Postoperative Tumor Volume Research Articles

Extent of resection affects prognosis for patients with glioblastoma in non-eloquent regions

Glioblastoma (GBM) is a malignant cerebral neoplasm carrying poor prognosis. The importance of extent of resection (EoR) in GBM patient outcomes has been argued in the literature. Previous studies included tumors in eloquent regions of the brain. This confounds the role of EoR by including patients with intrinsically worse outcomes but will be over-represented in the reduced EoR category. In a homogenous group of patients in whom GTR was considered achievable, we investigated the effect of increasing EoR on survival. A retrospective review of 51 patients was undertaken. Quantitative, volumetric analysis of pre-operative and post-operative magnetic resonance image was compared with corresponding clinical details. The primary outcome measured was post-operative overall survival. Median overall survival was 18.3 months for GTR patients compared to 11.6 months for non-GTR (p = 0.025). Median pre-operative contrast-enhancing tumor volume for GTR patients was 54.7 cm3 and 24.9 cm3 for non-GTR. Post-operative median residual tumor volume was 1.1 cm3 in the non-GTR cohort. In multivariate analyses, GTR (HR [95% CI] = 0.973 [0.954–0.994], p = 0.00559) and increasing EoR (HR [95% CI] = 0.964 [0.944–0.985], p = 0.000665) remained predictors of survival. Centile dichotomization of EoR revealed 74% (HR [95% CI] = 0.351 [0.128–0.958], p = 0.0409) as the lowest threshold conferring statistically significant survival benefit. Where technically feasible, both GTR and EoR remained as independent prognostic factors for survival. GTR remains the gold standard for surgical treatment of GBM in patients, 74% being the minimum EoR required to confer survival benefit.

Evaluation of natural growth rate and recommended age for shaving procedure by volumetric analysis of craniofacial fibrous dysplasia.

We evaluated the preoperative natural growth pattern of craniofacial fibrous dysplasia and postoperative volume changes in patients undergoing shaving procedures. Thirty-three patients who underwent serial computed tomography (CT) preoperatively and/or postoperatively were identified. The natural tumor growth rate was assessed using preoperative CT scans. The postoperative tumor regrowth rates and relevant variables were analyzed. The preoperative tumor growth rates were significantly lower in patients aged ≥ 16 years than in those aged < 16 years (P < .001). The postoperative tumor regrowth rates were significantly greater when a shaving operation was performed at age < 16 years than at age ≥ 16 years (P = .04). In patients with clinical recurrence, the postoperative remnant tumor volume was inversely correlated with the tumor regrowth rate. The tumor growth rate of craniofacial fibrous dysplasia significantly decreased after age 16. This should be considered when conducting functional and aesthetic assessments in planning for the shaving of craniofacial fibrous dysplasia.

Pre- and Post-Operative Volume Estimation of Medulloblastoma Using Magnetic Resonance Imaging: A Stereological Study

Background: Brain tumors are among the most lethal and devastating cancers. Medulloblastoma tumor is a common solid brain malignancy, arising in the posterior fossa. Stereological methods are used in combination with magnetic resonance imaging (MRI) to obtain unbiased estimation of the total volume of the structure of interest. Objectives: In the current study, we evaluated cerebellar tumor volume pre- and post-operative in patients suffering from meduloblastoma tumor using MRI and Cavalieri method. Patients and Methods: The study was performed on 16 subjects consisting of two groups of eight people including patient and control groups. Slide direction were in both sagittal and axial planes. Pre- and post-operative volume of medulloblastoma tumor were determined on MR scanning images using the point-counting approach of Cavalieri method. Results: The post-operative tumor volume in both sagittal (P = 0.028) and axial (P = 0.046) MR images was statistically reduced by 90% compared to the pre-operative volume. Moreover, the pre-operative volume of the cerebellum in patients increased by 38% in patients as compared to the normal subjects (P = 0.028). Conclusion: It could be concluded that MRI-estimated tumor-volume might be useful in evaluating the efficiency of surgical treatment and prognostication of tumor regression rate.

Stereotactic laser ablation for subependymal giant cell astrocytomas: personal experience and review of the literature.

