Novel Functional Radiomics for Prediction of Cardiac Positron Emission Tomography Avidity in Lung Cancer Radiotherapy

PURPOSE

Traditional methods of evaluating cardiotoxicity focus on radiation doses to the heart. Functional imaging has the potential to provide improved prediction for cardiotoxicity for patients with lung cancer. Fluorine-18 (18F) fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) imaging is routinely obtained in a standard cancer staging workup. This work aimed to develop a radiomics model predicting clinical cardiac assessment using 18F-FDG PET/CT scans before thoracic radiation therapy.

METHODS

Pretreatment 18F-FDG PET/CT scans from three study populations (N = 100, N = 39, N = 70) were used, comprising two single-institutional protocols and one publicly available data set. A clinician (V.J.) classified the PET/CT scans per clinical cardiac guidelines as no uptake, diffuse uptake, or focal uptake. The heart was delineated, and 210 novel functional radiomics features were selected to classify cardiac FDG uptake patterns. Training data were divided into training (80%)/validation (20%) sets. Feature reduction was performed using the Wilcoxon test, hierarchical clustering, and recursive feature elimination. Ten-fold cross-validation was carried out for training, and the accuracy of the models to predict clinical cardiac assessment was reported.

RESULTS

From 202 of 209 scans, cardiac FDG uptake was scored as no uptake (39.6%), diffuse uptake (25.3%), and focal uptake (35.1%), respectively. Sixty-two independent radiomics features were reduced to nine clinically pertinent features. The best model showed 93% predictive accuracy in the training data set and 80% and 92% predictive accuracy in two external validation data sets.

CONCLUSION

This work used an extensive patient data set to develop a functional cardiac radiomic model from standard-of-care 18F-FDG PET/CT scans, showing good predictive accuracy. The radiomics model has the potential to provide an automated method to predict existing cardiac conditions and provide an early functional biomarker to identify patients at risk of developing cardiac complications after radiotherapy.

Long-Term Outcomes of Non-Vestibular Cranial Nerve Schwannomas Treated with Fractionated Stereotactic Radiotherapy and Stereotactic Radiosurgery

PURPOSE/OBJECTIVE(S)

Non-vestibular cranial nerve schwannomas (NVCNS) are rare tumors that account for approximately 10% of cranial nerve schwannomas. They are commonly treated with radiation therapy (XRT) due to their location often precluding safe resection. We examined the long-term outcomes of NVCNS treated with XRT as primary management and for post-operative salvage.

MATERIALS/METHODS

We conducted a retrospective review of patients with NVCNS treated with fractionated stereotactic radiation therapy (FSRT) or Gamma Knife Stereotactic Radiosurgery (GK-SRS) from 1996 to 2018 at our institution. We examined patient demographics, cranial nerve (CN) involvement, CN function pre-/post-XRT, treatment volume (TV), toxicity, surgery pre-XRT, and local control. Kaplan-Meier analysis was performed for evaluation of local control.

RESULTS

We identified 66 patients (38 female, 28 male) with NVCNS, a portion of whom had tumors involving more than one cranial nerve. Forty-six (69.7%) were treated with FSRT (median dose 50.4 Gy in 1.8 Gy/fraction; range 45-54 Gy), and 20 (30.3%) with GK-SRS (median dose 12 Gy; range 12-15 Gy). Median follow-up time was 92.5 months (5-306). Median Karnofsky Performance Status was 90 (70-100). Median age at start of XRT was 45 years old (15-92). Prior to XRT, 34.8% (23) of patients had surgical resection, with median time from surgery to XRT of 4.25 months (0.5-130 months). Median treatment volume was 4.72 cc (0.26-29). The cranial nerve most commonly involved was CN V (48.4%), followed by CN X (15.2%), CN VII (13.6%), CN VI (6.1%), CN XII (6.1%), CN III (6.1%), and CN IX (3%). Twenty-nine (43.9%) patients experienced grade 1 acute toxicity during treatment. Six (9%) patients experienced grade 1 chronic toxicity. No grade 2 or higher acute or chronic toxicity was observed. No significant difference in rates of acute or chronic toxicity was observed between patients treated with GK-SRS vs. FSRT. Post-XRT, 37 patients (56.1%) had improvement in CN function/symptom, 24 patients (36.3%) had stable function/symptoms, and 5 patients (7.6%) had worsening function/symptoms. Local control at one and five years was 100%. In-field recurrence was observed in one patient (1.5%), at 9 years post-XRT. For salvage this patient was treated with a second course of FSRT to the recurrent tumor.

CONCLUSION

Our large institutional series with long term follow up showed excellent local control of NVCNS treated with FSRT or GK-SRS both for primary management and post-operative salvage. Treatment is well tolerated, with high rates of preservation or improvement of CN function, and minimal acute and chronic toxicity.

Novel Deep Learning Segmentation Models for Accurate GTV and OAR Segmentation in MR-Guided Adaptive Radiotherapy for Pancreatic Cancer Patients

PURPOSE/OBJECTIVE(S)

MR-guided adaptive radiotherapy (MRgART) improves target coverage and organ-at-risk (OAR) sparing in pancreatic cancer radiation therapy (RT). Inter-fractional changes in patients undergoing RT require time intensive re-delineation of gross tumor volume (GTV) and OARs prior to adaptive optimization. Accurate automatic segmentation has the potential to significantly improve efficiency of the adaptive workflow. We hypothesized that state-of-the-art deep learning (DL) segmentation models could adequately segment GTV and OARs in both planning and daily fractional MR scans.

MATERIALS/METHODS

The study included 21 patients with pancreatic cancer treated with MRgART (10 Gy x 5 fractions). The planning MR as well as all daily MR images and registrations were collected (6 image sets per patient and a total of 126 image sets). The planning MR and fraction 1-4 image sets were used as the training set (N = 105), while the test set (N = 21) comprised images for fraction 5, to simulate the last step of incremental learning from planning to final fraction. Evaluated contours included the GTV, Small Bowel, Large Bowel, Duodenum, Left and Right Kidney, Liver, Spinal Cord, and Stomach. To mimic clinical conditions, contour accuracy was evaluated within the ring structure surrounding the PTV, inside of which daily adaptive re-contouring is applied (2 cm expansion in the cradio-caudal direction, 3 cm expansion otherwise). We evaluated three DL model architectures: SegResNet, SegResNet 2D, and SwinUNETR to autosegment GTV and OARs. The segmentation models were trained on the training set using 5-fold cross-validation (CV) and quantitatively analyzed by comparing against clinically used contours with DICE scores. Qualitative analysis was performed by a radiation oncologist using a scoring scale: 1 = perfect, 2 = minor discrepancy, 3 = moderate discrepancy, and 4 = rejected.

RESULTS

Overall, the DL segmentations were in acceptable agreement with clinical contours. The best performing model was the SwinUNETR model with overall training DICE = 0.88±0.06, test DICE = 0.78±0.11, and qualitative score of 1.6±0.8. The agreement between the DL model and clinical segmentation for the GTV was 0.79±0.08, with a qualitative score of 2.2±0.9. The highest and lowest OAR DICE scores were for the Left Kidney (DICE = 0.93) and Small Bowel (DICE = 0.68), respectively. The highest qualitative OAR scores were for the Kidney, Liver, and Spinal Cord (score = 1.0) and the lowest qualitative score was for the Duodenum (score = 2.3) CONCLUSION: We report here the most comprehensive work on DL segmentation for pancreatic cancer MRgART, including quantitative and clinically-pertinent qualitative evaluations of 126 image sets and 3 DL architectures. Our data show good quantitative agreement between DL and clinical contours, and acceptable clinician evaluations for the majority of GTVs and OARs. The current work has great potential to significantly reduce a major bottleneck in the MRgART workflow for pancreatic cancer patients.

Early Outcomes of MR-Guided SBRT for Patients with Recurrent Pancreatic Adenocarcinoma

PURPOSE/OBJECTIVE(S)

Local treatment options for patients with locally recurrent pancreatic adenocarcinoma (L-PAC) are limited, with expected median survival time (MST) of 8-11 months (mo) following recurrence. MRI-guided radiation therapy (MRgRT) provides the ability to dose escalate while sparing normal tissue. The literature for MR-guided Stereotactic Body Radiotherapy (MRgSBRT) for L-PAC is sparse. Here we report on the early outcomes of MRgSBRT in patients with L-PAC.

MATERIALS/METHODS

Patients with prior resection of pancreatic adenocarcinoma with post-operative chemotherapy as indicated followed by local recurrence of disease at prior surgical site and treated with MRgSBRT at a single tertiary referral center from 5-2021 to 8-2022 for L-PAC were identified from our prospective database. MRgSBRT was delivered to 40-50 Gy in 4-5 fractions with target and OAR delineation per institutional standards. Descriptive analysis of the patient, disease, and treatment characteristics were performed. Endpoints included local control, defined as absence of tumor progression per RECIST criteria, distant failure, overall survival (OS), and acute and chronic toxicities per Common Terminology Criteria for Adverse Events (CTCAE), version 5.

RESULTS

Eleven patients with L-PAC were identified with median follow-up of 10.7 mo (3.2 - 22.3). Ten of those underwent surgical resection at the treating radiation facility and one patient underwent preoperative radiation for 50.4 Gy in 28 fractions followed by surgical resection at an outside hospital. MRgRT was delivered a median of 18.8 mo (3.5 - 48.0) following resection. There were 5 females and 6 males, with a median age of 72 years (52-83) and median KPS of 80 (60-100). OS rates following initial diagnosis at 12, 18 and 24 mo were 100%, 82%, and 61%, respectively, with an MST of 25.3 mo (12.4-53.1). OS rates following recurrence at 6 and 12 mo were 82% and 52%, respectively, with an MST of 10.7 mo (3.2 - 21.9). One patient experienced local failure at 7.8 mo, and 9 patients experienced distant failure at a median of 3.4 mo (0.3 - 21.9) following MRgSBRT. Five patients experienced distant failure less than 3 mo following radiation. Grade 1 or 2 acute GI toxicity was noted in 45% of patients and chronic GI toxicity, in 18% of patients. No Grade≥3 AEs were noted.

