Multifocal lumbar myxopapillary ependymoma presenting with drop metastasis: a case report and review of the literature.

INTRODUCTION: Spinal myxopapillary ependymomas (SME) are rare WHO grade II neoplasms of the spinal cord. Despite their good prognosis, they have a high propensity for metastasis and recurrence, although the presentation of SME as multifocal is uncommon. CASE PRESENTATION: Here we describe a rare case of a 34-year-old man who presented with painful bilateral radiculopathy with sexual dysfunction and altered sensation with defecation. The patient also reported worsening weakness of bilateral lower extremities when climbing stairs. Biopsy results revealed multifocal SME in the lumbar and sacral spine that was treated with staged surgical resection and post-operative focal radiation therapy. DISCUSSION: We discuss and evaluate surgical resection and the role of postoperative radiotherapy for SME. We also review the literature surrounding multifocal SME presenting in adults.

Guidelines for Palliative Treatment of Spinal Metastases: Choosing Between Stereotactic Body Radiation Therapy and Conventional Fractionation.

Symptomatic spinal metastasis is a frequent complication of cancer that had been treated, until relatively recently, with primitive techniques to modest radiation dose levels, with a baseline assumption of limited survival and poor patient performance in that setting. In the era of targeted and personalized therapies, many patients are living longer and more functionally and are able to manage their disease on the model of chronic illness. Given these developments, an attractive option is the use of stereotactic body radiation therapy (SBRT) to deliver high biologically effective doses of radiation conformally to maximize the palliative gains of treatment. However, randomized data to guide practice are scarce. We review the extant literature and present an algorithmic approach to selecting patients with metastatic disease for palliative spinal SBRT favoring the results of available randomized studies and remaining within the safety constraints supported by evidence from randomized trials.

Treating COVID-19 Positive Cancer Patients With Radiation Therapy: A Case Report From Epicenter of the Pandemic.

The coronavirus disease 2019 (SARS-Cov-2 or COVID-19) pandemic has resulted in unprecedented clinical challenges across the globe. Outcomes of patients with this infection are likely dependent on underlying comorbidities that predict worse outcome in older patients. However, it is unknown whether COVID-19 infected cancer patients receiving radiation therapy (RT) have any different outcome than non-infected patients. We present the first series from our center of COVID-19 infected patients who received RT for malignancy, their outcome, and toxicities.

Dose-Response Relationships for Meningioma Radiosurgery.

OBJECTIVE: Dose-response relationships for meningioma radiosurgery are poorly characterized. We evaluated determinants of local recurrence for meningiomas treated with Gamma Knife radiosurgery (GKRS), to guide future treatment approaches to optimize tumor control. MATERIALS AND METHODS: A total of 101 consecutive patients (108 tumors) who underwent GKRS for benign, atypical, or malignant meningiomas between 1998 and 2011 were studied. Local recurrence was assessed. Cox proportional hazards and logistic regression analyses were used to determine the association of patient-related, tumor-related, and treatment-related characteristics with local recurrence. Acute and late toxicity was evaluated. RESULTS: World Health Organization (2007 classification) tumor grade was I (82%), II (11%), or III (7%). Median dose was 14 Gy (range, 10 to 18 Gy) for grade I tumors and 16 Gy (range, 12 to 20 Gy) for grade II and III tumors. Median follow-up was 25 months (maximum, 17 y). Two- /5-year actuarial local control rates were 100%/98% for grade I tumors and 76%/56% for grade II/III tumors. Higher tumor grade and lower GKRS dose were associated with local failure. In this cohort, there was a 42% relative reduction in local recurrence for each 1 Gy of dose escalation. CONCLUSIONS: Treatment was well tolerated with no moderate or severe toxicity. Tumor control was excellent in benign tumors and suboptimal in higher grade tumors. Because the main determinant of local recurrence was GKRS dose, we recommend dose escalation for atypical or malignant tumors to doses between 16 and 20 Gy where critical structures allow.

Resection Followed by Involved-Field Fractionated Radiotherapy in the Management of Single Brain Metastasis.