Subependymal giant cell astrocytomas (SEGAs) are rare tumors typically found in tuberous sclerosis patients. They typically grow in the region of the foramen of Monro and can occlude it, leading to hydrocephalus. Currently, gross total resection is the standard of care, with low rates of recurrence but high rates of complication, especially with larger lesions. Laser interstitial thermal therapy (LITT) is a newly emerging treatment modality for a variety of pathologies. Here, we present a case series of SEGAs managed via LITT and endoscopic, stereotactic septostomy. A retrospective chart review was performed to identify three cases in which SEGAs were treated via LITT and septostomy. Stereotactic ablation was performed via magnetic resonance (MR) thermometry with laser output set to 69% for 2.5min, with post-ablation scans for visualization of treatment area. Average age at surgery was 8.2years. Pre-operative tumor volumes were 0.43, 1.51, and 3.88cm3. Post-operative tumor volumes were 0.25, 0.21, and 0.68cm3. Mean tumor volume reduction was 70%. No complications occurred. LITT with septostomy should be considered a viable primary or adjunct treatment modality for SEGAs.

Survival, Prognostic Factors, and Volumetric Analysis of Extent of Resection for Anaplastic Gliomas.

PurposeThe aim of this study is to evaluate the survival rate and prognostic factors of anaplastic gliomas according to the 2016 World Health Organization classification, including extent of resection (EOR) as measured by contrast-enhanced T1-weighted magnetic resonance imaging (MRI) and the T2-weighted MRI.Materials and MethodsThe records of 113 patients with anaplastic glioma who were newly diagnosed at our institute between 2000 and 2013 were retrospectively reviewed. There were 62 cases (54.9%) of anaplastic astrocytoma, isocitrate dehydrogenase (IDH) wild-type (AAw), 18 cases (16.0%) of anaplastic astrocytoma, IDH-mutant, and 33 cases (29.2%) of anaplastic oligodendroglioma, IDH-mutant and 1p/19q-codeleted.ResultsThe median overall survival (OS) was 48.4 months in the whole anaplastic glioma group and 21.5 months in AAw group. In multivariate analysis, age, preoperative Karnofsky Performance Scale score, O6-methylguanine-DNA methyltransferase (MGMT) methylation status, postoperative tumor volume, and EOR measured from the T2 MRI sequence were significant prognostic factors. The EOR cut-off point for OS measured in contrast-enhanced T1-weighted MRI and T2-weighted MRI were 99.96% and 85.64%, respectively.ConclusionWe found that complete resection of the contrast-enhanced portion (99.96%) and more than 85.64% resection of the non-enhanced portion of the tumor have prognostic impacts on patient survival from anaplastic glioma.

Erratum. Predictors of recurrence and high growth rate of residual meningiomas after subtotal resection.

OBJECTIVE The extent of resection has been shown to improve outcomes in patients with meningiomas. However, resection can be complicated by constraining local anatomy, leading to subtotal resections. An understanding of the natural history of residual tumors is necessary to better guide postsurgical management and minimize recurrence. This study seeks to identify predictors of recurrence and high growth rate following subtotal resection of intracranial meningiomas. METHODS Adult patients who underwent primary surgical resection of a WHO grade I meningioma at a tertiary care institution from 2007-2017 were retrospectively reviewed. Volumetric tumor measurements were made on patients with subtotal resections. Stepwise multivariate proportional hazards regression analyses were performed to identify factors associated with time to recurrence, as well as stepwise multivariate regression analyses to assess for factors associated with high postoperative growth rate. RESULTS Of the 141 patients (18%) who underwent radiographic subtotal resection of an intracranial meningioma during the reviewed period, 74 (52%) suffered a recurrence, in which the median (interquartile range, IQR) time to recurrence was 14 (IQR 6-34) months. Among those tumors subtotally resected, the median pre- and postoperative tumor volumes were 17.19 cm3 (IQR 7.47-38.43 cm3) and 2.31 cm3 (IQR 0.98-5.16 cm3), which corresponded to a percentage resection of 82% (IQR 68%-93%). Postoperatively, the median growth rate was 0.09 cm3/year (IQR 0-1.39 cm3/year). Factors associated with recurrence in multivariate analysis included preoperative tumor volume (hazard ratio [HR] 1.008,95% confidence interval [CI] 1.002-1.013, p = 0.008), falcine location (HR 2.215, 95% CI 1.179-4.161, p = 0.021), tentorial location (HR 2.410, 95% CI 1.203-4.829, p = 0.024), and African American race (HR 1.811, 95% CI 1.042-3.146, p = 0.044). Residual volume (RV) was associated with high absolute annual growth rate (odds ratio [OR] 1.175, 95% CI 1.078-1.280, p < 0.0001), with the maximum RV benefit at < 5 cm3 (OR 4.056, 95% CI 1.675-9.822, p = 0.002). CONCLUSIONS By identifying predictors of recurrence and growth rate, this study helps identify potential patients with a high chance of recurrence following subtotal resection, which are those with large preoperative tumor volume, falcine location, tentorial location, and African American race. Higher RVs were associated with tumors with higher postoperative growth rates. Recurrences typically occurred 14 months after surgery.

