Survival in Patients With Spinal Metastatic Disease Treated Nonoperatively With Radiotherapy: Are the SORG-ML Algorithms Relevant?

SUMMARY OF BACKGROUND DATA: The SORG-ML algorithms for survival in spinal metastatic disease were developed in patients who underwent surgery and were externally validated for patients managed operatively. OBJECTIVE: To externally validate the SORG-ML algorithms for survival in spinal metastatic disease in patients managed nonoperatively with radiation. STUDY DESIGN: Retrospective cohort. METHODS: The performance of the SORG-ML algorithms was assessed by discrimination [receiver operating curves and area under the receiver operating curve (AUC)], calibration (calibration plots), decision curve analysis, and overall performance (Brier score). The primary outcomes were 90-day and 1-year mortality. RESULTS: Overall, 2074 adult patients underwent radiation for spinal metastatic disease and 29% (n=521) and 59% (n=917) had 90-day and 1-year mortality, respectively. On complete case analysis (n=415), the AUC was 0.76 (95% CI: 0.71-0.80) and 0.78 (95% CI: 0.73-0.83) for 90-day and 1-year mortality with fair calibration and positive net benefit confirmed by the decision curve analysis. With multiple imputation (n=2074), the AUC was 0.85 (95% CI: 0.83-0.87) and 0.87 (95% CI: 0.85-0.89) for 90-day and 1-year mortality with fair calibration and positive net benefit confirmed by the decision curve analysis. CONCLUSION: The SORG-ML algorithms for survival in spinal metastatic disease generalize well to patients managed nonoperatively with radiation.

NRG Oncology/RTOG1205: A Randomized Phase II Trial of Concurrent Bevacizumab and Reirradiation Versus Bevacizumab Alone as Treatment for Recurrent Glioblastoma.

PURPOSE: To assess whether reirradiation (re-RT) and concurrent bevacizumab (BEV) improve overall survival (OS) and/or progression-free survival (PFS), compared with BEV alone in recurrent glioblastoma (GBM). The primary objective was OS, and secondary objectives included PFS, response rate, and treatment adverse events (AEs) including delayed CNS toxicities. METHODS: NRG Oncology/RTOG1205 is a prospective, phase II, randomized trial of re-RT and BEV versus BEV alone. Stratification factors included age, resection, and Karnofsky performance status (KPS). Patients with recurrent GBM with imaging evidence of tumor progression ≥ 6 months from completion of prior chemo-RT were eligible. Patients were randomly assigned 1:1 to re-RT, 35 Gy in 10 fractions, with concurrent BEV IV 10 mg/kg once in every 2 weeks or BEV alone until progression. RESULTS: From December 2012 to April 2016, 182 patients were randomly assigned, of whom 170 were eligible. Patient characteristics were well balanced between arms. The median follow-up for censored patients was 12.8 months. There was no improvement in OS for BEV + RT, hazard ratio, 0.98; 80% CI, 0.79 to 1.23; P = .46; the median survival time was 10.1 versus 9.7 months for BEV + RT versus BEV alone. The median PFS for BEV + RT was 7.1 versus 3.8 months for BEV, hazard ratio, 0.73; 95% CI, 0.53 to 1.0; P = .05. The 6-month PFS rate improved from 29.1% (95% CI, 19.1 to 39.1) for BEV to 54.3% (95% CI, 43.5 to 65.1) for BEV + RT, P = .001. Treatment was well tolerated. There were a 5% rate of acute grade 3+ treatment-related AEs and no delayed high-grade AEs. Most patients died of recurrent GBM. CONCLUSION: To our knowledge, NRG Oncology/RTOG1205 is the first prospective, randomized multi-institutional study to evaluate the safety and efficacy of re-RT in recurrent GBM using modern RT techniques. Overall, re-RT was shown to be safe and well tolerated. BEV + RT demonstrated a clinically meaningful improvement in PFS, specifically the 6-month PFS rate but no difference in OS.

Long-term outcomes and late toxicity of adult medulloblastoma treated with combined modality therapy: A contemporary single-institution experience.

