Historical controls for phase II surgically based trials requiring gross total resection of glioblastoma multiforme

Interactions Between Anti-Angiogenic Therapy and Immunotherapy in Glioblastoma

Glioblastoma is the most aggressive brain tumor with a median survival ranging from 6.2 to 16.7 months. The complex interactions between the tumor and the cells of tumor microenvironment leads to tumor evolution which ultimately results in treatment failure. Immunotherapy has shown great potential in the treatment of solid tumors but has been less effective in treating glioblastoma. Failure of immunotherapy in glioblastoma has been attributed to low T-cell infiltration in glioblastoma and dysfunction of the T-cells that are present in the glioblastoma microenvironment. Recent advances in single-cell sequencing have increased our understanding of the transcriptional changes in the tumor microenvironment pre and post-treatment. Another treatment modality targeting the tumor microenvironment that has failed in glioblastoma has been anti-angiogenic therapy such as the VEGF neutralizing antibody bevacizumab, which did not improve survival in randomized clinical trials. Interestingly, the immunosuppressed microenvironment and abnormal vasculature of glioblastoma interact in ways that suggest the potential for synergy between these two therapeutic modalities that have failed individually. Abnormal tumor vasculature has been associated with immune evasion and the creation of an immunosuppressive microenvironment, suggesting that inhibiting pro-angiogenic factors like VEGF can increase infiltration of effector immune cells into the tumor microenvironment. Remodeling of the tumor vasculature by inhibiting VEGFR2 has also been shown to improve the efficacy of PDL1 cancer immunotherapy in mouse models of different cancers. In this review, we discuss the recent developments in our understanding of the glioblastoma tumor microenvironment specially the tumor vasculature and its interactions with the immune cells, and opportunities to target these interactions therapeutically. Combining anti-angiogenic and immunotherapy in glioblastoma has the potential to unlock these therapeutic modalities and impact the survival of patients with this devastating cancer.

Supramaximal resection: A systematic review of its safety, efficacy and feasibility in glioblastoma

The philosophy of 'supramaximal resection' (SMR) beyond the T1-enhanced margin holds some potential in glioblastoma surgery, but the quality of available literature has not been elucidated. A systematic review of published studies of SMR in glioblastoma surgery was performed. Articles were sought in MEDLINE, EMBASE, Scopus and Cochrane Central Register for Clinical Trials. The search items were grouped into three themes; supramaximal resection, glioblastoma and outcomes. Cases were included wherein the initial extent of resection was described as exceeding gross total resection, that is to say, beyond the area of T1-enhancement on MRI. Only newly diagnosed glioblastoma was considered. Articles containing primary patient data, including outcome data, were included; reviews, editorials, descriptive articles and systematic reviews were excluded. Subsequently, 1123 unique articles were initially retrieved. After screening article titles and abstracts for relevance to SMR in glioblastoma, seven articles remained, and were all included post-full text review. No randomized controlled trials were discovered. Almost all studies were of Level 4 quality, according to Oxford Center for Evidence-Based Medicine guidelines. The included articles yielded a total of 2019 surgically treated glioblastoma patients, 13.5% of whom underwent SMR. Preliminary results suggest SMR of glioblastoma positively impacts overall and progression free survival. However, the contemporaneous literature supporting glioblastoma SMR is of low quality, with neither anatomical nor radiographic definitional consensus for what constitutes SMR. Prospective studies of larger pooled populations with standardized technical, radiological and outcome measures in designated centers would help minimize bias and validate SMR in appropriately selected glioblastoma patients.

Association between medical academic genealogy and publication outcome: impact of unconscious bias on scientific objectivity

BACKGROUND

Our previous studies suggest that the training history of an investigator, termed "medical academic genealogy", influences the outcomes of that investigator's research. Here, we use meta-analysis and quantitative statistical modeling to determine whether such effects contribute to systematic bias in published conclusions.

METHODS

A total of 108 articles were identified through a comprehensive search of the high-grade glioma (HGG) surgical resection literature. Analysis was performed on the 70 articles with sufficient data for meta-analysis. Pooled estimates were generated for key academic genealogies. Monte Carlo simulations were performed to determine whether the effects attributed to genealogy alone can arise due to chance alone.