CONCLUSION

MRgSBRT for recurrent pancreatic adenocarcinoma demonstrates good local control with acceptable acute and chronic toxicity as well as reasonable overall survival. Distant failure remains a substantial problem with a significant number of patients demonstrating metastases immediately following radiation, suggesting the presence of micro-metastatic disease prior to local therapy. Adequate patient selection for MRgSBRT, and proper integration of systemic therapy in this patient population remains a topic of discussion that requires further exploration.

Definitive radiotherapy for meningeal brainstem melanocytoma: a case report

Meningeal melanocytomas are rare, benign tumours of the central nervous system arising from the melanocytes of the leptomeninges. First-line treatment consists of either gross or subtotal resection with or without radiotherapy. However, given the sensitive locations of these tumours, alternative treatment options such as definitive radiotherapy may be warranted in patients deemed high-risk or without accessible tumours. A 67-year-old male presenting with spastic gait, frequent falls, and vertical gaze palsy was diagnosed with a 2.4 cm primary meningeal melanocytoma arising from the interpeduncular fossa. Given the critical tumour position within the brainstem, definitive radiotherapy was recommended. He received fractionated stereotactic radiotherapy (FSRT) to a total dose of 54 Gy in 27 fractions, resulting in a gradual improvement in gait and ocular range of motion. Follow-up imaging over the next three years revealed largely stable disease and an increase in edema with mild upper extremity weakness that improved with steroids. He was followed for three years and expired four years after treatment due to pneumonia. For patients unable to receive surgical resection, definitive RT may provide local control with minimal morbidity.

Evaluation of variables predicting PFT changes for lung cancer patients treated on a prospective 4DCT-ventilation functional avoidance clinical trial

PURPOSE

Functional avoidance radiotherapy uses functional imaging to reduce pulmonary toxicity by designing radiotherapy plans that reduce doses to functional regions of the lung. A phase-II, multi-center, prospective study of 4DCT-ventilation functional avoidance was completed. Pre and post-treatment pulmonary function tests (PFTs) were acquired and assessed pulmonary function change. This study aims to evaluate which clinical, dose and dose-function factors predict PFT changes for patients treated with 4DCT-ventilation functional avoidance radiotherapy.

MATERIALS AND METHODS

56 patients with locally advanced lung cancer receiving radiotherapy were accrued. PFTs were obtained at baseline and three months following radiotherapy and included forced expiratory volume in 1-second (FEV1), forced vital capacity (FVC), and FEV1/FVC. The ability of patient, clinical, dose (lung and heart), and dose-function metrics (metrics that combine dose and 4DCT-ventilation-based function) to predict PFT changes were evaluated using univariate and multivariate linear regression.

RESULTS

Univariate analysis showed that only dose-function metrics and the presence of chronic obstructive pulmonary disease (COPD) were significant (p<0.05) in predicting FEV1 decline. Multivariate analysis identified a combination of clinical (immunotherapy status, presence of thoracic comorbidities, smoking status, and age), along with lung dose, heart dose, and dose-function metrics in predicting FEV1 and FEV1/FVC changes.

CONCLUSION

The current work evaluated factors predicting PFT changes for patients treated in a prospective functional avoidance radiotherapy study. The data revealed that lung dose- function metrics could predict PFT changes, validating the significance of reducing the dose to the functional lung to mitigate the decline in pulmonary function and providing guidance for future clinical trials.

Consensus Quality Measures and Dose Constraints for Lung Cancer From the Veterans Affairs Radiation Oncology Quality Surveillance Program and ASTRO Expert Panel

PURPOSE

For patients with lung cancer, it is critical to provide evidence-based radiation therapy to ensure high-quality care. The US Department of Veterans Affairs (VA) National Radiation Oncology Program partnered with the American Society for Radiation Oncology (ASTRO) as part of the VA Radiation Oncology Quality Surveillance to develop lung cancer quality metrics and assess quality of care as a pilot program in 2016. This article presents recently updated consensus quality measures and dose-volume histogram (DVH) constraints.

METHODS AND MATERIALS

A series of measures and performance standards were reviewed and developed by a Blue-Ribbon Panel of lung cancer experts in conjunction with ASTRO in 2022. As part of this initiative, quality, surveillance, and aspirational metrics were developed for (1) initial consultation and workup; (2) simulation, treatment planning, and treatment delivery; and (3) follow-up. The DVH metrics for target and organ-at-risk treatment planning dose constraints were also reviewed and defined.

RESULTS

Altogether, a total of 19 lung cancer quality metrics were developed. There were 121 DVH constraints developed for various fractionation regimens, including ultrahypofractionated (1, 3, 4, or 5 fractions), hypofractionated (10 and 15 fractionations), and conventional fractionation (30-35 fractions).

CONCLUSIONS

The devised measures will be implemented for quality surveillance for veterans both inside and outside of the VA system and will provide a resource for lung cancer-specific quality metrics. The recommended DVH constraints serve as a unique, comprehensive resource for evidence- and expert consensus-based constraints across multiple fractionation schemas.

Predictors and characteristics of Rib fracture following SBRT for lung tumors

BACKGROUND

The utilization of stereotactic body radiation therapy (SBRT) is increasing for primary and secondary lung neoplasms. Despite encouraging results, SBRT is associated with an increased risk of osteoradionecrosis-induced rib fracture. We aimed to (1) evaluate potential clinical, demographic, and procedure-related risk factors for rib fractures and (2) describe the radiographic features of post-SBRT rib fractures.

METHODS

We retrospectively identified 106 patients who received SBRT between 2015 and 2018 for a primary or metastatic lung tumor with at least 12 months of follow up. Exclusion criteria were incomplete records, previous ipsilateral thoracic radiation, or relevant prior trauma. Computed tomography (CT) images were reviewed to identify and characterize rib fractures. Multivariate logistic regression modeling was employed to determine clinical, demographic, and procedural risk factors (e.g., age, sex, race, medical comorbidities, dosage, and tumor location).

RESULTS

A total of 106 patients with 111 treated tumors met the inclusion criteria, 35 (32%) of whom developed at least one fractured rib (60 total fractured ribs). The highest number of fractured ribs per patient was five. Multivariate regression identified posterolateral tumor location as the only independent risk factor for rib fracture. On CT, fractures showed discontinuity between healing edges in 77% of affected patients.

CONCLUSIONS

Nearly one third of patients receiving SBRT for lung tumors experienced rib fractures, 34% of whom experienced pain. Many patients developed multiple fractures. Post-SBRT fractures demonstrated a unique discontinuity between the healing edges of the rib, a distinct feature of post-SBRT rib fractures. The only independent predictor of rib fracture was tumor location along the posterolateral chest wall. Given its increasing frequency of use, describing the risk profile of SBRT is vital to ensure patient safety and adequately inform patient expectations.

Characterizing Pulmonary Function Test Changes for Patients With Lung Cancer Treated on a 2-Institution, 4-Dimensional Computed Tomography-Ventilation Functional Avoidance Prospective Clinical Trial

Purpose

Four-dimensional computed tomography (4DCT)-ventilation-based functional avoidance uses 4DCT images to generate plans that avoid functional regions of the lung with the goal of reducing pulmonary toxic effects. A phase 2, multicenter, prospective study was completed to evaluate 4DCT-ventilation functional avoidance radiation therapy. The purpose of this study was to report the results for pretreatment to posttreatment pulmonary function test (PFT) changes for patients treated with functional avoidance radiation therapy.

Methods and Materials

Patients with locally advanced lung cancer receiving chemoradiation were accrued. Functional avoidance plans based on 4DCT-ventilation images were generated. PFTs were obtained at baseline and 3 months after chemoradiation. Differences for PFT metrics are reported, including diffusing capacity for carbon monoxide (DLCO), forced expiratory volume in 1 second (FEV1), and forced vital capacity (FVC). PFT metrics were compared for patients who did and did not experience grade 2 or higher pneumonitis.

Results

Fifty-six patients enrolled on the study had baseline and posttreatment PFTs evaluable for analysis. The mean change in DLCO, FEV1, and FVC was -11.6% ± 14.2%, -5.6% ± 16.9%, and -9.0% ± 20.1%, respectively. The mean change in DLCO was -15.4% ± 14.4% for patients with grade 2 or higher radiation pneumonitis and -10.8% ± 14.1% for patients with grade <2 radiation pneumonitis (P = .37). The mean change in FEV1 was -14.3% ± 22.1% for patients with grade 2 or higher radiation pneumonitis and -3.9% ± 15.4% for patients with grade <2 radiation pneumonitis (P = .09).

Conclusions

The current work is the first to quantitatively characterize PFT changes for patients with lung cancer treated on a prospective functional avoidance radiation therapy study. In comparison with patients treated with standard thoracic radiation planning, the data qualitatively show that functional avoidance resulted in less of a decline in DLCO and FEV1. The presented data can help elucidate the potential pulmonary function improvement with functional avoidance radiation therapy.

Creating and Implementing a Principal Investigator Tool Kit for Enhancing Accrual to Late Phase Clinical Trials: Development and Usability Study

Background

Accrual to oncology clinical trials remains a challenge, particularly during the COVID-19 pandemic. For late phase clinical trials funded by the National Cancer Institute, the development of these research protocols is a resource-intensive process; however, mechanisms to optimize patient accrual after trial activation are underdeveloped across the National Clinical Trial Network (NCTN). Low patient accrual can lead to the premature closure of clinical trials and can ultimately delay the availability of new, potentially life-saving therapies in oncology.

Objective

The purpose of this study is to formally create an easily implemented tool kit of resources for investigators of oncology clinical trials within the NCTN, specifically the NRG Oncology cooperative group, in order to optimize patient accrual.