BACKGROUND: Medulloblastoma (MB) is a rare central nervous system malignancy of adults, with limited contemporary studies to define treatment guidelines and expected late toxicity. METHODS: A single-center, retrospective study was conducted of patients age ≥18 years from 1997-2019 with MB and who were treated with postoperative radiotherapy. Late toxicity was defined as a minimum of 18 months from diagnosis. Overall survival (OS) and progression-free survival (PFS) were characterized using Kaplan-Meier and Cox regression analyses. RESULTS: Fifty-nine patients met criteria, with median age of 25 years (range 18-62 y) and median follow-up of 6.5 years (range 0.7-23.1 y). At diagnosis, 68% were standard-risk, 88% Chang M0, and 22% with anaplastic histology. Gross total resection was achieved in 75%; median craniospinal irradiation dose was 30.6 Gy (relative biological effectiveness [RBE]), median total dose was 54.0 Gy (RBE), 80% received proton radiotherapy; 81% received chemotherapy. 5 year PFS and OS were 86.5% and 95.8%, respectively; 10 year PFS and OS were 83.9% and 90.7%, respectively. Anaplastic histology was associated with worse PFS (P = .04). Among eight recurrences, 25% presented after 5 years. Most common grade ≥2 late toxicities were anxiety/depressive symptoms (30%), motor dysfunction (25%), and ototoxicity (22%). Higher posterior fossa radiation dose was associated with increased risk of late toxicity, including worse cognitive dysfunction (P = .05). CONCLUSIONS: Adults with MB have favorable survival outcomes, but late failures and toxicity are not uncommon. Better understanding of prognostic factors, possibly from molecular subtyping, may help to define more personalized treatments for patients with high risk of recurrence and long-term treatment sequelae.

Adjuvant Radiation Therapy Versus Surveillance After Surgical Resection of Atypical Meningiomas.

PURPOSE: The optimal timing of adjuvant radiation therapy (RT) in the management of atypical meningiomas remains controversial. We compared the outcomes of atypical meningiomas managed with upfront adjuvant RT versus postoperative surveillance. METHODS AND MATERIALS: Patients with intracranial atypical meningiomas who underwent resection between 2000 and 2015 at a single institution were identified. Patients receiving adjuvant RT (n = 51), defined as RT within the first year of surgery before tumor progression/recurrence (P/R), were compared with those undergoing initial surveillance (n = 179). The primary endpoints were radiographic evidence of P/R and time to P/R from surgery. RESULTS: A total of 230 patients were identified. Fifty-one (22%) patients received upfront adjuvant RT, and 179 (78%) underwent surveillance. Compared with the surveillance group, patients who received adjuvant RT had larger tumors (5.2 cm vs 4.6 cm; P = .04), were more likely to have undergone subtotal resection (65% vs 26%; P < . 01), and more often had bone invasion (18% vs 7%; P = .02). On multivariable analysis, receipt of adjuvant RT was associated with a lower risk of P/R compared with surveillance (hazard ratio, 0.21; 95% confidence interval, 0.11-0.41; P < .01). Patients who initially underwent surveillance and then received salvage RT at time of P/R had a shorter median time to local progression after RT compared with patients who developed local P/R after upfront adjuvant RT (19 vs 64 months, respectively; P < . 01). CONCLUSION: Upfront adjuvant RT was associated with improved local control in atypical meningiomas irrespective of extent of initial resection compared with surveillance. Early adjuvant RT should be strongly considered after gross total resection of atypical meningiomas.

Post-operative radiation therapy to the surgical cavity with standard fractionation in patients with brain metastases.

The paradigm for post-operative cavity radiation therapy has shifted to more targeted, less morbid approaches. Single-fraction or hypofractionated radiation therapy is a common approach to treating the postoperative cavity but is associated with a local failure rate 20-40%. We employed an alternative treatment strategy involving fractionated partial brain radiation therapy to the surgical cavity. Patients with brain metastases who underwent radiation treatment 30-42 Gy in 3 Gy/fraction regimens to surgical cavity were retrospectively identified. The 6-month and 12-month freedom from local failure rates were 97.0% and 88.2%. Three patients (7%) experienced local failure at 4, 6, and 22 months. Of these, the histologies were colorectal adenocarcinoma (N = 1) and breast adenocarcinoma (N = 2). The 6-month and 12-month freedom from distant brain metastases rates were 74.1% and 68.8%, respectively, and the 6-month and 12-month overall survival rates were 84.9% and 64.3% respectively. The median overall survival was 39 months, and there were no events of late radionecrosis. Fractionated partial brain irradiation to the surgical cavity of resected brain metastases results in low rates of local failure. This strategy represents an alternative to SRS and WBRT.

Early experience with hippocampal avoidance whole brain radiation therapy and simultaneous integrated boost for brain metastases.

