Amino Acid PET in Neurooncology

For decades, several amino acid PET tracers have been used to optimize diagnostics in patients with brain tumors. In clinical routine, the most important clinical indications for amino acid PET in brain tumor patients are differentiation of neoplasm from nonneoplastic etiologies, delineation of tumor extent for further diagnostic and treatment planning (i.e., diagnostic biopsy, resection, or radiotherapy), differentiation of treatment-related changes such as pseudoprogression or radiation necrosis after radiation or chemoradiation from tumor progression at follow-up, and assessment of response to anticancer therapy, including prediction of patient outcome. This continuing education article addresses the diagnostic value of amino acid PET for patients with either glioblastoma or metastatic brain cancer.

Between-hospital variation in mortality and survival after glioblastoma surgery in the Dutch Quality Registry for Neuro Surgery

Purpose

Standards for surgical decisions are unavailable, hence treatment decisions can be personalized, but also introduce variation in treatment and outcome. National registrations seek to monitor healthcare quality. The goal of the study is to measure between-hospital variation in risk-standardized survival outcome after glioblastoma surgery and to explore the association between survival and hospital characteristics in conjunction with patient-related risk factors.

Methods

Data of 2,409 adults with first-time glioblastoma surgery at 14 hospitals were obtained from a comprehensive, prospective population-based Quality Registry Neuro Surgery in The Netherlands between 2011 and 2014. We compared the observed survival with patient-specific risk-standardized expected early (30-day) mortality and late (2-year) survival, based on age, performance, and treatment year. We analyzed funnel plots, logistic regression and proportional hazards models.

Results

Overall 30-day mortality was 5.2% and overall 2-year survival was 13.5%. Median survival varied between 4.8 and 14.9 months among hospitals, and biopsy percentages ranged between 16 and 73%. One hospital had lower than expected early mortality, and four hospitals had lower than expected late survival. Higher case volume was related with lower early mortality (P = 0.031). Patient-related risk factors (lower age; better performance; more recent years of treatment) were significantly associated with longer overall survival. Of the hospital characteristics, longer overall survival was associated with lower biopsy percentage (HR 2.09, 1.34–3.26, P = 0.001), and not with academic setting, nor with case volume.

Conclusions

Hospitals vary more in late survival than early mortality after glioblastoma surgery. Widely varying biopsy percentages indicate treatment variation. Patient-related factors have a stronger association with overall survival than hospital-related factors.

Electronic supplementary material

The online version of this article (10.1007/s11060-019-03229-5) contains supplementary material, which is available to authorized users.

Dynamic O-(2-18F-fluoroethyl)-L-tyrosine positron emission tomography differentiates brain metastasis recurrence from radiation injury after radiotherapy

Background

The aim of this study was to investigate the potential of dynamic O-(2-[18F]fluoroethyl)-L-tyrosine (18F-FET) PET for differentiating local recurrent brain metastasis from radiation injury after radiotherapy since contrast-enhanced MRI often remains inconclusive.

Methods

Sixty-two patients (mean age, 55 ± 11 y) with single or multiple contrast-enhancing brain lesions (n = 76) on MRI after radiotherapy of brain metastases (predominantly stereotactic radiosurgery) were investigated with dynamic 18F-FET PET. Maximum and mean tumor-to-brain ratios (TBRmax, TBRmean) of 18F-FET uptake were determined (20-40 min postinjection) as well as tracer uptake kinetics (ie, time-to-peak and slope of time-activity curves). Diagnoses were confirmed histologically (34%; 26 lesions in 25 patients) or by clinical follow-up (66%; 50 lesions in 37 patients). Diagnostic accuracies of PET parameters for the correct identification of recurrent brain metastasis were evaluated by receiver-operating-characteristic analyses or the chi-square test.

Results

TBRs were significantly higher in recurrent metastases (n = 36) than in radiation injuries (n = 40) (TBRmax 3.3 ± 1.0 vs 2.2 ± 0.4, P < .001; TBRmean 2.2 ± 0.4 vs 1.7 ± 0.3, P < .001). The highest accuracy (88%) for diagnosing local recurrent metastasis could be obtained with TBRs in combination with the slope of time-activity curves (P < .001).

Conclusions

The results of this study confirm previous preliminary observations that the combined evaluation of the TBRs of 18F-FET uptake and the slope of time-activity curves can differentiate local brain metastasis recurrence from radiation-induced changes with high accuracy. 18F-FET PET may thus contribute significantly to the management of patients with brain metastases.

Differentiation between Treatment-Induced Necrosis and Recurrent Tumors in Patients with Metastatic Brain Tumors: Comparison among 11C-Methionine-PET, FDG-PET, MR Permeability Imaging, and MRI-ADC-Preliminary Results

BACKGROUND AND PURPOSE

In patients with metastatic brain tumors after gamma knife radiosurgery, the superiority of PET using ¹¹C-methionine for differentiating radiation necrosis and recurrent tumors has been accepted. To evaluate the feasibility of MR permeability imaging, it was compared with PET using ¹¹C-methionine, FDG-PET, and DWI for differentiating radiation necrosis from recurrent tumors.

MATERIALS AND METHODS

The study analyzed 18 lesions from 15 patients with metastatic brain tumors who underwent gamma knife radiosurgery. Ten lesions were identified as recurrent tumors by an operation. In MR permeability imaging, the transfer constant between intra- and extravascular extracellular spaces (/minute), extravascular extracellular space, the transfer constant from the extravascular extracellular space to plasma (/minute), the initial area under the signal intensity-time curve, contrast-enhancement ratio, bolus arrival time (seconds), maximum slope of increase (millimole/second), and fractional plasma volume were calculated. ADC was also acquired. On both PET using ¹¹C-methionine and FDG-PET, the ratio of the maximum standard uptake value of the lesion divided by the maximum standard uptake value of the symmetric site in the contralateral cerebral hemisphere was measured (¹¹C-methionine ratio and FDG ratio, respectively). The receiver operating characteristic curve was used for analysis.