INTRODUCTION: We expanded upon our previous experience using involved-field fractionated radiotherapy (IFRT) as an alternative to whole brain radiotherapy or stereotactic radiosurgery for patients with surgically resected brain metastases (BM). MATERIALS AND METHODS: All patients with single BM who underwent surgical resection followed by IFRT at our institution from 2006 to 2013 were evaluated. Local recurrence (LR)-free survival, distant failure (DF)-free survival, and overall survival (OS) were determined. Analyses were performed associating clinical variables with LR and DF. Salvage approaches and toxicity of treatment for each patient were also assessed. RESULTS: Median follow-up was 19.1 months. Fifty-six patients were treated with a median dose of 40.05 Gy/15 fractions with IFRT to the resection cavity. LR-free survival was 91.4%, DF-free survival was 68.4%, and OS was 77.7% at 12 months. No variables were associated with increased LR; however, melanoma histopathology and infratentorial location were associated with DF on multivariate analysis. LRs were salvaged in 5/8 patients, and DFs were salvaged in 24/29 patients. Two patients developed radionecrosis. CONCLUSION: Adjuvant IFRT is feasible and safe for well-selected patients with surgically resected single BM. Acceptable rates of local control and salvage of distal intracranial recurrences continue to be achieved with continued follow-up.

Intraoperative fat placement in surgically refractory parasellar neoplasms to facilitate stereotactic radiosurgery.

BACKGROUND: In this article, we report on the technique of placing fat in between a sellar or parasellar neoplasm and the optic chiasm to possibly protect the optic chiasm from sequelae of radiation. METHODS: A review was performed on three patients, each of whom had planned subtotal resection with fat placed near their optic chiasm to facilitate future radiosurgery. RESULTS: Follow-up on our three patients varied from 6 months to 3 years post-stereotactic radiosurgery. The fat remained stable and in place. The tumors either remained stable or reduced in size. No infections, postoperative marker dependent neurological complications or unusual symptoms were encountered. CONCLUSIONS: Placement of fat between a parasellar neoplasm and the optic chiasm appears to be a safe approach to help define the tumor chiasm space, helping to facilitate radiosurgery. Future experience is warranted to determine the efficacy of this technique.

Role of HER2 status in the treatment for brain metastases arising from breast cancer with stereotactic radiosurgery.

HER2-positive breast cancer is a known risk factor for CNS metastases, and the use of trastuzumab in the adjuvant setting does not prevent brain metastases. The purpose of this study is to compare outcomes in HER2-positive and HER2-negative intracranial disease treated with stereotactic radiosurgery (SRS). Among 57 breast cancer patients with brain metastases, 28 patients were HER2-positive. All patients were treated with SRS as their first treatment modality for CNS metastases. The median dose was 20 Gy (range 12-20 Gy). Statistical analysis was performed using the Kaplan-Meier method and χ (2) test. With a median follow-up of 11.0 months, the median time to progression in the HER2-positive group compared with the HER2-negative group was 7 versus 11 months (p = 0.080), respectively. Salvage therapy was performed in 50 % of HER2-positive patients compared with 21 % of HER2-negative patients (p = 0.02). The median OS for the HER2-positive group compared with the HER2-negative group was 22 versus 12 months (p = 0.053). Stereotactic radiosurgery results in excellent local control in the treatment for breast cancer brain metastases. Compared with HER2-negative disease, HER2-positive disease appears to show higher rates of intracranial relapse despite better overall survival rates. This data suggests that we need effective adjuvant therapy to prevent and treat brain metastases in HER2-positive patients.

A phase 2 trial of stereotactic radiosurgery boost after surgical resection for brain metastases.

PURPOSE: To evaluate local control after surgical resection and postoperative stereotactic radiosurgery (SRS) for brain metastases. METHODS AND MATERIALS: A total of 49 patients (50 lesions) were enrolled and available for analysis. Eligibility criteria included histologically confirmed malignancy with 1 or 2 intraparenchymal brain metastases, age≥18 years, and Karnofsky performance status (KPS)≥70. A Cox proportional hazard regression model was used to test for significant associations between clinical factors and overall survival (OS). Competing risks regression models, as well as cumulative incidence functions, were fit using the method of Fine and Gray to assess the association between clinical factors and both local failure (LF; recurrence within surgical cavity or SRS target), and regional failure (RF; intracranial metastasis outside of treated volume). RESULTS: The median follow-up was 12.0 months (range, 1.0-94.1 months). After surgical resection, 39 patients with 40 lesions were treated a median of 31 days (range, 7-56 days) later with SRS to the surgical bed to a median dose of 1800 cGy (range, 1500-2200 cGy). Of the 50 lesions, 15 (30%) demonstrated LF after surgery. The cumulative LF and RF rates were 22% and 44% at 12 months. Patients who went on to receive SRS had a significantly lower incidence of LF (P=.008). Other factors associated with improved local control include non-small cell lung cancer histology (P=.048), tumor diameter<3 cm (P=.010), and deep parenchymal tumors (P=.036). Large tumors (≥3 cm) with superficial dural/pial involvement showed the highest risk for LF (53.3% at 12 months). Large superficial lesions treated with SRS had a 54.5% LF. Infratentorial lesions were associated with a higher risk of developing RF compared to supratentorial lesions (P<.001). CONCLUSIONS: Postoperative SRS is associated with high rates of local control, especially for deep brain metastases<3 cm. Tumors≥3 cm with superficial dural/pial involvement demonstrate the highest risk of LF.

