitudinal arteriole gradients, as originally described, are also microscopic in nature, it is possible for them to scale with tumor size if tumor blood flow is organized in an appropriate manner. In this organization, inflowing blood would arise from relatively well-oxygenated sources and would branch and then coalesce to poorly-oxygenated outflowing blood over distances much larger than the length of conventional arterioles (multi-millimeter scale). This novel concept differs from the common characterization of tumor blood flow as disorganized and/or chaotic. The organization of blood flow to produce extended longitudinal gradients and macroscopic regional hypoxia has many important implications for the imaging, therapy and biological properties of tumors. Herein, we report the first experimental evidence for such blood flow, using rat 9L gliosarcoma tumors grown on the epigastric artery/vein pair.

Measurements of hypoxia ([(18)F]-FMISO, [(18)F]-EF5) with positron emission tomography (PET) and perfusion using PET ([(15)O]-H(2)O) and power Doppler ultrasonography in feline fibrosarcomas*

Abstract The aim of this study was to evaluate if hypoxia in feline fibrosarcomas can be detected. This was done using positron emission tomography (PET), two hypoxia tracers and polarographic pO(2) measurements. Of the seven cats included, five received [(18)F]-fluoromisonidazole and two 2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl) acetamide. Perfusion was evaluated with [(15)O]-H(2)O (n = 4) and with contrast-enhanced power Doppler ultrasonography (n = 5). Hypoxia was detected in three cats. Polarographic pO(2) measurements did not confirm PET results. In the ultrasonographic evaluation, low vascularity and low perfusion were seen with a peripheral vascular pattern and no perfusion in the centre of the tumour. This was in contrast to the [(15)O]-H(2)O scans, where central perfusion of the tumour was also found. In conclusion, it appears that hypoxia exists in this tumour type. The presence of tumour necrosis and heterogeneous hypoxia patterns in these tumours may explain the found discrepancies between the applied techniques.

Radiation dosimetry and biodistribution of the hypoxia tracer (18)F-EF5 in oncologic patients

The primary goals of this study were to determine the biodistribution and excretion of (18)F-EF5 in oncologic patients, to estimate the radiation-absorbed dose and to determine the safety of this drug.

METHODS

Sixteen patients with histologically confirmed malignancy received a mean intravenous infusion of 217  MBq (range 107-364  MBq) of (18)F-EF5. Over a 4-6-hour period, four to five serial positron emission tomography (PET) or PET/computed tomography (CT) scans were obtained. To calculate the radiation dosimetry estimates, volumes of interest were drawn over the source organs for each PET scan or on the CT for each PET/CT scan. Serial blood samples were obtained to measure (18)F-EF5 blood clearance. Bladder-wall dose was calculated based on urine activity measurements.

RESULTS

The urinary bladder received the largest radiation-absorbed dose, 0.12 ± 0.034 mSv/MBq (mean ± SD). The average effective dose equivalent and the effective dose of (18)F-EF5 were 0.021 ± 0.003 mSv/MBq and 0.018 ± 0.002 mSv/MBq, respectively. (18)F-EF5 was well tolerated in all subjects.

CONCLUSIONS

(18)F-EF5 was demonstrated to be safe for patients, and the radiation exposure is clinically acceptable. As with any radiotracer with primary excretion in the urine, the bladder-wall dose can be minimized by active hydration and frequent voiding.

Abstract 5004: In vivo profiling of hypoxic mRNA and miRNA expression in gliomas and head and neck tumors

Hypoxia plays a key role in tumor aggressiveness and radiation resistance, yet little is known regarding hypoxic global gene regulation in vivo. Although the regulation of mRNA and miRNA expression by hypoxia has been investigated in isolation in vitro, it has not yet been analyzed directly in tumor samples.