Evidence-Based Medicine Through Development of Home-Grown Databases

Evidence-Based Medicine Through Development of Home-Grown Databases

Application of an Artificial Intelligence Algorithm to Prognostically Stratify Grade II Gliomas.

(1) Background: Recently, it has been shown that the extent of resection (EOR) and molecular classification of low-grade gliomas (LGGs) are endowed with prognostic significance. However, a prognostic stratification of patients able to give specific weight to the single parameters able to predict prognosis is still missing. Here, we adopt classic statistics and an artificial intelligence algorithm to define a multiparametric prognostic stratification of grade II glioma patients. (2) Methods: 241 adults who underwent surgery for a supratentorial LGG were included. Clinical, neuroradiological, surgical, histopathological and molecular data were assessed for their ability to predict overall survival (OS), progression-free survival (PFS), and malignant progression-free survival (MPFS). Finally, a decision-tree algorithm was employed to stratify patients. (3) Results: Classic statistics confirmed EOR, pre-operative- and post-operative tumor volumes, Ki67, and the molecular classification as independent predictors of OS, PFS, and MPFS. The decision tree approach provided an algorithm capable of identifying prognostic factors and defining both the cut-off levels and the hierarchy to be used in order to delineate specific prognostic classes with high positive predictive value. Key results were the superior role of EOR on that of molecular class, the importance of second surgery, and the role of different prognostic factors within the three molecular classes. (4) Conclusions: This study proposes a stratification of LGG patients based on the different combinations of clinical, molecular, and imaging data, adopting a supervised non-parametric learning method. If validated in independent case studies, the clinical utility of this innovative stratification approach might be proved.

Residual tumor volume discriminates prognosis after surgery for neuroendocrine liver metastasis.

We developed objective measurements of preoperative and residual tumor volume, and debulking rate, to evaluate their prognostic value for neuroendocrine liver metastasis (NELM). Seventy-three patients who underwent surgery for NELM were analyzed retrospectively. Indices of preoperative and postoperative residual tumor volume (pre-volume index [VI] and post-VI) were calculated as the sum of the cubes of individual tumor diameters on preoperative and postoperative imaging, respectively. The debulking rate (%) was calculated as 100 - 100 × post-VI/pre-VI. The classification and regression trees method was used to classify pre-VI and post-VI. Overall survival (OS) was discriminated by preoperative tumor volume (5-year OS rates, 87.8% for low pre-VI and 60.1% for high pre-VI; P = .037) and residual tumor volume (5-year OS rates, 88.1% for low post-VI and 24.8% for high post-VI; P < .001). In contrast, debulking rates of 100%, ≥90%, and <90% did not discriminate OS (5-year OS rates, 88.0%, 61.9%, and 58.9%, respectively, not significant). In multivariate analysis, residual tumor volume (high post-VI, hazard ratio, 6.40; 95% confidence interval, 1.45-32.3) was an independent prognostic factor for OS. Objective measurement of tumor volume demonstrates that residual tumor volume is prognostic after surgery for NELM.

SURG-30. CLINICAL COURSE OF IDH-MUTATED LOW-GRADE GLIOMAS DURING THE POSTSURGICAL ACTIVE MONITORING PHASE: ASYMPTOMATIC PATIENTS, WELL CONTROLLED SEIZURES, BUT CONTINUOUS GROWTH OF TUMOR RESIDUES