RESULTS

The area under the receiver operating characteristic curve for differentiating radiation necrosis from recurrent tumors was the best for the ¹¹C-methionine ratio (0.90) followed by the contrast-enhancement ratio (0.81), maximum slope of increase (millimole/second) (0.80), the initial area under the signal intensity-time curve (0.78), fractional plasma volume (0.76), bolus arrival time (seconds) (0.76), the transfer constant between intra- and extravascular extracellular spaces (/minute) (0.74), extravascular extracellular space (0.68), minimum ADC (0.60), the transfer constant from the extravascular extracellular space to plasma (/minute) (0.55), and the FDG-ratio (0.53). A significant difference in the ¹¹C-methionine ratio (P < .01), contrast-enhancement ratio (P < .01), maximum slope of increase (millimole/second) (P < .05), and the initial area under the signal intensity-time curve (P < .05) was evident between radiation necrosis and recurrent tumor.

CONCLUSIONS

The present study suggests that PET using ¹¹C-methionine may be superior to MR permeability imaging, ADC, and FDG-PET for differentiating radiation necrosis from recurrent tumors after gamma knife radiosurgery for metastatic brain tumors.

Predictors of Variation in Neurosurgical Supply Costs and Outcomes Across 4904 Surgeries at a Single Institution

BACKGROUND

There is high variability in neurosurgical costs, and surgical supplies constitute a significant portion of cost. Anecdotally, surgeons use different supplies for various reasons, but there is little understanding of how supply choices affect outcomes. Our goal is to evaluate the effect of patient, procedural, and provider factors on supply cost and to determine if supply cost is associated with patient outcomes.

METHODS

We obtained patient information (age, gender, payor, case mix index [CMI], body mass index, admission source), procedural data (procedure type, length, date), provider information (name, case volume), and total surgical supply cost for all inpatient neurosurgical procedures from 2013 to 2014 at our institution (n = 4904). We created mixed-effect models to examine the effect of each factor on surgical supply cost, 30-day readmission, and 30-day mortality.

RESULTS

There was significant variation in surgical supply cost between and within procedure types. Older age, female gender, higher CMI, routine/elective admission, longer procedure, and larger surgeon volume were associated with higher surgical supply costs (P < 0.05). Routine/elective admission and higher surgeon volume were associated with lower readmission rates (odds ratio, 0.707, 0.998; P < 0.01). Only patient factors of older age, male gender, private insurance, higher CMI, and emergency admission were associated with higher mortality (odds ratio, 1.029, 1.700, 1.692, 1.080, 2.809). There was no association between surgical supply cost and readmission or mortality (P = 0.307, 0.548).

CONCLUSIONS

A combination of patient, procedural, and provider factors underlie the significant variation in neurosurgical supply costs at our institution. Surgical supply costs are not correlated with 30-day readmission or mortality.

Adults with myelomeningocele and other forms of spinal dysraphism: hospital care in the United States since the turn of the millennium

OBJECTIVE

The natural history and management of myelomeningocele (MM) in children is fairly well understood. There is a deficiency of knowledge regarding the care of adults, however, even though there are now more adults than children living with MM. The purpose of this study was to characterize the hospital care of adults with MM and hydrocephalus on a nationwide population base. Adults with other forms of spina bifida (SB) were studied for contrast.

METHODS

The Nationwide Inpatient Sample for the years 2001, 2004, 2007, and 2010 was queried for admissions with diagnostic ICD-9-CM codes for MM with hydrocephalus and for other forms of SB.

RESULTS

There were 4657 admissions of patients with MM and 12,369 admissions of patients with SB in the sample. Nationwide rates of admission increased steadily for both MM and SB patients throughout the study period. Hospital charges increased faster than the health care component of the Consumer Price Index. Patients with MM were younger than patients with SB, but annual admissions of MM patients older than 40 years increased significantly during the study period. With respect to hospital death and discharge home, outcomes of surgery for hydrocephalus were superior at high-volume hospitals. Patients with MM and SB were admitted to the hospital more frequently than the general population for surgery to treat degenerative spine disease.

CONCLUSIONS

Patients with MM and SB continue to require neurosurgical attention in adulthood, and the demand for services for older patients with MM is increasing. Management of hydrocephalus at high-volume centers is advantageous for this population. Patients with MM or SB may experience high rates of degenerative spine disease.

Intracranial MR-guided laser-induced thermal therapy: single-center experience with the Visualase thermal therapy system

OBJECTIVE MR-guided laser-induced thermal therapy (MRgLITT) can be used to treat intracranial tumors, epilepsy, and chronic pain syndromes. Here, the authors report their single-center experience with 102 patients, the largest series to date in which the Visualase thermal therapy system was used. METHODS A retrospective analysis of all patients who underwent MRgLITT between 2010 and 2014 was performed. Pathologies included glioma, recurrent metastasis, radiation necrosis, chronic pain, and epilepsy. Laser catheters were placed stereotactically, and ablation was performed in the MRI suite. Demographics, operative parameters, length of hospital stay, and complications were recorded. Thirty-day readmission rates were calculated by using the standard method according to America's Health Insurance Plans Center for Policy and Research guidelines. RESULTS A total of 133 lasers were placed in 102 patients who required intervention for intracranial tumors (87 patients), chronic pain syndrome (cingulotomy, 5 patients), or epilepsy (10 patients). The procedure was completed in 98% (100) of these patients. Ninety-two patients (90.2%) had undergone previous treatment for their intracranial tumors. The average (± SD) total procedural time was 170.5 ± 34.4 minutes, and the mean laser-on time was 8.7 ± 6.8 minutes. The average intensive care unit (ICU) and hospital stays were 1.8 and 3.6 days, respectively, and the median length of stay for both the ICU and the hospital was 1 day. By postoperative Day 1, 54% of the patients (n = 55) were neurologically stable for discharge. There were 27 cases of morbidity, including new-onset neurological deficits, and 2 perioperative deaths. Fourteen patients (13.7%) developed new deficits after the MRgLITT procedure, and of those 14 patients, 64.3% (n = 9) had complete resolution of deficits within 1 month, 7.1% (n = 1) had partial resolution of symptoms within 1 month, 14.3% (n = 2) had not had resolution of symptoms at the most recent follow-up, and 14.3% (n = 2) died without resolution of symptoms. The 30-day readmission rate was 5.6% CONCLUSIONS MRgLITT, although minimally invasive, must be used with caution. Thermal damage to critical and eloquent structures can occur despite MRI guidance. Once the learning curve is overcome, the overall procedural complication rate is low, and most patients can be discharged within 24 hours, with a relatively low readmission rate. In cases in which they occurred, most neurological deficits were temporary. The therapeutic role of MRgLITT in various intracranial diseases will require larger and more rigorous studies.

