Response assessment in neuro-oncology (a report of the RANO group): assessment of outcome in trials of diffuse low-grade gliomas

Ongoing and prolonged response in adult low-grade gliomas treated with radiotherapy

The aim of the present study was to evaluate the impact of first-line radiotherapy on low-grade gliomas (LGGs) growth kinetics. The mean tumor diameter (MTD) of 39 LGGs was retrospectively measured on serial magnetic resonance images before (n = 16) and after radiotherapy onset (n = 39). After radiotherapy, a decrease of the MTD was observed in 37 patients. Median duration of the MTD decrease was 1.9 years (range 0-8.1 years). According to RANO criteria, the rates of partial and minor responses were 15 and 28 % at the first evaluation after radiotherapy and 36 and 34 % at the time of maximal MTD decrease. The presence of a 1p19q codeletion and the absence of p53 expression were associated with longer durations of MTD decrease (5.3 vs 1 years, p = 0.02 and 2.4 vs 1.8 years, p = 0.05, respectively) while no association was observed between IDH1-R132H expression and duration of MTD decrease. In most patients, MTD decrease after radiotherapy occurred in two phases: an initial phase of rapid MTD decrease followed by a second phase of slower MTD decrease. Patients with a high rate of MTD decrease during the initial phase (>7 mm/year) had both a shorter duration of response (1.9 vs 5.3 years, p = 0.003) and a shorter overall survival (5.5 vs 11.6 years, p = 0.0004). LGGs commonly display a prolonged and ongoing volume decrease after radiotherapy. However, patients who respond rapidly should be carefully monitored because they are at a higher risk of rapid progression.

PET in the clinical management of glioma: evidence map

OBJECTIVE

Several studies have assessed PET to complement the anatomic information obtained from other imaging modalities in various clinical contexts for the management of glioma. We constructed an evidence map of clinical evidence on the use of PET in glioma and identified research gaps.

MATERIALS AND METHODS

We searched PubMed and Scopus (from inception through June 30, 2011) to identify studies assessing the use of PET for glioma regardless of setting of care or indication. We extracted test objectives, study characteristics, and phases of diagnostic evidence and then assessed research diversity and temporal trends in the literature. We excluded studies assessing only technical feasibility and optimization of PET.

RESULTS

A total of 129 studies were considered eligible; the number of articles published annually has greatly increased over time (p for trend < 0.001). Most studies (n = 118, 91%) assessed diagnostic or prognostic performance; fewer studies reported on the impact of PET on diagnostic thinking (n = 4, 3%), therapeutic decisions (n = 4, 3%), or patient-relevant clinical outcomes (n = 3; 2%). Fluorine-18 FDG (n = 73, 57%) or (11)C-methionine (n = 44, 34%) were the two most commonly evaluated PET tracers. Pretherapy assessment (n = 72, 56%) and monitoring of treatment response (n = 48, 37%) were the most common settings of test use assessed in the research studies.

CONCLUSION

More primary studies, particularly studies of newer tracers focusing on biopsy or treatment planning, are needed to better characterize the role of PET in specific contexts.

Seizure control following radiotherapy in patients with diffuse gliomas: a retrospective study

BACKGROUND

Little information is available regarding the effect of conventional radiotherapy on glioma-related seizures.

METHODS

In this retrospective study, we analyzed the seizure response and outcome following conventional radiotherapy in a cohort of 43 patients with glioma (33 grade II, 10 grade III) and medically intractable epilepsy.

RESULTS

At 3 months after radiotherapy, seizure reduction was significant (≥ 50% reduction of frequency compared with baseline) in 31/43 patients (72%) of the whole series and in 25/33 patients (76%) with grade II gliomas, whereas at 12 months seizure reduction was significant in 26/34 (76%) and in 19/25 (76%) patients, respectively. Seizure reduction was observed more often among patients displaying an objective tumor response on MRI, but patients with no change on MRI also had a significant seizure reduction. Seizure freedom (Engel class I) was achieved at 12 months in 32% of all patients and in 38% of patients with grade II tumors. Timing of radiotherapy and duration of seizures prior to radiotherapy were significantly associated with seizure reduction.