PURPOSE: Cranial irradiation results in cognitive decline, which is hypothesized to be partially attributable to hippocampal injury and stem cell loss. Recent advances allow for targeted reduction of radiation dose to the hippocampi while maintaining adequate dose coverage to the brain parenchyma and additional increasing dose to brain metastases, a approach called hippocampal avoidance whole brain radiation therapy with a simultaneous integrated boost (HA-WBRT + SIB.) We review our early clinical experience with HA-WBRT + SIB. MATERIALS AND METHODS: We evaluated treatments and clinical outcomes for patients treated with HA-WBRT + SIB between 2014 and 2018. RESULTS: A total of 32 patients (median age, 63.5 years, range 45.3-78.8 years) completed HA-WBRT + SIB. Median follow-up for patients alive at the time of analysis was 11.3 months. The most common histology was non-small cell lung cancer (n = 22). Most patients (n = 25) were prescribed with WBRT dose of 30 Gy with SIB to 37.5 Gy in 15 fractions. Volumetric modulated arc therapy reduced treatment time (p < 0.0001). Median freedom from intracranial progression and overall survival from completion of treatment were 11.4 months and 19.6 months, respectively. Karnofsky Performance Status was associated with improved survival (p = 0.008). The most common toxicities were alopecia, fatigue, and nausea. Five patients developed cognitive impairment, including grade 1 (n = 3), grade 2 (n = 1), and grade 3 (n = 1). CONCLUSION: HA-WBRT + SIB demonstrated durable intracranial disease control with modest side effects and merits further investigation as a means of WBRT toxicity reduction while improving long-term locoregional control in the brain.

Atypical Histopathological Features and the Risk of Treatment Failure in Nonmalignant Meningiomas: A Multi-Institutional Analysis.

BACKGROUND: Histopathological grading of meningiomas is insufficient for optimal risk stratification. The purpose of the present study was to determine the prognostic value of atypical histopathological features across all nonmalignant meningiomas (World Health Organization [WHO] grade I-II). METHODS: The data from 334 patients with WHO grade I (n = 275) and grade II (n = 59) meningiomas who had undergone surgical resection from 2001 to 2015 at 2 academic centers were pooled. Progression/recurrence (P/R) was determined radiographically and measured from the date of surgery. RESULTS: The median follow-up was 52 months. The patients were stratified by the number of atypical features: 0 (n = 151), 1 (n = 71), 2 (n = 66), 3 (n = 22), and 4 or 5 (n = 24). The risk of P/R increased with an increasing number of atypical features (log-rank test, P = 0.001). The 5-year actuarial rates of P/R stratified by the number of atypical features were as follows: 0, 16.3% (95% confidence interval [CI], 10.7-24.4); 1, 21.7% (95% CI, 12.8-35.2); 2, 28.2% (95% CI, 18.4-41.7); 3, 30.4% (95% CI, 13.8-58.7); and 4 or 5, 51.4% (95% CI, 31.7-74.5). On univariate analysis, the presence of high nuclear/cytoplasmic ratio (P = 0.007), prominent nucleoli (P = 0.007), and necrosis (P < 0.00005) were associated with an increased risk of P/R. On multivariate analysis, the number of atypical features (hazard ratio [HR], 1.30; 95% CI, 1.03-1.63; P = 0.03), ≥4 mitoses per high-power fields (HR, 2.45; 95% CI, 1.17-5.15; P = 0.02), subtotal resection (HR, 3.9; 95% CI, 2.5-6.3; P < 0.0005), and the lack of adjuvant radiotherapy (HR, 2.40; 95% CI, 1.19-4.80; P = 0.01) were associated with an increased risk of P/R. CONCLUSIONS: An increased number of atypical features, ≥4 mitoses per 10 high-power fields, subtotal resection, and the lack of adjuvant radiotherapy were independently associated with P/R of WHO grade I-II meningiomas. Patients with these features might benefit from intensified therapy.

Volumetric and actuarial analysis of brain necrosis in proton therapy using a novel mixture cure model.