Methods

NRG Oncology sought to formally develop a tool kit of resources to use at specific time points during the lifetime of NRG Oncology clinical trials. The tools are clearly described and involve the facilitation of engagement of the study principal investigator with the scientific and patient advocate community during the planning, activation, and accrual periods. Social media tools are also leveraged to enhance such engagement. The principal investigator (PI) tool kit was created in 2019 and thereafter piloted with the NRG Oncology/Alliance NRG-LU005 phase II or III trial in small-cell lung cancer. The PI tool kit was developed by the NRG Oncology Protocol Operations Management committee and was tested with the NRG/Alliance LU005 randomized trial within the NCTN.

Results

NRG Oncology/Alliance NRG-LU005 has seen robust enrollment, currently 127% of the projected accrual. Importantly, many of the tool kit elements are already being used in ongoing NRG Oncology trials, with 56% of active NRG trials using at least one element of the PI tool kit and all in-development trials offered the resource. This underscores the feasibility and potential benefits of deploying the PI tool kit across all NRG Oncology trials moving forward.

Conclusions

While clinical trial accrual can be challenging, the PI tool kit has been shown to augment accrual in a low-cost and easily implementable fashion. It could be widely and consistently deployed across the NCTN to improve accrual in oncology clinical trials.

Trial Registration

ClinicalTrials.gov NCT03811002; https://clinicaltrials.gov/ct2/show/NCT03811002

Safety results of NRG-LU004: Phase I trial of accelerated or conventionally fractionated radiotherapy combined with durvalumab in PD-L1–high locally advanced non-small cell lung cancer

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Background: In advanced non-small cell lung cancer (NSCLC), high Programmed-Death-1 Ligand (PD-L1) (>50%) expression demonstrate superior response and survival with immune checkpoint inhibitors compared to chemotherapy. We hypothesize that it is safe and feasible to substitute durvalumab instead of chemotherapy concurrently with radiotherapy (RT) in patients with Locally Advanced-NSCLC (LA-NSCLC) and high PD-L1. Methods: NRG-LU004 (NCT03801902) is a Phase I study for patients with stage II-III unresectable or inoperable, LA-NSCLC with PD-L1> 50% (Dako 22C3 or Ventana SP263) expression. There were safety and expansion phases with a primary endpoint of safety. Patients started with 1500 mg durvalumab Q4 weeks and thoracic RT within 2 weeks from 1st infusion. Durvalumab continued once a month up to 1 year. In the safety cohort, 6 patients in cohort 1 were treated with accelerated fractionated RT (ACRT) to 60 Gy in 15 fractions, followed by a required safety hold for 90 days. During cohort 1 safety hold, cohort 2 patients were treated with conventional RT 60 Gy in 30 fractions (CONV) followed by a 60-day safety hold. A cohort advanced to the expansion phase to enroll 6 more patients if safety criteria (0-1 patients with a dose limiting toxicity [DLT]) were met. If both cohorts were deemed safe, patients would be randomized 1:1 to ACRT or CONV with safety defined as < 4 of 12 evaluable patients per arm experiencing a DLT. Feasibility was defined as at least 80% of patients in each arm receiving at least 80% of the planned dose of durvalumab during the first 8 weeks. Results: 24 evaluable patients enrolled between January 2019 and June 2021. No DLTs were reported in cohort 1, and 1 (unrelated bronchopulmonary hemorrhage leading to discontinuation of durvalumab) in cohort 2. Both safety cohorts advanced to the expansion phase. All but one patient (CONV) received RT per protocol/with an acceptable variation. At the time of analysis, 24% had received all 13 cycles of durvalumab. For the ACRT cohort, there were 4 grade 3, 1 grade 4 (lymphopenia), and 1 grade 5 AE (lung infection, assessed as unrelated to therapy). For CONV, there were 8 grade 3, 0 grade 4, and 1 grade 5 AE (respiratory failure, unrelated to therapy). For feasibility, 10 of 12 (85%) patients in the ACRT cohort received the second dose of durvalumab (2 not received due to shingles and unrelated death), while 9 of 12 (75%) of the CONV cohort received the second dose (reasons for not receiving: viral hepatitis, bronchopulmonary hemorrhage, and respiratory failure, all assessed as unrelated to therapy). Conclusions: Chemotherapy-free thoracic RT approaches (ACRT or CONV RT) are safe, when given with concurrent durvalumab in patients with PD-L1 high LA-NSCLC. A trial to compare immunoradiotherapy and consolidation durvalumab to standard chemoradiation and consolidation durvalumab is planned. Clinical trial information: NCT03801902.

Scalp-Sparing Radiation With Concurrent Temozolomide and Tumor Treating Fields (SPARE) for Patients With Newly Diagnosed Glioblastoma

Introduction

Standard-of-care treatment for patients with newly diagnosed glioblastoma (GBM) after surgery or biopsy includes concurrent chemoradiation followed by maintenance temozolomide (TMZ) with tumor treating fields (TTFields). Preclinical studies suggest TTFields and radiotherapy work synergistically. We report the results of our trial evaluating the safety of TTFields used concurrently with chemoradiation.

Methods

This is a single-arm pilot study (clinicaltrials.gov Identifier: NCT03477110). Adult patients (age ≥ 18 years) with newly diagnosed glioblastoma and a Karnofsky performance score (KPS) of ≥ 60 were eligible. All patients received concurrent scalp-sparing radiation (60 Gy in 30 fractions) with TMZ (75 mg/m² daily) and TTFields (200 kHz). Maintenance therapy included TMZ and continuation of TTFields. Scalp-sparing radiation treatment was used to reduce radiation dermatitis. Radiation treatment was delivered through the TTFields arrays. The primary endpoint was safety and toxicity of tri-modality treatment within 30 days of completion of chemoradiation treatment.

Results

There were 30 patients enrolled, including 20 (66.7%) men and 10 (33.3%) women, with a median age of 58 years (range 19 to 77 years). Median KPS was 90 (range 70 to 100). A total of 12 (40%) patients received a gross total resection and 18 (60%) patients had a subtotal resection. A total of 12 (40%) patients had multifocal disease at presentation. There were 20 (66.7%) patients who had unmethylated O(6)-methylguanine-DNA-methyltransferase (MGMT) promotor status and 10 (33.3%) patients who had methylated MGMT promoter status. Median follow-up was 15.2 months (range 1.7 to 23.6 months). Skin adverse events were noted in 83.3% of patients, however, these were limited to Grade 1 or 2 events, which resolved spontaneously or with topical medications. The primary end point was met; no TTFields discontinuation occurred during the evaluation period due to high grade scalp toxicity. A total of 27 (90%) patients had progression, with a median progression-free survival (PFS) of 9.3 months (95% confidence interval (CI): 8.5-11.6 months). The 1-year progression-free survival was 23% (95% CI: 12%-45%). The median overall survival (OS) was 15.8 months (95% CI: 12.5 months-infinity). The 1-year overall survival was 66% (95% CI: 51%-86%).

Conclusions

Concurrent TTFields with scalp-sparing chemoradiation is a feasible and well-tolerated treatment option with limited toxicity. A phase 3, randomized clinical trial (EF-32, clinicaltrials.gov Identifier: NCT04471844) investigating the clinical benefit of concurrent TTFields with chemoradiation treatment is currently enrolling.

Clinical Trial Registration

Clinicaltrials.gov, identifier NCT03477110.

CTNI-19. CONCURRENT CHEMORADIATION AND TUMOR TREATING FIELDS (TTFields, 200 kHz) FOR PATIENTS WITH NEWLY DIAGNOSED GLIOBLASTOMA MAY INCREASE THE RATE OF DISTANT RECURRENCE

INTRODUCTION: Current standard of care for glioblastoma (GBM) includes concurrent chemoradiation and maintenance temozolomide (TMZ) along with Tumor Treating Fields (TTFields). Preclinical studies suggest TTFields and radiation treatment have synergistic effects. Secondary analysis of EF14 trial demonstrated TTFields treatment may increase the rate of distant recurrence. We report our experience evaluating areas of progression in our pilot clinical trial of concurrent chemoradiation with TTFields. METHODS: This is a single arm pilot study (clinicaltrials.gov Identifier: NCT03477110). Adult patients (age ≥ 18 years) with KPS ≥ 60 with newly diagnosed GBM were eligible. All patients received concurrent scalp-sparing radiation (60 Gy in 30 fractions), standard concurrent TMZ (75 mg/m2 daily), and TTFields. Maintenance therapy included standard TMZ and continuation of TTFields. Radiation treatment was delivered through TTFields arrays. Incidence and location of progression was documented. Distant recurrence was defined as recurrence more than 2 cm from primary enhancing lesion. RESULTS: A total of 30 patients were enrolled on the trial. Twenty were male, and ten were female, with median age 58 years (19-77 years). Median KPS was 90 (70-100). Median follow-up was 11.6 months (1.7-22.1 months). Twenty (66.7%) patients had an unmethylated MGMT promotor status and ten (33.3%) patients had a methylated promoter status. Twenty patients (66.7%) had progression, with median PFS of 9.1 months (range 1.6 to 12.9 months). Five patients (26%) of patient presented with distant recurrence, with median distance from primary lesion of 5.1 cm (2.26-9.12 cm). One infratentorial progression was noted. Another patient transferred care and location of progression is unknown. CONCLUSIONS: Concurrent chemoradiation with TTFields for patients with newly diagnosed glioblastoma may have increased incidence of distant recurrence. This finding is suggestive of improved local control of primary site. Further data are needed to validate this finding.

RADT-13. SPARE TRIAL: SCALP-SPARING RADIATION WITH CONCURRENT TEMOZOLOMIDE AND TUMOR TREATING FIELDS FOR PATIENTS WITH NEWLY DIAGNOSED GLIOBLASTOMA

INTRODUCTION

Current adjuvant treatment for patients with newly diagnosed glioblastoma includes concurrent chemoradiation and maintenance temozolomide with Tumor Treating Fields (TTFields). We report our clinical trial evaluating feasibility and tolerability of scalp-sparing radiation with concurrent temozolomide and TTFields.