RESULTS

Meta-analysis of the HGG literature without consideration for academic medical genealogy revealed that gross total resection (GTR) was associated with a significant decrease in the odds ratio (OR) for the hazard of death after surgery for both anaplastic astrocytoma (AA) and glioblastoma (AA: log [OR] = - 0.04, 95% CI [- 0.07 to - 0.01]; glioblastoma log [OR] = - 0.36, 95% CI [- 0.44 to - 0.29]). For the glioblastoma literature, meta-analysis of articles contributed by members of a genealogy consisting of mostly radiation oncologists revealed no reduction in the hazard of death after GTR [log [OR] = - 0.16, 95% CI [- 0.41 to 0.09]. In contrast, meta-analysis of published articles contributed by members of a genealogy consisting of mostly neurosurgeons revealed that GTR was associated with a significant reduction in the hazard of death [log [OR] = - 0.29, 95% CI [- 0.40 to 0.18]. Monte Carlo simulation revealed that the observed discrepancy between the articles contributed by the members of these two genealogies was unlikely to arise by chance alone (p < 0.006).

CONCLUSIONS

Meta-analysis of articles contributed by authors belonging to the different medical academic genealogies yielded distinct and contradictory pooled point-estimates, suggesting that genealogy contributes to systematic bias in the published literature.

A Phase 1 Dose-Escalation Study of Oral 5-Aminolevulinic Acid in Adult Patients Undergoing Resection of a Newly Diagnosed or Recurrent High-Grade Glioma

BACKGROUND

The utility of oral 5-aminolevulinic acid (5-ALA)/protoporphyrin fluorescence for the resection of high-grade gliomas is well documented. This drug has received regulatory approval in Europe but awaits approval in the United States.

OBJECTIVE

To identify the appropriate dose and toxicity or harms of 5-ALA used for enhanced intraoperative visualization of malignant brain tumors, reported from a single medical center in the United States.

METHODS

Prior to craniotomy for resection of a presumed high-grade glioma, individuals were given oral 5-ALA as part of a rapid dose-escalation scheme. At least 3 patients were selected for each dose level from 10 to 50 mg/kg in 10 mg/kg increments. Adverse events, intensity of tumor fluorescence, and results of biopsies in areas of tumor and the tumor bed under white light and deep blue light were recorded.

RESULTS

A total of 19 patients were studied in this phase 1 study. Serious adverse events were unrelated to the ingestion of 5-ALA. At the highest dose level studied (50 mg/kg), 2 out of 6 patients were observed to have transient dermatologic redness and peeling. These were grade 1 adverse events, which were not serious enough to be dose limiting. Patients at higher dose levels (>40 mg/kg) were more likely to have strong tumor fluorescence. There were no instances of false positive fluorescence.

CONCLUSION

The use of 5-ALA for brain tumor fluorescence is safe and effective to a dose of 50 mg/kg. Dose-limiting toxicity was not reached in this study.

Intracranial rat glioma model for tumor resection and local treatment

BACKGROUND

Although tumor resection is among the most important prognostic factors, high grade gliomas regrow in most cases. Also, resection of glial tumors in eloquent brain regions is not or only partially possible. Despite these severe restraints, however, only a few in-vivo models have been established to investigate tumor recurrence and local treatment. Here we characterize the intracranial BT4Ca rat glioma as a model for these aspects.

NEW METHOD

BT4Ca cells were stereotaxically implanted into the frontal cortex of BDIX rats. Rats were than allocated to (1) a control group, which received no further treatment; (2) a catheter group, where a catheter was implanted for repeated microinjection of vehicle every 3rd day as catheter-control; (3) a resection group, where the tumor was microsurgically removed eight days after cell injection. Postoperatively, survival time, weight and general health condition were scored and the tumor size was histologically assessed.

RESULTS

Injection of BT4Ca cells induced fast-growing tumors with a mean survival time of 16 days in the control and catheter groups. Resection significantly prolonged survival time whereby the tumor regrew in all rats. Tumor size was similar between all groups.

COMPARISON WITH EXISTING METHOD(S)

We here present a robust and reliable intracranial rat glioma model, which is suitable to simulate tumor recurrence after surgical resection and local treatment. Importantly, this model does not require advanced imaging or elaborate surgical techniques.

CONCLUSIONS

The intracranial BT4Ca glioma model appears to be a feasible tool to investigate tumor recurrence after resection and to test local treatment.