From the clinician's point of view - What is the status quo of positron emission tomography in patients with brain tumors?

The most common type of primary brain tumor is malignant glioma. Despite intensive therapeutic efforts, the majority of these neoplasms remain incurable. Imaging techniques are important for initial tumor detection and comprise indispensable tools for monitoring treatment. Structural imaging using contrast-enhanced MRI is the method of choice for brain tumor surveillance, but its capacity to differentiate tumor from nonspecific tissue changes can be limited, particularly with posttreatment gliomas. Metabolic imaging using positron-emission-tomography (PET) can provide relevant additional information, which may allow for better assessment of tumor burden in ambiguous cases. Specific PET tracers have addressed numerous molecular targets in the last decades, but only a few have achieved relevance in routine clinical practice. At present, PET studies using radiolabeled amino acids appear to improve clinical decision-making as these tracers can offer better delineation of tumor extent as well as improved targeting of biopsies, surgical interventions, and radiation therapy. Amino acid PET imaging also appears useful for distinguishing glioma recurrence or progression from postradiation treatment effects, particularly radiation necrosis and pseudoprogression, and provides information on histological grading and patient prognosis. In the last decade, the tracers O-(2-[(18)F]fluoroethyl)-L-tyrosine (FET) and 3,4-dihydroxy-6-[(18)F]-fluoro-L-phenylalanine (FDOPA) have been increasingly used for these indications. This review article focuses on these tracers and summarizes their recent applications for patients with brain tumors. Current uses of tracers other than FET and FDOPA are also discussed, and the most frequent practical questions regarding PET brain tumor imaging are reviewed.

Drivers of hospitalization cost after craniotomy for tumor resection: creation and validation of a predictive model

Background

The economic sustainability of all areas of medicine is under scrutiny. Limited data exist on the drivers of cost after a craniotomy for tumor resection (CTR). The objective of the present study was to develop and validate a predictive model of hospitalization cost after CTR.

Methods

We performed a retrospective study involving CTR patients who were registered in the Nationwide Inpatient Sample (NIS) database from 2005–2010. This cohort underwent 1:1 randomization to create derivation and validation subsamples. Regression techniques were used for the creation of a parsimonious predictive model.

Results

Of the 36,433 patients undergoing CTR, 14638 (40.2%) underwent craniotomies for primary malignant, 9574 (26.3%) for metastatic, and 11414 (31.3%) for benign tumors. The median hospitalization cost was $24,504 (Interquartile Range (IQR), $4,265-$44,743). Common drivers of cost identified in the multivariate analyses included: length of stay, number of procedures, hospital size and region, and patient income. The models were validated in independent cohorts and demonstrated final R² very similar to the initial models. The predicted and observed values in the validation cohort demonstrated good correlation.

Conclusions

This national study identified significant drivers of hospitalization cost after CTR. The presented model can be utilized as an adjunct in the cost containment debate and the creation of data-driven policies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12913-015-0742-2) contains supplementary material, which is available to authorized users.

Volume-outcome relationships in neurosurgery

For a variety of neurosurgical conditions, increasing surgeon and hospital volumes correlate with improved outcomes, such as mortality, complication rates, length of stay, hospital charges, and discharge disposition. Neurosurgeons can improve patient outcomes at the population level by changing practice and referral patterns to regionalize care for select conditions at high-volume specialty treatment centers. Individual practitioners should be aware of where they fall on the volume spectrum and understand the implications of their practice and referral habits on their patients.

Are patients open to elective re-sampling of their glioblastoma? A new way of assessing treatment innovations

BACKGROUND

This is a qualitative study designed to examine patient acceptability of re-sampling surgery for glioblastoma multiforme (GBM) electively post-therapy or at asymptomatic relapse.

METHODS

Thirty patients were selected using the convenience sampling method and interviewed. Patients were presented with hypothetical scenarios including a scenario in which the surgery was offered to them routinely and a scenario in which the surgery was in a clinical trial.

RESULTS

The results of the study suggest that about two thirds of the patients offered the surgery on a routine basis would be interested, and half of the patients would agree to the surgery as part of a clinical trial. Several overarching themes emerged, some of which include: patients expressed ethical concerns about offering financial incentives or compensation to the patients or surgeons involved in the study; patients were concerned about appropriate communication and full disclosure about the procedures involved, the legalities of tumor ownership and the use of the tumor post-surgery; patients may feel alone or vulnerable when they are approached about the surgery; patients and their families expressed immense trust in their surgeon and indicated that this trust is a major determinant of their agreeing to surgery.

CONCLUSION

The overall positive response to re-sampling surgery suggests that this procedure, if designed with all the ethical concerns attended to, would be welcomed by most patients. This approach of asking patients beforehand if a treatment innovation is acceptable would appear to be more practical and ethically desirable than previous practice.

The price of decreased mortality in the operative management of diverticulitis

BACKGROUND

Healthcare costs in the United States are increasing. It is thought that as cost increases, outcomes should improve. The aim of this study was to analyze patient charges and mortality in the operative management of diverticulitis over time.

METHODS

A retrospective analysis of the Nationwide Inpatient Sample database was performed. Adults with diverticulitis who underwent laparoscopic or open partial colectomy were identified by ICD-9 codes. Multivariate analyses examined in-hospital mortality and total charges. Results were adjusted for age, race, gender, Charlson comorbidity index, surgical approach (open vs. laparoscopic), and insurance status.

RESULTS

From 1998 to 2010, 148,348 patients had a partial colectomy for diverticulitis. After adjusting for other covariates and inflation, the average charge of hospitalization per admission increased by $34,057 from 1998 to 2010. In the same observation period, adjusted in-hospital mortality decreased significantly by 2005 compared to 1998 (p < 0.001, OR 0.77, 95% CI 0.68-0.88) and remained unchanged for the remainder of the study period. Additionally, laparoscopic management was associated with lower rate of charge increase compared to open management (p < 0.001), such that charges are currently higher for open management than laparoscopic.