METHODS

Adult patients (age ≥ 18 years) with newly diagnosed glioblastoma with a KPS of ≥ 60 were eligible. All patients received concurrent scalp-sparing radiation (60 Gy in 30 fractions) with temozolomide (75 mg/m2 daily) and TTFields (200 kHz). Maintenance therapy included temozolomide and continuation of TTFields. Radiation treatment was delivered through TTFields arrays. The primary endpoint was safety and toxicity of tri-modality treatment within 30 days of completion of chemoradiation treatment.

RESULTS

Thirty patients were enrolled. Twenty were male and ten were female, with a median age of 58 years (range 19 to 77 years). Median follow-up was 10.8 months (range 1.6 to 21.3 months). Twenty (66.7%) patients had unmethylated MGMT promotor and ten (33.3%) patients had methylated promoter. Scalp dose constraints were achieved for all patients. Skin adverse events (erythema, dermatitis, irritation, folliculitis) were noted in 83.3% of patients, however, these were limited to Grade 1 or 2 events, which resolved spontaneously or with topical medications. No patient had radiation treatment interruption due to skin AEs. Other Grade 1 events included pruritus (33.3%), fatigue (30%), nausea (13.3%), headache (10%), dizziness (6.7%), and cognitive impairment (3.3%). Other Grade 2 events included headache (3.3%). The median PFS for the entire cohort was 9.1 months (at least 8.5 months, 95% confidence). The median PFS for patients with MGMT promoter methylation status was 11.4 months (at least 9.5 months, 95% confidence). Overall survival was not reached.

CONCLUSIONS

Concurrent TTFields with scalp-sparing chemoradiation is feasible treatment option with limited toxicity. Future randomized prospective trials are warranted to define therapeutic advantages of concurrent TTFields with chemoradiation.

How to Respond to a Ransomware Attack? One Radiation Oncology Department's Response to a Cyber-Attack on Their Record and Verify System

The digitization of healthcare for patient safety and efficiency introduced third party networks into closed hospital systems increasing the probability of cyberattacks and their consequences(1). In April 2021, a major vendor of a Radiation Oncology (RO) record and verify system (RVS) suffered a ransomware attack, affecting our department and many others across the United States. This article summarizes our response to the ransomware event including workflows, team member roles, responsibilities, communications and departmental recovery. The RVS created or housed accurate patient dose records for 6 locations. The immediate response to the ransomware attack was to shut down the system including the ability to treat patients. With the utilization of the hospital EMR and pre-existing interfaces with RVS, the department was able to safely continue patient radiotherapy treatments innovatively utilizing a direct Digital Imaging and Communications in Medicine (DICOM) transfer of patient data to the linear accelerators and implementing paper charting. No patients were treated in the first 24 hours of the attack. Within 48 hours of the ransomware event, 50% of patients were treated, and within 1 week, 95% of all patients were treated using direct DICOM transfer and paper charts. The RVS was completely unavailable for 2.5 weeks and full functionality was not restored for 4.5 weeks. A phased approach was adopted for re-introduction of patient treatments back into the RVS. Human capital costs included communication, outreach, workflow creation, quality assurance and extended clinical hours. Key lessons learned were to have a back-up of essential information, employ 'dry run' emergency training, having consistent parameter requirements across different vendor hardware and software, and having a plan for the recovery effort of restoring normal operations once software is operational. The provided report presents valuable information for the development of cyber-attack preparedness for RO departments.

Long-Term Report of a Comprehensive Molecular and Genomic Analysis in NRG Oncology/RTOG 0424: A Phase II Study of Radiation and Temozolomide in High-Risk Grade II Glioma

PURPOSE

This study sought to determine the prognostic significance of the WHO-defined glioma molecular subgroups along with additional alterations, including MGMT promoter methylation and mutations in ATRX, CIC, FUBP1, TERT, and TP53, in NRG/RTOG 0424 using long-term follow-up data.

METHODS

Mutations were determined using an Ion Torrent sequencing panel. 1p/19q co-deletion and MGMT promoter methylation were determined by Affymetrix OncoScan and Illumina 450K arrays. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method and tested using the log-rank test. Hazard ratios were calculated using the Cox proportional hazard model. Multivariable analyses (MVAs) included patient pretreatment characteristics.

RESULTS

We obtained complete molecular data to categorize 80/129 eligible patients within the WHO subgroups. Of these, 26 (32.5%) were IDHmutant/co-deleted, 28 (35%) were IDHmutant/non-co-deleted, and 26 (32.5%) were IDHwild-type. Upon single-marker MVA, both IDHmutant subgroups were associated with significantly better OS and PFS (P values < .001), compared with the IDHwild-type subgroup. MGMT promoter methylation was obtained on 76 patients, where 58 (76%) were methylated and 18 (24%) were unmethylated. Single-marker MVAs demonstrated that MGMT promoter methylation was statistically significant for OS (P value < .001) and PFS (P value = .003). In a multimarker MVA, one WHO subgroup comparison (IDHmutant/co-deleted v IDHwild-type) was significant for OS (P value = .045), whereas MGMT methylation did not retain significance.

CONCLUSION

This study reports the long-term prognostic effect of the WHO molecular subgroups, MGMT promoter methylation, and other mutations in NRG/RTOG 0424. These results demonstrate that the WHO molecular classification and MGMT both serve as strong prognostic indicators, but that MGMT does not appear to add statistically significant prognostic value to the WHO subgrouping, above and beyond IDH and 1p/19q status.

Addition of Metformin to Concurrent Chemoradiation in Patients With Locally Advanced Non-Small Cell Lung Cancer: The NRG-LU001 Phase 2 Randomized Clinical Trial

Importance

Non-small cell lung cancer (NSCLC) has relatively poor outcomes. Metformin has significant data supporting its use as an antineoplastic agent.

Objective

To compare chemoradiation alone vs chemoradiation and metformin in stage III NSCLC.

Design, Setting, and Participants

The NRG-LU001 randomized clinical trial was an open-label, phase 2 study conducted from August 24, 2014, to December 15, 2016. Patients without diabetes who were diagnosed with unresectable stage III NSCLC were stratified by performance status, histology, and stage. The setting was international and multi-institutional. This study examined prespecified endpoints, and data were analyzed on an intent-to-treat basis. Data were analyzed from February 25, 2019, to March 6, 2020.

Interventions

Chemoradiation and consolidation chemotherapy with or without metformin.

Main Outcomes and Measures

The primary outcome was 1-year progression-free survival (PFS), designed to detect 15% improvement in 1-year PFS from 50% to 65% (hazard ratio [HR], 0.622). Secondary end points included overall survival, time to local-regional recurrence, time to distant metastasis, and toxicity per Common Terminology Criteria for Adverse Events, version 4.03.

Results

A total of 170 patients were enrolled, with 167 eligible patients analyzed after exclusions (median age, 64 years [interquartile range, 58-72 years]; 97 men [58.1%]; 137 White patients [82.0%]), with 81 in the control group and 86 in the metformin group. Median follow-up was 27.7 months (range, 0.03-47.21 months) among living patients. One-year PFS rates were 60.4% (95% CI, 48.5%-70.4%) in the control group and 51.3% (95% CI, 39.8%-61.7%) in the metformin group (HR, 1.15; 95% CI, 0.77-1.73; P = .24). Clinical stage was the only factor significantly associated with PFS on multivariable analysis (HR, 1.79; 95% CI, 1.19-2.69; P = .005). One-year overall survival was 80.2% (95% CI, 69.3%-87.6%) in the control group and 80.8% (95% CI, 70.2%-87.9%) in the metformin group. There were no significant differences in local-regional recurrence or distant metastasis at 1 or 2 years. No significant difference in adverse events was observed between treatment groups.

Conclusions and Relevance

In this randomized clinical trial, the addition of metformin to concurrent chemoradiation was well tolerated but did not improve survival among patients with unresectable stage III NSCLC.

Trial Registration

ClinicalTrials.gov Identifier: NCT02186847.

Scalp-sparing radiation with concurrent temozolomide and tumor treating fields (SPARE) for patients with newly diagnosed glioblastoma

2056

Background: Standard of care for patients with newly diagnosed glioblastoma includes concurrent chemoradiation and maintenance temozolomide with Tumor Treating Fields (TTFields). Preclinical studies suggest TTFields and radiation treatment have synergistic effects. We report our clinical trial evaluating safety and tolerability of scalp-sparing radiation with concurrent temozolomide and TTFields. Methods: This is a single arm pilot study. Adult patients (age ≥ 18 years) with newly diagnosed glioblastoma and a KPS of ≥ 60 were eligible. All patients received concurrent scalp-sparing radiation (60 Gy in 30 fractions) with temozolomide (75 mg/m2 daily) and TTFields (200 kHz). Maintenance therapy included temozolomide and continuation of TTFields. Radiation treatment was delivered through TTFields arrays. The primary endpoint was safety and toxicity of TTFields concurrent with chemoradiation in patients with newly diagnosed glioblastoma. Results: A total of 30 patients were enrolled in the trial. Twenty were male and ten were female, with a median age of 58 years (range 19 to 77 years). Median KPS was 90 (range 70 to 100). Median follow-up was 8.9 months (range 1.6 to 21.4 months). Twenty (66.7%) patients had unmethylated MGMT promotor status and ten (33.3%) patients had methylated promoter status. Median time from surgery to radiation was 34 days (26 to 49 days). Scalp dose constraints were achieved for all patients, with the mean dose having a median value of 8.3 Gy (range 4.3 to 14.8 Gy), the D20cc median was 26.1 Gy (range 17.7 to 42.8 Gy), and the D30cc median was 23.5 Gy (range 14.8 to 35.4 Gy). Skin adverse events (AEs; erythema, dermatitis, irritation, folliculitis) were noted in 83.3% of patients, however, these were limited to Grade 1 or 2 events, which resolved spontaneously or with topical medications. No patient had radiation treatment interruption due to skin AEs. Other Grade 1 events included pruritus (33.3%), fatigue (30%), nausea (13.3%), headache (10%), dizziness (6.7%), and cognitive impairment (3.3%). Other Grade 2 events included headache (3.3%). Nineteen patients (63.3%) had progression, with a median PFS of 7.6 months (range 1.6 to 12.7 months). Overall survival was not reached. Conclusions: Concurrent TTFields (200 kHz) with scalp-sparing chemoradiation is a safe and feasible treatment option with limited toxicity. Future randomized prospective trials are warranted to define therapeutic advantages of concurrent TTFields with chemoradiation. Clinical trial information: NCT03477110.

