Investigating the Effect of Reirradiation or Systemic Therapy in Patients With Glioblastoma After Tumor Progression: A Secondary Analysis of NRG Oncology/Radiation Therapy Oncology Group Trial 0525

PURPOSE

To determine the impact on overall survival with different salvage therapies, including no treatment, reirradiation, systemic therapy, or radiation and systemic therapy, in participants of a phase 3 clinical trial evaluating dose-dense versus standard-dose temozolomide for patients with newly diagnosed glioblastoma.

METHODS AND MATERIALS

This analysis of patients from Trial RTOG 0525 investigated the effect of reirradiation or systemic treatment after tumor progression. Survival from first progression was compared between patients receiving no therapy, systemic therapy alone, radiation alone, and both modalities. The Cox proportional hazards model was used to compare the mortality hazard, controlling for potential confounders.

RESULTS

The analysis included 637 patients who progressed and had information on their management, excluding those who died less than half a month after progression. A total of 267 patients (42%) received neither reirradiation nor systemic treatment at progression, 24 (4%) received radiation alone, 282 (44%) received systemic treatment only, and 64 (10%) received both radiation and systemic therapy. Patients who received no treatment had a median survival of 4.8 months, lower than with radiation treatment alone (8.2 months), systemic therapy alone (10.6 months), and both radiation and systemic therapy (12.2 months). In survival models controlling for potential confounders, those who received radiation alone had modestly better survival (hazard ratio HR 0.74, 95% confidence interval [CI] 0.43-1.28), whereas those who underwent systemic therapy either without (HR 0.42, 95% CI 0.34-0.53) or with radiation therapy (HR 0.44, 95% CI 0.30-0.63) had better survival. There was no significant survival difference between patients who received radiation only and those who received systemic therapy (either with radiation or alone).

CONCLUSIONS

Patients who received no salvage treatment had poorer survival than those who received radiation, chemotherapy, or the combination. However, patient selection for no treatment likely reflects poorer expected prognosis. There was no significant survival difference among those receiving radiation therapy, systemic therapy, or both. Ongoing clinical trials will help define the role of reirradiation after glioblastoma progression.

Phase 1 Study of Ipilimumab Combined With Whole Brain Radiation Therapy or Radiosurgery for Melanoma Patients With Brain Metastases

PURPOSE

We performed a phase 1 study to determine the maximum tolerable dose and safety of ipilimumab with stereotactic radiosurgery (SRS) or whole brain radiation therapy (WBRT) in patients with brain metastases from melanoma.

METHODS AND MATERIALS

Based on the intracranial disease burden, patients underwent WBRT (arm A) or SRS (arm B). The ipilimumab starting dose was 3 mg/kg every 3 weeks, starting on day 3 of WBRT or 2 days after SRS. The ipilimumab dose was escalated to 10 mg/kg using a 2-stage, 3+3 design. The primary endpoint was to determine the maximum tolerable dose of ipilimumab combined with radiation therapy. The secondary endpoints were overall survival, intracranial and extracranial control, progression-free survival, and toxicity. The ClinicalTrials.gov registration number is NCT01703507.

RESULTS

The characteristics of the 16 patients enrolled between 2011 and 2014 were mean age, 60 years; median number of brain metastases, 2 (range 1->10); and number with EC disease, 13 (81%). Treatment included WBRT (n=5), SRS (n=11), and ipilimumab 3 mg/kg (n=7) or 10 mg/kg (n=9). The median follow-up was 8 months (arm A) and 10.5 months (arm B). A total of 21 grade 1 to 2 neurotoxic effects occurred, with no dose-limiting toxicities. One patient experienced grade 3 neurotoxicity before ipilimumab administration. Ten additional grade 3 toxicities were reported, with gastrointestinal toxicities (n=5; 31%) the most common. No patient developed grade 4 or 5 toxicity. The median progression-free survival and overall survival in arm A was 2.5 months and 8 months and in arm B was 2.1 months and not reached, respectively.

CONCLUSIONS

Concurrent ipilimumab 10 mg/kg with SRS is safe. The WBRT arm was closed early because of slow accrual but demonstrated safety with ipilimumab 3 mg/kg. No patient experienced dose-limiting toxicity. Larger studies, including those with combination checkpoint inhibitor therapy and SRS, are warranted.