We have used the hypoxia marker EF5 coupled with laser capture microdissection (LCM) to isolate RNA from viable hypoxic and normoxic regions of 9L experimental rat gliomas and from human head and neck (H&N) tumor samples. This was followed by microarray analysis of mRNA expression and comparison of this signature with that obtained from treating 9L cells with hypoxia in vitro. Through this, we have identified several mRNAs (including the HIF targets Vegf, Glut-1 and Hsp27) with increased levels under hypoxia compared to normoxia both in vitro and in vivo. We also found striking differences between the global in vitro and in vivo hypoxic mRNA profiles. An intriguing finding was the hypoxic-downregulation of a number of immunomodulatory and DNA repair proteins including CXCL9, CD3D and RAD51 in vivo, consistent with a pro-tumorigenic role of hypoxia in solid tumors. Immunohistochemical staining verified increased HSP27 and decreased RAD51 protein levels in hypoxic vs. normoxic tumor regions. Moreover, CD8+ T cells which are recruited to tumors upon stimulation by CXCL9 and CXCL10, were largely excluded from viable hypoxic areas in vivo.

Global microRNA expression changes have been reported to occur in response to hypoxia in vitro. Hence, our second objective was to identify the cluster of miRNAs differentially expressed in hypoxic vs. normoxic regions of the human tumors using TaqMan® Array MicroRNA Cards. We employed the same technique used with the 9L tumors to analyze miRNA expression patterns in hypoxic vs. normoxic samples from H&N cancer patients who have been administered EF5 prior to surgical removal of the tumor. Consistent with published in vitro studies, miR-210 emerged as a major miRNA robustly induced in the hypoxic regions. We also confirmed miR-210 induction by an individual real time-PCR assay and found it to be upregulated &gt; 2-fold in all hypoxic RNA samples. In addition, we have also found several miRNAs whose levels were upregulated and downregulated in hypoxic vs. normoxic areas. This is the first study to analyze the influence of hypoxia on mRNA and miRNA levels in vivo and can be readily adapted to obtain a comprehensive picture of hypoxic regulation of gene expression and its influence on biological functions in solid tumors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5004. doi:10.1158/1538-7445.AM2011-5004

In vivo profiling of hypoxic gene expression in gliomas using the hypoxia marker EF5 and laser-capture microdissection

Hypoxia is a key determinant of tumor aggressiveness, yet little is known regarding hypoxic global gene regulation in vivo. We used the hypoxia marker EF5 coupled with laser-capture microdissection to isolate RNA from viable hypoxic and normoxic regions of 9L experimental gliomas. Through microarray analysis, we identified several mRNAs (including the HIF targets Vegf, Glut-1, and Hsp27) with increased levels under hypoxia compared with normoxia both in vitro and in vivo. However, we also found striking differences between the global in vitro and in vivo hypoxic mRNA profiles. Intriguingly, the mRNA levels of a substantial number of immunomodulatory and DNA repair proteins including CXCL9, CD3D, and RAD51 were found to be downregulated in hypoxic areas in vivo, consistent with a protumorigenic role of hypoxia in solid tumors. Immunohistochemical staining verified increased HSP27 and decreased RAD51 protein levels in hypoxic versus normoxic tumor regions. Moreover, CD8(+) T cells, which are recruited to tumors upon stimulation by CXCL9 and CXCL10, were largely excluded from viable hypoxic areas in vivo. This is the first study to analyze the influence of hypoxia on mRNA levels in vivo and can be readily adapted to obtain a comprehensive picture of hypoxic regulation of gene expression and its influence on biological functions in solid tumors.

Biodistribution and dosimetry of (18)F-EF5 in cancer patients with preliminary comparison of (18)F-EF5 uptake versus EF5 binding in human glioblastoma

PURPOSE

The primary purpose of this study was to assess the biodistribution and radiation dose resulting from administration of (18)F-EF5, a lipophilic 2-nitroimidazole hypoxia marker in ten cancer patients. For three of these patients (with glioblastoma) unlabeled EF5 was additionally administered to allow the comparative assessment of (18)F-EF5 tumor uptake with EF5 binding, the latter measured in tumor biopsies by fluorescent anti-EF5 monoclonal antibodies.

METHODS

(18)F-EF5 was synthesized by electrophilic addition of (18)F(2) gas, made by deuteron bombardment of a neon/fluorine mixture in a high-pressure gas target, to an allyl precursor in trifluoroacetic acid at 0° then purified and administered by intravenous bolus. Three whole-body images were collected for each of ten patients using an Allegro (Philips) scanner. Gamma counts were determined in blood, drawn during each image, and urine, pooled as a single sample. PET images were analyzed to determine radiotracer uptake in several tissues and the resulting radiation dose calculated using OLINDA software and standard phantom. For three patients, 21 mg/kg unlabeled EF5 was administered after the PET scans, and tissue samples obtained the next day at surgery to determine EF5 binding using immunohistochemistry techniques (IHC).