Association of the Extent of Resection With Survival in Glioblastoma: A Systematic Review and Meta-analysis

Importance

Glioblastoma multiforme (GBM) remains almost invariably fatal despite optimal surgical and medical therapy. The association between the extent of tumor resection (EOR) and outcome remains undefined, notwithstanding many relevant studies.

Objective

To determine whether greater EOR is associated with improved 1- and 2-year overall survival and 6-month and 1-year progression-free survival in patients with GBM.

Data Sources

Pubmed, CINAHL, and Web of Science (January 1, 1966, to December 1, 2015) were systematically reviewed with librarian guidance. Additional articles were included after consultation with experts and evaluation of bibliographies. Articles were collected from January 15 to December 1, 2015.

Study Selection

Studies of adult patients with newly diagnosed supratentorial GBM comparing various EOR and presenting objective overall or progression-free survival data were included. Pediatric studies were excluded.

Data Extraction and Synthesis

Data were extracted from the text of articles or the Kaplan-Meier curves independently by investigators who were blinded to each other's results. Data were analyzed to assess mortality after gross total resection (GTR), subtotal resection (STR), and biopsy. The body of evidence was evaluated according to Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria and PRISMA guidelines.

Main Outcome and Measures

Relative risk (RR) for mortality at 1 and 2 years and progression at 6 months and 1 year.

Results

The search produced 37 studies suitable for inclusion (41 117 unique patients). The meta-analysis revealed decreased mortality for GTR compared with STR at 1 year (RR, 0.62; 95% CI, 0.56-0.69; P < .001; number needed to treat [NNT], 9) and 2 years (RR, 0.84; 95% CI, 0.79-0.89; P < .001; NNT, 17). The 1-year risk for mortality for STR compared with biopsy was reduced significantly (RR, 0.85; 95% CI, 0.80-0.91; P < .001). The risk for mortality was similarly decreased for any resection compared with biopsy at 1 year (RR, 0.77; 95% CI, 0.71-0.84; P < .001; NNT, 21) and 2 years (RR, 0.94; 95% CI, 0.89-1.00; P = .04; NNT, 593). The likelihood of disease progression was decreased with GTR compared with STR at 6 months (RR, 0.72; 95% CI, 0.48-1.09; P = .12; NNT, 14) and 1 year (RR, 0.66; 95% CI, 0.43-0.99; P < .001; NNT, 26). The quality of the body of evidence by the GRADE criteria was moderate to low.

Conclusion and Relevance

This analysis represents the largest systematic review and only quantitative systematic review to date performed on this subject. Compared with STR, GTR substantially improves overall and progression-free survival, but the quality of the supporting evidence is moderate to low.

Role of adjuvant or salvage radiosurgery in the management of unresected residual or progressive glioblastoma multiforme in the pre-bevacizumab era

OBJECT

After initial standard of care management of glioblastoma multiforme (GBM), relatively few proven options remain for patients with unresected progressive tumor. Numerous reports describe the value of radiosurgery, yet this modality appears to remain underutilized. The authors analyzed the outcomes of early adjuvant stereotactic radiosurgery (SRS) for unresected tumor or later salvage SRS for progressive GBM. Radiosurgery was performed as part of the multimodality management and was combined with other therapies. Patients continued to receive additional chemotherapy after SRS and prior to progression being documented. In this retrospective analysis, the authors evaluated factors that affected patient overall survival (OS) and progression-free survival.

METHODS

Between 1987 and 2008 the authors performed Gamma Knife SRS in 297 patients with histologically proven GBMs. All patients had received prior fractionated radiation therapy, and 66% had undergone one or more chemotherapy regimens. Ninety-six patients with deep-seated unresectable GBMs underwent biopsy only. Of those in whom excision had been possible, resection was considered to be gross total in 68 and subtotal in 133. The median patient age was 58 years (range 23-89 years) and the median tumor volume was 14 cm(3) (range 0.26-84.2 cm(3)). The median prescription dose delivered to the imaging-defined tumor margin was 15 Gy (range 9-25 Gy). The median follow-up duration was 8.6 months (range 1.1-173 months). Cox regression models were used to analyze survival outcomes. Variables examined included age, residual versus recurrent tumor, prior chemotherapy, time to first recurrence, SRS dose, and gross tumor volume.