Abstract INTRODUCTION Postponing adjuvant treatment after resection in IDH-mutated low-grade glioma (LGG) seems appropriate in selected patients. Here we describe the clinical course of these patients during post-resection active monitoring with MRI scans, as literature on this topic is scarce. METHODS We included IDH-mutated LGG patients that underwent surgery between 2003–2016, with clinical follow-up including MR scans available. Samples were classified according to the 2016 WHO classification. We collected baseline clinical information, estimates of seizure control during follow-up, longitudinal evolution of post-resection LGG volumes when adjuvant therapy was postponed, and the clinicians’ reasons to either start immediate adjuvant treatment or postpone treatment, and reasons to initiate adjuvant treatment in later stage. We compared patients that underwent immediate postsurgical adjuvant treatment with patients that underwent active MRI monitoring until further progression. RESULTS AND CONCLUSIONS 197 patients were included, of which 108 were IDH-mutated astrocytomas, and 89 were oligodendrogliomas. Of these, 97 patients were actively followed with MRI scans, and 100 patients underwent immediate adjuvant therapy after initial surgery. Patients that received immediate adjuvant therapy were older and had less extensive resections than patients wherein adjuvant treatment was postponed (median age 45 years vs. 37 years, P&lt; 0.001; median postoperative tumor volume 31cm3 vs 2.68cm3, P&lt; 0.001). The duration of the active surveillance period in the patients wherein adjuvant treatment was postponed correlated with the extent of resection, with shorter time until adjuvant treatment in case of larger postoperative tumor volumes. All LGG lesions showed continuous growth during the active surveillance period, with median growth rates of 3mm/year for oligodendrogliomas and 4mm/year in IDH- mutated astrocytomas (P = 0.0093). Seizures were well controlled, with the majority of patients using only one anti-epileptic drug. The majority of patients stayed asymptomatic during follow-up, and the reason to initiate further adjuvant treatment was always radiological growth.

Accuracy of the neurosurgeons estimation of extent of resection in glioblastoma

BackgroundThe surgeons’ estimate of the extent of resection (EOR) shows little accuracy in previous literature. Considering the developments in surgical techniques of glioblastoma (GBM) treatment, we hypothesize an improvement in this estimation. This study aims to compare the EOR estimated by the neurosurgeon with the EOR determined using volumetric analysis on the post-operative MR scan.MethodsPre- and post-operative tumor volumes were calculated through semi-automatic volumetric assessment by three observers. Interobserver agreement was measured using intraclass correlation coefficient (ICC). A univariate general linear model was used to study the factors influencing the accuracy of estimation of resection percentage.ResultsICC was high for all three measurements: pre-operative tumor volume was 0.980 (0.969–0.987), post-operative tumor volume 0.974 (0.961–0.984), and EOR 0.947 (0.917–0.967). Estimation of EOR by the surgeon showed moderate accuracy and agreement. Multivariable analysis showed a statistically significant effect of operating neurosurgeon (p = 0.01), use of fluorescence (p < 0.001), and resection percentage (p < 0.001) on the accuracy of the EOR estimation.ConclusionAll measurements through semi-automatic volumetric analysis show a high interobserver agreement, suggesting this to be a reliable assessment of EOR. We found a moderate reliability of the surgeons’ estimate of EOR. Therefore, (early) post-operative MRI scanning for evaluation of EOR remains paramount.

Contemporary assessment of extent of resection in molecularly defined categories of diffuse low-grade glioma: a volumetric analysis.

While the effect of increased extent of resection (EOR) on survival in diffuse infiltrating low-grade glioma (LGG) patients is well established, there is still uncertainty about the influence of the new WHO molecular subtypes. The authors designed a retrospective analysis to assess the interplay between EOR and molecular classes. The authors retrospectively reviewed the records of 326 patients treated surgically for hemispheric WHO grade II LGG at Brigham and Women's Hospital and Massachusetts General Hospital (2000-2017). EOR was calculated volumetrically and Cox proportional hazards models were built to assess for predictive factors of overall survival (OS), progression-free survival (PFS), and malignant progression-free survival (MPFS). There were 43 deaths (13.2%; median follow-up 5.4 years) among 326 LGG patients. Median preoperative tumor volume was 31.2 cm3 (IQR 12.9-66.0), and median postoperative residual tumor volume was 5.8 cm3 (IQR 1.1-20.5). On multivariable Cox regression, increasing postoperative volume was associated with worse OS (HR 1.02 per cm3; 95% CI 1.00-1.03; p = 0.016), PFS (HR 1.01 per cm3; 95% CI 1.00-1.02; p = 0.001), and MPFS (HR 1.01 per cm3; 95% CI 1.00-1.02; p = 0.035). This result was more pronounced in the worse prognosis subtypes of IDH-mutant and IDH-wildtype astrocytoma, for which differences in survival manifested in cases with residual tumor volume of only 1 cm3. In oligodendroglioma patients, postoperative residuals impacted survival when exceeding 8 cm3. Other significant predictors of OS were age at diagnosis, IDH-mutant and IDH-wildtype astrocytoma classes, adjuvant radiotherapy, and increasing preoperative volume. The results corroborate the role of EOR in survival and malignant transformation across all molecular subtypes of diffuse LGG. IDH-mutant and IDH-wildtype astrocytomas are affected even by minimal postoperative residuals and patients could potentially benefit from a more aggressive surgical approach.