Comparison of Online 6 Degree-of-Freedom Image Registration of Varian TrueBeam Cone-Beam CT and BrainLab ExacTrac X-Ray for Intracranial Radiosurgery

PURPOSE

The study was aimed to compare online 6 degree-of-freedom image registrations of TrueBeam cone-beam computed tomography and BrainLab ExacTrac X-ray imaging systems for intracranial radiosurgery.

METHODS

Phantom and patient studies were performed on a Varian TrueBeam STx linear accelerator (version 2.5), which is integrated with a BrainLab ExacTrac imaging system (version 6.1.1). The phantom study was based on a Rando head phantom and was designed to evaluate isocenter location dependence of the image registrations. Ten isocenters at various locations representing clinical treatment sites were selected in the phantom. Cone-beam computed tomography and ExacTrac X-ray images were taken when the phantom was located at each isocenter. The patient study included 34 patients. Cone-beam computed tomography and ExacTrac X-ray images were taken at each patient's treatment position. The 6 degree-of-freedom image registrations were performed on cone-beam computed tomography and ExacTrac, and residual errors calculated from cone-beam computed tomography and ExacTrac were compared.

RESULTS

In the phantom study, the average residual error differences (absolute values) between cone-beam computed tomography and ExacTrac image registrations were 0.17 ± 0.11 mm, 0.36 ± 0.20 mm, and 0.25 ± 0.11 mm in the vertical, longitudinal, and lateral directions, respectively. The average residual error differences in the rotation, roll, and pitch were 0.34° ± 0.08°, 0.13° ± 0.09°, and 0.12° ± 0.10°, respectively. In the patient study, the average residual error differences in the vertical, longitudinal, and lateral directions were 0.20 ± 0.16 mm, 0.30 ± 0.18 mm, 0.21 ± 0.18 mm, respectively. The average residual error differences in the rotation, roll, and pitch were 0.40°± 0.16°, 0.17° ± 0.13°, and 0.20° ± 0.14°, respectively. Overall, the average residual error differences were <0.4 mm in the translational directions and <0.5° in the rotational directions. ExacTrac X-ray image registration is comparable to TrueBeam cone-beam computed tomography image registration in intracranial treatments.

Phase III randomized study of radiation and temozolomide versus radiation and nitrosourea therapy for anaplastic astrocytoma: results of NRG Oncology RTOG 9813

Background

The primary objective of this study was to compare the overall survival (OS) of patients with anaplastic astrocytoma (AA) treated with radiotherapy (RT) and either temozolomide (TMZ) or a nitrosourea (NU). Secondary endpoints were time to tumor progression (TTP), toxicity, and the effect of IDH1 mutation status on clinical outcome.

Methods

Eligible patients with centrally reviewed, histologically confirmed, newly diagnosed AA were randomized to receive either RT+TMZ (n = 97) or RT+NU (n = 99). The study closed early because the target accrual rate was not met.

Results

Median follow-up time for patients still alive was 10.1 years (1.9-12.6 y); 66% of the patients died. Median survival time was 3.9 years in the RT/TMZ arm (95% CI, 3.0-7.0) and 3.8 years in the RT/NU arm (95% CI, 2.2-7.0), corresponding to a hazard ratio (HR) of 0.94 (P = .36; 95% CI, 0.67-1.32). The differences in progression-free survival (PFS) and TTP between the 2 arms were not statistically significant. Patients in the RT+NU arm experienced more grade ≥3 toxicity (75.8% vs 47.9%, P < .001), mainly related to myelosuppression. Of the 196 patients, 111 were tested for IDH1-R132H status (60 RT+TMZ and 51 RT+NU). Fifty-four patients were IDH negative and 49 were IDH positive with a better OS in IDH-positive patients (median survival time 7.9 vs 2.8 y; P = .004, HR = 0.50; 95% CI, 0.31-0.81).

Conclusions

RT+TMZ did not appear to significantly improve OS or TTP for AA compared with RT+ NU. RT+TMZ was better tolerated. IDH1-R132H mutation was associated with longer survival.

Stereotactic Body Radiation Therapy in Octo- and Nonagenarians for the Treatment of Early-Stage Lung Cancer

PURPOSE

To determine the safety and efficacy of lung stereotactic body radiation therapy (SBRT) in octo- and nonagenarians and to compare their outcomes with those of younger patients.