CONCLUSIONS

This study showed that a high proportion of patients with medically intractable epilepsy from diffuse gliomas derive a significant and durable benefit from radiotherapy in terms of epilepsy control and that this positive effect is not strictly associated with tumor shrinkage as shown on MRI. Radiotherapy at tumor progression seems as effective as early radiotherapy after surgery. Prospective studies must confirm and better characterize the response to radiotherapy.

Adenovirus-mediated gene therapy with sitimagene ceradenovec followed by intravenous ganciclovir for patients with operable high-grade glioma (ASPECT): a randomised, open-label, phase 3 trial

BACKGROUND

Besides the use of temozolomide and radiotherapy for patients with favourable methylation status, little progress has been made in the treatment of adult glioblastoma. Local control of the disease by complete removal increases time to progression and survival. We assessed the efficacy and safety of a locally applied adenovirus-mediated gene therapy with a prodrug converting enzyme (herpes-simplex-virus thymidine kinase; sitimagene ceradenovec) followed by intravenous ganciclovir in patients with newly diagnosed resectable glioblastoma.

METHODS

For this international, open-label, randomised, parallel group multicentre phase 3 clinical trial, we recruited patients from 38 sites in Europe. Patients were eligible if they were aged 18-70 years, had newly diagnosed supratentorial glioblastoma multiforme amenable to complete resection, and had a Karnofsky score of 70 or more at screening. We used a computer-generated randomisation sequence to allocate patients in a one-to-one ratio (with block sizes of four) to receive either surgical resection of the tumour and intraoperative perilesional injection of sitimagene ceradenovec (1 × 10(12) viral particles) followed by ganciclovir (postoperatively, 5 mg/kg intravenously twice a day) in addition to standard care or resection and standard care alone. Temozolomide, not being standard in all participating countries at the time of the study, was allowed at the discretion of the treating physician. The primary endpoint was a composite of time to death or re-intervention, adjusted for temozolamide use, assessed by intention-to-treat (ITT) analysis. This trial is registered with EudraCT, number 2004-000464-28.

FINDINGS

Between Nov 3, 2005, and April 16, 2007, 250 patients were recruited and randomly allocated: 124 to the experimental group and 126 to the standard care group, of whom 119 and 117 patients, respectively, were included in the ITT analyses. Median time to death or re-intervention was longer in the experimental group (308 days, 95% CI 283-373) than in the control group (268 days, 210-313; hazard ratio [HR] 1·53, 95% CI 1·13-2·07; p=0·006). In a subgroup of patients with non-methylated MGMT, the HR was 1·72 (95% CI 1·15-2·56; p=0·008). However, there was no difference between groups in terms of overall survival (median 497 days, 95% CI 369-574 for the experimental group vs 452 days, 95% CI 437-558 for the control group; HR 1·18, 95% CI 0·86-1·61, p=0·31). More patients in the experimental group had one or more treatment-related adverse events those in the control group (88 [71%] vs 51 [43%]). The most common grade 3-4 adverse events were hemiparesis (eight in the experimental group vs three in the control group) and aphasia (six vs two).

INTERPRETATION

Our findings suggest that use of sitimagene ceradenovec and ganciclovir after resection can increase time to death or re-intervention in patients with newly diagnosed supratentorial glioblastoma multiforme, although the intervention did not improve overall survival. Locally delivered gene therapy for glioblastoma should be further developed, especially for patients who are unlikely to respond to standard chemotherapy.

FUNDING

Ark Therapeutics Ltd.

Chemotherapy in low-grade gliomas

PURPOSE OF REVIEW

This review summarizes the recent studies in adults' diffuse low-grade gliomas (LGGs) chemotherapy, including response assessment and potential predictive biomarkers of chemosensitivity.