CONCLUSION

In-hospital mortality following partial colectomy for diverticulitis has improved over time, most dramatically after 2005. With decreasing mortality, an increase in hospital charges is observed on an annual basis. However, while mortality reached a plateau after 2005, overall charges continue to rise.

Key determinants of short-term and long-term glioblastoma survival: a 14-year retrospective study of patients from the Hermelin Brain Tumor Center at Henry Ford Hospital

OBJECTIVE

Glioblastoma (GBM) is a heterogeneous neoplasm with a small percentage of long-term survivors. Despite aggressive surgical resection and advances in radiotherapy and chemotherapy, the median survival for patients with GBM is 12-14 months. Factors associated with a favorable prognosis include young age, high performance status, gross resection >98%, non-eloquent tumor location and O6-methylguanine methyltransferase (MGMT) promoter methylation. We retrospectively analyzed the relationship of clinical, epidemiologic, genetic and molecular characteristics with survival in patients with GBM.

METHODS

This retrospective analysis of overall survival looked at the outcomes of 480 patients diagnosed with GBM over 14 years at a single institution. Multivariate analysis was performed examining multiple patient characteristics.

RESULTS

Median survival time improved from 11.8 months in patients diagnosed from 1995 to 1999 to 15.9 months in those diagnosed from 2005 to 2008. Factors associated with survivor groups were age, KPS, tumor resection, treatment received and early progression. 18 cancer-related genes were upregulated in short-term survivors and five genes were downregulated in short-term survivors.

CONCLUSIONS

Epidemiologic, clinical, and molecular characteristics all contribute to GBM prognosis. Identifying factors associated with survival is important for treatment strategies as well as research for novel therapeutics and technologies. This study demonstrated improved survival for patients over time as well as significant differences among survivor groups.

(18)F-FDOPA PET for differentiating recurrent or progressive brain metastatic tumors from late or delayed radiation injury after radiation treatment

Brain metastases are frequently treated with radiation. It is critical to distinguish recurrent or progressive brain metastases (RPBM) from late or delayed radiation injury (LDRI). The purpose of this study was to examine the diagnostic accuracy as well as the prognostic power of 6-(18)F-fluoro-l-dopa ((18)F-FDOPA) PET for differentiating RPBM from LDRI.

METHODS

Thirty-two patients who had 83 previously irradiated brain metastases and who underwent (18)F-FDOPA PET because of an MR imaging-based suggestion of RPBM were studied retrospectively. PET studies were analyzed semiquantitatively (lesion-to-striatum and lesion-to-normal brain tissue ratios based on both maximum and mean standardized uptake values) and visually (4-point scale). The diagnostic accuracy of PET was verified by histopathologic analysis (n = 9) or clinical follow-up (n = 74) on a lesion-by-lesion basis. Receiver operating characteristic curve analysis was used to identify the best diagnostic indices. The power of (18)F-FDOPA PET to predict disease progression was evaluated with the Kaplan-Meier and Cox regression methods.

RESULTS

The best overall accuracy was achieved by visual scoring, with which a score of 2 or more (lesion uptake greater than or equal to striatum uptake) resulted in a sensitivity of 81.3% and a specificity of 84.3%. Semiquantitative (18)F-FDOPA PET uptake indices based on lesion-to-normal brain tissue ratios were significantly higher for RPBM than for LDRI. Among the various predictors tested, (18)F-FDOPA PET was the strongest predictor of tumor progression (hazard ratio, 6.26; P < 0.001), and the lesion-to-normal brain tissue ratio or visual score was the best discriminator. The mean time to progression was 4.6 times longer for lesions with negative (18)F-FDOPA PET results than for lesions with positive (18)F-FDOPA PET results (76.5 vs. 16.7 mo; P < 0.001). (18)F-FDOPA PET findings tended to predict overall survival.

CONCLUSION

Metabolic imaging with (18)F-FDOPA PET was useful for differentiating RPBM from LDRI. Semiquantitative indices, particularly lesion-to-normal uptake ratios, could be used. A visual score comparing tumor (18)F-FDOPA uptake and striatum (18)F-FDOPA uptake provided the highest sensitivity and specificity and was predictive of disease progression.

Unchanged safety outcomes in deep brain stimulation surgery for Parkinson disease despite a decentralization of care

OBJECT

Early work on deep brain stimulation (DBS) surgery, when procedures were mostly carried out in a small number of high-volume centers, demonstrated a relationship between surgical volume and procedural safety. However, over the past decade, DBS has become more widely available in the community rather than solely at academic medical centers. The authors examined the Nationwide Inpatient Sample (NIS) to study the safety of DBS surgery for Parkinson disease (PD) in association with this change in practice patterns.

METHODS

The NIS is a stratified sample of 20% of all patient discharges from nonfederal hospitals in the United States. The authors identified patients with a primary diagnosis of PD (332.0) and a primary procedure code for implantation/replacement of intracranial neurostimulator leads (02.93) who underwent surgery between 2002 and 2009. They analyzed outcomes using univariate and hierarchical, logistic regression analyses.

RESULTS

The total number of DBS cases remained stable from 2002 through 2009. Despite older and sicker patients undergoing DBS, procedural safety (rates of non-home discharges, complications) remained stable. Patients at low-volume hospitals were virtually indistinguishable from those at high-volume hospitals, except that patients at low-volume hospitals had slightly higher comorbidity scores (0.90 vs 0.75, p < 0.01). Complications, non-home discharges, length of hospital stay, and mortality rates did not significantly differ between low- and high-volume hospitals when accounting for hospital-related variables (caseload, teaching status, location).

CONCLUSIONS

Prior investigations have demonstrated a robust volume-outcome relationship for a variety of surgical procedures. However, the present study supports safety of DBS at smaller-volume centers. Prospective studies are required to determine whether low-volume centers and higher-volume centers have similar DBS efficacy, a critical factor in determining whether DBS is comparable between centers.

Patterns of care and outcome for patients with glioblastoma diagnosed during 2008-2010 in Spain

BACKGROUND

To assess management patterns and outcome in patients with glioblastoma multiforme (GBM) treated during 2008-2010 in Spain.