RESULTS

EF5 distributes evenly throughout soft tissue within minutes of injection. Its concentration in blood over the typical time frame of the study (∼3.5 h) was nearly constant, consistent with a previously determined EF5 plasma half-life of ∼13 h. Elimination was primarily via urine and bile. Radiation exposure from labeled EF5 is similar to other (18)F-labeled imaging agents (e.g., FDG and FMISO). In a de novo glioblastoma multiforme patient, focal uptake of (18)F-EF5 was confirmed by IHC.

CONCLUSION

These results confirm predictions of biodistribution and safety based on EF5's characteristics (high biological stability, high lipophilicity). EF5 is a novel hypoxia marker with unique pharmacological characteristics allowing both noninvasive and invasive measurements.

The radiation response of cells from 9L gliosarcoma tumours is correlated with [F18]-EF5 uptake

PURPOSE

Tumour hypoxia affects cancer biology and therapy-resistance in both animals and humans. The purpose of this study was to determine whether EF5 ([2-(2-nitro-1-H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)-acetamide]) binding and/or radioactive drug uptake correlated with single-dose radiation response in 9L gliosarcoma tumours.

MATERIALS AND METHODS

Twenty-two 9L tumours were grown in male Fischer rats. Rats were administered low specific activity (18)F-EF5 and their tumours irradiated and assessed for cell survival and hypoxia. Hypoxia assays included EF5 binding measured by antibodies against bound-drug adducts and gamma counts of (18)F-EF5 tumour uptake compared with uptake by normal muscle and blood. These assays were compared with cellular radiation response (in vivo to in vitro assay). In six cases, uptake of tumour versus muscle was also assayed using images from a PET (positron emission tomography) camera (PENN G-PET).

RESULTS

The intertumoural variation in radiation response of 9L tumour-cells was significantly correlated with uptake of (18)F-labelled EF5 (i.e., including both bound and non-bound drug) using either tumour to muscle or tumour to blood gamma count ratios. In the tumours where imaging was performed, there was a significant correlation between the image analysis and gamma count analysis. Intertumoural variation in cellular radiation response of the same 22 tumours was also correlated with mean flow cytometry signal due to EF5 binding.

CONCLUSION

To our knowledge, this is the first animal model/drug combination demonstrating a correlation of radioresponse for tumour-cells from individual tumours with drug metabolism using either immunohistochemical or non-invasive techniques.

Measuring the quality of hospital care: an inventory of indicators

BACKGROUND

Development of indicators to measure health-care quality has progressed rapidly. This development has, however, rarely occurred in a systematic fashion, and some aspects of care have received more attention than others. The aim of this study is to identify and classify indicators currently in use to measure the quality of care provided by hospitals, and to identify gaps in current measurement.

METHODS

A literature search was undertaken to identify indicator sets. Indicators were included if they related to hospital care and were clearly being collected and reported to an external body. A two-person independent review was undertaken to classify indicators according to aspects of care provision (structure, process or outcome), dimensions of quality (safety, effectiveness, efficiency, timeliness, patient-centredness and equity), and domain of application (hospital-wide, surgical and non-surgical clinical specialities).

RESULTS

383 discrete indicators were identified from 22 source organizations or projects. Of these, 27.2% were relevant hospital-wide, 26.1% to surgical patients and 46.7% to non-surgical specialities, departments or diseases. Cardiothoracic surgery, cardiology and mental health were the specialities with greatest coverage, while nine clinical specialities had fewer than three specific indicators. Processes of care were measured by 54.0% of indicators and outcomes by 38.9%. Safety and effectiveness were the domains most frequently represented, with relatively few indicators measuring the other dimensions.

CONCLUSION

Despite the large number of available indicators, significant gaps in measurement still exist. Development of indicators to address these gaps should be a priority. Work is also required to evaluate whether existing indicators measure what they purport to measure.