RECENT FINDINGS

Recent studies have confirmed that chemotherapy is an interesting treatment option in LGGs. About 25-50% of LGGs achieve radiological responses with temozolomide or a procarbazine-CCNU-vincristine (PCV) regimen. Clinical and quality-of-life improvements are commonly observed with more than half of the patients with epilepsy, demonstrating a significant reduction of seizure frequency. Dynamic volumetric studies have provided a better description of LGGs evolution after chemotherapy. They have shown that an ongoing volume decrease can be observed many months after chemotherapy discontinuation, particularly after PCV, raising the question of how and for how long should LGGs be treated. New response criteria have been defined by the Response Assessment in Neuro-Oncology group. In addition to 1p/19q codeletion and MGMT promoter methylation, IDH1 mutation might also be a potential predictive biomarker of chemosensitivity.

SUMMARY

It has now been widely accepted that chemotherapy is an interesting treatment option in LGGs. However, several questions remain unanswered regarding its optimal use. Ongoing phase III studies will allow a better delineation of the role of chemotherapy in LGGs and will also help to better determine the potential predictive value of a 1p/19q codeletion, a MGMT promoter methylation and an IDH1 mutation.

Posttreatment evaluation of central nervous system gliomas

Although conventional contrast-enhanced MR imaging remains the standard-of-care imaging method in the posttreatment evaluation of gliomas, recent developments in therapeutic options such as chemoradiation and antiangiogenic agents have caused the neuro-oncology community to rethink traditional imaging criteria. This article highlights the latest recommendations. These recommendations should be viewed as works in progress. As more is learned about the pathophysiology of glioma treatment response, quantitative imaging biomarkers will be validated within this context. There will likely be further refinements to glioma response criteria, although the lack of technical standardization in image acquisition, postprocessing, and interpretation also need to be addressed.

[First intraoperative magnetic resonance imaging in a Spanish hospital of the public healthcare system: initial experience, feasibility and difficulties in our environment]

OBJECTIVE

Intraoperative MRI is considered the gold standard among all intraoperative imaging technologies currently available. Its main indication is in the intraoperative detection of residual disease during tumour resections. We present our initial experience with the first intraoperative low-field MRI in a Spanish hospital of the public healthcare system. We evaluate its usefulness and accuracy to detect residual tumours and compare its intraoperative results with images obtained postoperatively using conventional high-field devices.

MATERIAL AND METHODS

We retrospectively reviewed the first 21 patients operated on the aid of this technology. Maximal safe resection was the surgical goal in all cases. Surgeries were performed using conventional instrumentation and the required assistance in each case.

RESULTS

The mean number of intraoperative studies was 2.3 per procedure (range: 2 to 4). Intraoperative studies proved that the surgical goal had been achieved in 15 patients (71.4%), and detected residual tumour in 6 cases (28.5%). After comparing the last intraoperative image and the postoperative study, 2 cases (9.5%) were considered as "false negatives".

CONCLUSIONS

Intraoperative MRI is a safe, reliable and useful tool for guided resection of brain tumours. Low-field devices provide images of sufficient quality at a lower cost; therefore their universalisation seems feasible.

Functional imaging in adult and paediatric brain tumours

Imaging is a key component in the management of brain tumours, with MRI being the preferred modality for most clinical scenarios. However, although conventional MRI provides mainly structural information, such as tumour size and location, it leaves many important clinical questions, such as tumour type, aggressiveness and prognosis, unanswered. An increasing number of studies have shown that additional information can be obtained using functional imaging methods (which probe tissue properties), and that these techniques can give key information of clinical importance. These techniques include diffusion imaging, which can assess tissue structure, and perfusion imaging and magnetic resonance spectroscopy, which measures tissue metabolite profiles. Tumour metabolism can also be investigated using PET, with 18F-deoxyglucose being the most readily available tracer. This Review discusses these methods and the studies that have investigated their clinical use. A strong emphasis is placed on the measurement of quantitative parameters, which is a move away from the qualitative nature of conventional radiological reporting and presents major challenges, particularly for multicentre studies.