Chordoma of the Craniocervical Junction: Endoscopic Endonasal Approach.

Objective This study was aimed to achieve gross-total removal of a chordoma of the craniocervical junction via an endonasal approach ( Fig. 1 ). Fig. 1 Pre- and postoperative images of the craniocervical junction chordoma. ( A ) It shows a preoperative sagittal T2-weighted MRI image. ( B ) It shows a preoperative axial T2-weighted MRI image. Note that a T2-hyperintense lesion is located in the lower clivus and the odontoid. ( C ) It shows the postoperative sagittal T1-weighted gadolinium enhanced MRI image. ( D ) shows a postoperative axial T2-weighted MRI image. These images show the fat graft used for closure, but no evident tumor remnant. MRI, magnetic resonance imaging Design The present study is a case report. Setting The study was conducted at neurosurgical clinic of university hospital. Participant A 40-year-old male, with normal neurologic exam and no prior medical history, presented with a 2-year history of cervicalgia. On preoperative imaging, a midline lesion, with image characteristics of chordoma, was seen in the lower clivus and odontoid. It had limited lateral extension. Main Outcome Measures This study measures postoperative neurological deficits and postoperative tumor volume on magnetic resonance imaging (MRI). Results A binostril approach to the upper nasopharynx was performed using endoscope at 30- and 45-degree angles. Subsequently, a heart-shaped mucosal flap was made and the clivus was drilled to expose the lesion ( Fig. 2 ). After initial debulking, the ring of C1 was slightly drilled to reach the tumor in and around the odontoid. Postoperative MRI showed that a gross-total resection was achieved. The patient had no neurologic deficits postoperatively. Pathologic examination revealed a chordoma of the classical type. Fig. 2 Illustration of the endoscopic endonasal surgical technique. ( A ) It shows the surgical route (blue arrow), and location of the heart-shaped mucosal flap that was made in the upper nasopharynx (blue crescent). This figure highlights that angled endoscopes are needed to visualize the relevant operative field (yellow translucent triangle). ( B ) shows the axial view, ( C ) shows an intraoperative endoscopic view of the incision performed to achieve a heart-shaped mucosal flap, as was utilized during this case, and ( D ) shows the coronal view. ( B and D ) They show the results of postoperative image analysis, during which we segmented the drill cavity (in blue) and projected it on the preoperative CT scan of the patient. Note that besides the inferior clivus, the superior part of the ring of C1 was also drilled slightly to reach the tumor in the odontoid. CT, computed tomography. Conclusion An endoscopic endonasal approach, utilizing the heart-shaped flap and angled endoscopes and instruments, can be considered for resection of select cases of craniocervical junction chordoma with limited lateral expansion. The link to the video can be found at: https://youtu.be/rwVoZJRBIEo .

432P - Role of Intraoperative MRI (iMRI) in neurosurgery, potential imaging tool for maximizing gross total resection (GTR) rate of CNS tumours

BackgroundHigh field iMRI with integrated neuronavigation system is an advanced diagnostic tool gives information about extent of resection allowing immediate update of neuronavigation parameters after anatomic changes occuring as a result of tumour resection, cerebrospinal fluid evacuation and brain shift. Methods20 CNS tumour cases underwent Brain suite MRI prior to surgery, then surgery was done after patient registration in navigation system using iMRI. Preoperative tumor volume was manually segmented, compared with intraoperative volume after first resection attempt and final post operative volume after surgical closure to calculate extent of resection (EOR).Descriptive statistics were used to find mean, SD, frequency, percentage of variables. Normally distributed interval data reported as means by two-sample t- test. Non-normally distributed interval/ordinal data reported as median{inter-quartile ranges} and compared among groups by Wilcoxon exact test to obtain EOR values. Results20 cases allocated to two groups (G), 1st in whom surgery was complete after first iMRI and 2nd who underwent further tumour removal. In G1 surgery was terminated in 11 cases after iMRI, GTR in 81.8% cases. iMRI showed subtotal resection(STR) in 18.2% patients but surgery stopped owing to infiltration of eloquent brain. Median preoperative tumour volume was 40.8cm3. Median postoperative tumour volume was 0.81cm3 with a significant p value (<0.001). Median EOR was 98.5% in G1. In G2, 9 of 20 (45%) underwent further resection of residual tumour after post resection iMRI. GTR in 77.7% and STR in 22.3%, because of tumour’s close proximity to eloquent brain area. Median % of tumour resection after the first iMRI was 82.65%. Median EOR from the final postoperative iMRI was 98.3%. GTR increased from 45% to 80 % after use of iMRI. Median % of residual tumour volume significantly decreased from 5.3% to 1.7 % (p value <0.001). Mean control tumour volume was 9.67% and final post operative volume of 4.72% , which is almost half of intraoperative tumour volume (p value <0.001). ConclusionsiMRI has potential role in maximizing gross total resection rates of CNS tumours which has an overall great prognostic impact. Legal entity responsible for the studyInstitutional ethics committee, Max Superspeciality Hospital, New Delhi. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