METHODS AND MATERIALS

Patients with primary lung cancer treated with SBRT were identified from a multi-institutional (5 institutions) database of 1083 cases. Details of patient factors, treatment specifics, toxicity, and clinical outcomes were extracted from the database. All events were calculated from the end of radiation therapy. Estimates of local recurrence, regional recurrence, and distant metastases were calculated using the competing risk method. Cause-specific survival (CSS) and overall survival (OS) were calculated using the Kaplan-Meier method. Outcomes were compared for those aged <70, 70 to 79, and ≥80 years. Univariable and multivariable analyses were performed to determine associations with CSS and OS in patients aged ≥80 years.

RESULTS

The median (range) follow-up was 1.7 (1-10) years, and median age was 75 (41-94) years. There were 305 patients aged <70 years (28%), 448 aged 70 to 79 years (41%), and 330 aged ≥80 years (30%). There was no difference in 2-year local recurrence (4.2% vs 5.4% vs 3.7%, respectively, P=.7), regional recurrence (10.4% vs 7.8% vs 5.3%, P=.1), distant metastases (12.2% vs 7.7% vs 9.5%, P=.2), or CSS (90.6% vs 90.3% vs 90.4%, P=.6). Those aged ≥80 years had significantly lower 2-year OS (73.6% vs 67.2% vs 63.3%, P<.01). The grade 3+ pneumonitis rate was 1.3% versus 1.6% versus 1.5% (P=1.0) in patients aged <70, 70 to 79, and ≥80 years, respectively. The 90-day mortality rates for patients aged <70, 70 to 79, and ≥80 years were 1.3%, 2.5%, and 2.4% (P=.01), respectively. In patients aged ≥80 years OS was associated with T category (hazard ratio 1.7; P<.01).

CONCLUSION

Stereotactic body radiation therapy is a safe treatment modality in elderly patients (aged ≥80 years). Despite larger tumor volumes, the tumor control outcomes were comparable to those in younger patients treated with SBRT. All patients with early-stage lung cancer, regardless of age, should be considered for treatment with SBRT.

Predictors and Patterns of Regional Recurrence Following Lung SBRT: A Report From the Elekta Lung Research Group

INTRODUCTION

The objective of this study was to determine the predictors and patterns of regional recurrence (RR) following stereotactic body radiotherapy (SBRT) for primary lung cancers.

MATERIAL AND METHODS

Details of patient factors, treatment, and outcome factors were extracted from a multi-institutional (5) database. All events were calculated from the end of radiotherapy. Estimates of local recurrence, RR, and distant metastases (DM) were calculated using the competing risk method. Cause-specific and overall survival were calculated using the Kaplan-Meier method. Details of locations and number of simultaneous RRs were categorized by lymph node anatomic station.

RESULTS

A total of 734 patients were analyzed. The median follow-up was 3.0 years in surviving patients. Four hundred seventy-six (65%) patients had pathologic proof of disease. There were 64 patients with RR. The 2-year local recurrence, RR, and distant metastases rates were 5.6%, 9.0%, and 14.6% respectively. The 2-year cause-specific and overall survival were 89.9% and 63.7%, respectively. There were 136 simultaneous sites of RR. There were 21 recurrences in stations 4R (15.4%), 9 (6.6%) in 4L, 30 (22%) in 7, 19 (13.9%) in 10R, and 14 (10.3%) in 10L. The most common stations for isolated recurrence (n = 19) were station 7 (n = 5; 26.3%) and station 10R (n = 6; 31.6%). The most common RR levels were stations 4 and 7 for right and left upper lobe, stations 5, 7, and 10 for left lower lobe tumors, and stations 7 and 10 for right lower lobe tumors.

CONCLUSION

Stations 4, 7, and 10 were the most common stations for RR. These patterns of recurrence may guide nodal staging procedures prior to SBRT.

Dosimetric validation for an automatic brain metastases planning software using single-isocenter dynamic conformal arcsDosimetric validation for an automatic brain metastases planning software using single-isocenter dynamic conformal arcs