Initial Clinical Experience of MR-Guided Radiotherapy for Non-Small Cell Lung Cancer

Curative-intent radiotherapy plays an integral role in the treatment of lung cancer and therefore improving its therapeutic index is vital. MR guided radiotherapy (MRgRT) systems are the latest technological advance which may help with achieving this aim. The majority of MRgRT treatments delivered to date have been stereotactic body radiation therapy (SBRT) based and include the treatment of (ultra-) central tumors. However, there is a move to also implement MRgRT as curative-intent treatment for patients with inoperable locally advanced NSCLC. This paper presents the initial clinical experience of using the two commercially available systems to date: the ViewRay MRIdian and Elekta Unity. The challenges and potential solutions associated with MRgRT in lung cancer will also be highlighted.

Stereotactic body radiation therapy (SBRT) for patients with stage I non-small cell lung cancer is applicable to more tumors than sublobar resection

Background

Virtually all patients with medically inoperable stage I non-small cell lung cancer (NSCLC) can receive stereotactic body radiation therapy. However, the percentage of such patients in whom sublobar resection is technically feasible is unknown. This discrepancy can confound clinical trial eligibility and designs comparing stereotactic body radiation therapy vs. sublobar resection.

Methods

A total of 137 patients treated with stereotactic body radiation therapy for lung lesions (3/2013–11/2017) underwent retrospective review. Diagnostic CT chest and PET/CT images, stereotactic body radiation therapy dates, and demographic data were collected on 100 of 137 patients. Two experienced board-certified thoracic surgeons independently reviewed anonymized patients’ pre-stereotactic body radiation therapy diagnostic imaging and completed a custom survey about the technical feasibility of sublobar resection for each patient. Interrater agreement was measured using Cohen’s kappa coefficient by bootstrap methodology. Summary statistics were performed for baseline demographics and tumor characteristics.

Results

Of the 100 patients, 57% were female, with median age of 75 years (range, 52–95 years) and Karnofsky Performance Status of 80 (range, 40–100). Most patients (61%) had Stage IA1, T1a tumors. For interrater agreement analysis, one patient was removed from each cohort due to inability to locate tumor on images, leaving 98 patients analyzed. Comparing Surgeon #1 vs. Surgeon #2, 64 (65.3%) vs. 69 (70.3%) of tumors were thought eligible for sublobar resection, respectively (κ=0.414).

Conclusions

Stereotactic body radiation therapy for stage I NSCLC is applicable to more tumors than sublobar resection, with ~30–35% of stereotactic body radiation therapy patients unable to undergo sublobar resection assessed by pretreatment diagnostic imaging based on technical grounds. This study illustrates that clinical trials comparing stereotactic body radiation therapy vs. sublobar resection are limited to only a subpopulation of patients with stage I NSCLC.

Phase Ib Clinical Trial of IGV-001 for Patients with Newly Diagnosed Glioblastoma

PURPOSE

Despite standard of care (SOC) established by Stupp, glioblastoma remains a uniformly poor prognosis. We evaluated IGV-001, which combines autologous glioblastoma tumor cells and an antisense oligonucleotide against IGF type 1 receptor (IMV-001), in newly diagnosed glioblastoma.

PATIENTS AND METHODS

This open-label protocol was approved by the Institutional Review Board at Thomas Jefferson University. Tumor cells collected during resection were treated ex vivo with IMV-001, encapsulated in biodiffusion chambers with additional IMV-001, irradiated, then implanted in abdominal acceptor sites. Patients were randomized to four exposure levels, and SOC was initiated 4-6 weeks later. On the basis of clinical improvements, randomization was halted after patient 23, and subsequent patients received only the highest exposure. Safety and tumor progression were primary and secondary objectives, respectively. Time-to-event outcomes were compared with the SOC arms of published studies.

RESULTS

Thirty-three patients were enrolled, and median follow-up was 3.1 years. Six patients had adverse events (grade ≤3) possibly related to IGV-001. Median progression-free survival (PFS) was 9.8 months in the intent-to-treat population (vs. SOC, 6.5 months; P = 0.0003). In IGV-001-treated patients who met Stupp-eligible criteria, PFS was 11.6 months overall (n = 22; P = 0.001) and 17.1 months at the highest exposure (n = 10; P = 0.0025). The greatest overall survival was observed in Stupp-eligible patients receiving the highest exposure (median, 38.2 months; P = 0.044). Stupp-eligible patients with methylated O⁶-methylguanine-DNA methyltransferase promoter (n = 10) demonstrated median PFS of 38.4 months (P = 0.0008). Evidence of immune activation was noted.

CONCLUSIONS

IGV-001 was well tolerated, PFS compared favorably with SOC, and evidence suggested an immune-mediated mechanism (ClinicalTrials.gov: NCT02507583).

Resected WHO grade I meningioma and predictors of local control

INTRODUCTION

Despite optimal surgical resection, meningiomas may recur, with increasing grade and the degree of resection being predictive of risk. We hypothesize that an increasing Ki67 correlates with a higher risk of recurrence of resected WHO grade I meningiomas.

METHODS

The study population consisted of patients with resected WHO grade 1 meningiomas in locations outside of the base of skull. Digitally scanned slides stained for Ki67 were analyzed using automatic image analysis software in a standardized fashion.

RESULTS

Recurrence was observed in 53 (17.7%) of cases with a median follow up time of 25.8 months. Ki67 ranged from 0 to 30%. Median Ki67 was 5.1% for patients with recurrence and 3.5% for patients without recurrence. In unadjusted analyses, high Ki-67 (≥ 5 vs. < 5) vs. ≥ 5) was associated with over a twofold increased risk of recurrence (13.1% vs. 27% respectively; HR 2.1731; 95% CI [1.2534, 3.764]; p = 0.006). After Adjusting for patient or tumor characteristics, elevated Ki-67 remained significantly correlated with recurrence. Grade 4 Simpson resection was noted in 71 (23.7%) of patients and it was associated with a significantly increased risk of recurrence (HR 2.56; 95% CI [1.41, 4.6364]; p = 0.002).

CONCLUSIONS

WHO grade 1 meningiomas exhibit a significant rate of recurrence following resection. While Ki-67 is not part of the WHO grading criteria of meningiomas, a value greater than 5% is an independent predictor for increased risk of local recurrence following surgical resection.

CTNI-21. SCALP SPARING RADIATION WITH CONCURRENT TEMOZOLOMIDE AND TUMOR TREATMENT FIELDS (SPARE) FOR PATIENTS WITH NEWLY DIAGNOSED GLIOBLASTOMA

INTRODUCTION

Standard of care for glioblastoma includes concurrent chemoradiation and maintenance temozolomide (TMZ) with tumor treatment fields (TTFields). Preclinical studies suggest TTFields and radiotherapy work synergistically. We report our experience evaluating toxicity of scalp-sparing radiation with concurrent TTFields.

METHODS

This is a single-arm pilot study (clinicaltrials.gov Identifier: NCT03477110). Patients (age≥ 18 years) with KPS≥ 60 with newly diagnosed glioblastoma were eligible. Patients received concurrent scalp-sparing radiation (60 Gy/30 fx), standard TMZ (75 mg/m2 daily), and TTFields. Maintenance therapy included standard TMZ and TTFields continuation. Radiotherapy was delivered through TTFields arrays. Primary endpoint was safety and toxicity of concurrent TTFields with chemoradiation.

RESULTS

We report the first eighteen patients on trial. Majority were male (66.7%) with median age 59 years (34 to 77). Median KPS was 90 (70–100). Median follow-up was 6.0 months (1.4 to 18.0). Twelve (66.6%) patients had unmethylated MGMT, five (27.8%) were methylated, and one patient’s status was not obtained. Scalp dose constraints were achieved, with mean dose having a median value of 7.4 Gy (4.3–13.2), D20cc median 23.2 Gy (17.7–36.8), and D30cc median 20.3 Gy (14.8–33.4). Only one possible Grade 3 toxicity was observed in a patient who experienced a seizure in month six of the maintenance phase. Skin toxicity (erythema or dermatitis) was limited to Grade 1 (83.3%) or 2 (5.6%) during the concurrent phase and resolved spontaneously or responded to topical medications. Other Grade 1 events included fatigue (47.3%), cognitive impairment (31.6%), pruritis (52.6%), headache (26.3%), dizziness (15.8%), and nausea (26.3%). Other Grade 2 events included fatigue (21.1%) and headache (10.5%). Nine patients (50%) had progression, with median PFS of 7.6 months (2.2–9.6 months).

CONCLUSIONS

Concurrent TTFields with scalp-sparing chemoradiation is a safe and feasible treatment option with limited toxicity. Future randomized prospective trials are warranted to define therapeutic advantages of concurrent TTFields with chemoradiation.

Impact of Sarcopenia on Survival in Patients With Early-Stage Lung Cancer Treated With Stereotactic Body Radiation Therapy

Background

Sarcopenia has been associated with poor survival among cancer patients. Normalized total psoas area (NTPA) has been used as a surrogate for defining sarcopenia. Few data exist characterizing the impact of sarcopenia and other metrics of fitness on clinical outcomes in patients with early-stage non-small cell lung cancer (NSCLC) treated non-invasively with stereotactic body radiotherapy (SBRT).