P14.109 Standard error of measurement (SEM) and intraclass coefficient (ICC) in volumetric assessment of postoperative residual tumor volume in glioblastoma

Abstract BACKGROUND Residual contrast-enhancing tumor volume (RTV) is an important parameter in glioblastoma (GBM) treatment. MR imaging within 48hrs after surgery is the preferred imaging modality but is prone to variability because of different interpretation by different raters. Variability can be statistically assessed using agreement and reliability parameters. The former are underreported in medical literature and are often mixed up with the latter. But agreement parameters are to be preferred in assessment of the level of agreement between repeated measurements. A typical agreement parameter is the standard error of measurement (SEM), which is expressed in the same unit as the original variable. Reliability parameters on the other hand relate the measurement error to the variability between study objects. A typical and well-known reliability parameter is the intraclass coefficient (ICC), expressed on a scale from 0 to 1. We investigated both SEM and ICC between and within raters concerning RTV in GBM. MATERIAL AND METHODS Ten cases were randomly selected from a glioblastoma database. Three observers (a neuroradiologist, NR; a neurosurgeon, NS; a junior neurosurgical trainee, JNT) performed two sessions of volumetric assessment of RTV, blinded for each others results and independently from each other. At least 2 months passed in between sessions. Volumetric assessment was performed using Magnetisation Prepared-Rapid Echo Gradient (MPRAGE) 0.9mm images in standard neuronavigation software (Medtronic Inc, Louisville, CO, USA), in comparison with other images when deemed necessary by the individual rater. Semi-automated segmentation was applied, meaning that the rater used automated segmentation technique on each slice, but adjusted according to his of her own judgement (segmentational growing around the region of interest). Volumes were expressed in mL. Statistical analysis was performed using R software (version 3.4.3 (30-11-2017); Attached packages: psych foreign pander date knitr) to calculate ICCs. SEMs were manually calculated using the formulae by De Vet et al. RESULTS Intrarater ICC agreement was 0.96 (0.87–0.99), 1 (0.98–1) and 0.77 (0.34–0.94) for NS, NR and JNT resp. SEM agreement was 0.87mL, 0.25mL and 2.67mL resp. Interrater variability was as follows: NS-NR 0.89 (0.65–0.97) ICC and 1.42mL SEM; NS-JNT 0.93 (0.77–0.98) ICC and 1.52mL SEM; NR-JNT 0.74 (0.28–0.93) ICC and 2.81mL SEM. CONCLUSION Agreement on postoperative residual contrast-enchancing tumor volume in GBM was high between neurosurgeon and neuroradiologist, with SEM 1.42mL. SEM probably reflects the differences in interpretation, especially of areas with blood products on postoperative MR imaging. Both intrarater and interrater agreement was highest for more experienced raters.

Perioperative outcomes following reoperation for recurrent insular gliomas.