Imaging and analytical methods as applied to the evaluation of vasculature and hypoxia in human brain tumors

Tissue hypoxia results from the interaction of cellular respiration, vascular oxygen carrying capacity, and vessel distribution. We studied the relationship between tumor vasculature and regions of low pO(2) using quantitative analysis of binding of the 2-nitroimidazole EF5 given to patients intravenously (21 mg/kg) approximately 24 h preceding surgery. We describe new computer algorithms for determining EF5 binding as a function of radial distance from individual blood vessels and converting this value to tissue pO(2). Tissues from six human brain tumors were assessed. In a hemangiopericytoma, a WHO Grade 2 and WHO Grade 3 glial brain tumor, all tissue pO(2) values calculated by EF5 binding were >20 mmHg (described as "physiologically oxygenated"). In these three tumors, EF5 binding gradients (measured as a function of distance from each observed vessel) were low, with small positive and negative values averaging close to zero. Much lower tissue oxygen levels were found, including near some vessels, in glioblastomas. Gradients of EF5 binding away from vessels were larger in glioblastomas than in the low-grade tumors, but positive and negative values again averaged to near zero. Based on these preliminary data, we hypothesize a new paradigm for tumor blood flow in human brain tumors whereby in-flowing and out-flowing blood patterns may have contrasting effects on average tissue EF5 (and by inference, oxygen) gradients. Our studies also imply that neither distance to the nearest blood vessel nor distance from each observed blood vessel provide reliable estimates of tissue pO(2).

18F-EF5: a new PET tracer for imaging hypoxia in head and neck cancer

The aim of this study was to evaluate 2-(2-nitro-(1)H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)-acetamide (EF5) labeled with (18)F-fluorine to image hypoxia in patients with squamous cell carcinoma of the head and neck (HNSCC).

METHODS

Fifteen patients with HNSCC were studied. Measurement of tumor blood flow was followed by an (18)F-EF5 PET/CT scan. On a separate day, (18)F-FDG PET/CT was performed to determine the metabolically active tumor volume. In 6 patients, dynamic (18)F-EF5 images of the head and neck area were acquired, followed by static images acquired at 1, 2, and 3 h after injection. In the remaining 9 patients, only static images were obtained. (18)F-EF5 uptake in tumors was compared with that in neck muscle, and the (18)F-EF5 findings were correlated with the (18)F-FDG PET/CT studies.

RESULTS

A total of 13 primary tumors and 5 lymph node metastases were evaluated for their uptake of (18)F-EF5. The median tumor-to-muscle (18)F-EF5 uptake ratio (T/M) increased over time and was 1.38 (range, 1.1-3.2) 3 h after tracer injection. The median blood flow in tumors was 36.7 mL/100 g/min (range, 23.3-78.6 mL/100 g/min). Voxel-by-voxel analysis of coregistered blood flow and (18)F-EF5 images revealed a distinct pattern, resulting in a T/M of 1.5 at 3 h to be chosen as a cutoff for clinically significant hypoxia. Fourteen of 18 tumors (78%) had subvolumes within the metabolically active tumor volumes with T/M greater than or equal to 1.5.

CONCLUSION

On the basis of these data, the potential of (18)F-EF5 to detect hypoxia in HNSCC is encouraging. Further development of (18)F-EF5 for eventual targeting of antihypoxia therapies is warranted.

In situ oxygen utilization in the rat intervertebral disc

Nucleus pulposus cells of the intervertebral disc have no endogenous vasculature and have thus been hypothesized to be hypoxic. This hypothesis was tested using 2-nitroimidazole, EF5, a drug that at low oxygen concentrations forms covalent adducts with cellular proteins. After administrating EF5 to rats, sections of the intervertebral disc were analysed for EF5 adducts. Drug adducts were quantified in tissue sections using a fluorescent monoclonal antibody. Although the level of EF5 fluorescence in all intervertebral disc tissues was low, the transition zone at the periphery of the nucleus pulposus exhibited the highest level of EF5 binding. To substantiate this result, tissue nitroreductase levels and drug pharmacology were evaluated. Nitroreductase levels were measured in whole discs under severe hypoxia. We noted that there was robust EF5 binding to cells in the annulus fibrosus and transition zone with modest binding to cells of the nucleus pulposus and endplate. High-performance liquid chromatography analysis indicated limitations in EF5 access to the nucleus pulposus, most probably related to the lack of vasculature and slow drug distribution through the gel-like interior of the disc. However, despite diffusion problems, the drug dose was determined to be sufficient to report the oxygen status of the nucleus pulposus cells. Based on these findings, we conclude that despite poor vascularization, the disc cells accommodate to the local environment by displaying a limited need for oxygen. Accordingly, the cells of the intervertebral disc are not severely hypoxic.

