P14.79 Randomized phase II trial of Tumor Treating Fields plus radiation therapy plus temozolomide compared to radiation therapy plus temozolomide in patients with newly diagnosed glioblastoma

BACKGROUND

In last decade, there were numerous attempts to improve the outcome of patients with glioblastoma (GBM), but even after maximal surgical resection, radiation therapy (RT) and temozolomide (TMZ), followed by maintenance TMZ for 6 months the median OS is 14.6 months. In the EF-14 Phase III trial, the addition of Tumor Treating Fields (TTFields) at 200 kHz to maintenance TMZ increased the median OS to 20.9 months, compared with 16.0 months with maintenance TMZ alone (HR, 0.63; 95% CI, 0.53–0.76; p<0.001). Based on these results, the currently accepted standard of care for newly diagnosed GBM (ndGBM) is surgical resection if safely feasible, followed by RT with concomitant TMZ, and then followed by maintenance TMZ in combination with TTFields. Preclinical investigations have shown a radio-sensitizing effect of TTFields on glioma cells, suggesting synergistic effects between TTFields and radiotherapy. In a pilot study of 10 patients with ndGBM, we demonstrated that there was no increased treatment-related toxicity when TTFields were given in combination with RT/TMZ. The only TTFields-related adverse event was skin toxicity below the arrays. Preliminary progression free survival (PFS) data was encouraging. Based on the results of the pilot study, we designed this prospective, randomized Phase II study to further investigate if the addition of TTFields TMZ/RT treatment in ndGBM patients improves treatment efficacy and delays disease progression.

MATERIAL AND METHODS

Following debulking surgery or biopsy, 60 adult patients (≥18 years) with histologically confirmed GBM, KPS≥70 and life expectancy of at least 3 months will be randomized 1:1 to either a) RT with concomitant TMZ and TTFields (200 kHz) for 6 weeks followed by up to 6 months of maintenance TMZ in combination with TTFields (experimental arm) up to 24 months; or b) RT with concomitant TMZ alone followed by maintenance TMZ in combination with TTFields (control arm). Exclusion criteria: patients with early progressive disease, significant comorbidities precluding maintenance RT or TMZ or patients with an implanted electronic device. The primary endpoint is progression free survival at 12 months (PFS12). Treatment with TTFields will be continued until second progression or 24 months (the earlier of the two). All patients will be followed for survival. Grading and severity of all adverse events will be recorded using CTCAE V5.0. The sample size of 60 patients provides 80% power with a two-sided alpha level of 0.05 to detect a PFS12 of 46.5% with RT/TMZ/TTFields compared to 29.4% with RT/TMZ followed, respectively, by maintenance TMZ/TTFields (calculated from the RT/TMZ followed by maintenance TMZ/TTFields arm of the EF-14 trial). It is forecasted to take 24 months to fully recruit. Follow-up will continue for >12 months from recruitment of the last patient.

P14.71 Tumor Treating Fields combined with radiotherapy and temozolomide for newly diagnosed glioblastoma: final safety and efficacy results from a pilot study

BACKGROUND

Tumor Treating Fields (TTFields) are a non-invasive, loco-regional, anti-mitotic treatment consisting of low intensity alternating electric fields. The combination of TTFields with maintenance temozolomide significantly improved survival versus temozolomide alone in the phase 3 EF-14 study in newly diagnosed glioblastoma (ndGBM). In preclinical studies, TTFields increased the number of glioma cells undergoing cellular death following radiotherapy (RT) by inhibiting DNA damage repair, suggesting a radio-sensitizing effect of TTFields. This pilot study is the first to evaluate the safety and feasibility of administering TTFields concomitant to RT and TMZ in ndGBM patients.

MATERIAL AND METHODS

Patients diagnosed with ndGBM were treated with TTFields/RT/TMZ followed by maintenance TMZ and TTFields for up to 24 months. TTFields (200kHz) were delivered for >18 hours/day while the transducer arrays were removed during delivery of RT. TMZ was administered at a dose of 75 mg/m2/daily for 6 weeks and RT at a total dose of 60 Gy. The primary endpoint was safety of the combined TTFields/RT/TMZ; secondary endpoints included progression-free survival (PFS), overall survival (OS) and toxicity. Adverse events (AEs) were graded according to CTCAE V4.0.