First experiences in treatment of low-grade glioma grade I and II with proton therapy

Background

To retrospectively assess feasibility and toxicity of proton therapy in patients with low-grade glioma (WHO °I/II).

Patients and methods

Proton beam therapy only administered in 19 patients (median age 29 years; 9 female, 10 male) for low-grade glioma between 2010 and 2011 was reviewed. In 6 cases proton therapy was performed due to tumor progression after biopsy, in 8 cases each due to tumor progression after (partial-) resection, and in 5 cases due to tumor progression after chemotherapy. Median total dose applied was 54 GyE (range, 48,6-54 GyE) in single fractions of median 1.8 GyE. Median clinical target volume was 99 cc (range, 6–463 cc) and treated using median 2 beams (range, 1–2).

Results

Proton therapy was finished as planned in all cases. At end of proton therapy, 13 patients showed focal alopecia, 6 patients reported mild fatigue, one patient with temporal tumor localization concentration deficits and speech errors and one more patient deficits in short-term memory. Four patients did not report any side effects. During follow-up, one patient presented with pseudo-progression showing worsening of general condition and brain edema 1–2 months after last irradiation and restitution after 6 months. In the present MR imaging (median follow-up 5 months; range 0–22 months) 12 patients had stable disease, 2 (1) patients partial (complete) remission, one more patient pseudo-progression (differential diagnosis: tumor progression) 4 weeks after irradiation without having had further follow-up imaging so far, and one patient tumor progression approximately 9 months after irradiation.

Conclusion

Regarding early side effects, mild alopecia was the predominant finding. The rate of alopecia seems to be due to large treatment volumes as well as the anatomical locations of the target volumes and might be avoided by using multiple beams and the gantry in the future. Further evaluations including neuropsychological testing are in preparation.

Chemotherapy-related cognitive dysfunction

Many cancer patients develop treatment-related cognitive dysfunction that affects their quality of life and can result in diminished functional independence. There is an emerging body of transdisciplinary research demonstrating that chemotherapeutic agents can produce neurobiological changes within the brain, which are associated with a constellation of cognitive changes that can result in decreased quality of life and functional independence. The increased incidence of cancer, coupled with longer survival times, has resulted in larger numbers of cancer survivors who are struggling with this neurotoxicity. This review summarizes the neuropsychological findings in patients with breast and brain cancer who receive systemic chemotherapy as well as the recent animal and imaging research elucidating the mechanisms by which these therapies impact brain structure, function, and consequent behavior.

Current treatment of low grade gliomas

Low grade gliomas affect predominantly young adults, and have a relatively favorable prognosis compared to grade III and grade IV gliomas. The challenge for an optimal management of these patients is to find the balance between an optimal survival and the preservation of neurological function including cognition. Because all medical treatments may induce side effects, in young and nearly asymptomatic patients the choices can be difficult. This review summarizes the current strategies: a watch-and-wait policy, surgery, chemotherapy, and radiotherapy.

Role of neurosurgery and radiation therapy in the management of brain tumors

In the United States, approximately 65,000 people are diagnosed with primary brain tumors each year, with an incidence of 19.3 cases per 100,000 person-years. These numbers represent a wide spectrum of disease, from benign to malignant, and prognosis varies widely based on disease. Treatment of primary brain tumors most often uses a combination of surgery and radiation. However, over the past several generations, technological advancements have significantly altered the treatment paradigm. This article reviews the current role of neurosurgery and radiation therapy in the management of primary brain tumors.

Dose dense 1 week on/1 week off temozolomide in recurrent glioma: a retrospective study