RESULTS

The median survival times after radiosurgery and after diagnosis were 9.03 and 18.1 months, respectively. The 1-year and 2-year OS after SRS were 37.9% and 16.7%, respectively. The 1-year and 2-year OS after diagnosis were 76.2% and 30.8%, respectively. Using multivariate analysis, factors associated with improved OS after diagnosis were younger age (< 60 years) at diagnosis (p < 0.0001), tumor volume < 14 cm(3) (p < 0.001), use of prior chemotherapy (p = 0.001), and radiosurgery at the time of recurrence (p < 0.0001). Multivariate analysis showed that younger age (p < 0.0001) and smaller tumor volume (< 14 cm(3)) (p = 0.001) were significantly associated with increased OS after SRS. Adverse radiation effects were seen in 69 patients (23%). Fifty-eight patients (19.5%) underwent additional resection after SRS. The median survivals after diagnosis for recursive partitioning analysis Classes III, IV and V+VI were 31.6, 20.8, and 16.7 months, respectively.

CONCLUSIONS

In this analysis 30% of a heterogeneous cohort of GBM patients eligible for SRS had an OS of 2 years. Radiosurgery at the time of tumor progression was associated with a median survival of 21.8 months. The role of radiosurgery for GBMs remains controversial. The findings in this study support the need for a funded and appropriately designed clinical trial that will provide a higher level of evidence regarding the future role of SRS for glioblastoma patients in whom disease has progressed despite standard management.

5-Aminolevulinic acid fluorescence in high grade glioma surgery: surgical outcome, intraoperative findings, and fluorescence patterns

Background. 5-Aminolevulinic acid (5-ALA) fluorescence is a validated technique for resection of high grade gliomas (HGG); the aim of this study was to evaluate the surgical outcome and the intraoperative findings in a consecutive series of patients. Methods. Clinical and surgical data from patients affected by HGG who underwent surgery guided by 5-ALA fluorescence at our Department between June 2011 and February 2014 were retrospectively evaluated. Surgical outcome was evaluated by assessing the resection rate as gross total resection (GTR) > 98% and GTR > 90%. We finally stratified data for recurrent surgery, tumor location, tumor size, and tumor grade (IV versus III grade sec. WHO). Results. 94 patients were finally enrolled. Overall GTR > 98% and GTR > 90% was achieved in 93% and 100% of patients. Extent of resection (GTR > 98%) was dependent on tumor location, tumor grade (P < 0.05), and tumor size (P < 0.05). In 43% of patients the boundaries of fluorescent tissue exceeded those of tumoral tissue detected by neuronavigation, more frequently in larger (57%) (P < 0.01) and recurrent (60%) tumors. Conclusions. 5-ALA fluorescence in HGG surgery enables a GTR in 100% of cases even if selection of patients remains a main bias. Recurrent surgery, and location, size, and tumor grade can predict both the surgical outcome and the intraoperative findings.

5-aminolevulinic acid (5-ALA) fluorescence guided surgery of high-grade gliomas in eloquent areas assisted by functional mapping. Our experience and review of the literature

BACKGROUND

Only few data are available on the specific topic of 5-aminolevulinic acid (5-ALA) guided surgery of high-grade gliomas (HGG) located in eloquent areas. Studies focusing specifically on the post-operative clinical outcome of such patients are yet not available, and it has not been so far explored whether such approach could be more suitable for some particular subgroups of patients.

METHODS

Patients affected by HGG in eloquent areas who underwent surgery assisted by 5-ALA fluorescence and intra-operative monitoring were prospectively recruited in our Department between June 2011 and August 2012. Resection rate was reported as complete resection of enhancing tumor (CRET), gross total resection (GTR) >98 % and GTR > 90 %. Clinical outcome was evaluated at 7, 30, and 90 days after surgery.

RESULTS

Thirty-one patients were enrolled. Resection was complete (CRET) in 74 % of patients. Tumor removal was stopped to avoid neurological impairment in 26 % of cases. GTR > 98 % and GTR > 90 % was achieved in 93 % and 100 % of cases, respectively. First surgery and awake surgery had a CRET rate of 80 % and 83 %, respectively. Even though at the first-week assessment 64 % of patients presented neurological impairment, there was a 3 % rate of severe morbidity at the 90th day assessment. Newly diagnosed patients had a significantly lower morbidity (0 %) and post-operative higher median KPS. Both pre-operative neurological condition and improvement after corticosteroids resulted significantly predictive of post-operative functional outcome.