RESULTS

10 ndGBM patients that recovered from maximal debulking surgery or biopsy were enrolled at a single center in Israel between April and December 2017. Five patients (50%) had undergone gross total resection while the rest had biopsy only. Eight of the patients were male, median age was 59, median KPS was 80 and median dose of RT was 60 Gy. Six patients (60%) reported at least one AE. The most common AE was TTFields-related skin toxicity, reported in four patients (40%), all of which were grade 1–2 in severity. Two patients reported serious AEs (seizures and general deterioration) that were considered unrelated to TTFields. Median PFS with RT/TMZ/TTFields was 10.5 months. Median OS has not yet been reached.

CONCLUSION

The proportion of patients with TTFields-related skin toxicity was similar to that reported in ndGBM patients in the randomized Phase III study (52%), where patients started TTFields at least 4 weeks after RT. No other TTFields-related toxicities were reported and there were no increase in RT- or TMZ-related toxicities as a result of combining TTFields with RT in addition to TMZ. Based on the safety and preliminary efficacy results of this pilot study, a phase II randomized study has been initiated to investigate the efficacy of concomitant RT/TMZ/TTFields in 60 ndGBM patients.

Spinal and Paraspinal Plexiform Neurofibromas in Patients with Neurofibromatosis Type 1: A Novel Scoring System for Radiological-Clinical Correlation

BACKGROUND AND PURPOSE

Neurofibromatosis type 1 is a common tumor predisposition syndrome. The aim of this study was to characterize the radiologic presentation of patients with neurofibromatosis type 1 with widespread spinal disease and to correlate it to clinical presentation and outcome.

MATERIALS AND METHODS

We conducted a historical cohort study of adult patients with neurofibromatosis type 1 with spinal involvement. Longitudinal clinical evaluation included pain and neurologic deficits. Radiologically, spinal involvement was classified according to a novel classification system, and a radiologic risk score was calculated.

RESULTS

Two hundred fifty-seven adult patients with neurofibromatosis type 1 are followed in our center. Thirty-four of these patients qualified for inclusion in this study. Three independent factors were found to be associated with increased risk for neurologic deficit: 1) bilateral tumors at the same level in the cervical region that approximated each other, 2) paraspinal tumors at the lumbar region, and 3) intradural lesions. On the basis of these factors, we calculated a combined risk score for neurologic deficits for each patient. We found a clear correlation between patient status and the calculated radiologic risk score. Patients with neurologic deficits were found to have a higher risk score (9 ± 8.3) than patients without neurologic deficits (2.5 ± 2.9, P < .05). Patients who progressed during the follow-up period had significantly higher scores at presentation than patients with stable conditions (9.9 ± 8.73 versus 3.9 ± 5.3, respectively; P < .05).

CONCLUSIONS

In this series, neurologic deficit is correlated with tumor burden and subtype. We found no direct correlation with tumor burden and pain. Our novel radiologic classification scoring system may be used to predict increased risk for neurologic morbidity.

Classification of High-Grade Glioma into Tumor and Nontumor Components Using Support Vector Machine

BACKGROUND AND PURPOSE

Current imaging assessment of high-grade brain tumors relies on the Response Assessment in Neuro-Oncology criteria, which measure gross volume of enhancing and nonenhancing lesions from conventional MRI sequences. These assessments may fail to reliably distinguish tumor and nontumor. This study aimed to classify enhancing and nonenhancing lesion areas into tumor-versus-nontumor components.

MATERIALS AND METHODS

A total of 140 MRI scans obtained from 32 patients with high-grade gliomas and 6 patients with brain metastases were included. Classification of lesion areas was performed using a support vector machine classifier trained on 4 components: enhancing and nonenhancing, tumor and nontumor, based on T1-weighted, FLAIR, and dynamic-contrast-enhancing MRI parameters. Classification results were evaluated by 2-fold cross-validation analysis of the training set and MR spectroscopy. Longitudinal changes of the component volumes were compared with Response Assessment in Neuro-Oncology criteria.

RESULTS

Normalized T1-weighted values, FLAIR, plasma volume, volume transfer constant, and bolus-arrival-time parameters differentiated components. High sensitivity and specificity (100%) were obtained within the enhancing and nonenhancing areas. Longitudinal changes in component volumes correlated with the Response Assessment in Neuro-Oncology criteria in 27 patients; 5 patients (16%) demonstrated an increase in tumor component volumes indicating tumor progression. These changes preceded Response Assessment in Neuro-Oncology assessments by several months. Seven patients treated with bevacizumab showed a shift to an infiltrative pattern of progression.