BACKGROUND AND PURPOSE: High-dose fractionated radiotherapy is often necessary to achieve long-term tumor control in several types of tumors involving or within close proximity to the brain. There is limited data to guide on optimal constraints to the adjacent nontarget brain. This investigation explored the significance of the three-dimensional (3D) dose distribution of passive scattering proton therapy to the brain with other clinicopathological factors on the development of symptomatic radiation necrosis. MATERIALS AND METHODS: All patients with head and neck, skull base, or intracranial tumors who underwent proton therapy (minimum prescription dose of 59.4 Gy(RBE)) with collateral moderate to high dose radiation exposure to the nontarget brain were retrospectively reviewed. A mixture cure model with respect to necrosis-free survival was used to derive estimates for the normal tissue complication probability (NTCP) model while adjusting for potential confounding factors. RESULTS: Of 179 identified patients, 83 patients had intracranial tumors and 96 patients had primary extracranial tumors. The optimal dose measure obtained to describe the occurrence of radiation necrosis was the equivalent uniform dose (EUD) with parameter a = 9. The best-fit parameters of logistic NTCP models revealed D50 = 57.7 Gy for intracranial tumors, D50 = 39.5 Gy for extracranial tumors, and γ50 = 2.5 for both tumor locations. Multivariable analysis revealed EUD and primary tumor location to be the strongest predictors of brain radiation necrosis. CONCLUSION: In the current clinical volumetric data analyses with multivariable modelling, EUD was identified as an independent and strong predictor for brain radiation necrosis from proton therapy.

Radiation and chemotherapy for high-risk lower grade gliomas: Choosing between temozolomide and PCV.

PURPOSE: The majority of patients with high-risk lower grade gliomas (LGG) are treated with single-agent temozolomide (TMZ) and radiotherapy despite three randomized trials showing a striking overall survival benefit with adjuvant procarbazine, lomustine, and vincristine (PCV) chemotherapy and radiotherapy. This article aims to evaluate the evidence and rationale for the widespread use of TMZ instead of PCV for high-risk LGG. METHODS AND MATERIALS: We conducted a literature search utilizing PubMed for articles investigating the combination of radiotherapy and chemotherapy for high-risk LGG and analyzed the results of these studies. RESULTS: For patients with IDH mutant 1p/19q codeleted LGG tumors, there is limited evidence to support the use of TMZ. In medically fit patients with codeleted disease, existing data demonstrate a large survival benefit for PCV as compared to adjuvant radiation therapy alone. For patients with non-1p/19q codeleted LGG, early data from the CATNON study supports inclusion of adjuvant TMZ for 12 months. Subset analyses of the RTOG 9402 and EORTC 26951 do not demonstrate a survival benefit for adjuvant PCV for non-1p/19q codeleted gliomas, however secondary analyses of RTOG 9802 and RTOG 9402 demonstrated survival benefit in any IDH mutant lower grade gliomas, regardless of 1p/19q codeletion status. CONCLUSIONS: At present, we conclude that current evidence does not support the widespread use of TMZ over PCV for all patients with high-risk LGG, and we instead recommend tailoring chemotherapy recommendation based on IDH status, favoring adjuvant PCV for patients with any IDH mutant tumors, both those that harbor 1p/19q codeletion and those non-1p/19q codeleted. Given the critical role radiation plays in the treatment of LGG, radiation oncologists should be actively involved in discussions regarding chemotherapy choice in order to optimize treatment for their patients.

Long-term outcomes and late adverse effects of a prospective study on proton radiotherapy for patients with low-grade glioma.

BACKGROUND: Patients with low-grade gliomas (LGG) can survive years with their illness. Proton radiotherapy (PRT) can reduce off-target dose and decrease the risk of treatment-related morbidity. We examined long-term morbidity following proton therapy in this updated prospective cohort of patients with LGG. METHODS: Twenty patients with LGG were enrolled prospectively and received PRT to 54 Gy(RBE) in 30 fractions. Comprehensive baseline and longitudinal assessments of toxicity, neurocognitive and neuroendocrine function, quality of life, and survival outcomes were performed up to 5 years following treatment. RESULTS: Six patients died (all of disease) and six had progression of disease. Median follow-up was 6.8 years for the 14 patients alive at time of reporting. Median progression-free survival (PFS) was 4.5 years. Of tumors tested for molecular markers, 71% carried the IDH1-R132H mutation and 29% had 1p/19q co-deletion. There was no overall decline in neurocognitive function; however, a subset of five patients with reported cognitive symptoms after radiation therapy had progressively worse function by neurocognitive testing. Six patients developed neuroendocrine deficiencies, five of which received Dmax ≥20 Gy(RBE) to the hypothalamus-pituitary axis (HPA). Most long-term toxicities developed within 2 years after radiation therapy. CONCLUSIONS: The majority of patients with LGG who received proton therapy retained stable cognitive and neuroendocrine function. The IDH1-R132H mutation was present in the majority, while 1p/19q loss was present in a minority. A subset of patients developed neuroendocrine deficiencies and was more common in those with higher dose to the HPA.

Predicting 90-Day and 1-Year Mortality in Spinal Metastatic Disease: Development and Internal Validation.