Reducing excess radiation from portal imaging of pediatric brain tumors.

Previously we have shown that our routine portal imaging (PI) of the craniofacial region in pediatric brain tumor patients contributed an additional 2%-3% of the prescribed dose and up to 200 cGy to the planning target volume (PTV) and nearby organs at risk (OARs). The purpose of this study is to quantify the reduction in dose to PTV and OARs from portal imaging (PI) of the craniofacial region of pediatric patients treated after the implementation of changes in our portal imaging practices. Twenty consecutive pediatric patients were retrospectively studied since the implementation of changes to our portal imaging procedure. Each received portal imaging of treatment fields and orthogonal setup fields to the craniofacial region. PI modifications included a reduction in the field size of setup orthogonal fields without loss of radiographic information needed for treatment verification. In addition, treatment fields were imaged using a single exposure, rather than double exposure. Dose-volume histograms were generated to quantify the dose to the target and critical structures through PI acquisition. These results were compared with our previous cohort of 20 patients who were treated using the former portal imaging practices. The mean additional target dose from portal imaging following the new guidelines was 1.5% of the prescribed dose compared to 2.5% prior to the new portal image practices (p < 0.001). With the new portal imaging practices, the percentage decrease in portal imaging dose to the brainstem, optic structures, cochlea, hypothalamus, temporal lobes, thyroid, and eyes were 25%, 35%, 35%, 51%, 45%, 80%, and 55%, respectively. Reductions in portal imaging doses were significant in all OARs with exception of the brainstem, which showed a trend towards significance. Changes to portal imaging practices can reduce the radiation dose contribution from portal imaging to surrounding OARs by up to 80%. This may have implications on both late toxicity and second cancer development in pediatric brain tumors.

Vemurafenib and radiation therapy in melanoma brain metastases.

Brain metastases in malignant melanoma carries a poor prognosis with minimal response to any therapy. The purpose of this pilot analysis was to find the effectiveness of vemurafenib, an oral BRAF inhibitor, and radiation therapy in V600 mutated melanoma with brain metastases. BRAF mutation status of the melanoma patients was determined by real-time PCR assay. Retrospective analysis was performed on twelve patients who had the mutation and were treated with either stereotactic radiosurgery or whole brain radiation therapy prior to or along with vemurafenib at a dose of 960 mg orally twice a day. Clinical and radiological responses, development of new brain metastases, overall survival and toxicity were assessed. Improvement in neurological symptoms was seen in 7/11 (64 %) following therapy. Radiographic responses were noted in 36/48 (75 %) of index lesions with 23 (48 %) complete responses and 13 (27 %) partial responses. Six month local control, freedom from new brain metastases and overall survival were 75, 57 and 92 %. Four patients had intra-tumoral bleed prior to therapy and two patients developed steroid dependence. One patient experienced radiation necrosis. This retrospective study suggests that melanoma patients with brain metastases harboring BRAF mutation appear to be a distinct sub-group with a favorable response to vemurafenib and radiation therapy and acceptable morbidity.

Ipilimumab in melanoma with limited brain metastases treated with stereotactic radiosurgery.