Bone marrow transplantation for feline mucopolysaccharidosis I

Severe mucopolysaccharidosis type I (MPS I) is a fatal neuropathic lysosomal storage disorder with significant skeletal involvement. Treatment involves bone marrow transplantation (BMT), and although effective, is suboptimal, due to treatment sequelae and residual disease. Improved approaches will need to be tested in animal models and compared to BMT. Herein we report on bone marrow transplantation to treat feline mucopolysaccharidosis I (MPS I). Five MPS I stably engrafted kittens, transplanted with unfractionated bone marrow (6.3x10(7)-1.1x10(9) nucleated bone marrow cells per kilogram) were monitored for 13-37 months post-engraftment. The tissue total glycosaminoglycan (GAG) content was reduced to normal levels in liver, spleen, kidney, heart muscle, lung, and thyroid. Aorta GAG content was between normal and affected levels. Treated cats had a significant decrease in the brain GAG levels relative to untreated MPS I cats and a paradoxical decrease relative to normal cats. The alpha-l-iduronidase (IDUA) activity in the livers and spleens of transplanted MPS I cats approached heterozygote levels. In kidney cortex, aorta, heart muscle, and cerebrum, there were decreases in GAG without significant increases in detectable IDUA activity. Treated animals had improved mobility and decreased radiographic signs of disease. However, significant pathology remained, especially in the cervical spine. Corneal clouding appeared improved in some animals. Immunohistochemical and biochemical analysis documented decreased central nervous system ganglioside storage. This large animal MPS I study will serve as a benchmark of future therapies designed to improve on BMT.

Quantitative comparison of tissue oxygen and motexafin lutetium uptake by ex vivo and noninvasive in vivo techniques in patients with intraperitoneal carcinomatosis

Near-infrared diffuse reflectance spectroscopy (DRS) has been used to noninvasively monitor optical properties during photodynamic therapy (PDT). This technique has been extensively validated in tissue phantoms; however, validation in patients has been limited. This pilot study compares blood oxygenation and photosensitizer tissue uptake measured by multiwavelength DRS with ex vivo assays of the hypoxia marker, 2-(2-nitroimida-zol-1[H]-yl)-N-(2,2,3,3,3-pentafluoropropyl)acetamide (EF5), and the photosensitizer (motexafin lutetium, MLu) from tissues at the same tumor site of three tumors in two patients with intra-abdominal cancers. Similar in vivo and ex vivo measurements of MLu concentration are carried out in murine radiation-induced fibrosarcoma (RIF) tumors (n=9). The selection of optimal DRS wavelength range and source-detector separations is discussed and implemented, and the association between in vivo and ex vivo measurements is examined. The results demonstrate a negative correlation between blood oxygen saturation (StO(2)) and EF5 binding, consistent with published relationships between EF5 binding and electrode measured pO(2), and between electrode measured pO(2) and StO(2). A tight correspondence is observed between in vivo DRS and ex vivo measured MLu concentration in the RIF tumors; similar data are positively correlated in the human intraperitoneal tumors. These results further demonstrate the potential of in vivo DRS measurements in clinical PDT.

Cardiovascular development: towards biomedical applicability

The LIM-homeodomain transcription factor Islet-1 (Isl1) marks a cell population which makes a substantial contribution to the embryonic heart. Isl1 expression is downregulated as soon as the cells adopt a differentiated phenotype, suggesting that this transcription factor delineates a cardiogenic progenitor cell population. Taking advantage of this developmental lineage marker, we have identified in the postnatal heart a novel cardiac cell type, which is capable of self-renewal and readily differentiates into mature cardiomyocytes. Utilization of embryonic stem (ES) cells that harbour knock-ins of reporter genes into the endogenous Isl1 locus will enable us to isolate Isl1+ cardiac progenitors from mouse and human ES cell systems during in vitro cardiogenesis. These genetic cell-based systems should allow the direct identification of signalling pathways which guide formation, renewal and diversification of Isl1+ cardiogenic progenitors into distinct heart cell lineages, and would complement in vitro studies in the mouse embryo during cardiac development.