BACKGROUND: Increasing prevalence of metastatic disease has been accompanied by increasing rates of surgical intervention. Current tools have poor to fair predictive performance for intermediate (90-d) and long-term (1-yr) mortality. OBJECTIVE: To develop predictive algorithms for spinal metastatic disease at these time points and to provide patient-specific explanations of the predictions generated by these algorithms. METHODS: Retrospective review was conducted at 2 large academic medical centers to identify patients undergoing initial operative management for spinal metastatic disease between January 2000 and December 2016. Five models (penalized logistic regression, random forest, stochastic gradient boosting, neural network, and support vector machine) were developed to predict 90-d and 1-yr mortality. RESULTS: Overall, 732 patients were identified with 90-d and 1-yr mortality rates of 181 (25.1%) and 385 (54.3%), respectively. The stochastic gradient boosting algorithm had the best performance for 90-d mortality and 1-yr mortality. On global variable importance assessment, albumin, primary tumor histology, and performance status were the 3 most important predictors of 90-d mortality. The final models were incorporated into an open access web application able to provide predictions as well as patient-specific explanations of the results generated by the algorithms. The application can be found at https://sorg-apps.shinyapps.io/spinemetssurvival/. CONCLUSION: Preoperative estimation of 90-d and 1-yr mortality was achieved with assessment of more flexible modeling techniques such as machine learning. Integration of these models into applications and patient-centered explanations of predictions represent opportunities for incorporation into healthcare systems as decision tools in the future.

Patterns of Failure Among Patients With Low-grade Glioma Treated With Proton Radiation Therapy.

PURPOSE: Proton treatment may be a useful radiation therapy modality for long-term surviving patients with glioma to reduce normal tissue toxicities. Photon studies demonstrate that most low-grade glioma (LGG) failures occur within the radiation field, supporting the use of more conformal treatment plans, yet it is unclear whether this can be translated to proton radiation therapy (PRT). Our objective is to examine our institutional experience to determine patterns of failure in patients with LGG with respect to the volume irradiated with PRT. METHODS AND MATERIALS: Patients with World Health Organization 2007 grade I to II or isocitrate dehydrogenase 1-positive mutation grade III LGG treated with PRT between 2005 and 2015 were retrospectively reviewed. Patients with documented local recurrences on magnetic resonance imaging after receipt of PRT underwent a comparison with the initial treatment plan dosimetry to evaluate patterns of failure. A total of 141 patients were included in the final cohort. RESULTS: The median follow-up time was 46.7 months (range, 2.8-144 months), and 5-year overall survival was 84%. The median PRT dose delivered was 54 Gy (relative biological effectiveness) (range, 45-60 Gy). There were 42 failures after PRT (30%). The median time to progression after treatment was 32.7 months (range, 4.8-93.6 months). Thirty-one patients (74%) failed in-field (defined as within the 95% isodose volume), 5 patients (12%) failed out-of-field, and 5 patients (12%) had marginal failures (defined as within the 50%-95% isodose volume). The 5-year freedom from progression after PRT was 60.1% (95% confidence interval, 48.7-70.0). The 5-year cumulative incidence of overall survival was 33% among those with recurrence after PRT and 96% among those without recurrence after PRT (P < .001). CONCLUSIONS: Of the patients with LGG who had documented failures after PRT, most recurred within the radiation field with few marginal failures, indicating that even with PRT, which often can have steeper dose gradients, coverage is adequate. Survival was poor for patients whose tumors recurred.

Hypopituitarism After Cranial Irradiation for Meningiomas: A Single-Institution Experience.

PURPOSE: Patients undergoing cranial irradiation are at high risk for development of subsequent pituitary deficiencies. Patients with meningiomas can expect to live many years after treatment and are therefore particularly vulnerable to long-term sequalae of radiation therapy (RT). The purpose of this study was to determine the rates and timing of onset of pituitary dysfunction across each hypothalamic-pituitary axis in patients with meningiomas in the sellar region. METHODS AND MATERIALS: Data from 74 patients with meningiomas in the sellar or perisellar region who underwent RT between 2001 and 2017 at a single academic center were analyzed. Dose-volume histograms were generated to determine the dose of radiation to the pituitary gland. Pituitary function tests were evaluated before and after completion of RT. RESULTS: There was a 20% risk for new hypopituitarism across any hypothalamic-pituitary axis after RT at a median follow-up of 43 months. Identified rates of dysfunction across each axis were 24% for thyroid and adrenal, 19% for growth hormone, and 10% for gonadal. Median time to develop deficiencies ranged from 11 months for growth hormone deficiency to 32 months for adrenal insufficiency. Deficiencies were likely to be correlated, with increased risk for thyroid dysfunction in patients with adrenal, gonadal, or prolactin deficiencies (P < .05). On univariate analysis, mean dose to the pituitary gland and male sex were associated with increased risk for post-RT thyroid deficiency (P = .01 and P = .004, respectively). There was no difference in rates of hypothyroidism after protons compared with photons (P = .14). CONCLUSIONS: Cranial irradiation for sellar meningiomas carries a risk for subsequent hypopituitarism that appears to be dose dependent and may occur years after completion of RT. Growth hormone deficiency and gonadal dysfunction were likely underestimated here secondary to a lack of routine testing. Given the favorable tumor prognosis in this patient population, early and long-term endocrine follow-up is warranted.