METHODS

Retrospective analysis of clinical, therapeutic, and survival data collected through filled questionnaires from patients with histologically confirmed GBM diagnosed in 19 Spanish hospitals.

RESULTS

We identified 834 patients (23% aged >70 years). Surgical resection was achieved in 66% of patients, although the extent of surgery was confirmed by postoperative MRI in only 41%. There were major postoperative complications in 14% of patients, and age was the only independent predictor (Odds ratio [OR], 1.03; 95% confidence interval [CI],1.01-1.05; P = .006). After surgery, 57% received radiotherapy (RT) with concomitant and adjuvant temozolomide, 21% received other regimens, and 22% were not further treated. In patients treated with surgical resection, RT, and chemotherapy (n = 396), initiation of RT ≤42 days was associated with longer progression-free survival (hazard ratio [HR], 0.8; 95% CI, 0.64-0.99; P = .042) but not with overall survival (HR, 0.79; 95% CI, 0.62-1.00; P = .055). Only 32% of patients older than 70 years received RT with concomitant and adjuvant temozolomide. The median survival in this group was 10.8 months (95% CI, 6.8-14.9 months), compared with 17.0 months (95% CI, 15.5-18.4 months; P = .034) among younger patients with GBM treated with the same regimen.

CONCLUSIONS

In a community setting, 57% of all patients with GBM and only 32% of older patients received RT with concomitant and adjuvant temozolomide. In patients with surgical resection who were eligible for chemoradiation, initiation of RT ≤42 days was associated with better progression-free survival.

Racial disparities in Medicaid patients after brain tumor surgery

The presence of healthcare-related disparities is an ongoing, widespread, and well-documented societal and health policy issue. We investigated the presence of racial disparities among post-operative patients either with meningioma or malignant, benign, or metastatic brain tumors. We used the Medicaid component of the Thomson Reuter's MarketScan database from 2000 to 2009. Univariate and multivariate analysis assessed death, 30-day post-operative risk of complications, length of stay, and total charges. We identified 2321 patients, 73.7% were Caucasian, 57.8% were women; with Charlson comorbidity scores of <3 (56.2%) and treated at low-volume centers (73.4%). Among all, 26.3% of patients were of African-American ethnicity and 22.1% had meningiomas. Mortality was 2.0%, mean length of stay (LOS) was 9 days, mean total charges were US$42,422, an adverse discharge occurred in 22.5% of patients, and overall 30-day complication rate was 23.4%. In a multivariate analysis, African-American patients with meningiomas had higher odds of developing a 30-day complication (p=0.05) and were significantly more likely to have longer LOS (p<0.001) and greater total charges (p<0.001) relative to Caucasian counterparts. The presence of one post-operative complication doubled LOS and nearly doubled total charges, while the presence of two post-operative complications tripled these outcomes. Patients of African-American ethnicity had significantly higher post-operative complications than those of Caucasian ethnicity. This higher rate of complications seems to have driven greater healthcare utilization, including greater LOS and total charges, among African-American patients. Interventions aimed at reducing complications among African-American patients with brain tumor may help reduce post-operative disparities.

Role of O-(2-(18)F-fluoroethyl)-L-tyrosine PET for differentiation of local recurrent brain metastasis from radiation necrosis

The aim of this study was to investigate the potential of O-(2-(18)F-fluoroethyl)-L-tyrosine ((18)F-FET) PET for differentiating local recurrent brain metastasis from radiation necrosis after radiation therapy because the use of contrast-enhanced MRI for this issue is often difficult.

METHODS

Thirty-one patients (mean age ± SD, 53 ± 11 y) with single or multiple contrast-enhancing brain lesions (n = 40) on MRI after radiation therapy of brain metastases were investigated with dynamic (18)F-FET PET. Maximum and mean tumor-to-brain ratios (TBR(max) and TBR(mean), respectively; 20-40 min after injection) of (18)F-FET uptake were determined. Time-activity curves were generated, and the time to peak (TTP) was calculated. Furthermore, time-activity curves of each lesion were assigned to one of the following curve patterns: (I) constantly increasing (18)F-FET uptake, (II) (18)F-FET uptake peaking early (TTP ≤ 20 min) followed by a plateau, and (III) (18)F-FET uptake peaking early (TTP ≤ 20 min) followed by a constant descent. The diagnostic accuracy of the TBR(max) and TBR(mean) of (18)F-FET uptake and the curve patterns for the correct identification of recurrent brain metastasis were evaluated by receiver-operating-characteristic analyses or Fisher exact test for 2 × 2 contingency tables using subsequent histologic analysis (11 lesions in 11 patients) or clinical course and MRI findings (29 lesions in 20 patients) as reference.

RESULTS

Both TBR(max) and TBR(mean) were significantly higher in patients with recurrent metastasis (n = 19) than in patients with radiation necrosis (n = 21) (TBR(max), 3.2 ± 0.9 vs. 2.3 ± 0.5, P < 0.001; TBR(mean), 2.1 ± 0.4 vs. 1.8 ± 0.2, P < 0.001). The diagnostic accuracy of (18)F-FET PET for the correct identification of recurrent brain metastases reached 78% using TBR(max) (area under the ROC curve [AUC], 0.822 ± 0.07; sensitivity, 79%; specificity, 76%; cutoff, 2.55; P = 0.001), 83% using TBR(mean) (AUC, 0.851 ± 0.07; sensitivity, 74%; specificity, 90%; cutoff, 1.95; P < 0.001), and 92% for curve patterns II and III versus curve pattern I (sensitivity, 84%; specificity, 100%; P < 0.0001). The highest accuracy (93%) to diagnose local recurrent metastasis was obtained when both a TBR(mean) greater than 1.9 and curve pattern II or III were present (AUC, 0.959 ± 0.03; sensitivity, 95%; specificity, 91%; P < 0.001).

CONCLUSION

Our findings suggest that the combined evaluation of the TBR(mean) of (18)F-FET uptake and the pattern of the time-activity curve can differentiate local brain metastasis recurrence from radionecrosis with high accuracy. (18)F-FET PET may thus contribute significantly to the management of patients with brain metastases.