An automatic brain‐metastases planning (ABMP) software has been installed in our institution. It is dedicated for treating multiple brain metastases with radiosurgery on linear accelerators (linacs) using a single‐setup isocenter with noncoplanar dynamic conformal arcs. This study is to validate the calculated absolute dose and dose distribution of ABMP. Three types of measurements were performed to validate the planning software: 1, dual micro ion chambers were used with an acrylic phantom to measure the absolute dose; 2, a 3D cylindrical phantom with dual diode array was used to evaluate 2D dose distribution and point dose for smaller targets; and 3, a 3D pseudo‐in vivo patient‐specific phantom filled with polymer gels was used to evaluate the accuracy of 3D dose distribution and radiation delivery. Micro chamber measurement of two targets (volumes of 1.2 cc and 0.9 cc, respectively) showed that the percentage differences of the absolute dose at both targets were less than 1%. Averaged GI passing rate of five different plans measured with the diode array phantom was above 98%, using criteria of 3% dose difference, 1 mm distance to agreement (DTA), and 10% low‐dose threshold. 3D gel phantom measurement results demonstrated a 3D displacement of nine targets of 0.7±0.4 mm (range 0.2 ~ 1.1 mm). The averaged two‐dimensional (2D) GI passing rate for several region of interests (ROI) on axial slices that encompass each one of the nine targets was above 98% (5% dose difference, 2 mm DTA, and 10% low‐dose threshold). Measured D95, the minimum dose that covers 95% of the target volume, of the nine targets was 0.7% less than the calculated D95. Three different types of dosimetric verification methods were used and proved the dose calculation of the new automatic brain metastases planning (ABMP) software was clinical acceptable. The 3D pseudo‐in vivo patient‐specific gel phantom test also served as an end‐to‐end test for validating not only the dose calculation, but the treatment delivery accuracy as well.

PACS number(s): 87.53.Lv, 87.55.km, 87.55.Qr

Adjuvant radiation therapy in locally advanced non-small cell lung cancer: Executive summary of an American Society for Radiation Oncology (ASTRO) evidence-based clinical practice guideline

PURPOSE

To provide guidance to physicians and patients with regard to the use of adjuvant external beam radiation therapy (RT) in locally advanced non-small cell lung cancer (LA NSCLC) based on available medical evidence complemented by consensus-based expert opinion.

METHODS AND MATERIALS

A panel authorized by the American Society for Radiation Oncology (ASTRO) Board of Directors and Guidelines Subcommittee conducted 2 systematic reviews on the following topics: (1) indications for postoperative adjuvant RT and (2) indications for preoperative neoadjuvant RT. Practice guideline recommendations were approved using an a priori-defined consensus-building methodology supported by ASTRO and approved tools for the grading of evidence quality and the strength of guideline recommendations.

RESULTS

For patients who have undergone surgical resection, high-level evidence suggests that use of postoperative RT does not influence survival, but optimizes local control for patients with N2 involvement, and its use in the setting of positive margins or gross primary/nodal residual disease is recommended. No high-level evidence exists for the routine use of preoperative induction chemoradiation therapy; however, modern surgical series and a post-hoc Intergroup 0139 clinical trial analysis suggest that a survival benefit may exist if patients are properly selected and surgical techniques/postoperative care is optimized.

CONCLUSIONS

A consensus and evidence-based clinical practice guideline for the adjuvant radiotherapeutic management of LA NSCLC has been created addressing 2 important questions.

Definitive radiation therapy in locally advanced non-small cell lung cancer: Executive summary of an American Society for Radiation Oncology (ASTRO) evidence-based clinical practice guideline

PURPOSE

To provide guidance to physicians and patients with regard to the use of definitive external beam radiation therapy (RT) in locally advanced non-small cell lung cancer (LA NSCLC) based on available medical evidence complemented by consensus-based expert opinion.

METHODS AND MATERIALS

A panel authorized by the American Society for Radiation Oncology (ASTRO) Board of Directors and Guidelines Subcommittee conducted 3 systematic reviews on the following topics: (1) ideal radical RT dose fractionation for RT alone; (2) ideal radical RT dose fractionation for chemoradiation; and (3) ideal timing of radical radiation therapy with systemic chemotherapy. Practice guideline recommendations were approved using an a priori-defined consensus-building methodology supported by ASTRO and approved tools for the grading of evidence quality and the strength of guideline recommendations.

RESULTS

For patients managed by RT alone, a minimum dose of 60 Gy of RT is recommended. Dose escalation beyond 60 Gy in the context of combined modality concurrent chemoradiation has not been found to be associated with any clinical benefits. In the context of combined modality therapy, chemotherapy and radiation should ideally be given concurrently to maximize survival, local control, and disease response rate.

CONCLUSIONS

A consensus and evidence-based clinical practice guideline for the definitive radiotherapeutic management of LA NSCLC has been created that addresses 3 important questions.