CONCLUSIONS

This study proposes an automatic classification method: segmented Response Assessment in Neuro-Oncology criteria based on advanced imaging that reliably differentiates tumor and nontumor components in high-grade gliomas. The segmented Response Assessment in Neuro-Oncology criteria may improve therapy-response assessment and provide earlier indication of progression.

Early Biomarkers from Conventional and Delayed-Contrast MRI to Predict the Response to Bevacizumab in Recurrent High-Grade Gliomas

BACKGROUND AND PURPOSE

The interpretation of the radiologic response of bevacizumab-treated patients with recurrent high-grade gliomas represents a unique challenge. Delayed-contrast MR imaging was recently introduced for calculating treatment-response-assessment maps in patients with brain tumors, providing clear separation between active tumor and treatment effects. We studied the application of standard and delayed-contrast MR imaging for assessing and predicting the response to bevacizumab.

MATERIALS AND METHODS

Twenty-four patients with recurrent high-grade gliomas were scanned before and during bevacizumab treatment by standard and delayed-contrast MR imaging. The mean change in lesion volumes of responders (overall survival, ≥1 year) and nonresponders (overall survival, <1 year) was studied. The lesion volumes at baseline and the changes in lesion volumes 1 month after treatment initiation, calculated from standard and delayed-contrast MRIs, were studied as possible predictors of outcome. In scans acquired at progression, the average change in lesion volume from previous follow-up in standard and delayed-contrast MRIs was compared.

RESULTS

Response and progression patterns were identified from the mean change in lesion volumes, depicted from conventional T1WI, delayed contrast-enhanced MR imaging, and DSC MR imaging. Thresholds for early prediction of response were calculated by using these sequences. For each predictor, sensitivity, specificity, positive predictive values, and negative predictive values were calculated, reaching 85.7%, 87.5%, 75%, and 93.3% for conventional T1WI; 100%, 87.5%, 77.8%, and 100% for delayed-contrast MR imaging; and 75%, 78.6%, 50%, and 91.7% for DSC MR imaging. The benefit of delayed-contrast MR imaging in separating responders and nonresponders was further confirmed by using log-rank tests (conventional T1WI, P = .0022; delayed-contrast MR imaging, P < .0001; DSC MR imaging, P = .0232) and receiver operating characteristic analyses. At progression, the increase in lesion volumes in delayed-contrast MR imaging was 37.5% higher than the increase in conventional T1WI (P < .01); these findings suggest that progression may be depicted more effectively in treatment-response-assessment maps.

CONCLUSIONS

The benefit of contrast-enhanced MR imaging for assessing and predicting the response to bevacizumab was demonstrated. The increased sensitivity of the treatment-response-assessment maps reflects their potential contribution to the management of bevacizumab-treated patients with recurrent high-grade glioma.

A common sense approach to radiation treatment planning of temporal lobe GBM

2044

Background: Irradiation remains the cornerstone of management for glioblastoma multiforme (GBM). Guidelines adopted by the RTOG and EORTC advocate encompassing the primary tumor (sometimes with edema), and a 2 cm margin in the high dose volume. These recommendations have emerged from imaging studies and post-mortem analyses. A shortcoming of this approach is the exposure of critical structures (e.g. optic apparatus) to doses of radiation that may exceed organ tolerance. We sought to determine whether the temporal bone (rather than the aforementioned 2 cm radius) serves as a barrier to tumor spread when regarded as the anterior margin for temporal lobe lesions. We hypothesized that toxicity could be reduced without compromising tumor control. Methods: During the period 2003–2006, 250 patients with GBM were treated with surgery and primary irradiation at our institution. Chemotherapy (e.g., Stupp regimen) was given to approximately one-third of patients. 31 patients had lesions confined to the temporal lobe. All patients had MRI at baseline and at monthly intervals following a course of 60 Gy delivered by conformal techniques. The Clinical Target Volume included the primary lesion, the edema when present and a 2 cm margin except in the direction of the temporal bone. At follow-up (median = 10 months), patients were judged to have stable disease, local progression (i.e. failure within the temporal lobe), distant progression (i.e., brain failure beyond the temporal lobe) or combinations of the latter 2. Results: 11 patients have remained with stable disease. 17 have failed locally. 3 have manifested distant failure. Of the latter, only one patient failed in the infratemporal fossa. Conclusions: An acceptable level of recurrence (e.g., <5% beyond the temporal bone) is seen when the temporal bone, rather than a 2 cm margin is employed as the anterior border of the CTV. As GBM patients live longer in the era of combined modality therapy, a greater opportunity will exist to express radiation damage. The strategy proposed herein provides tumor control while respecting optic tolerance without resorting to complex, expensive approaches such as IMRT.