Greater extent of resection (EOR) improves overall survival and progression-free survival for patients with low- and high-grade glioma. While resection for newly diagnosed insular gliomas can be performed with minimal morbidity, perioperative morbidity is not clearly defined for patients undergoing a repeat resection for recurrent insular gliomas. In this study the authors report on tumor characteristics, tumor EOR, and functional outcomes in patients undergoing reoperation for recurrent insular glioma. Adult patients with insular gliomas (WHO grades II-IV) who underwent index resection followed by reoperation were identified through the University of California San Francisco Brain Tumor Center. Treatment history and functional outcomes were collected retrospectively from the electronic medical record. Pre- and postoperative tumor volumes were quantified using software with region-of-interest analysis based on FLAIR and T1-weighted postgadolinium sequences from pre- and postoperative MRI. Forty-four patients (63.6% male, 36.4% female) undergoing 49 reoperations for recurrent insular tumors were identified with a median follow-up of 741 days. Left- and right-sided tumors comprised 52.3% and 47.7% of the cohort, respectively. WHO grade II, III, and IV gliomas comprised 46.9%, 28.6%, and 24.5% of the cohort, respectively. Ninety-five percent (95.9%) of cases involved language and/or motor mapping. Median EOR of the insular component of grade II, III, and IV tumors were 82.1%, 75.0%, and 94.6%, respectively. EOR during reoperation was not impacted by Berger-Sanai insular zone or tumor side. At the time of reoperation, 44.9% of tumors demonstrated malignant transformation to a higher WHO grade. Ninety-day postoperative assessment confirmed that 91.5% of patients had no new postoperative deficit attributable to surgery. Of those with new deficits, 3 (6.4%) had a visual field cut and 1 (2.1%) had hemiparesis (strength grade 1-2/5). The presence of a new postoperative deficit did not vary with EOR. Recurrent insular gliomas, regardless of insular zone and pathology, may be reoperated on with an overall acceptable degree of resection and safety despite their anatomical and functional complexities. The use of intraoperative mapping utilizing asleep or awake methods may reduce morbidity to acceptable rates despite prior surgery.

Deep learning derived tumor infiltration maps for personalized target definition in Glioblastoma radiotherapy

PurposeGlioblastoma is routinely treated by concomitant radiochemotherapy. Current target definition guidelines use anatomic MRI (magnetic resonance imaging) scans, taking into account contrast enhancement and the rather unspecific hyperintensity on the fluid-attenuated inversion recovery (FLAIR) sequence. Methods and materialsWe applied deep learning based free water correction of diffusion tensor imaging (DTI) scans to estimate the infiltrative gross tumor volume (iGTV) inside of the FLAIR hyperintense region. We analyzed the resulting iGTVs and their impact on target volume definition in a retrospective cohort of 33 GBM patients. ResultsiGTVs were significantly smaller compared to standard pre- and post-operative gross tumor volume (GTV) definitions. Two novel infiltrative tumor GTVs (nGTVPRE-OP and nGTVPOST-OP) defined as the conjunction volume of the standard GTV and the iGTV showed only a moderate increase in size compared to standard GTV definitions. On postoperative scans, the iGTV was predominantly covered by the two clinical target volume (CTV) concepts CTVEORTC and CTVROTG1. A novel infiltrative tumor CTV (nCTV) [nGTVPOST-OP + 2 cm margin] was significantly smaller compared to CTVROTG1 but larger than CTVEORTC. The overlap volume and conformity index demonstrated a distinct spatial configuration of the nCTV. Tumor recurrences overlapped with the iGTV in all but one patients and were completely covered by the nCTV in all patients. After reducing the margin to 1 cm recurrences coverage was at least in-field in all patients. ConclusionTo conclude, free water corrected DTI scans may help to define infiltrative tumor areas of GBM that could ultimately be used to individualize RT treatment planning in terms of dose sparing or dose escalation.

Automatic assessment of glioma burden: a deep learning algorithm for fully automated volumetric and bidimensional measurement.

BackgroundLongitudinal measurement of glioma burden with MRI is the basis for treatment response assessment. In this study, we developed a deep learning algorithm that automatically segments abnormal fluid attenuated inversion recovery (FLAIR) hyperintensity and contrast-enhancing tumor, quantitating tumor volumes as well as the product of maximum bidimensional diameters according to the Response Assessment in Neuro-Oncology (RANO) criteria (AutoRANO).MethodsTwo cohorts of patients were used for this study. One consisted of 843 preoperative MRIs from 843 patients with low- or high-grade gliomas from 4 institutions and the second consisted of 713 longitudinal postoperative MRI visits from 54 patients with newly diagnosed glioblastomas (each with 2 pretreatment “baseline” MRIs) from 1 institution.ResultsThe automatically generated FLAIR hyperintensity volume, contrast-enhancing tumor volume, and AutoRANO were highly repeatable for the double-baseline visits, with an intraclass correlation coefficient (ICC) of 0.986, 0.991, and 0.977, respectively, on the cohort of postoperative GBM patients. Furthermore, there was high agreement between manually and automatically measured tumor volumes, with ICC values of 0.915, 0.924, and 0.965 for preoperative FLAIR hyperintensity, postoperative FLAIR hyperintensity, and postoperative contrast-enhancing tumor volumes, respectively. Lastly, the ICCs for comparing manually and automatically derived longitudinal changes in tumor burden were 0.917, 0.966, and 0.850 for FLAIR hyperintensity volume, contrast-enhancing tumor volume, and RANO measures, respectively.ConclusionsOur automated algorithm demonstrates potential utility for evaluating tumor burden in complex posttreatment settings, although further validation in multicenter clinical trials will be needed prior to widespread implementation.