Methods

To assess the association between sarcopenia and clinical outcomes, we conducted a retrospective analysis of consecutive patients treated with SBRT from 2013 to 2019 . Overall survival (OS), local failure free survival (LFS), distant failure free survival (DFS), NTPA, body mass index (BMI), and Charlson comorbidity index (CCI) were included for analysis. NTPA was calculated by measuring the psoas volume at the L3 vertebra and normalizing for patient height and gender. Survival functions were evaluated using the Kaplan-Meier method. Log-rank test and Cox-proportional hazards were performed for categorical and continuous variables, respectively. Significance was set as p < 0.05.

Results

A total of 91 patients met the criteria. The median age was seven years and Karnofsky Performance Status score (KPS) was 80 (range: 60-100). Approximately 79% of patients had T1 tumors. Median radiation dose and number of fractions were 60 Gy (range: 45-60) and 5 fractions (range: 3-5). Median NTPA was 531.16 mm²/m² (range: 90.4-1356.2). After normalization (sarcopenia: <385 mm²/m², female; <585 mm²/m^2, male), 39 patients (42.8%) had sarcopenia. NTPA had no association with OS (p = 0.7), LFS (p = 0.9), or DFS (p = 0.5). Increasing BMI was associated with improved OS (HR 0.90, 95% CI 0.83-0.98). With a median follow-up of 23.4 months, median OS was 60, 60, and 45.9 months (p = 0.37) in all patients, non-sarcopenic patients, and sarcopenic patients, respectively.

Conclusion

Sarcopenia was not associated with OS, LFS, or DFS. Increasing BMI is associated with improved OS. Future, prospective work is needed to define the impact of sarcopenia and other fitness metrics on clinical outcomes among NSCLC patients treated non-invasively with SBRT.

Correlating Dose Variables with Local Tumor Control in Stereotactic Body Radiation Therapy for Early-Stage Non-Small Cell Lung Cancer: A Modeling Study on 1500 Individual Treatments

BACKGROUND

Large variation regarding prescription and dose inhomogeneity exists in stereotactic body radiation therapy (SBRT) for early-stage non-small cell lung cancer. The aim of this modeling study was to identify which dose metric correlates best with local tumor control probability to make recommendations regarding SBRT prescription.

METHODS AND MATERIALS

We combined 2 retrospective databases of patients with non-small cell lung cancer, yielding 1500 SBRT treatments for analysis. Three dose parameters were converted to biologically effective doses (BEDs): (1) the (near-minimum) dose prescribed to the planning target volume (PTV) periphery (yielding BEDmin); (2) the (near-maximum) dose absorbed by 1% of the PTV (yielding BEDmax); and (3) the average between near-minimum and near-maximum doses (yielding BEDave). These BED parameters were then correlated to the risk of local recurrence through Cox regression. Furthermore, BED-based prediction of local recurrence was attempted by logistic regression and fast and frugal trees. Models were compared using the Akaike information criterion.

RESULTS

There were 1500 treatments in 1434 patients; 117 tumors recurred locally. Actuarial local control rates at 12 and 36 months were 96.8% (95% confidence interval, 95.8%-97.8%) and 89.0% (87.0%-91.1%), respectively. In univariable Cox regression, BEDave was the best predictor of risk of local recurrence, and a model based on BEDmin had substantially less evidential support. In univariable logistic regression, the model based on BEDave also performed best. Multivariable classification using fast and frugal trees revealed BEDmax to be the most important predictor, followed by BEDave.

CONCLUSIONS

BEDave was generally better correlated with tumor control probability than either BEDmax or BEDmin. Because the average between near-minimum and near-maximum doses was highly correlated to the mean gross tumor volume dose, the latter may be used as a prescription target. More emphasis could be placed on achieving sufficiently high mean doses within the gross tumor volume rather than the PTV covering dose, a concept needing further validation.

Neoadjuvant nivolumab (N) plus cisplatin (C)/pemetrexed (P) or cisplatin /gemcitabine (G) in resectable NSCLC

9051

Background: Patients (pts) with resectable stage IB (≥4cm)-IIIA non-small-cell lung cancer (NSCLC) derive modest overall survival benefit with neoadjuvant or postoperative adjuvant chemotherapy. Neoadjuvant therapy can speed the discovery of promising regimens by using pathologic response as a surrogate for OS. Major pathologic response (MPR), defined as < 10% viable tumor, was strongly associated with improved OS. PD-(L)1 checkpoint inhibitors in combination with chemotherapy are standard of care in advanced NSCLC. We hypothesize that the addition of N to neoadjuvant CP or CG will increase the MPR rate compared to historical controls. Methods: This is an investigator-initiated trial for pts with newly diagnosed AJCC 8th stage IB (≥4cm)-IIIA squamous or non-squamous EGFR/ALK WT NSCLC with a plan to have surgery. Pts receive 3 courses of N 360mg IV q 3w added to C 75mg/m2 IV q 3w plus P 500 mg/m2 IV q 3wks or G 1250mg/m2 IV d1, d8 with surgery 3 wks after the last dose. The primary objective is MPR. To estimate pathologic response, the resected pathology specimens are cut >1 section/cm. Using the Aperio Digital scanning system©, slides were imaged, and then annotated by at least 2 pathologists for viable tumor vs. treatment effect with respective areas then automatically calculated and percentage of viable tumor calculated. Our primary endpoint will be reached if 10/34 (29%) planned pts have at least an MPR. Results: From 6/2018-8/2019, 13 pts were enrolled all of whom had surgery. Median age was 69 (49-80), 38% women, 31% nonsquamous, 54% stage IIIA, and 77% PD-L1 positive (≥1%, SP263). Pre-surgical grade 3 toxicity occurred in 2/13 pts, one of whom was changed to carboplatin for courses 2 and 3. Grade 3 toxicities were neutropenia (2/13), anemia (1/13), and renal (1/13). One pt. developed hypothyroidism 4 mos after surgery. One pt died 6 weeks after surgery from complications unrelated to study drugs. Our primary endpoint was met; 11/13 (85%), had at least an MPR with 6/13 (46%) and 5/13 (38%) having an MPR and pCR respectively. Radiologic response rate was 46% (PR 5, CR 1). Pts with either PD-L1+ or PD-L1- had MPRs. With a median follow-up of 10 months there are no recurrences. Conclusions: The combination of nivolumab added to platinum doublets was well tolerated. The primary endpoint of MPR in at least 10/34 pts was surpassed with MPR or pCR in 11/13 pts post-surgery. MPR was seen independent of PD-L1 score. Exploratory outcomes assessing markers of immune bias in tumor tissue and plasma are in process. Clinical trial information: NCT03366766.

Long-term analysis of the WHO-defined molecular subgroups of high-risk grade II gliomas treated with radiation and temozolomide on NRG Oncology/RTOG 0424

2518

Background: This study sought to evaluate the prognostic significance of the three WHO-defined molecular glioma subgroups ( IDHwt, IDHmt/non-codel, and IDHmt/codel) in NRG Oncology/RTOG 0424, a phase II trial of high-risk low-grade gliomas treated with radiation (RT) and concurrent and adjuvant temozolomide (TMZ) after biopsy/surgical resection. Notably, this is the first clinical study to evaluate the prognostic value of the WHO subgroups in RT + TMZ-treated high-risk grade II (G2) gliomas using prospectively-collected long-term survival data. Methods: IDH1/2 mutation status was determined by next-generation sequencing. 1p/19q co-deletion status was determined by Oncoscan and/or 450K methylation data. Overall survival (OS) and progression-free survival (PFS) by marker status were determined by the Cox proportional hazard model and tested using the log-rank test in a post-hoc analysis. Patient pre-treatment characteristics were included as covariates in multivariate analyses. Results: Of all the eligible patients (N=129), 80 (62%) had sufficient quality DNA for both IDH and 1p/19q analyses. Of these 80, 54 (67.5%) were IDHmt, and 26 (32.5%) were IDHwt. Of the 54 IDHmt patients, 26 (32.5% of total, 48% of IDHmt) were IDHmt/codel, and 28 (35% of total, 52% of IDHmt) were IDHmt/non-codel. Both IDHmt subgroups were significantly correlated with longer PFS ( IDHmt/co-del = 8.1yrs (5.2-not reached (NR)); IDHmt/non-codel = 7.5yrs (3.9-11.8); IDHwt = 1.0yr (0.6-1.7), p<0.001) and OS ( IDHmt/co-del = 9.4yrs (8.2-NR); IDHmt/non-codel = 8.8yrs (5.9-NR); IDHwt = 2.3yrs (1.4-3.4), p<0.001) relative to the IDHwt subgroup. Upon univariate and multivariate analyses, both molecular IDHmt subgroup comparisons relative to IDHwt remained significant (p<0.001) even after incorporation of known clinical variables. Conclusions: These analyses suggest that G2 glioma patients harboring IDH1/2 mutations, regardless of co-deletion status, demonstrated longer survival with RT + TMZ relative to IDHwt tumors, although sample size is limited and analyses were post-hoc. These results also support the notion that outcomes for IDHwt high-risk G2 gliomas remain dismal (median = 2.3yrs, similar to G3 anaplastic astrocytoma); these patients should be separated from IDHmt patients in future G2 glioma trials, and warrant novel treatment strategies. Funding: U10CA180868, U10CA180822, U24CA196067, CURE, PA Dept. of Health, and Merck. Also, R01CA108633, R01CA169368, RC2CA148190, U10CA180850, BTFC, OSUCCC (all to AC). Clinical trial information: NCT00114140 .