Nelfinavir down-regulates hypoxia-inducible factor 1alpha and VEGF expression and increases tumor oxygenation: implications for radiotherapy

The phosphatidylinositol 3-kinase (PI3K)/Akt pathway can increase vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1alpha (HIF-1alpha) expression. We examined the effect of nelfinavir, an HIV protease inhibitor that inhibits Akt signaling, on VEGF and HIF-1alpha expression and on angiogenesis, tumor oxygenation, and radiosensitization. Nelfinavir decreases VEGF expression under normoxia via the transcription factor Sp1, which regulates the proximal core VEGF promoter. Nelfinavir decreased Sp1 phosphorylation and decreased Sp1 binding to a probe corresponding to the proximal VEGF promoter in a gel shift assay. Nelfinavir also decreased the hypoxic induction of HIF-1alpha, which also regulates the VEGF promoter, most likely by decreasing its translation. The effect of nelfinavir on VEGF expression had the functional consequence of decreasing angiogenesis in an in vivo Matrigel plug assay. To determine the effect this might have on tumor radiosensitization, we did tumor regrowth assays with xenografts in nude mice. The combination of nelfinavir and radiation increased time to regrowth compared with radiation alone whereas nelfinavir alone had little effect on tumor regrowth. This radiosensitizing effect was greater than suggested by in vitro clonogenic survival assays. One possible explanation for the discordance is that nelfinavir has an effect on tumor oxygenation. Therefore, we examined this with the hypoxia marker EF5 and found that nelfinavir leads to increased oxygenation within tumor xenografts. Our results suggest that nelfinavir decreases HIF-1alpha/VEGF expression and tumor hypoxia, which could play a role in its in vivo radiosensitizing effect. These data support the use of nelfinavir in combination with radiation in future clinical trials.

Oxygen levels in normal and previously irradiated human skin as assessed by EF5 binding

The oxygen status of skin is a controversial topic. Skin is radiosensitive, suggesting it is well-oxygenated. However, it can be further sensitized with nitroimidazole drugs, implying that it is partially hypoxic. Skin oxygen levels are difficult to measure with either electrodes or the hypoxia-monitoring agent (3)H-misonidazole. For the latter, binding has previously been reported to be high in murine skin, but this could be attributed to either non-oxygen-dependent variations in nitroreductase activity, drug metabolism, and/or actual oxygen gradients. We obtained tumor and skin from patients given EF5, a 2-nitroimidazole tissue hypoxia monitor. We performed immunohistochemical studies using highly specific monoclonal antibodies for the hypoxia-dependent production of EF5 tissue adducts. Some tissue sections were counterstained using either Ki67 for proliferation or CD31 for vessels. We found that the human dermis is well-oxygenated, the epidermis is modestly hypoxic and portions of some sebaceous glands and hair follicles are moderately to severely hypoxic. Normal and irradiated skin had similar oxygenation patterns. Control studies demonstrated that these observations are not due to tissue variations in nitroreductase activity. The importance of the highly heterogeneous distribution of oxygen in skin requires further study, but recent investigations suggest that skin hypoxia may have important clinical ramifications including mediating cellular transformation.

Attitudes and barriers to incident reporting: a collaborative hospital study

OBJECTIVES

To assess awareness and use of the current incident reporting system and to identify factors inhibiting reporting of incidents in hospitals.

DESIGN, SETTING AND PARTICIPANTS

Anonymous survey of 186 doctors and 587 nurses from diverse clinical settings in six South Australian hospitals (response rate = 70.7% and 73.6%, respectively).

MAIN OUTCOME MEASURES

Knowledge and use of the current reporting system; barriers to incident reporting.