No significant financial relationships to disclose.

Temozolomide treatment for newly diagnosed anaplastic oligodendrogliomas: a clinical efficacy trial

PURPOSE

Chemotherapy with alkylating agents is of proven efficacy in recurrent anaplastic oligodendroglioma (AO) with reported response rates ranging between 50% and 70%. The response of newly diagnosed AO to initial treatment with temozolomide (TMZ) has not yet been reported. This study evaluated the response and time to tumor progression of newly diagnosed AO initially treated with TMZ.

PATIENTS AND METHODS

Twenty patients with a median age of 47 (range: 26-65) received a median of 14 (range: 3-24) cycles of TMZ as their first modality of therapy following diagnosis of AO. Treatment was given every 28 days for 5 days at a starting dose of 200 mg/m2/d and was continued for 24 cycles unless toxicity or tumor progression required withdrawal of TMZ. MRI evaluations were repeated every 8 weeks and scales of Karnofsky performance status (KPS) and of neurological function were used to assess clinical response.

RESULTS

Clinical improvement was observed in 60% of the patients with statistically significant gain measured by KPS and the neurologic function scales. The objective response rate was 75%, and median time to tumor progression was 24 months. Maximal objective response was reached within a median of 6 months (range: 3-12). Tumors with 1p loss had longer progression free survival compared to tumors without deletions (PFS at 24 months: 1p LOH = 100%, 1p intact = 20%; P = 0.057). TMZ was well tolerated with only two events of grade 3/4 hematological toxicity.

CONCLUSIONS

Newly diagnosed AO demonstrates a high rate of response to initial therapy with TMZ, similar to the response reported for PCV combination therapy. Further studies are needed to determine the optimal duration of treatment and whether radiotherapy should immediately follow chemotherapy.

Pharmacokinetics of methotrexate in cerebrospinal fluid and serum after osmotic blood-brain barrier disruption in patients with brain lymphoma

OBJECTIVE

To evaluate the pharmacokinetics of methotrexate in ventricular cerebrospinal fluid and serum after osmotic blood-brain barrier disruption and intra-arterial administration compared with intravenous or simple intra-arterial infusion in patients with primary central nervous system lymphoma.

METHODS

Serum and ventricular cerebrospinal fluid were sampled after methotrexate administration in 12 patients. Blood-brain barrier disruption was induced on 2 sequential days by mannitol (25%) infusion delivered to the vertebral or internal carotid artery territories followed by intra-arterial methotrexate (dose, 1.4 g/m2; 47 treatments). Sixteen treatments were given without barrier disruption by intravenous (3.5 g/m2; nine treatments) or intra-arterial (2.8 g/m2; seven treatments) infusion.

RESULTS

Ventricular cerebrospinal fluid-methotrexate peak levels after blood-brain barrier disruption of the vertebral and the internal carotid arteries territories were 19.3 +/- 2.9 and 8.5 +/- 0.7 micromol/L (P < .001), and the area under the curve from time 0 to infinity was 178.0 +/- 21.3 and 110.0 +/- 12.4 [micromol/L x h, respectively (P < .01). No significant differences were observed in serum levels. After intra-arterial infusion was performed without disruption, the serum peak level was higher than that achieved by intravenous treatment (518.2 +/- 67.7 versus 180.6 +/- 31.8 micromol/L; P < .001). No differences were observed in cerebrospinal fluid concentrations, which dropped below 1 micromol/L at 6 hours. The cerebrospinal fluid/serum ratio [AUC(%)] of methotrexate after blood-brain barrier disruption was three to four times greater than that by systemic administration.

CONCLUSION

Enhanced methotrexate delivery to the central nervous system can be attained by intra-arterial administration combined with osmotic disruption of the blood-brain barrier compared with simple intra-arterial or intravenous administration.