The anti-cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) monoclonal antibody ipilimumab has been shown to improve survival in patients with metastatic non-CNS melanoma. The purpose of this study was to investigate the efficacy of CTLA-4 inhibitors in the treatment of metastatic melanoma with limited brain metastases treated with stereotactic radiosurgery (SRS). Between January 2008 and June 2011, 58 patients with limited brain metastases from melanoma were treated with SRS with a median dose of 20 Gy delivered to the 50% isodose line (range, 15-20 Gy). In 25 patients, ipilimumab was administered intravenously at a dose of 3 mg/kg over 90 min every 3 weeks for a median of four doses (range, 1-8). Local control (LC), freedom from new brain metastases, and overall survival (OS) were assessed from the date of the SRS procedure. The median LC, freedom from new brain metastases, and OS for the entire group were 8.7, 4.3, and 5.9 months, respectively. The cause of death was CNS progression in all but eight patients. Six-month LC, freedom from new brain metastases, and OS were 65, 35, and 56%, respectively, for those who received ipilimumab and 63, 47, and 46% for those who did not (P=NS). Intracranial hemorrhage was noted in seven patients who received ipilimumab compared with 10 patients who received SRS alone (P=NS). In this retrospective study, administration of ipilimumab neither increased toxicity nor improved intracerebral disease control in patients with limited brain metastases who received SRS.

Involved field radiation therapy after surgical resection of solitary brain metastases--mature results.

BACKGROUND: Whole brain radiation therapy (WBRT) reduces local recurrence in patients after surgical resection of brain metastases without improving overall survival. Involved field radiation therapy (IFRT) has been used at our center to avoid delayed neurotoxicity associated with WBRT in well-selected patients with surgically resected single brain metastases. The purpose of this study was to evaluate the long-term outcomes of these patients. METHODS: Thirty-three consecutive patients with single brain metastases from a known primary tumor were treated with gross total resection followed by IFRT between 2006 and 2011. The postoperative surgical bed was treated to 40.05 Gy in 15 fractions of 2.67 Gy with conformal radiation therapy. Patients received serial MRIs and neurological exams in follow-up. Surgery, WBRT, or stereotactic radiosurgery was performed as salvage treatment when necessary. RESULTS: The median follow-up was 16 months (range: 2-65 months). Local control, distant brain recurrence-free survival, and overall survival at 12 and 24 months were 90.3% and 85.8%, 60.7% and 51.4%, and 65.6% and 61.5%, respectively. Overall, 5 (15%) patients developed recurrence at the resection cavity, and 13 (39%) patients experienced recurrence at a new intracranial site. Two patients received WBRT, 8 stereotactic radiosurgery, 2 surgery, and 2 both chemotherapy and IFRT as salvage. Four patients died from CNS disease progression. CONCLUSION: For patients with newly diagnosed single brain metastases treated with surgical resection, postoperative IFRT to the resection cavity achieves reasonable rates of local control and is an excellent alternative to WBRT.

Antiangiogenic therapy in the management of brain tumors: a clinical overview.

Central to the process of brain tumor development is angiogenesis, which involves a host of molecules and receptors. In recent years, antiangiogenic therapies have been developed and tested for their effectiveness against these tumors. Among them are inhibitors against vascular endothelial growth factor and its receptors, as well as inhibitors targeting the platelet-derived growth factor family, integrins, and histone deacetylase. While many have been shown to be effective with limited toxicity, some tumors are able to adopt escape mechanisms. Further research is needed in the development of effective multi-targeted agents to reduce these effects.

Long-term outcomes after staged-volume stereotactic radiosurgery for large arteriovenous malformations.

BACKGROUND: Stereotactic radiosurgery is an effective treatment modality for small arteriovenous malformations (AVMs) of the brain. For larger AVMs, the treatment dose is often lowered to reduce potential complications, but this decreases the likelihood of cure. One strategy is to divide large AVMs into smaller anatomic volumes and treat each volume separately. OBJECTIVE: To prospectively assess the long-term efficacy and complications associated with staged-volume radiosurgical treatment of large, symptomatic AVMs. METHODS: Eighteen patients with AVMs larger than 15 mL underwent prospective staged-volume radiosurgery over a 13-year period. The median AVM volume was 22.9 mL (range, 15.7-50 mL). Separate anatomic volumes were irradiated at 3- to 9-month intervals (median volume, 10.9 mL; range, 5.3-13.4 mL; median marginal dose, 15 Gy; range, 15-17 Gy). The AVM was divided into 2 volumes in 10 patients, 3 volumes in 5 patients, and 4 volumes in 3 patients. Seven patients underwent retreatment for residual disease. RESULTS: Actuarial rates of complete angiographic occlusion were 29% and 89% at 5 and 10 years. Five patients (27.8%) had a hemorrhage after radiosurgery. Kaplan-Meier analysis of cumulative hemorrhage rates after treatment were 12%, 18%, 31%, and 31% at 2, 3, 5, and 10 years, respectively. One patient died after a hemorrhage (5.6%). CONCLUSION: Staged-volume radiosurgery for AVMs larger than 15 mL is a viable treatment strategy. The long-term occlusion rate is high, whereas the radiation-related complication rate is low. Hemorrhage during the lag period remains the greatest source of morbidity and mortality.