Development of Machine Learning Algorithms for Prediction of 30-Day Mortality After Surgery for Spinal Metastasis.

BACKGROUND: Preoperative prognostication of short-term postoperative mortality in patients with spinal metastatic disease can improve shared decision making around end-of-life care. OBJECTIVE: To (1) develop machine learning algorithms for prediction of short-term mortality and (2) deploy these models in an open access web application. METHODS: The American College of Surgeons, National Surgical Quality Improvement Program was used to identify patients that underwent operative intervention for metastatic disease. Four machine learning algorithms were developed, and the algorithm with the best performance across discrimination, calibration, and overall performance was integrated into an open access web application. RESULTS: The 30-d mortality for the 1790 patients undergoing surgery for spinal metastatic disease was 8.49%. Preoperative factors used for prognostication were albumin, functional status, white blood cell count, hematocrit, alkaline phosphatase, spinal location (cervical, thoracic, lumbosacral), and severity of comorbid systemic disease (American Society of Anesthesiologist Class). In this population, machine learning algorithms developed to predict 30-d mortality performed well on discrimination (c-statistic), calibration (assessed by calibration slope and intercept), Brier score, and decision analysis. An open access web application was developed for the best performing model and this web application can be found here: https://sorg-apps.shinyapps.io/spinemets/. CONCLUSION: Machine learning algorithms are promising for prediction of postoperative outcomes in spinal oncology and these algorithms can be integrated into clinically useful decision tools. As the volume of data in oncology continues to grow, creation of learning systems and deployment of these systems as accessible tools may significantly enhance prognostication and management.

Spinal Growth Patterns After Craniospinal Irradiation in Children With Medulloblastoma.

PURPOSE: This study aimed to evaluate the impact on spine growth in children with medulloblastoma using either photon or electron craniospinal irradiation (CSI). METHODS AND MATERIALS: This was a single institution retrospective review of children who were treated with CSI for medulloblastoma. Spine growth was measured on magnetic resonance imaging scans at defined locations on the basis of a published predictive model of spine growth after CSI. Differences between spine growth in the anterior, middle, and posterior aspect of the designated vertebral segments were also assessed. Differences between the groups treated with photons or electrons were assessed with student's t test. RESULTS: A total of 19 patients (10 patients treated with electrons and 9 with photons) with a median follow-up time of 45.5 months (confidence interval, 34.9-55.1 months) were evaluated. Patients treated with electrons were younger than those who received photons (5.1 years [range, 3.8-9.0 years] vs 9.6 years [range, 3.5-12.9 years]); however, there were no differences in other clinical characteristics, treatment, or follow-up between the groups. Spine growth rate for patients treated with electrons fit the predictive model (104% ± 5.2%), but patients treated with photons had growth that was faster than predicted by the model (150% ± 47%) and different from that observed with electrons. The differences between treatment the modalities were statistically significant (P = .03). For patients treated with photons, there were no statistical differences between the growth rate of the anterior vertebral body compared with the posterior aspect, but for patients treated with electrons, a faster spine growth in the anterior L1-L5 lumbar spine was observed compared with the posterior lumbar spine (3.90 vs 2.52 mm/year; P = .006) without differences in the cervical or thoracic spine. CONCLUSIONS: The use of electrons to treat the craniospinal axis in children with medulloblastoma resulted in no significant difference in spine growth compared with the predicted spine growth on the basis of previously published models using photons, but with a clinically insignificant faster spine growth rate in the anterior lumbar spine.

Increase of pseudoprogression and other treatment related effects in low-grade glioma patients treated with proton radiation and temozolomide.