Randomized phase II study of rituximab, methotrexate (MTX), procarbazine, vincristine, and cytarabine (R-MPV-A) with and without low-dose whole-brain radiotherapy (LD-WBRT) for newly diagnosed primary CNS lymphoma (PCNSL)

2501

Background: MTX-based chemoradiotherapy is effective in PCNSL, but carries a risk of severe neurotoxicity (NT), especially in the elderly. In a phase II single arm study, R-MPV-A chemotherapy was combined with substantially reduced doses of radiotherapy (23.4 Gy), achieving prolonged progression free survival (PFS) and overall survival (OS) with acceptable NT. Because R-MPV-A had never been tested without radiotherapy, we conducted a randomized study to determine if the low doses of radiation played a role in the observed disease control, and to characterize NT as compared to chemotherapy alone. Methods: Patients were stratified by MSK RPA class and randomized to receive R-MPV-A with LD-WBRT (chemoRT arm) versus R-MPV-A alone (chemo arm). MTX dose was 3.5g/m2 infused over 2 hours. Filgrastim and pegfilgrastim support was given to all patients. LD-WBRT dose was 23.4 Gy (1.8 Gy X 13). The primary endpoint was intent-to-treat (ITT) PFS. A sample size of 89 would provide 80% power to detect a hazard ratio (HR) of 0.63, with one-sided alpha level of 0.15. Results: A total of 91 patients were randomized, of whom 4 were ineligible. Among eligible patients, 43 were enrolled in the chemoRT arm and 44 in the chemo arm. Median age was 66 (chemoRT) and 59 (chemo). Median KPS was 80 for both arms. Response rates following R-MPV were 81% (chemoRT) and 83% (chemo). In the chemoRT arm, 37 patients (86%) received LD-WBRT. After median follow-up of 55 months (m), the median ITT PFS was 25 m in the chemo arm and not reached in the chemoRT arm (HR 0.51; 95% CI [0.27, 0.95]; p = 0.015). The 2-year PFS was 54% (chemo) and 78% (chemoRT). Salvage radiotherapy has been given to 11 patients in the chemo arm. Median OS was not reached in either arm, with data still maturing. In both arms, most common grades 3 or 4 toxicities were anemia (27%), lymphopenia (41%), neutropenia (35%), thrombocytopenia (26%), ALT (23%) and AST (13%). One patient died from sepsis (chemo arm). As per investigators’ assessment, the rate of clinically defined moderate to severe NT was 11.4% (chemo) and 14% (chemoRT), p = 0.75. Conclusions: The study met the primary endpoint, demonstrating the addition of LD-WBRT to R-MPV-A improves PFS in newly diagnosed PCNSL. As per investigator’s assessment, NT rates were not statistically significantly increased, but further neuropsychological testing and neuroimaging analyses are ongoing to characterize cognitive decline and how it compares to other consolidation treatments. Clinical trial information: NCT01399372 .

Alternative Multidisciplinary Management Options for Locally Advanced NSCLC During the Coronavirus Disease 2019 Global Pandemic

The coronavirus disease 2019 (COVID-19) pandemic is currently accelerating. Patients with locally advanced NSCLC (LA-NSCLC) may require treatment in locations where resources are limited, and the prevalence of infection is high. Patients with LA-NSCLC frequently present with comorbidities that increase the risk of severe morbidity and mortality from COVID-19. These risks may be further increased by treatments for LA-NSCLC. Although guiding data is scarce, we present an expert thoracic oncology multidisciplinary (radiation oncology, medical oncology, surgical oncology) consensus of alternative strategies for the treatment of LA-NSCLC during a pandemic. The overarching goals of these approaches are the following: (1) reduce the number of visits to a health care facility, (2) reduce the risk of exposure to severe acute respiratory syndrome–coronavirus-2, (3) attenuate the immunocompromising effects of lung cancer therapies, and (4) provide effective oncologic therapy. Patients with resectable disease can be treated with definitive nonoperative management if surgical resources are limited or the risks of perioperative care are high. Nonoperative options include chemotherapy, chemoimmunotherapy, and radiation therapy with sequential schedules that may or may not affect long-term outcomes in an era in which immunotherapy is available. The order of treatments may be on the basis of patient factors and clinical resources. Whenever radiation therapy is delivered without concurrent chemotherapy, hypofractionated schedules are appropriate. For patients who are confirmed to have COVID-19, usually, cancer therapies may be withheld until symptoms have resolved with negative viral test results. The risk of severe treatment-related morbidity and mortality is increased for patients undergoing treatment for LA-NSCLC during the COVID-19 pandemic. Adapting alternative treatment strategies as quickly as possible may save lives and should be implemented through communication with the multidisciplinary cancer team.

Phase 2 Study of a Temozolomide-Based Chemoradiation Therapy Regimen for High-Risk, Low-Grade Gliomas: Long-Term Results of Radiation Therapy Oncology Group 0424

PURPOSE

To report the long-term outcomes of the RTOG 0424 study of a high-risk, low-grade glioma population treated with concurrent and adjuvant temozolomide (TMZ) and radiation therapy (RT).

METHODS AND MATERIALS

For this single-arm, phase 2 study, patients with low-grade gliomas with ≥3 risk factors (age ≥40 years, astrocytoma, bihemispheric tumor, size ≥6 cm, or preoperative neurologic function status >1) received RT (54 Gy in 30 fractions) with TMZ and up to 12 cycles of post-RT TMZ. The initial primary endpoint P was overall survival (OS) at 3 years after registration. Secondary endpoints included progression-free survival (PFS) and the association of survival outcomes with methylation status. The initial 3-year report of this study was published in 2015.

RESULTS

The study accrued 136 patients, of whom 129 were analyzable. The median follow-up for surviving patients was 9.0 years. The 3-year OS was 73.5% (95% confidence interval, 65.8%-81.1%), numerically superior to the 3-year OS historical control of 54% (P < .001). The median survival time was 8.2 years (95% confidence interval, 5.6-9.1). Five- and 10-year OS rates were 60.9% and 34.6%, respectively, and 5- and 10-year PFS rates were 46.8% and 25.5%, respectively.

CONCLUSIONS

The long-term results confirmed the findings from the initial report for efficacy, suggesting OS and PFS outcomes with the RT-TMZ regimen exceeded historical control groups treated with radiation alone. Toxicity was acceptable.

Abstract B71: Phase 1b/2 prospective randomized trial of four autologous cell vaccine dose cohorts for initial treatment of glioblastoma

Introduction: We present a novel autologous cell vaccine therapy designed to treat patients with newly diagnosed glioblastoma (Trial Registration: IND 14379, NCT01550523).

Methods: This phase 1b trial has a phase 2 design with 4 randomized vaccine dose cohorts in 33 patients with the objective being safety assessment but also including clinical, radiographic, and immune analyses. Eligibility criteria included age &gt; 18 and Karnofsky score of &gt; 60; neither bihemispheric disease nor extent of resection were exclusion criteria but autoimmune diseases were. During craniotomy for tumor resection, if frozen section confirmed GBM, incisions were made in the lower abdomen through the rectus sheath and pockets created between the sheath and the muscle and the wounds closed with a temporary three-layer closure. Tumor resection involved an aspirator that collected morselized viable tumor tissue in sterile traps. The tissue was processed by overnight culture with 0.2 mg of an IGF-1R antisense oligodeoxynucleotide/gm. The next (first postoperative) day, treated tumor cells were harvested, encapsulated in either ten or twenty small biodiffusion chambers along with 4 micrograms of the IGF-1R antisense, irradiated and then implanted at bedside in the abdominal acceptor sites as previously described (1). Chambers were explanted 24 or 48 hours later, depending on randomization. Standard of care according to Stupp (2) was initiated at 6 weeks. Studies included 3T MRI imaging and analysis of serial blood samples for T cell function and cytokine levels. Disease progression was assessed using RANO (3) and iRANO (4) criteria with a data cutoff of March 1 (N=30) used for this analysis.

Results: The trial opened September 1, 2015 and completed accrual on March 1, 2018. A midpoint interim analysis revealed significantly more robust cytokine responses at the highest vaccine dose. Randomization was therefore stopped at subject 23 and amended to treat using only the highest dose. Progression-free survival (PFS) was compared to three historic SOC comparators (Stupp [2], Kong [5], and an antecedent cohort of 37 consecutive patients treated with SOC at our institution [TJUH]). PFS was significantly improved at 10.5 mo v. SOC comparators: 6.9 mo (Stupp, p = .003), 5.3 mo (Kong, p = .002) and 7 mo (TJUH, p = .013). Seventy-five percent of the 14 patients in the highest-dose cohort had robust proinflammatory and early evidence of sustained immune reactivity associated with tumor regression or no recurrence after surgery.

Conclusion: These data reflect a therapeutic benefit defined as significant improvement in PFS without increased safety risk compared to three different SOC cohorts. Since GBM remains one of the most challenging solid tumors, this treatment design invites investigator collaboration in a multicenter phase 2 trial.

References: 1. Andrew et al. J Clin Oncol 19:2189-2200; 2. Stupp et al. NEJM 352:987-96; 3. Wen et al. J Clin. Oncol 28:1963-72; 4. Okada et al. Lancet Oncol 16:534-42; 5. Kong et al. Oncotarget 8:7003-13.

Citation Format: Kevin D. Judy, David W. Andrews, Larry Harshyne, Lawrence Kenyon, Kiran Talekar, Kofi-Buaku Atsina, Lyndon Kim, Wenyin Shi, Maria Werner-Wasik, Rhonda Kean, Samantha Garcia, Kara Pigott, Charles B. Scott, D. Craig Hooper. Phase 1b/2 prospective randomized trial of four autologous cell vaccine dose cohorts for initial treatment of glioblastoma [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr B71.

Influence of Residual Disease Following Surgical Resection in Newly Diagnosed Glioblastoma on Clinical, Neurocognitive, and Patient Reported Outcomes

BACKGROUND

The influence of subtotal resection (STR) on neurocognitive function (NCF), quality of life, and symptom burden in glioblastoma is unknown. If bevacizumab preferentially benefits patients with STR is unknown.

OBJECTIVE

To examine these uncertainties.

METHODS

NCF and patient reported outcomes (PRO) were prospectively collected in NRG Oncology RTOG 0525 and 0825. Changes in NCF and PRO measures from baseline to prespecified times were examined by Wilcoxon test, and mixed effects longitudinal modeling, to assess differences between patients who received STR vs gross-total resection. Changes were also compared among STR patients on 0825 receiving placebo vs bevacizumab to assess for a preferential therapeutic effect. Overall survival between STR and gross-total resection patients was compared using the Kaplan-Meier method.