Resistance of glioblastoma-initiating cells to radiation mediated by the tumor microenvironment can be abolished by inhibiting transforming growth factor-ß.

The poor prognosis of glioblastoma (GBM) routinely treated with ionizing radiation (IR) has been attributed to the relative radioresistance of glioma-initiating cells (GIC). Other studies indicate that although GIC are sensitive, the response is mediated by undefined factors in the microenvironment. GBM produce abundant transforming growth factor-ß (TGF-ß), a pleotropic cytokine that promotes effective DNA damage response. Consistent with this, radiation sensitivity, as measured by clonogenic assay of cultured murine (GL261) and human (U251, U87MG) glioma cell lines, increased by approximately 25% when treated with LY364947, a small-molecule inhibitor of TGF-ß type I receptor kinase, before irradiation. Mice bearing GL261 flank tumors treated with 1D11, a pan-isoform TGF-ß neutralizing antibody, exhibited significantly increased tumor growth delay following IR. GL261 neurosphere cultures were used to evaluate GIC. LY364947 had no effect on the primary or secondary neurosphere-forming capacity. IR decreased primary neurosphere formation by 28%, but did not reduce secondary neurosphere formation. In contrast, LY364947 treatment before IR decreased primary neurosphere formation by 75% and secondary neurosphere formation by 68%. Notably, GL261 neurospheres produced 3.7-fold more TGF-ß per cell compared with conventional culture, suggesting that TGF-ß production by GIC promotes effective DNA damage response and self-renewal, which creates microenvironment-mediated resistance. Consistent with this, LY364947 treatment in irradiated GL261 neurosphere-derived cells decreased DNA damage responses, H2AX and p53 phosphorylation, and induction of self-renewal signals, Notch1 and CXCR4. These data motivate the use of TGF-ß inhibitors with radiation to improve therapeutic response in patients with GBM.

Dose to craniofacial region through portal imaging of pediatric brain tumors.

The purpose of this study was to determine dose to the planning target volume (PTV) and organs at risk (OARs) from portal imaging (PI) of the craniofacial region in pediatric brain tumor patients treated with intensity-modulated radiation therapy (IMRT). Twenty pediatric brain tumor patients were retrospectively studied. Each received portal imaging of treatment fields and orthogonal setup fields in the craniofacial region. The number of PI and monitor units used for PI were documented for each patient. Dose distributions and dose-volume histograms were generated to quantify the maximum, minimum, and mean dose to the PTV, and the mean dose to OARs through PI acquisition. The doses resulting from PI are reported as percentage of prescribed dose. The average maximum, minimum, and mean doses to PTV from PI were 2.9 ± 0.7%, 2.2 ± 1.0%, and 2.5 ± 0.7%, respectively. The mean dose to the OARs from PI were brainstem 2.8 ± 1.1%, optic nerves/chiasm 2.6 ± 0.9%, cochlea 2.6 ± 0.9%, hypothalamus/pituitary 2.4 ± 0.6%, temporal lobes 2.3 ± 0.6%, thyroid 1.6 ± 0.8%, and eyes 2.6 ± 0.9%. The mean number of portal images and the mean number of PI monitor units per patient were 58.8 and 173.3, respectively. The dose from PI while treating pediatric brain tumors using IMRT is significant (2%-3% of the prescribed dose). This may result in exceeding the tolerance limit of many critical structures and lead to unwanted late complications and secondary malignancies. Dose contributions from PI should be considered in the final documented dose. Attempts must be made in PI practices to lower the imaging dose when feasible.

External beam radiation therapy for PTFE dialysis grafts: a pilot study.