INTRODUCTION: Concurrent radiotherapy and temozolomide (TMZ) is associated with radiographic pseudoprogression (PsP) in glioblastoma. The occurrence of PsP and other treatment effects is less well understood in low-grade gliomas (LGG). The purpose of this study is to evaluate whether the addition of TMZ to radiotherapy increases the incidence of PsP in adults with LGG treated with proton radiotherapy (PRT). METHODS: Chart review and volumetric MRI-analysis was performed on radiotherapy-naive adults with WHO grade II or IDH mutant WHO grade III gliomas treated with PRT between 2005 and 2015. Progression was defined by histology, new chemotherapy initiation, or progressive increase in lesion volume beyond 40% from baseline. Post treatment related effects (PTRE) were defined as new/increased T2/FLAIR or abnormal enhancement which eventually resolved or stabilized without evidence of progression for a period of 6-12 months. PsP was defined as the subset of PRTE suspicious for progression or volumetrically increased at least 40% from baseline. Pearson's chi-squared test and Cox-proportional hazards models were used for statistical analysis. RESULTS: There were 119 patients meeting inclusion criteria. There was an increased risk of PsP following PRT + TMZ versus PRT-alone (HR = 2.2, p = 0.006, on Cox univariate analysis). Presence of PsP was associated with improved OS (p = 0.02 with PsP as time-varying covariate). CONCLUSIONS: TMZ use, when added to PRT, was associated with increased PsP in patients with LGG; however, patients with PsP tended to achieve longer survival.

Enrichment of HER2 Amplification in Brain Metastases from Primary Gastrointestinal Malignancies.

BACKGROUND: In nongastric gastrointestinal (GI) cancers, HER2-positive (HER2+) disease is not common. In breast cancer, HER2 status is associated with increased risk of brain metastases and response to HER2-targeted therapy. The purpose of this project was to compare HER2 status in GI cancer brain metastases versus matched prior sites of disease in order to determine if HER2+ disease is more common intracranially. MATERIALS AND METHODS: We identified 28 patients with GI cancer who had craniotomy for brain metastases between 1999 and 2017 with intracranial metastatic tissue available at Massachusetts General Hospital. Twenty-four patients also had tissue from a prior site of disease. Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) for HER2 were performed on all samples. A tumor was defined as HER2+ if it had 3+ staining by IHC or amplification by FISH. RESULTS: A prior site of disease (including intracranial metastases) was HER2+ for 13% of evaluable patients: 3 of 11 patients with colorectal cancer and no patients with esophageal or pancreatic cancer. The most recent brain metastases were HER2+ for 32% of patients: 2 of 3 esophageal squamous cell carcinomas, 3 of 10 esophageal adenocarcinomas (ACs), 3 of 14 colorectal ACs, and 1 of 1 pancreatic AC. Only 37.5% of patients with HER2+ brain metastasis had concordant HER2+ prior tissue (κ = 0.38, p = .017). CONCLUSION: In this cohort of patients with GI cancer with brain metastases, HER2+ status was more common intracranially compared with prior sites of disease. These findings suggest that testing HER2 in patients with GI cancer with brain metastases may lead to additional therapeutic options, regardless of HER2 status in previously examined tissue. IMPLICATIONS FOR PRACTICE: HER2 amplification is a well-known driver of oncogenesis in breast cancer, with associated increased risk of brain metastases and response to HER2-directed therapy. In nongastric gastrointestinal (GI) cancers, HER2 amplification is not common and consequently is infrequently tested. The current study shows that brain metastases in patients with GI primary malignancies have a relatively high likelihood of being HER2 positive despite HER2 amplification or overexpression being less commonly found in matched tissue from prior sites of disease. This suggests that regardless of prior molecular testing, patients with GI cancer with brain metastases who have tissue available are likely to benefit from HER2 assessment to identify potential novel therapeutic options.

The impact of timing of immunotherapy with cranial irradiation in melanoma patients with brain metastases: intracranial progression, survival and toxicity.

