Impact of Intraoperative Magnetic Resonance Imaging and Other Factors on Surgical Outcomes for Newly Diagnosed Grade II Astrocytomas and Oligodendrogliomas: A Multicenter Study

Neurosurgery 88 (1) 2021: 63–73,

Few studies use large, multi-institutional patient cohorts to examine the role of intraoperative magnetic resonance imaging (iMRI) in the resection of grade II gliomas.

OBJECTIVE: To assess the impact of iMRI and other factors on overall survival (OS) and progression-free survival (PFS) for newly diagnosed grade II astrocytomas and oligodendrogliomas.

METHODS: Retrospective analyses of a multicenter database assessed the impact of patient-, treatment-, and tumor-related factors on OS and PFS.

RESULTS: A total of 232 resections (112 astrocytomas and 120 oligodendrogliomas) were analyzed. Oligodendrogliomas had longer OS (P < .001) and PFS (P = .01) than astrocytomas. Multivariate analyses demonstrated improved OS for gross total resection (GTR) vs subtotal resection (STR; P = .006, hazard ratio [HR]: .23) and near total resection (NTR; P = .02, HR: .64). GTR vs STR (P = .02, HR: .54), GTR vs NTR (P = .04, HR: .49), and iMRI use (P = .02, HR: .54) were associated with longer PFS. Frontal (P = .048, HR: 2.11) and occipital/parietal (P = .003, HR: 3.59) locations were associated with shorter PFS (vs temporal). Kaplan-Meier analyses showed longer OS with increasing extent of surgical resection (EOR) (P=.03) and 1p/19q gene deletions (P=.02). PFS improved with increasing EOR (P = .01), GTR vs NTR (P = .02), and resections above STR (P = .04). Factors influencing adjuvant treatment (35.3% of patients) included age (P=.002, odds ratio [OR]: 1.04) and EOR (P=.003,OR: .39) but not glioma subtype or location. Additional tumor resection after iMRI was performed in 105/159 (66%) iMRI cases, yielding GTR in 54.5% of these instances.

CONCLUSION: EOR is a major determinant of OS and PFS for patients with grade II astrocytomas and oligodendrogliomas. Intraoperative MRI may improve EOR and was associated with increased PFS.

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

J Neurosurg 133:1291–1301, 2020

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.

METHODS 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).

RESULTS 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.

CONCLUSIONS 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.

Staged Laser Interstitial Thermal Therapy (LITT) Treatments to Left Insular Low-Grade Glioma

Neurosurgery 2019 DOI:10.1093/neuros/nyz120

Low-grade insular gliomas remain challenging tumors for aggressive resection because of the numerous functional and vascular structures surrounding them. Because of the potential morbidities associated with open surgical resection, less invasive techniques may confer a more optimal balance between cytoreduction and surgical complications. For this reason, we evaluated the use of laser interstitial thermal therapy (LITT) for resection of a dominant hemisphere oligodendroglioma World Health Organization (WHO) grade II in a 68-yr-old patient by use of multiple staged surgeries for its resection.

CLINICAL PRESENTATION: Patient KK was a 68-yr-old female who was found to have a large, left-sided insular mass that was shown to be an oligodendroglioma WHO grade II, positive for codeletion 1p/19q and IDH1 mutant on biopsy. Over the course of 3 mo, KK underwent 2 stages of LITT, targeting different areas of the 5-cmtumor. The 60-d magnetic resonance imaging (MRI) demonstrated a reduction in size of the tumor from5.2×3.3×2.4 cm to 3.6 × 1.9 × 1.4 cm. She returned for a second stage targeting the anterior portion of the tumor. KK did well postoperatively and went on to postsurgical chemoradiation. At the
2-yr follow-up, the lesion showed near resolution on MRI.

CONCLUSION: This case report demonstrates successful use of LITT for staged surgeries to treat a left hemisphere-dominant insular lesion. This establishes the use of LITT as a viable, minimally invasive option to treat tumors that are difficult to access or pose concerns for increased morbidity through an open surgery.

Insular glioma surgery: an evolution of thought and practice

J Neurosurg 130:9–16, 2019

The goal of this article is to review the history of surgery for low- and high-grade gliomas located within the insula with particular focus on microsurgical technique, anatomical considerations, survival, and postoperative morbidity.

METHODS The authors reviewed the literature for published reports focused on insular region anatomy, neurophysiol- ogy, surgical approaches, and outcomes for adults with World Health Organization grade II–IV gliomas.

RESULTS While originally considered to pose too great a risk, insular glioma surgery can be performed safely due to the collective efforts of many individuals. Similar to resection of gliomas located within other cortical regions, maximal resection of gliomas within the insula offers patients greater survival time and superior seizure control for both newly diagnosed and recurrent tumors in this region. The identification and the preservation of M2 perforating and lateral len- ticulostriate arteries are critical steps to preventing internal capsule stroke and hemiparesis. The transcortical approach and intraoperative mapping are useful tools to maximize safety.

CONCLUSIONS The insula’s proximity to middle cerebral and lenticulostriate arteries, primary motor areas, and perisyl- vian language areas makes accessing and resecting gliomas in this region challenging. Maximal safe resection of insular gliomas not only is possible but also is associated with excellent outcomes and should be considered for all patients with low- and high-grade gliomas in this area.

Outcomes in Reoperated Low-Grade Gliomas


Neurosurgery 77:175–184, 2015

Low-grade gliomas (LGGs) comprise a diverse set of intrinsic brain tumors that correlate strongly with survival. Data on the effect of reoperation are sparse.

OBJECTIVE: To evaluate the effect of reoperation on patients with LGG.

METHODS: Fifty-two consecutive patients with reoperated LGGs treated at the University of Washington between 1986 and 2004 were identified and evaluated in a retrospective analysis.

RESULTS: The average overall survival (OS) for this cohort was 12.95 ± 0.96 years. The overall 10-year survival rate was 57%. The absence of any residual tumor at either the first or second operation was associated with significantly increased OS. Negative prognostic variables for OS included the use of upfront radiation and pathology at recurrence. The average overall progression-free survival to the first recurrence (PFS1) was 6.23 ± 0.51 years. Positive prognostic factors for improved PFS1 included the use of upfront radiation therapy. Variables not associated with differences in PFS1 included the use of upfront chemotherapy, enhancement, pathology, extent of resection, the presence of residual tumor, and Karnofsky Performance Scale score <80. The average overall progression-free survival to the second recurrence was 2.73 ± 0.39 years. Pathology at recurrence was associated with significant differences in progression-free survival to the second recurrence, as was extent of resection at time of first recurrence, and Karnofsky Performance Scale score <80.

CONCLUSION: This is among the largest studies to assess variables associated with outcome in patients with reoperated LGG. Reresection appears to provide significant benefit, and extent of resection remains the strongest predictor of OS.