Fractionated Gamma Knife radiosurgery for skull base meningiomas: a single-institution experience

OBJECTIVEGamma Knife radiosurgery (GKRS) has been successfully used for the treatment of intracranial meningiomas given its steep dose gradients and high-dose conformality. However, treatment of skull base meningiomas (SBMs) may pose significant risk to adjacent radiation-sensitive structures such as the cranial nerves. Fractionated GKRS (fGKRS) may decrease this risk, but until recently it has not been practical with traditional pin-based systems. This study reports the authors' experience in treating SBMs with fGKRS, using a relocatable, noninvasive immobilization system.METHODSThe authors performed a retrospective review of all patients who underwent fGKRS for SBMs between 2013 and 2018 delivered using the Extend relocatable frame system or the Icon system. Patient demographics, pre- and post-GKRS tumor characteristics, perilesional edema, prior treatment details, and clinical symptoms were evaluated. Volumetric analysis of pre-GKRS, post-GKRS, and subsequent follow-up visits was performed.RESULTSTwenty-five patients met inclusion criteria. Nineteen patients were treated with the Icon system, and 6 patients were treated with the Extend system. The mean pre-fGKRS tumor volume was 7.62 cm3 (range 4.57-13.07 cm3). The median margin dose was 25 Gy delivered in 4 (8%) or 5 (92%) fractions. The median follow-up time was 12.4 months (range 4.7-17.4 months). Two patients (9%) experienced new-onset cranial neuropathy at the first follow-up. The mean postoperative tumor volume reduction was 15.9% with 6 patients (27%) experiencing improvement of cranial neuropathy at the first follow-up. Median first follow-up scans were obtained at 3.4 months (range 2.8-4.3 months). Three patients (12%) developed asymptomatic, mild perilesional edema by the first follow-up, which remained stable subsequently.CONCLUSIONSfGKRS with relocatable, noninvasive immobilization systems is well tolerated in patients with SBMs and demonstrated satisfactory tumor control as well as limited radiation toxicity. Future prospective studies with long-term follow-up and comparison to single-session GKRS or fractionated stereotactic radiotherapy are necessary to validate these findings and determine the efficacy of this approach in the management of SBMs.

Differences in spatial distribution between WHO 2016 low-grade glioma molecular subgroups.

BackgroundSeveral studies reported a correlation between anatomic location and genetic background of low-grade gliomas (LGGs). As such, tumor location may contribute to presurgical clinical decision-making. Our purpose was to visualize and compare the spatial distribution of different WHO 2016 gliomas, frequently aberrated single genes and DNA copy number alterations within subgroups, and groups of postoperative tumor volume.MethodsAdult grade II glioma patients (WHO 2016 classified) diagnosed between 2003 and 2016 were included. Tumor volume and location were assessed with semi-automatic software. All volumes of interest were mapped to a standard reference brain. Location heatmaps were created for each WHO 2016 glioma subgroup, frequently aberrated single genes and copy numbers (CNVs), as well as heatmaps according to groups of postoperative tumor volume. Differences between subgroups were determined using voxelwise permutation testing.ResultsA total of 110 IDH mutated astrocytoma patients, 92 IDH mutated and 1p19q co-deleted oligodendroglioma patients, and 22 IDH wild-type astrocytoma patients were included. We identified small regions in which specific molecular subtypes occurred more frequently. IDH-mutated LGGs were more frequently located in the frontal lobes and IDH wild-type tumors more frequently in the basal ganglia of the right hemisphere. We found no localizations of significant difference for single genes/CNVs in subgroups, except for loss of 9p in oligodendrogliomas with a predilection for the left parietal lobes. More extensive resections in LGG were associated with frontal locations.ConclusionsWHO low-grade glioma subgroups show differences in spatial distribution. Our data may contribute to presurgical clinical decision-making in LGG patients.