PURPOSE: The aim of this study was to identify the effects of external beam radiation on PTFE dialysis graft dysfunction. METHODS: Seven patients who underwent PTFE dialysis graft angioplasty were randomized to receive either two 8 Gy doses of external beam radiation or no radiation. The primary endpoint was time to graft thrombosis with a secondary endpoint of time to first intervention. RESULTS: There was no statistically significant difference between the two groups in either of the endpoints, although grafts in the radiation group had a shorter time to thrombosis or intervention. CONCLUSIONS: Our results demonstrate technical feasibility for use of external beam radiation in the setting of dialysis vascular access graft dysfunction. Larger randomized studies are required to identify whether there is a clinical benefit from this intervention.

A clinical trial of bevacizumab, temozolomide, and radiation for newly diagnosed glioblastoma.

OBJECT: The presence of angiogenesis is a hallmark of glioblastoma (GBM). Vascular endothelial growth factor (VEGF), which drives angiogenesis, provides an additional target for conventional therapy. The authors conducted a prospective clinical trial to test the effectiveness of bevacizumab, an inhibitor of VEGF, in newly diagnosed GBM. METHODS: From 2006 through 2010, 51 eligible patients with newly diagnosed GBM were treated with involved-field radiation therapy and concomitant temozolomide (75 mg/m(2) daily for 42 days) along with bevacizumab (10 mg/kg every 2 weeks), starting 29 days after surgery. This was followed by 6 cycles of adjuvant temozolomide therapy (150 mg/m(2) on Days 1-7 of a 28-day cycle) with bevacizumab administered at 10 mg/kg on Days 8 and 22 of each 28-day cycle. RESULTS: The 6- and 12-month progression-free survival (PFS) rates were 85.1% and 51%, respectively. The 12- and 24-month overall survival (OS) rates were 85.1% and 42.5%, respectively. Grade III/IV toxicities were noted in 10 patients (19.6%). No treatment-related deaths were observed. Asymptomatic intracranial bleeding was noted in 5 patients. CONCLUSIONS: The addition of bevacizumab to conventional therapy in newly diagnosed GBM appears to improve both PFS and OS in patients with newly diagnosed GBM, with acceptable morbidity. A shift toward diffuse relapse was noted in a significant number of patients. Ongoing Phase III clinical trials will show the true benefit of this antiangiogenic approach.

Change in pattern of relapse after antiangiogenic therapy in high-grade glioma.

PURPOSE: Local recurrence is the dominant pattern of relapse in high-grade glioma (HGG) after conventional therapy. The recent use of antiangiogenic therapy has shown impressive radiologic and clinical responses in adult HGG. The preclinical data suggesting increased invasiveness after angiogenic blockade have necessitated a detailed analysis of the pattern of recurrence after therapy. METHODS AND MATERIALS: A total of 162 consecutive patients with HGG, either newly diagnosed (n = 58) or with recurrent disease (n = 104) underwent therapy with bevacizumab at 10 mg/kg every 2 weeks and conventional chemotherapy with or without involved field radiotherapy until disease progression. The pattern of recurrence and interval to progression were the primary aims of the present study. Diffuse invasive recurrence (DIR) was defined as the involvement of multiple lobes with or without crossing the midline. RESULTS: At a median follow-up of 7 months (range, 1-37), 105 patients had recurrence, and 79 patients ultimately developed DIR. The interval to progression was similar in the DIR and local recurrence groups (6.5 and 6.3 months, p = .296). The hazard risk of DIR increased exponentially with time and was similar in those with newly diagnosed and recurrent HGG (R(2) = 0.957). The duration of bevacizumab therapy increased the interval to recurrence (p < .0001) and improved overall survival (p < .0001). However, the pattern of relapse did not affect overall survival (p = .253). CONCLUSION: Along with an increase in median progression-free survival, bevacizumab therapy increased the risk of DIR in HGG patients. The risk of increased invasion with prolonged angiogenic blockade should be addressed in future clinical trials.

Treatment-related change versus tumor recurrence in high-grade gliomas: a diagnostic conundrum--use of dynamic susceptibility contrast-enhanced (DSC) perfusion MRI.

OBJECTIVE: The purpose of this article is to address radiation necrosis, pseudoprogression, and pseudoresponse relative to high-grade gliomas and evaluate the role of conventional MRI and, in particular, dynamic susceptibility contrast-enhanced perfusion MRI in assessing such treatment-related changes from tumor recurrence. CONCLUSION: Posttreatment imaging assessment of high-grade gliomas remains challenging. Familiarity with the expected MR imaging appearances of treatment-related change and tumor recurrence will help distinguish these entities allowing appropriate management.