The effect of centralization of caseload for primary brain tumor surgeries: trends from 2001-2007

BACKGROUND

Improved patient outcomes have been associated with high-caseload hospitals for a multitude of conditions. This study analyzed adult patients undergoing surgical resection or biopsy of primary brain tumors. The aim of this study is two-fold: (1) to evaluate whether the trend towards centralization of primary brain tumor care in the US has continued during the period of between 2001 and 2007, and (2) to analyze volume-outcome effects.

METHODS

Surgical volume trends of adults undergoing resection/biopsy of primary supratentorial brain tumors were analyzed using the Nationwide Inpatient Sample. High- and low-caseload hospitals were defined as those performing in the highest and lowest quintile of procedures, respectively. Length of stay (LOS), mortality and discharge disposition were the main outcomes of interest.

RESULTS

NIS estimated 124,171 patients underwent resection/biopsy of primary supratentorial brain tumors between 2001 and 2007 in the US. The average number of annual resections in the highest 2 % and lowest 25 % caseload hospitals were 322 and 12 cases, respectively. Surgeries in high-caseload hospitals increased by 137 %, while those in low-caseload centers declined by 16.0 %. Overall, mortality decreased 35 %, with a reduction of 45 % in high- (from 2.2 % to 1.2 %) and 19 % in low- (from 3.2 % to 2.6 %) caseload hospitals. High-caseload centers had lower LOS than hospitals with lower caseload centers (6.4 vs. 8.0 days, p < 0.001). Multivariate analysis showed that patients treated in low-volume hospitals had an increased risk of death (OR 1.8, CI: 1.2-2.7, p = 0.006) and adverse discharge (OR 1.4, CI: 1.1-1.7, p = 0.01).

CONCLUSIONS

Neurosurgical caseload at the nation's high volume craniotomy centers has continued to rise disproportionately, while low-caseload centers have seen a decrease in overall surgical volume. Over the time period between 2001 and 2007 there was a trend towards improved in-hospital mortality, LOS and discharge disposition for all hospitals; however, the trend is convincingly favorable for high-caseload hospitals.

Incidence and causes of perioperative mortality after primary surgery for intracranial tumors: a national, population-based study

OBJECT

Surgical mortality is a frequent outcome measure in studies of volume-outcome relationships, and the Agency for Healthcare Research and Quality has endorsed surgical mortality after craniotomies as an Inpatient Quality Indicator. Still, the frequency and causes of 30-day mortality after neurosurgical procedures have not been much explored. The authors sought to study the frequency and possible causes of death following primary intracranial tumor operations. They also sought to explore a possible predictive value of perioperative mortality rates from neurosurgical centers in relation to long-term survival.

METHODS

Using population-based data from the Norwegian cancer registry, the authors identified 15,918 primary operations for primary CNS tumors treated in Norway in the period from August 1955 through December 2008. Patients were followed up until death, emigration, or September 2009. Causes of mortality as indicated on death certificates were studied. Factors associated with an increased risk of perioperative death were identified.

RESULTS

The overall risk of perioperative death after first-time surgery for primary intracranial tumors is currently 2.2% and has decreased over the last decades. An age ≥ 70 years and histopathological entities with poor long-term prognoses are risk factors. Overlapping lesions are also associated with excess risk, indicating that lesion size or multifocality may matter. The overall risk of perioperative death is also higher in biopsy cases than in resection cases. Perioperative mortality rates of the 4 Norwegian neurosurgical centers were not predictive of their respective long-term survival rates.

CONCLUSIONS

Although considered surgically related if they occur within the first 30 days of surgery, most early postoperative deaths can happen independent of the handiwork of the operating surgeon or anesthesiologist. Overall prognosis of the disease seems to be a strong predictor of perioperative death-perhaps not surprisingly since the 30-day mortality rate is merely the intonation of the Kaplan-Meier curve. Both referral and treatment policies at a neurosurgical center will therefore markedly affect such early outcomes, but early deaths may not necessarily reflect overall quality of care or long-term results. The low incidence of perioperative death in intracranial tumor surgery also greatly limits the statistical power in comparative analyses, such as between published patient series or between centers and certainly between surgeons. Therefore the authors question the value of perioperative mortality rates as a quality indicator in modern neurosurgery for tumors.

Postoperative outcomes following closed head injury and craniotomy for evacuation of hematoma in patients older than 80 years

OBJECT

Advances in the management of trauma-induced intracranial hematomas and hemorrhage (epidural, subdural, and intraparenchymal hemorrhage) have improved survival in these conditions over the last several decades. However, there is a paucity of research investigating the relation between patient age and outcomes of surgical treatment for these conditions. In this study, the authors examined the relation between patient age over 80 years and postoperative outcomes following closed head injury and craniotomy for intracranial hemorrhage.

METHODS

A consecutive population of patients undergoing emergent craniotomy for evacuation of intracranial hematoma following closed head trauma between 2006 and 2009 was identified. Using multivariable logistic regression models, the authors assessed the relation between age (> 80 vs ≤ 80 years) and postoperative complications, intensive care unit stay, hospital stay, morbidity, and mortality.

RESULTS

Of 103 patients, 27 were older than 80 years and 76 patients were 80 years of age or younger. Older age was associated with longer length of hospital stay (p = 0.014), a higher rate of complications (OR 5.74, 95% CI 1.29-25.34), and a higher likelihood of requiring rehabilitation (OR 3.28, 95% CI 1.13-9.74). However, there were no statistically significant differences between the age groups in 30-day mortality or ability to recover to functional baseline status.

CONCLUSIONS

The findings suggest that in comparison with younger patients, patients over 80 years of age may be similarly able to return to preinjury functional baselines but may require increased postoperative medical attention in the forms of rehabilitation and longer hospital stays. Prospective studies concerned with the relation between older age, perioperative parameters, and postoperative outcomes following craniotomy for intracranial hemorrhage are needed. Nonetheless, the findings of this study may allow for more informed decisions with respect to the care of elderly patients with intracranial hemorrhage.