CONCLUSIONS

5-ALA surgery assisted by functional mapping makes high HGG resection in eloquent areas feasible , through a reasonable rate of late morbidity. This emerges even more remarkably for selected patients.

Gross Total Resection Rates in Contemporary Glioblastoma Surgery

BACKGROUND:

Complete resection of contrast-enhancing tumor has been recognized as an important prognostic factor in patients with glioblastoma and is a primary goal of surgery. Various intraoperative technologies have recently been introduced to improve glioma surgery.

OBJECTIVE:

To evaluate the impact of using 5-aminolevulinic acid and intraoperative mapping and monitoring on the rate of complete resection of enhancing tumor (CRET), gross total resection (GTR), and new neurological deficits as part of an institutional protocol.

METHODS:

One hundred three consecutive patients underwent resection of glioblastoma from August 2008 to November 2010. Eligibility for CRET was based on the initial magnetic resonance imaging assessed by 2 reviewers. The primary end point was the number of patients with CRET and GTR. Secondary end points were volume of residual contrast-enhancing tissue and new postoperative neurological deficits.

RESULTS:

Fifty-three patients were eligible for GTR/CRET (n = 43 newly diagnosed glioblastoma, n = 10 recurrent); 13 additional patients received surgery for GTR/CRET-ineligible glioblastoma. GTR was achieved in 96% of patients (n = 51, no residual enhancement &gt; 0.175 cm3); CRET was achieved in 89% (n = 47, no residual enhancement). Postoperatively, 2 patients experienced worsening of preoperative hemianopia, 1 patient had a new mild hemiparesis, and another patient sustained sensory deficits.

CONCLUSION:

Using 5-aminolevulinic acid imaging and intraoperative mapping/monitoring together leads to a high rate of CRET and an increased rate of GTR compared with the literature without increasing the rate of permanent morbidity. The combination of safety and resection-enhancing intraoperative technologies was likely to be the major drivers for this high rate of CRET/GTR.

A novel volume-age-KPS (VAK) glioblastoma classification identifies a prognostic cognate microRNA-gene signature

BACKGROUND

Several studies have established Glioblastoma Multiforme (GBM) prognostic and predictive models based on age and Karnofsky Performance Status (KPS), while very few studies evaluated the prognostic and predictive significance of preoperative MR-imaging. However, to date, there is no simple preoperative GBM classification that also correlates with a highly prognostic genomic signature. Thus, we present for the first time a biologically relevant, and clinically applicable tumor Volume, patient Age, and KPS (VAK) GBM classification that can easily and non-invasively be determined upon patient admission.

METHODS

We quantitatively analyzed the volumes of 78 GBM patient MRIs present in The Cancer Imaging Archive (TCIA) corresponding to patients in The Cancer Genome Atlas (TCGA) with VAK annotation. The variables were then combined using a simple 3-point scoring system to form the VAK classification. A validation set (N = 64) from both the TCGA and Rembrandt databases was used to confirm the classification. Transcription factor and genomic correlations were performed using the gene pattern suite and Ingenuity Pathway Analysis.

RESULTS

VAK-A and VAK-B classes showed significant median survival differences in discovery (P = 0.007) and validation sets (P = 0.008). VAK-A is significantly associated with P53 activation, while VAK-B shows significant P53 inhibition. Furthermore, a molecular gene signature comprised of a total of 25 genes and microRNAs was significantly associated with the classes and predicted survival in an independent validation set (P = 0.001). A favorable MGMT promoter methylation status resulted in a 10.5 months additional survival benefit for VAK-A compared to VAK-B patients.

CONCLUSIONS

The non-invasively determined VAK classification with its implication of VAK-specific molecular regulatory networks, can serve as a very robust initial prognostic tool, clinical trial selection criteria, and important step toward the refinement of genomics-based personalized therapy for GBM patients.

Ultrasound-guided operations in unselected high-grade gliomas--overall results, impact of image quality and patient selection

BACKGROUND

A number of tools, including intraoperative ultrasound, are reported to facilitate surgical resection of high-grade gliomas. However, results from selected surgical series do not necessarily reflect the effectiveness in common neurosurgical practice. Delineation of seemingly similar brain tumours vary in different ultrasound-guided operations, perhaps limiting usefulness in certain patients.