In vivo assessment of the window of barrier opening after osmotic blood-brain barrier disruption in humans

OBJECT

Osmotic blood-brain barrier (BBB) disruption induced by intraarterial infusion of mannitol is used in conjunction with chemotherapy to treat human brain tumors. The time course to barrier closure, or the so-called therapeutic window, has been examined in animals but little information is available in humans. The authors, therefore assessed the time course to barrier closure after osmotic BBB disruption in humans.

METHODS

Disruption of the BBB was demonstrated using 99mTc-glucoheptonate (TcGH) single-photon emission computerized tomography (SPECT) scanning in 12 patients who were treated monthly with combination chemotherapy in conjunction with BBB disruption. The primary diagnosis was primary central nervous system lymphoma in seven patients and primitive neuroectodermal tumors in five. The TcGH (20 mCi) was injected at 1- to 480-minute intervals after osmotic BBB disruption, and patients underwent SPECT scanning after 4 hours. A total of 38 studies was performed. Good-to-excellent BBB disruption was obtained in 29 procedures and poor-to-moderate disruption was seen in the other nine studies. The TcGH indices correlated with the degree of BBB disruption as measured postprocedure on contrast-enhanced CT scans (r = 0.852). Mean baseline TcGH indices were 1.02+/-0.07. For the group of patients with good-to-excellent disruptions the mean indices at 1 minute postdisruption measured 2.19+/-0.18. After 40 minutes no significant change was noted (mean index 2.13+/-0.2). Then the indices declined more steeply and at 120 minutes after the disruption the index was 1.36+/-0.02. A very slow decline was noted between 120 and 240 minutes after mannitol infusion. At 240 minutes the barrier was still open for all good-to-excellent disruptions (index 1.33+/-0.08) but at 480 minutes the mean indices had returned to the baseline level.

CONCLUSIONS

Results of these in vivo human studies indicate that the time course to closure of the disrupted BBB for low-molecular-weight complexes is longer than previously estimated. The barrier is widely open during the first 40 minutes after osmotic BBB disruption and returns to baseline levels only after 6 to 8 hours following the induction of good or excellent disruption. These findings have important clinical implications for the design of therapeutic protocols.

Leptomeningeal metastases from solid tumors: a comparison of two prospective series treated with and without intra-cerebrospinal fluid chemotherapy

BACKGROUND

It has been suggested that an aggressive treatment of patients with leptomeningeal metastases (LM) that groups radiotherapy and intra-cerebrospinal fluid (intra-CSF) chemotherapy has improved treatment outcomes. Based on their previous series of 137 patients treated with such an intensive standard protocol, the authors expected 20% of the patients to maintain their responses for at least 6 months after withdrawal of therapy. They also observed that, in patients with solid tumors, a partial response was compatable with sustained off-therapy response and that the maximal response was reached soon after completion of radiotherapy. The authors concluded that the role of intra-CSF chemotherapy, with its associated high rate of complications, is unclear. In this study, which was a further evaluation of this dilemma, they compared the outcomes of two prospective treatment protocols that were identical in their use of radiotherapy and systemic chemotherapy and varied only in their inclusion or exclusion of intra-CSF chemotherapy.

METHODS

Adult patients with LM from systemic solid tumors were prospectively included in the treatment protocol active at the time of their diagnosis. Group 1 comprised 54 patients treated by radiotherapy, intra-CSF chemotherapy, and systemic therapy, whereas Group 2 comprised 50 patients treated with radiotherapy, and systemic chemotherapy but no intra-CSF chemotherapy.

RESULTS

The analysis of treatment outcomes was performed retrospectively. The median patient age and distribution of primary neoplasms did not differ between the two groups. The proportion of early deaths that occurred during radiotherapy was similar for the two groups, as was the overall rate of response to treatment. The two groups also had the same median survival, which was 4 months for both groups, as well as the same proportion of long term survivors. Thirty-one percent of patients in Group 1 developed early complications related to intra-CSF chemotherapy, whereas patients in Group 2 were spared these complications. Delayed symptomatic leukoencephalopathy was observed in 20% of Group 1 patients compared with none in Group 2 (P = 0.02).

CONCLUSIONS

The exclusion of intra-CSF chemotherapy from the treatment schedule of patients with LM does not change their overall response to treatment, their median survival, or the proportion of long term survivors. It does, however, significantly reduce the rate of early and delayed treatment-related complications.