Differentiating treatment-induced necrosis from recurrent/progressive brain tumor using nonmodel-based semiquantitative indices derived from dynamic contrast-enhanced T1-weighted MR perfusion

Differentiating treatment-induced necrosis (TIN) from recurrent/progressive tumor (RPT) in brain tumor patients using conventional morphologic imaging features is a very challenging task. Functional imaging techniques also offer moderate success due to the complexity of the tissue microenvironment and the inherent limitation of the various modalities and techniques. The purpose of this retrospective study was to assess the utility of nonmodel-based semiquantitative indices derived from dynamic contrast-enhanced T1-weighted MR perfusion (DCET1MRP) in differentiating TIN from RPT. Twenty-nine patients with previously treated brain tumors who showed recurrent or progressive enhancing lesion on follow-up MRI underwent DCET1MRP. Another 8 patients with treatment-naive high-grade gliomas who also underwent DCET1MRP were included as the control group. Semiquantitative indices derived from DCET1MRP included maximum slope of enhancement in initial vascular phase (MSIVP), normalized MSIVP (nMSIVP), normalized slope of delayed equilibrium phase (nSDEP), and initial area under the time-intensity curve (IAUC) at 60 and 120 s (IAUC(60) and IAUC(120)) obtained from the enhancement curve. There was a statistically significant difference between the 2 groups (P < .01), with the RPT group showing higher MSIVP (15.78 vs 8.06), nMSIVP (0.046 vs 0.028), nIAUC(60) (33.07 vs 6.44), and nIAUC(120) (80.14 vs 65.55) compared with the TIN group. nSDEP was significantly lower in the RPT group (7.20 × 10(-5) vs 15.35 × 10(-5)) compared with the TIN group. Analysis of the receiver-operating-characteristic curve showed nMSIVP to be the best single predictor of RPT, with very high (95%) sensitivity and high (78%) specificity. Thus, nonmodel-based semiquantitative indices derived from DCET1MRP that are relatively easy to derive and do not require a complex model-based approach may aid in differentiating RPT from TIN and can be used as robust noninvasive imaging biomarkers.

The impact of provider surgical volumes on survival in children with primary tumors of the central nervous system--a population-based study

BACKGROUND

Provider volume is often a central topic in debates about centralization of procedures. In Norway, there is considerable variation in provider volumes of the neurosurgical centers treating children. We sought to explore long-term survival after surgery for central nervous system tumors in children in relation to regional provider volumes.

METHOD

Based on data from the Norwegian Cancer Registry we analyzed survival in all reported central nervous system tumors in children under the age of 16 treated over two decades, between March 1988 and April 2008; a total of 816 patients with histologically confirmed disease.

RESULTS

There was no overall difference in survival between regions. In the subgroup of PNET/medulloblastomas, both living in the high-provider volume health region and receiving treatment in the high-volume region was significantly associated with inferior survival.

CONCLUSIONS

In this population-based study of children operated over a period of two decades, we found no evidence of improved long-term survival in the high-provider volume region. Surprisingly, a subgroup analysis indicated that survival in PNET/medulloblastomas was significantly better if living outside the most populated health region with the highest provider volumes. One should, however, be careful of interpreting this directly as a symptom of quality of care, as there may be unseen confounders. Our study demonstrates that provider case volume may serve as an axiom in debates about centralization of cancer surgery while perhaps much more reliable and valid but less quantifiable factors are important for the final results.

Diagnostic dilemma of pseudoprogression in the treatment of newly diagnosed glioblastomas: the role of assessing relative cerebral blood flow volume and oxygen-6-methylguanine-DNA methyltransferase promoter methylation status

BACKGROUND AND PURPOSE

Methylation of the MGMT gene promoter is associated with a favorable prognosis in adult patients with GBM treated with TMZ. We determined the incidence of pseudoprogression according to the MGMT methylation status and the potential value of DSC perfusion MR images for predicting pseudoprogression.

MATERIALS AND METHODS

New or enlarged enhancing lesions after CCRT in adult patients with newly diagnosed GBMs were prospectively assessed by measuring their rCBV by using DSC perfusion MR images. Tumor tissue was assayed to determine MGMT promoter methylation status. All patients were regularly followed up at an interval of 2 months by MR images, including DSC perfusion MR images.

RESULTS

Ninety eligible patients were enrolled in this study. After CCRT, new or enlarged enhanced lesions were found in 59 of 90 patients, which were subsequently classified as pseudoprogression (26 patients, 28.9%) and real progression (33 patients, 36.7%). Overall, there was a significant difference in the mean rCBV between pseudoprogression and real tumor progression (P = .003). The ROC curve revealed that an rCBV ratio >1.47 had an 81.5% sensitivity and a 77.8% specificity. The unmethylated MGMT promoter group had a significant difference of mean rCBV between pseudoprogression and real progression (P = .009), though the methylated MGMT promoter group had no significant difference (P = .258).

CONCLUSIONS

The current study suggests that rCBV measured by DSC perfusion MR images has a differential impact on the predictability of pseudoprogression in patients with GBM.

Measuring quality for public reporting of health provider quality: making it meaningful to patients

Public quality reports of hospitals, health plans, and physicians are being used to promote efficiency and quality in the health care system. Shrinkage estimators have been proposed as superior measures of quality to be used in these reports because they offer more conservative and stable quality ranking of providers than traditional, nonshrinkage estimators. Adopting the perspective of a patient faced with choosing a local provider on the basis of publicly provided information, we examine the advantages and disadvantages of shrinkage and nonshrinkage estimators and contrast the information made available by them. We demonstrate that 2 properties of shrinkage estimators make them less useful than nonshrinkage estimators for patients making choices in their area of residence.

Disparities in access to pediatric neurooncological surgery in the United States

OBJECTIVE

The objective of this study was to investigate whether disparities in access to high-volume centers for neurooncological care existed in the United States in 1988-2005.

METHODS

A retrospective analysis of the Nationwide Inpatient Sample (1988-2005) was performed, with additional factors incorporated from the Area Resource File (2006). International Classification of Diseases, Ninth Revision, diagnosis/procedure coding was used to identify patients. High-volume centers were defined as those with > or =50 neurosurgical cases per year. Patients >18 years of age were excluded. Covariates included age, gender, race, Charlson Index score, insurance, and county-level characteristics (including median home value, proportion of foreign born residents, and county neurosurgeon density). Multivariate analysis was performed by using multiple logistic regression models. P values of <.05 were considered statistically significant.