METHODS

We explore and describe the results associated with use of the SonoWand system with intraoperative ultrasound in a population-based, unselected, high-grade glioma series. Surgeons filled out questionnaires about presumed extent of resection, use of ultrasound and ultrasound image quality just after surgery. We evaluate the impact of ultrasound image quality. We also explore the importance of patient selection for surgical results.

RESULTS

Of 156 consecutive malignant glioma operations, 142 (91%) were resections whilst 14 (9%) were only biopsies. We achieved gross total resection (GTR) in 37% of all high-grade glioma resections, whilst worsening of functional status was seen in 13%. The risk of getting worse was significantly higher in reoperations, resections in eloquent locations, resections in cases with poor ultrasound image quality, resection when surgeons' resection grade estimates were inaccurate and in cases with surgery-related complications. Aiming for GTR, unifocality of lesion, non-eloquent location and medium or good ultrasound image quality were identified as independent factors associated with achieving GTR.

CONCLUSION

We report good overall results, both in terms of resection grades and functional outcome in consecutive malignant glioma resections, in which intraoperative ultrasound was used in 95%. We observed a seeming dose-response relationship between ultrasound image quality and clinical and radiological results. This may suggest that better ultrasound facilitates better surgery. The study also clearly demonstrates that, in terms of surgical results, the selection of patients seems to be much more important than the selection of surgical tools.

ASSOCIATION OF SURGICALLY ACQUIRED MOTOR AND LANGUAGE DEFICITS ON OVERALL SURVIVAL AFTER RESECTION OF GLIOBLASTOMA MULTIFORME

OBJECTIVE

Balancing the benefits of extensive tumor resection with the consequence of potential postoperative deficits remains a challenge in malignant astrocytoma surgery. Although studies have suggested that increasing extent of resection may benefit survival, the effect of new postoperative deficits on survival remains unclear. We set out to determine whether new-onset postoperative motor or speech deficits were associated with survival in our institutional experience with glioblastoma multiforme (GBM).

METHODS

We retrospectively reviewed records of all patients (age range, 18–70 years; Karnofsky Performance Scale score, 80–100) who had undergone GBM resection between 1996 and 2006 at a single institution. Survival was compared between patients who had experienced surgically acquired motor or language deficits versus those who did not experience these deficits.

RESULTS

Three hundred six consecutive patients (age, 54 ± 11 years; median Karnofsky Performance Scale score, 80) underwent primary GBM resection. Nineteen patients (6%) developed surgically acquired motor deficits and 15 (5%) developed surgically acquired language deficits. Median survival was decreased in patients who acquired language deficits (9.6 months; P &lt; 0.05) or motor deficits (9.0 months; P &lt; 0.05) versus patients without surgically acquired deficits (12.8 months). Two-year survival was 8% and 0% for patients with surgically acquired motor or language deficits, respectively, versus 23% for patients without new-onset deficits.

CONCLUSION

In our experience, the development of new perioperative motor or language deficits was associated with decreased overall survival despite similar extent of resection and adjuvant therapy. Although it is well known that surgically induced neurological deficits affect quality of life, our results suggest that these surgical morbidities may also affect survival. Care should be taken to avoid surgically induced deficits in the management of GBM.

Independent association of extent of resection with survival in patients with malignant brain astrocytoma

OBJECT

With recent advances in the adjuvant treatment of malignant brain astrocytomas, it is increasingly debated whether extent of resection affects survival. In this study, the authors investigate this issue after primary and revision resection of these lesions.

METHODS

The authors retrospectively reviewed the cases of 1215 patients who underwent surgery for malignant brain astrocytomas (World Health Organization [WHO] Grade III or IV) at a single institution from 1996 to 2006. Patients with deep-seated or unresectable lesions were excluded. Based on MR imaging results obtained < 48 hours after surgery, gross-total resection (GTR) was defined as no residual enhancement, near-total resection (NTR) as having thin rim enhancement of the resection cavity only, and subtotal resection (STR) as having residual nodular enhancement. The independent association of extent of resection and subsequent survival was assessed via a multivariate proportional hazards regression analysis.