RESULTS

A total of 427 patients were eligible with STR present in 37%. At baseline, patients with STR had worse NCF, worse MD Anderson Symptom Inventory Brain Tumor Neurological Factor ratings (P = .004), and European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire (P = .002). Longitudinal multivariate analysis associated STR with worse NCF (Hopkins Verbal Learning Test-Revised Delayed Recognition [P = .048], Trail Making Test Part A [P = .035], and Controlled Oral Word Association [P = .049]). One hundred eighty-three STR patients from 0825 were analyzed (89 bevacizumab, 94 placebo); bevacizumab failed to demonstrate improvement in select NCF or PRO measures.

CONCLUSION

STR patients had worse NCF and PROs before therapy. During adjuvant therapy, STR patients had worse objective NCF, despite accounting for tumor location. STR did not result in a detriment to OS. The addition of bevacizumab did not preferentially improve PRO or NCF outcomes in STR patients.

Stereotactic Image Guided Lung Radiation Therapy for Clinical Early Stage Non-Small Cell Lung Cancer: A Long-Term Report From a Multi-Institutional Database of Patients Treated With or Without a Pathologic Diagnosis

PURPOSE

Early stage lung cancer is treated with stereotactic body radiation therapy (SBRT) in patients who are unable or unwilling to undergo surgical resection. Some patients' comorbidities are so severe that they are unable to even undergo a biopsy. A clinical diagnosis without biopsy before SBRT has been used, but there are limited data on its efficacy.

METHODS AND MATERIALS

Data on patients treated with SBRT for non-small cell lung cancer, with and without tissue confirmation, were collected from multiple institutions across Europe, Canada, and the United States. Patients with a minimum of 2 years of comprehensive follow up were selected for analysis. Treatment and patient characteristics were compared. Overall survival (OS), disease-free survival (DFS), cause-specific survival (CSS), and rates of local recurrence (LR), regional recurrence (RR), and distant metastasis (DM) were calculated and analyzed.

RESULTS

A total of 701 patients were identified, of which 67% had tissue confirmation of their tumors. The 3- and 5-year outcomes for OS, CSS, and DFS were 83.8%, 93.1%, 69%, and 60.6%, 86.7%, 45.5%, respectively. The rates for LR, RR, and DM at 3 and 5 years were 6.4%, 9.3%, 14.3%, and 10.5%, 14.3%, 19.7%, respectively. There were no statistically significant differences in survival outcomes or recurrences between the biopsy and no-biopsy cohorts.

CONCLUSIONS

SBRT for clinically diagnosed lung cancers is efficacious in appropriately selected patients, with similar outcomes as those with a pathologic diagnosis. Thorough clinical and radiographic evaluations in a multidisciplinary setting are critical to the management of these patients.

ACTR-13. FINAL RESULTS WITH CHEMORADIOTHERAPY FOR ANAPLASTIC OLIGODENDROGLIAL TUMORS FROM NRG ONCOLOGY/RTOG 9402

BACKGROUND

Adding intensive-procarbazine, lomustine, and vincristine (iPCV) to radiotherapy (RT) prolonged progression-free (PFS) and overall survival (OS) for patients with 1p19q codeleted anaplastic oligodendroglial tumors (AOTs); some benefit was also observed for IDH-mutant non-codeleted cases (Cairncross et al 2013, 2014, 2016). Now, 25 years after study activation, we updated survival, further assessed IDH as a predictive biomarker, and are exploring the benefit from vincristine.

METHODS

Eligible adults (KPS ≥ 60, adequate end-organ function) were randomized to pre-RT iPCV (4 cycles x 6 weeks each) vs. RT alone, stratified by age (< or ≥ 50), KPS (60–70 or ≥ 80), and level of anaplasia. Histology (anaplastic oligodendroglioma/oligo-astrocytoma required) and biomarkers (IDH and 1p19q, post-hoc) were determined centrally. Survival was estimated by Kaplan-Meier and Hazard Ratios (HRs) by Cox-regression.

RESULTS

Overall (n=289), median follow-up was 16.4 years vs. 11.3 years at last report. In codeleted cases, 40% randomized to iPCV remained alive vs. 53% at last report; 5, 10, and 14 year-PFS and -OS rates were 62%, 50%, 41% and 70%, 57%, 46%, respectively; and iPCV unequivocally prolonged PFS (median 9.8 vs. 2.9 years, HR 0.46, 95% CI 0.3–0.7, p< 0.001) and OS (median 13.2 vs. 7.3 years, HR 0.61, 95% CI 0.40–0.94; p=0.02). With IDH mutation but without codeletion (n=66), iPCV prolonged PFS (median 2.8 vs. 1.9 years, HR 0.58, 95% CI 0.34–0.99, p=0.046); OS was longer with a trend for significance (median 5.5 vs. 3.3 years, HR 0.6, 95% CI 0.34–1.03, p=0.06) on this underpowered exploratory post-hoc analysis.

CONCLUSION

For codeleted AOTs, long-term analyses confirmed that pre-RT iPCV produced meaningful and significant prolongations of PFS and OS. With IDH mutation but without codeletion, iPCV significantly prolonged PFS and showed a trend for prolonged OS. The value of vincristine is being assessed. Supported by NCI grants U10CA180868, U10CA180822, U24CA196067, and UG1CA189867.

Association of MGMT Promoter Methylation Status With Survival Outcomes in Patients With High-Risk Glioma Treated With Radiotherapy and Temozolomide: An Analysis From the NRG Oncology/RTOG 0424 Trial

Importance

The initial report of NRG Oncology/Radiation Therapy Oncology Group (RTOG) 0424 demonstrated a 3-year overall survival benefit with the addition of temozolomide to radiotherapy compared with a historical control. However, an important end point of the trial-evaluation of the association between O6-methylgaunine-DNA-methyltransferase (MGMT) promoter methylation and survival outcomes-was not previously reported.

Objective

To examine the proportion of patients in NRG Oncology/RTOG 0424 with MGMT promoter methylation and its association with survival outcomes.

Design, Setting, and Participants

Specimens collected were analyzed after trial completion to determine MGMT promoter methylation and IDH1/2 status and the association between MGMT status and survival outcomes. A model derived from logistic regression (MGMT-STP27) was used to calculate MGMT promoter methylation status. Univariate and multivariable analyses were performed using the Cox proportional hazards regression model to determine the association of MGMT status with survival outcomes. Patient pretreatment characteristics were included as covariates in multivariable analyses.

Main Outcomes and Measures

Progression-free survival (PFS) and overall survival (OS).

Results

Of all 129 eligible patients in NRG Oncology/RTOG 0424, 75 (58.1%) had MGMT status available (median age, 48 years; age range, 20-76 years; 42 [56.0%] male): 57 (76.0%) methylated and 18 (24.0%) unmethylated. A total of 13 unmethylated patients (72.2%) had astrocytoma as opposed to oligoastrocytoma or oligodendroglioma, whereas 23 methylated patients (40.4%) had astrocytoma. On univariate analyses, an unmethylated MGMT promoter was significantly associated with worse OS (hazard ratio [HR], 3.52; 95% CI, 1.64-7.56; P < .001) and PFS (HR, 3.06; 95% CI, 1.55-6.04; P < .001). The statistical significances were maintained in multimarker multivariable analyses, including IDH1/2 status for both OS (HR, 2.70; 95% CI, 1.02-7.14; P = .045) and PFS (HR, 2.74; 95% CI, 1.19-6.33; P = .02).

Conclusions and Relevance

In this study, MGMT promoter methylation was an independent prognostic biomarker of high-risk, low-grade glioma treated with temozolomide and radiotherapy. This is the first study, to our knowledge, to validate the prognostic importance of MGMT promoter methylation in patients with grade II glioma treated with combined radiotherapy and temozolomide and highlights its potential prognostic value beyond IDH1/2 mutation status.

Trial Registration

ClinicalTrials.gov Identifier: NCT00114140.

Short delay in initiation of radiotherapy for patients with glioblastoma-effect of concurrent chemotherapy: a secondary analysis from the NRG Oncology/Radiation Therapy Oncology Group database

Background

We previously reported the unexpected finding of significantly improved survival for newly diagnosed glioblastoma in patients when radiation therapy (RT) was initiated later (>4 wk post-op) compared with earlier (≤2 wk post-op). In that analysis, data were analyzed from 2855 patients from 16 NRG Oncology/Radiotherapy Oncology Group (RTOG) trials conducted prior to the era of concurrent temozolomide (TMZ) with RT. We now report on 1395 newly diagnosed glioblastomas from 2 studies, treated with RT and concurrent TMZ followed by adjuvant TMZ. Our hypothesis was that concurrent TMZ has a synergistic/radiosensitizing mechanism, making RT timing less significant.

Methods

Data from patients treated with TMZ-based chemoradiation from NRG Oncology/RTOG 0525 and 0825 were analyzed. An analysis comparable to our prior study was performed to determine whether there was still an impact on survival by delaying RT. Overall survival (OS) was investigated using the Kaplan-Meier method and Cox proportional hazards model. Early progression (during time of diagnosis to 30 days after RT completion) was analyzed using the chi-square test.

Results

Given the small number of patients who started RT early following surgery, comparisons were made between >4 and ≤4 weeks delay of radiation from time of operation. There was no statistically significant difference in OS (hazard ratio = 0.93; P = 0.29; 95% CI: 0.80-1.07) after adjusting for known prognostic factors (recursive partitioning analysis and O6-methylguanine-DNA methyltransferase methylation status). Similarly, the rate of early progression did not differ significantly (P = 0.63).

Conclusions

We did not observe a significant prognostic influence of delaying radiation when given concurrently with TMZ for newly diagnosed glioblastoma. The effects of early (1-3 wk post-op) or late (>5 wk) initiation of radiation tested in our prior study could not be replicated.