RESULTS

A total of 4421 patients were identified; 1651 (37.34%) were admitted to high-volume centers. Overall access to high-volume centers improved slightly over the 18-year period (odds ratio [OR]: 1.04). Factors associated with greater access to high-volume centers included greater county neurosurgeon density (OR: 1.72) and greater county home value (OR: 1.66). Factors associated with worse access included Hispanic ethnicity (OR: 0.68) and each 1% increase in foreign residents per county (OR: 0.59). All reported P values were <.05.

CONCLUSION

This study demonstrates that racial and socioeconomic disparities in access to high-volume neurooncological care exist for the pediatric population. We also identify numerous prehospital factors that potentially contribute to persistent disparities and may be amenable to change through national health policy interventions.

Racial, ethnic and socioeconomic disparities in the treatment of brain tumors

Disparities in American health care based on socially-defined patient characteristics such as race, ethnicity, and socioeconomic position are well-documented. We review differences and disparities in incidence, pathobiology, processes and outcomes of care, and survival based on social factors for brain tumors of all histologies. In the US, black patients have lower incidences of most brain tumor types and lower-income patients have lower incidences of low grade glioma, meningioma and acoustic neuroma; ascertainment bias may contribute to these findings. Pathogenetic differences between malignant gliomas in patients of different races have been demonstrated, but their clinical significance is unclear. Patients in disadvantaged groups are less often treated by high-volume providers. Mortality and morbidity of initial treatment are higher for brain tumor patients in disadvantaged groups, and they present with markers of more severe disease. Long term survival differences between malignant glioma patients of different races have not yet been shown. Clinical trial enrollment appears to be lower among brain tumor patients from disadvantaged groups. We propose future research both to better define disparities and to alleviate them.

Tumor cell metabolism imaging

Molecular imaging of tumor metabolism has gained considerable interest, since preclinical studies have indicated a close relationship between the activation of various oncogenes and alterations of cellular metabolism. Furthermore, several clinical trials have shown that metabolic imaging can significantly impact patient management by improving tumor staging, restaging, radiation treatment planning, and monitoring of tumor response to therapy. In this review, we summarize recent data on the molecular mechanisms underlying the increased metabolic activity of cancer cells and discuss imaging techniques for studies of tumor glucose, lipid, and amino acid metabolism.

RURAL NEUROTRAUMA IN AUSTRALIA: IMPLICATIONS FOR SURGICAL TRAINING

BACKGROUND

Australia's vast size and small population preclude a neurosurgical service in most rural areas. Thus, general surgeons often initially manage rural neurotrauma. This study aimed to define the neurotrauma surgical caseload in rural Australia and to examine the level of training and confidence of rural surgeons for neurotrauma management.

METHODS

A questionnaire was sent to all Australian members of the Division of Rural Surgery of the Royal Australasian College of Surgeons. Responses were grouped by distance from a neurosurgical centre and analysed using one-way anova.

RESULTS

The response rate was 91%, and 161 rural surgeons were included. In total, 90 surgeons carried out approximately 600 procedures for neurotrauma in 5 years. The number of procedures per surgeon increased with distance from a neurosurgical centre (P < 0.0001), as did pre-transport delays (P < 0.001). Combined pre-transport and transport time was at least 2 h for 84% of surgeons. The majority (75% or more) of rural surgeons accessed hospitals with necessary basic infrastructure, including 24-h computed tomography scan, emergency department, and intensive care unit. There was no association between distance from a neurosurgical centre and level of neurosurgical training. Only 28% of rural surgeons had neurosurgery training more advanced than resident level. However, confidence with management of cranial trauma increased significantly with distance. More distant surgeons felt more confident with computed tomography reading (P = 0.02); burr hole (P = 0.02); craniotomy (P = 0.03) and intracranial pressure monitor insertion (P < 0.0001).

CONCLUSIONS

A significant volume of neurotrauma is managed surgically in rural Australia as dictated by distance. However, neurotrauma training of rural surgeons has occurred on an ad hoc basis, with those most exposed and most distant developing some confidence. Evidence for specific adequate training is lacking, but this study suggests that it is necessary.

Craniotomy for meningioma in the United States between 1988 and 2000: decreasing rate of mortality and the effect of provider caseload

Object. The goal of this study was to determine the risk of adverse outcomes after contemporary surgical treatment of meningiomas in the US and trends in patient outcomes and patterns of care.

Methods. The authors performed a retrospective cohort study by using the Nationwide Inpatient Sample covering the period of 1988 to 2000. Multivariate regression models with disposition end points of death and hospital discharge were used to test patient, surgeon, and hospital characteristics, including volume of care, as outcome predictors.

Multivariate analyses revealed that larger-volume centers had lower mortality rates for patients who underwent craniotomy for meningioma (odds ratio [OR] 0.74, 95% confidence interval [CI] 0.59–0.93, p = 0.01). Adverse discharge disposition was also less likely at high-volume hospitals (OR 0.71, 95% CI 0.62–0.80, p < 0.001). With respect to the surgeon caseload, there was a trend toward a lower rate of mortality after surgery when higher-caseload providers were involved, and a significantly less frequent adverse discharge disposition (OR 0.71, 95% CI 0.62–0.80, p <, 0.001).

The annual meningioma caseload in the US increased 83% between 1988 and 2000, from 3900 patients/year to 7200 patients/year. In-hospital mortality rates decreased 61%, from 4.5% in 1988 to 1.8% in 2000. Reductions in the mortality rates were largest at high-volume centers (a 72% reduction in the relative mortality rate at largest-volume-quintile centers, compared with a 6% increase in the relative mortality rate at lowest-volume-quintile centers). The number of US hospitals where craniotomies were performed for meningiomas increased slightly. Fewer centers hosted one meningioma resection annually, whereas the largest centers had disproportionate increases in their caseloads, indicating a modest centralization of meningioma surgery in the US during this interval.

Conclusions. The mortality and adverse hospital discharge disposition rates were lower when meningioma surgery was performed by high-volume providers. The annual US caseload increased, whereas the mortality rates decreased, especially at high-volume centers.