Alternative temozolomide regimens have been proposed to overcome O(6)-methylguanine-DNA methyltransferase mediated resistance. We investigated the efficacy and tolerability of 1 week on/1 week off temozolomide (ddTMZ) regimen in a cohort of patients treated with ddTMZ between 2005 and 2011 for the progression of a glioblastoma during or after chemo-radiation with temozolomide or a recurrence of another type of glioma after radiotherapy and at least one line of chemotherapy. Patients received ddTMZ at 100-150 mg/m(2)/d (days 1-7 and 15-21 in cycles of 28-days). All patients had a contrast enhancing lesion on MRI and the response was assessed by MRI using the RANO criteria; complete and partial responses were considered objective responses. Fifty-three patients were included. The median number of cycles of ddTMZ was 4 (range 1-12). Eight patients discontinued chemotherapy because of toxicity. Two of 24 patients with a progressive glioblastoma had an objective response; progression free survival at 6 months (PFS-6) in glioblastoma was 29%. Three of the 16 patients with a recurrent WHO grade 2 or 3 astrocytoma or oligodendroglioma or oligo-astrocytoma without combined 1p and 19q loss had an objective response and PFS-6 in these patients was 38%. Four out of the 12 evaluable patients with a recurrent WHO grade 2 or 3 oligodendroglioma or oligo-astrocytoma with combined 1p and 19q loss had an objective response; PFS-6 in these patients was 62%. This study indicates that ddTMZ is safe and effective in recurrent glioma, despite previous temozolomide and/or nitrosourea chemotherapy. Our data do not suggest superior efficacy of this schedule as compared to the standard day 1-5 every 4 weeks schedule.

Early measures of cognitive function predict survival in patients with newly diagnosed glioblastoma

Cognitive dysfunction is a common manifestation of primary brain tumors. We evaluated the association between early cognitive dysfunction and prognosis in a cohort of patients with newly diagnosed glioblastoma. Ninety-one patients who completed neuropsychological assessment after tumor resection but before further treatment were identified in the MD Anderson Neuropsychology database. The relationship between performance on cognitive testing and survival was evaluated using not only Cox proportional hazards models that included clinical factors such as age and KPS but also the Kaplan-Meier method. Median survival time from surgery was 20.7 months. Rates of impairment on cognitive testing ranged from 7.1% for Similarities, to 60.0% for Hopkins Verbal Learning Test-Revised Total Recall. As continuous variables, the Clinical Trial Battery Composite, Trail Making Test Part B, and Controlled Oral Word Association test were associated with survival. Impairment on the Trail Making Test Part B, Controlled Oral Word Association, Similarities, and Digit Span were associated with mortality. Kaplan-Meier analysis demonstrated the survival impact of these tests on the group as a whole and in select patient subgroups defined by classification by the Radiation Therapy Oncology Group (RTOG) Recursive Partitioning Analysis (RPA). Cognitive impairment as measured by specific neuropsychological tests is independently associated with poor prognosis in patients with newly diagnosed glioblastoma, and this effect remains significant even within patient subgroups defined by RTOG RPA class. Executive function and attention are the cognitive domains most closely associated with prognosis in this analysis.

Dynamic imaging response following radiation therapy predicts long-term outcomes for diffuse low-grade gliomas

Quantitative imaging assessment of radiation therapy (RT) for diffuse low-grade gliomas (DLGG) by measuring the velocity of diametric expansion (VDE) over time has never been studied. We assessed the VDE changes following RT and determined whether this parameter can serve as a prognostic factor. We reviewed a consecutive series of 33 adults with supratentorial DLGG treated with first-line RT with available imaging follow-up (median follow-up, 103 months). Before RT, all patients presented with a spontaneous tumor volume increase (positive VDE, mean 5.9 mm/year). After RT, all patients demonstrated a tumor volume decrease (negative VDE, mean, -16.7 mm/year) during a mean 49-month duration. In univariate analysis, initial tumor volume (>100 cm(3)), lack of IDH1 expression, p53 expression, high proliferation index, and fast post-RT tumor volume decrease (VDE at -10 mm/year or faster, fast responders) were associated with a significantly shorter overall survival (OS). The median OS was significantly longer (120.8 months) for slow responders (post-RT VDE slower than -10.0 mm/year) than for fast responders (47.9 months). In multivariate analysis, fast responders, larger initial tumor volume, lack of IDH1 expression, and p53 expression were independent poor prognostic factors for OS. A high proliferation index was significantly more frequent in the fast responder subgroup than in the slow responder subgroup. We conclude that the pattern of post-RT VDE changes is an independent prognostic factor for DLGG and offers a quantitative parameter to predict long-term outcomes. We propose to monitor individually the post-RT VDE changes using MRI follow-up, with particular attention to fast responders.