RESULTS

Magnetic resonance imaging studies were available for review in 949 cases. The mean age and mean Karnofsky Performance Scale (KPS) score at time of surgery were 51 +/- 16 years and 80 +/- 10, respectively. Surgery consisted of primary resection in 549 patients (58%) and revision resection for tumor recurrence in 400 patients (42%). The lesion was WHO Grade IV in 700 patients (74%) and Grade III in 249 (26%); there were 167 astrocytomas and 82 mixed oligoastrocytoma. Among patients who underwent resection, GTR, NTR, and STR were achieved in 330 (35%), 388 (41%), and 231 cases (24%), respectively. Adjusting for factors associated with survival (for example, age, KPS score, Gliadel and/or temozolomide use, and subsequent resection), GTR versus NTR (p < 0.05) and NTR versus STR (p < 0.05) were independently associated with improved survival after both primary and revision resection of glioblastoma multiforme (GBM). For primary GBM resection, the median survival after GTR, NTR, and STR was 13, 11, and 8 months, respectively. After revision resection, the median survival after GTR, NTR, and STR was 11, 9, and 5 months, respectively. Adjusting for factors associated with survival for WHO Grade III astrocytoma (age, KPS score, and revision resection), GTR versus STR (p < 0.05) was associated with improved survival. Gross-total resection versus NTR was not associated with an independent survival benefit in patients with WHO Grade III astrocytomas. The median survival after primary resection of WHO Grade III (mixed oligoastrocytomas excluded) for GTR, NTR, and STR was 58, 46, and 34 months, respectively.

CONCLUSIONS

In the authors' experience with both primary and secondary resection of malignant brain astrocytomas, increasing extent of resection was associated with improved survival independent of age, degree of disability, WHO grade, or subsequent treatment modalities used. The maximum extent of resection should be safely attempted while minimizing the risk of surgically induced neurological injury.

EXTENT OF SURGICAL RESECTION IS INDEPENDENTLY ASSOCIATED WITH SURVIVAL IN PATIENTS WITH HEMISPHERIC INFILTRATING LOW-GRADE GLIOMAS

OBJECTIVE

It remains unknown whether the extent of surgical resection affects survival or disease progression in patients with supratentorial low-grade gliomas.

METHODS

We conducted a retrospective cohort study (n = 170) between 1996 and 2007 at a single institution to determine whether increasing extent of surgical resection was associated with improved progression-free survival (PFS) and overall survival (OS). Surgical resection of gliomas defined as gross total resection (GTR) (complete resection of the preoperative fluid-attenuated inversion recovery signal abnormality), near total resection (NTR) (&lt;3-mm thin residual fluid-attenuated inversion recovery signal abnormality around the rim of the resection cavity only), or subtotal resection (STR) (residual nodular fluid-attenuated inversion recovery signal abnormality) based on magnetic resonance imaging performed less than 48 hours after surgery. Our main outcome measures were OS, PFS, and malignant degeneration-free survival (conversion to high-grade glioma).

RESULTS

One hundred thirty-two primary and 38 revision resections were performed for low-grade astrocytomas (n = 93) or oligodendrogliomas (n = 77). GTR, NTR, and STR were achieved in 65 (38%), 39 (23%), and 66 (39%) cases, respectively. GTR versus STR was independently associated with increased OS (hazard ratio, 0.36; 95% confidence interval, 0.16–0.84; P = 0.017) and PFS (HR, 0.56; 95% confidence interval, 0.32–0.98; P = 0.043) and a trend of increased malignant degeneration-free survival (hazard ratio, 0.46; 95% confidence interval, 0.20–1.03; P = 0.060). NTR versus STR was not independently associated with improved OS, PFS, or malignant degeneration-free survival. Five-year OS after GTR, NTR, and STR was 95, 80, 70%, respectively, and 10-year OS was 76, 57, and 49%, respectively. After GTR, NTR, and STR, median time to tumor progression was 7.0, 4.0, and 3.5 years, respectively. Median time to malignant degeneration after GTR, NTR, and STR was 12.5, 5.8, and 7 years, respectively.

CONCLUSION

GTR was associated with a delay in tumor progression and malignant degeneration as well as improved OS independent of age, degree of disability, histological subtype, or revision versus primary resection. GTR should be safely attempted when not limited by eloquent cortex.