RESULTS

Most doctors and nurses (98.3%) were aware that their hospital had an incident reporting system. Nurses were more likely than doctors to know how to access a report (88.3% v 43.0%; relative risk (RR) 2.05, 95% CI 1.61 to 2.63), to have ever completed a report (89.2% v 64.4%; RR 1.38, 95% CI 1.19 to 1.61), and to know what to do with the completed report (81.9% v 49.7%; RR 1.65, 95% CI 1.27 to 2.13). Staff were more likely to report incidents which are habitually reported, often witnessed, and usually associated with immediate outcomes such as patient falls and medication errors requiring corrective treatment. Near misses and incidents which occur over time such as pressure ulcers and DVT due to inadequate prophylaxis were least likely to be reported. The most frequently stated barrier to reporting for doctors and nurses was lack of feedback (57.7% and 61.8% agreeing, respectively).

CONCLUSIONS

Both doctors and nurses believe they should report most incidents, but nurses do so more frequently than doctors. To improve incident reporting, especially among doctors, clarification is needed of which incidents should be reported, the process needs to be simplified, and feedback given to reporters.

EF5 binding and clinical outcome in human soft tissue sarcomas

PURPOSE

To study the 2-nitroimidazole agent EF5 as a surrogate for measuring hypoxia in a series of patients with soft tissue sarcomas, and to determine whether hypoxia measured with this technique was associated with patient outcome.

METHODS AND MATERIALS

Patients with soft tissue sarcomas of the head and neck, extremity, trunk, or retroperitoneum for whom surgical excision was the initial treatment of choice, were given 21 mg/kg EF5 24-48 hours before surgery. Biopsy specimens were stained for EF5 binding with fluorescence-labeled monoclonal antibodies, and the images were analyzed quantitatively. Endpoints included the relationship between EF5 binding, clinically important prognostic factors, and patient outcome.

RESULTS

Two patients with recurrent and 14 patients with de novo sarcomas were studied. There were seven low-grade, one intermediate-grade, and eight high-grade tumors. No relationship was found between EF5 binding and patient age, sex, hemoglobin level, or tumor size. In de novo tumors, the presence of mitoses and histologic grade were positively correlated with hypoxia. High-grade and -stage de novo tumors had higher levels of EF5 binding compared with low-grade and -stage tumors. Patients with de novo tumors containing moderate to severe hypoxia (> or = 20% EF5 binding), high grade, or > or = 7% mitoses were more likely to develop metastases.

CONCLUSIONS

Further studies in a larger cohort of patients are necessary to determine whether hypoxia, as measured by EF5 binding, is an independent prognostic factor for outcome in high-grade sarcomas. Such data should be useful to identify high-risk patients for clinical trials to determine whether early chemotherapy will influence the occurrence of metastasis.

Osteoporosis screening in people with airways disease

We tested associations between risk factors and bone mineral density in airways disease subjects, and developed a clinical screening tool to identify people who could benefit from bone mineral density testing. Subjects were recruited through hospital outpatients and pharmacies (Newcastle, n = 172). With survey refinement, we then tested a revised tool in a second sample (Adelaide, n = 317). Study factors included oral/inhaled corticosteroid use, asthma severity, respiratory admissions, physical activity, percent predicted forced expiratory volume in one second (FEV1), body mass index, and smoking history. Outcomes were bone mineral density of lumbar vertebra (L2-4) and total (or neck of) femur. Analysis was logistic regression with generation of a simple screening algorithm based upon coefficients. Scoring algorithm risk factors for T-score of < - 2.0: age > or = 68 = 10 points, bone mineral density < 20 = 25, weight < 60 kg = 20, 60-69 kg = 10, > or = 80 cigarette pack years = 15, low-level leisure activity = 5, area under receiver operator curve 0.83. For a cut-off score of 10, sensitivity was 91.2%, specificity 53.9%, positive and negative predictive values 52.3 and 91.7%, and 67.2% were correctly classified. In conclusions, our model has acceptable sensitivity, although limited specificity. Use of this tool may reduce unnecessary referrals for bone mineral density measurement.

Randomized controlled trial of alendronate in airways disease and low bone mineral density

BACKGROUND

Patients with airways disease have been demonstrated to be at risk of osteoporosis, and this is likely to be multifactorial. Our aim was to identify patients with low bone mineral density (BMD) using a screening program, and then evaluate the benefit of daily alendronate.