Phase II study of Gleevec plus hydroxyurea in adults with progressive or recurrent low-grade glioma

BACKGROUND

We evaluated the efficacy of imatinib plus hydroxyurea in patients with progressive/recurrent low-grade glioma.

METHODS

A total of 64 patients with recurrent/progressive low-grade glioma were enrolled in this single-center study that stratified patients into astrocytoma and oligodendroglioma cohorts. All patients received 500 mg of hydroxyurea twice a day. Imatinib was administered at 400 mg per day for patients not on enzyme-inducing antiepileptic drugs (EIAEDs) and at 500 mg twice a day if on EIAEDs. The primary endpoint was progression-free survival at 12 months (PFS-12) and secondary endpoints were safety, median progression-free survival, and radiographic response rate.

RESULTS

Thirty-two patients were enrolled into each cohort. Eleven patients (17%) had before radiotherapy and 24 (38%) had received before chemotherapy. The median PFS and PFS-12 were 11 months and 39%, respectively. Outcome did not differ between the histologic cohorts. No patient achieved a radiographic response. The most common grade 3 or greater adverse events were neutropenia (11%), thrombocytopenia (3%), and diarrhea (3%).

CONCLUSIONS

Imatinib plus hydroxyurea was well tolerated among recurrent/progressive LGG patients but this regimen demonstrated negligible antitumor activity.

Glioblastoma biomarkers from bench to bedside: advances and challenges

Glioblastoma multiforme (GBM) is the most common and aggressive primary brain tumour, with few available therapies providing significant improvements in mortality. Biomarkers, which are defined by the National Institutes of Health as 'characteristics that are objectively measured and evaluated as indicators of normal biologic processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention', have the potential to play valuable roles in the diagnosis and treatment of GBM. Although GBM biomarker research is still in its early stages because of the tumour's complex pathophysiology, a number of potential markers have been identified which can be measured in either brain tissue or blood serum. In conjunction with other clinical data, particularly neuroimaging modalities such as MRI, these proteins could contribute to the clinical management of GBM by helping to classify tumours, predict prognosis and assess treatment response. In this article, we review the current understanding of GBM pathophysiology and recent advances in GBM biomarker research, and discuss the potential clinical implications of promising biomarkers. A better understanding of GBM pathophysiology will allow researchers and clinicians to identify optimal biomarkers and methods of interpretation, leading to advances in tumour classification, prognosis prediction and treatment assessment.

Advances in PET imaging of brain tumors: a referring physician's perspective

PURPOSE OF REVIEW

To highlight the most recent advances in PET imaging of brain tumors, aiming at expanding the referring physician's knowledge in the field, the sine qua non for translating PET into the practice of neuro-oncology.

RECENT FINDINGS

The role of PET with amino acid tracers in the setting of brain lesions of unknown significance has been better defined, reducing the need for invasive procedures. The impact of PET-guided resection of high-grade glioma using ¹¹C-methionine (¹¹C-MET) has been strongly documented. [¹⁸F]Fluoroethyl-L-tyrosine is currently available for glioma management; advances in targeting glial tumor biopsy and monitoring response to standard chemoradiation of malignant glioma have been remarkable. 2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-penta-fluoropropyl)-acetamide is a rationally designed radiotracer with potential for imaging hypoxia in glioblastoma. New insights regarding the predictive value of 3-deoxy-3-[¹⁸F]fluorothymidine in outcome of recurrent malignant glioma treated with bevacizumab/irinotecan have been provided. First steps are being made toward apoptosis PET imaging for early assessment of radiotherapy response in brain metastases.

SUMMARY

The use of ¹¹C-MET and ¹⁸F-labeled PET tracers is getting a more precise position in the management of brain tumors. Advances hold promises in routine decision-making and in the design and conduct of clinical trials.