Immunotherapy (IT) is increasingly incorporated in the management of metastatic melanoma patients with brain metastases, but the impact of timing of IT with stereotactic radiosurgery (SRS) remains unclear. The aim of this study was to determine the temporal significance of IT in melanoma patients treated with cranial radiation therapy (RT) with respect to patterns of intracranial progression, overall survival (OS), and toxicity. We retrospectively reviewed consecutive melanoma patients with brain metastases undergoing cranial RT and IT between 2008 and 2015. Concurrent IT/RT was defined as IT administration within 30 days of RT. Intracranial progression, OS and radionecrosis were assessed. We identified 74 patients with 136 treated brain metastases. Median OS was 13.9 months. Performance status, pre-SRS surgery, and intracranial progression were correlated with OS. Concurrent IT/RT was used in 35 (47.3%) patients. Patients receiving concurrent IT/RT were less likely to have a BRAF mutation (p = 0.027) and more likely to be treated after 2013 (p = 0.010) compared to non-concurrently treated patients. Patients receiving concurrent IT/RT were more likely to have intracranial progression within 60-days (54.3% vs. 30.8%, p = 0.041). However, 25.7% of concurrent IT/RT patients attained ≥ 1 year intracranial progression-free survival. There were no significant differences in symptomatic radionecrosis (11.4% vs. 12.8%, p = 0.67). In conclusion, although melanoma patients with brain metastases receiving concurrent IT/RT were more likely to exhibit early intracranial disease progression, a significant proportion of non-early-progressors attained durable intracranial control. The combination of IT and cranial RT appears to be efficacious and safe. Prospective studies are required to clarify these retrospective findings.

Safety of Combined PD-1 Pathway Inhibition and Intracranial Radiation Therapy in Non-Small Cell Lung Cancer.

INTRODUCTION: Intracranial metastases are a common cause of morbidity and mortality in patients with advanced NSCLC, and are frequently managed with radiation therapy (RT). The safety of cranial RT in the setting of treatment with immune checkpoint inhibitors (ICIs) has not been established. METHODS: We identified patients with advanced NSCLC with brain metastases who received cranial RT and were treated with or without programmed cell death 1/programmed death ligand 1 inhibitors between August 2013 and September 2016. RT-related adverse events (AEs) were retrospectively evaluated and analyzed according to ICI treatment status, cranial RT type, and timing of RT with respect to ICI. RESULTS: Of 163 patients, 50 (31%) received ICIs, whereas 113 (69%) were ICI naive. Overall, 94 (58%), 28 (17%), and 101 (62%) patients received stereotactic radiosurgery, partial brain irradiation, and/or whole brain RT, respectively. Fifty percent of patients received more than one radiation course. We observed no significant difference in rates of all-grade AEs and grade 3 or higher AEs between the ICI-naive and ICI-treated patients across different cranial RT types (grade ≥3 AEs in 8% of ICI-naive patients versus in 9% of ICI-treated patients for stereotactic radiosurgery [p = 1.00] and in 8% of ICI-naive patients versus in 10% of ICI-treated patients for whole brain RT [p = 0.71]). Additionally, there was no difference in AE rates on the basis of timing of ICI administration with respect to RT. CONCLUSIONS: Treatment with an ICI and cranial RT was not associated with a significant increase in RT-related AEs, suggesting that use of programmed cell death 1/programmed death ligand 1 inhibitors in patients receiving cranial RT may have an acceptable safety profile. Nonetheless, additional studies are needed to validate this approach.

Consensus Contouring Guidelines for Postoperative Completely Resected Cavity Stereotactic Radiosurgery for Brain Metastases.

PURPOSE: To propose contouring guidelines based on consensus contours generated by 10 international experts for cavity stereotactic radiosurgery (SRS), an emerging treatment option after surgical resection of brain metastases. No guidelines for contouring the surgical cavity volume have been previously reported. METHODS AND MATERIALS: Ten postoperative completely resected cases with varying clinical scenarios and locations within the brain were selected. For each case, 10 experts independently contoured the surgical cavity clinical target volume (CTV). All the contours were analyzed, and agreement was calculated using the simultaneous truth and performance level estimation (STAPLE) with the kappa statistic. A follow-up survey was also completed by each investigator to summarize their contouring rationale for a number of different clinical scenarios. The results from the survey and the consensus STAPLE contours were both summarized to establish contouring guidelines. RESULTS: A high level of agreement was found between the expert CTV contours (mean sensitivity 0.75, mean specificity 0.98), and the mean kappa was 0.65. The agreement was statistically significant at P<.001 for all cases. From these results and analyses of the survey answers, the recommendations for CTV include fusion of the preoperative magnetic resonance imaging scan to aid in volume delineation; contouring the entire surgical tract regardless of the preoperative location of the tumor; extension of the CTV 5 to 10 mm along the dura overlying the bone flap to account for microscopic disease extension in cases with preoperative dural contact; and a margin of ≤5 mm into the adjacent sinus when preoperative venous sinus contact was present. CONCLUSIONS: Consensus contouring guidelines for postoperative completely resected cavity SRS treatment were established using expert contours and clinical practice. However, in the absence of clinical data supporting these recommendations, these guidelines serve as a baseline for further study and refinement.