METHOD

Subjects with hip or lumbar spine baseline T-scores < - 2.5, or Z-score < - 1.0 commenced on alendronate/calcium (10 mg/600 mg day) or placebo/calcium, in a double blind randomized controlled trial. BMD by dual emission X-ray absorptiometry (lumbar vertebrae 2-4, neck of femur, total femur) was repeated after 12 months, with adverse events recorded.

RESULTS

145 subjects (74 male, 71 female, mean age 67, median FEV1 1.0 litres = 43% of predicted) were enrolled; 66 alendronate/calcium, 79 placebo/calcium with 24 and 26 withdrawals, respectively. Per protocol but not intention to treat analysis of covariance demonstrated statistically significant improvements in T and Z scores for lumbar spine bone mineral density (P = 0.035, P = 0.040), with no improvement demonstrated at the hip.

CONCLUSIONS

Improvement in bone mineral density has been demonstrated at the lumbar spine, but not hip, by per protocol analysis, with daily alendronate, at 12 months.

Hypoxia and Photofrin uptake in the intraperitoneal carcinomatosis and sarcomatosis of photodynamic therapy patients

PURPOSE

Response to photodynamic therapy depends on adequate tumor oxygenation as well as sufficient accumulation of photosensitizer in the tumor. The goal of this study was to investigate the presence of hypoxia and retention of the photosensitizer Photofrin in the tumors of patients with intra-abdominal carcinomatosis or sarcomatosis.

EXPERIMENTAL DESIGN

Tumor nodules from 10 patients were studied. In nine of these patients, hypoxia was identified in histological sections of biopsied tumor after administration of the hypoxia marker 2-(2-nitroimidazol-1[H]-yl)-N-(2,2,3,3,3-pentafluoropropyl)acetamide (EF5). In separate tumor nodules from 10 patients, Photofrin uptake was measured by fluorescence after tissue solubilization.

RESULTS

Hypoxia existed in the tumors of five patients, with three of these patients demonstrating at least one severely hypoxic nodule. Physiological levels of oxygen were present in the tumors of four patients. An association between tumor size and hypoxia was not evident because some tumor nodules as small as approximately 2 mm in diameter were severely hypoxic. However, even these tumor nodules contained vascular networks. Three patients with severely hypoxic tumor nodules exhibited moderate levels of Photofrin uptake of 3.9 +/- 0.4 to 3.9 +/- 0.5 ng/mg (mean +/- SE). The four patients with tumors of physiological oxygenation did not consistently exhibit high tumor concentrations of Photofrin: mean +/- SE drug uptake among these patients ranged from 0.6 +/- 0.8 to 5.8 +/- 0.5 ng/mg.

CONCLUSIONS

Carcinomatosis or sarcomatosis of the i.p. cavity may exhibit severe tumor hypoxia. Photofrin accumulation in tumors varied by a factor of approximately 10x among all patients, and, on average, those with severe hypoxia in at least one nodule did not demonstrate poor Photofrin uptake in separate tumor samples. These data emphasize the need for reconsideration of the generally accepted paradigm of small tumor size, good oxygenation, and good drug delivery because this may vary on an individual tumor basis.

Hypoxia Is Important in the Biology and Aggression of Human Glial Brain Tumors

We investigated whether increasing levels of tissue hypoxia, measured by the binding of EF5 [2-(2-nitro-1-H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl) acetamide] or by Eppendorf needle electrodes, were associated with tumor aggressiveness in patients with previously untreated glial brain tumors. We hypothesized that more extensive and severe hypoxia would be present in tumor cells from patients bearing more clinically aggressive tumors. Hypoxia was measured with the 2-nitroimidazole imaging agent EF5 in 18 patients with supratentorial glial neoplasms. In 12 patients, needle electrode measurements were made intraoperatively. Time to recurrence was used as an indicator of tumor aggression and was analyzed as a function of EF5 binding, electrode values and recursive partitioning analysis (RPA) classification. On the basis of EF5 binding, WHO grade 2 tumors were characterized by modest cellular hypoxia (pO2s approximately 10%) and grade 3 tumors by modest-to-moderate hypoxia (pO2s approximately 10%- 2.5%). Severe hypoxia (approximately 0.1% oxygen) was present in 5 of 12 grade 4 tumors. A correlation between more rapid tumor recurrence and hypoxia was demonstrated with EF5 binding, but this relationship was not predicted by Eppendorf measurements.