Phase I and II Study of Induction Chemotherapy With Methotrexate, Rituximab, and Temozolomide, Followed By Whole-Brain Radiotherapy and Postirradiation Temozolomide for Primary CNS Lymphoma: NRG Oncology RTOG 0227

PURPOSE

This study investigated the treatment of primary CNS lymphoma with methotrexate, temozolomide (TMZ), and rituximab, followed by hyperfractionated whole-brain radiotherapy (hWBRT) and subsequent TMZ. The primary phase I end point was the maximum tolerated dose of TMZ. The primary phase II end point was the 2-year overall survival (OS) rate. Secondary end points were preirradiation response rates, progression-free survival (PFS), neurologic toxicities, and quality of life.

PATIENTS AND METHODS

The phase I study increased TMZ doses from 100 to 150 to 200 mg/m(2). Patients were treated with rituximab 375 mg/m(2) 3 days before cycle 1; methotrexate 3.5 g/m(2) with leucovorin on weeks 1, 3, 5, 7, and 9; TMZ daily for 5 days on weeks 4 and 8; hWBRT 1.2 Gy twice-daily on weeks 11 to 13 (36 Gy); and TMZ 200 mg/m(2) daily for 5 days every 28 days on weeks 14 to 50.

RESULTS

Thirteen patients (one ineligible) were enrolled in phase I of the study. The maximum tolerated dose of TMZ was 100 mg/m(2). Dose-limiting toxicities were hepatic and renal. In phase II, 53 patients were treated. Median follow-up for living eligible patients was 3.6 years, and 2-year OS and PFS were 80.8% and 63.6%, respectively. Compared with historical controls from RTOG-9310, 2-year OS and PFS were significantly improved (P = .006 and .030, respectively). In phase II, the objective response rate was 85.7%. Among patients, 66% (35 of 53) had grade 3 and 4 toxicities before hWBRT, and 45% (24 of 53) of patients experienced grade 3 and 4 toxicities attributable to post-hWBRT chemotherapy. Cognitive function and quality of life improved or stabilized after hWBRT.

CONCLUSION

This regimen is safe, with the best 2-year OS and PFS achieved in any Radiation Therapy Oncology Group primary CNS lymphoma trial. Randomized trials that incorporate this regimen are needed to determine its efficacy compared with other strategies.

Pretreatment 18F-FDG PET Textural Features in Locally Advanced Non-Small Cell Lung Cancer: Secondary Analysis of ACRIN 6668/RTOG 0235

In a secondary analysis of American College of Radiology Imaging Network (ACRIN) 6668/RTOG 0235, high pretreatment metabolic tumor volume (MTV) on (18)F-FDG PET was found to be a poor prognostic factor for patients treated with chemoradiotherapy for locally advanced non-small cell lung cancer (NSCLC). Here we utilize the same dataset to explore whether heterogeneity metrics based on PET textural features can provide additional prognostic information.

METHODS

Patients with locally advanced NSCLC underwent (18)F-FDG PET prior to treatment. A gradient-based segmentation tool was used to contour each patient's primary tumor. MTV, maximum SUV, and 43 textural features were extracted for each tumor. To address overfitting and high collinearity among PET features, the least absolute shrinkage and selection operator (LASSO) method was applied to identify features that were independent predictors of overall survival (OS) after adjusting for MTV. Recursive binary partitioning in a conditional inference framework was utilized to identify optimal thresholds. Kaplan-Meier curves and log-rank testing were used to compare outcomes among patient groups.

RESULTS

Two hundred one patients met inclusion criteria. The LASSO procedure identified 1 textural feature (SumMean) as an independent predictor of OS. The optimal cutpoint for MTV was 93.3 cm(3), and the optimal SumMean cutpoint for tumors above 93.3 cm(3) was 0.018. This grouped patients into three categories: low tumor MTV (n = 155; median OS, 22.6 mo), high tumor MTV and high SumMean (n = 23; median OS, 20.0 mo), and high tumor MTV and low SumMean (n = 23; median OS, 6.2 mo; log-rank P < 0.001).

CONCLUSION

We have described an appropriate methodology to evaluate the prognostic value of textural PET features in the context of established prognostic factors. We have also identified a promising feature that may have prognostic value in locally advanced NSCLC patients with large tumors who are treated with chemoradiotherapy. Validation studies are warranted.