Radiation Dose–Volume Effects in the Spinal Cord

Plan evaluation tool for spatially fractionated radiation therapy for unresectable large tumors via spatial biological effective dose modeling in combination therapy

We present the utility of a plan evaluation tool for a multi-course radiation treatment consisting of a highly heterogeneous SFRT plan followed by a course of curative radiation therapy for large and bulky unresectable tumors. For a more accurate plan assessment, this novel method calculates the voxelized biological effective dose (BED) spatially from each course and combines them into a single spatial BED distribution (s-BED). Ten previously treated head and neck (H&N) cancer patients with MLC-based 3D-conformal SFRT (15 Gy in 1 fraction) followed by a curative course of VMAT for 66-70 Gy in 33-35 fractions were retrospectively analyzed using this new s-BED method. The s-BED calculations were based on the standard linear-quadratic (LQ) model. Evaluations of mean BED using this s-BED method were compared to other methodologies that use each course's DVH, mean dose, and prescription dose. From this, tumor control probability (TCP) was calculated using these different methodologies. Lastly, doses to nearby organs at risk (OARs) were evaluated using the s-BED method and compared to each course's physical dose distribution. The OARs evaluated were the spinal cord, brainstem, optic pathway, cochlea, parotid glands, larynx, esophagus, and mandible. From the physical dose distributions, a s-BED distribution and a spatial EQD2 (s-EQD2) distribution were able to be calculated and visualized. The various methods of calculating mean BED using each course's dose prescription, mean dose, DVH, and from the s-BED resulted in varying mean BED: 121.8 Gy, 99.7 Gy, 88.3 Gy, and 100.6 Gy, respectively. In turn, this also gave varying predictions in tumor response: 100.0%, 98.2%, 92.3%, and 91.1%, respectively. Of the 8 H&N patients who received follow-up imaging, 7 (87.5%) had local tumor control. Reported toxicities of this cohort saw 2 cases of grade 3 toxicities (skin desquamation), 3 grade 1 toxicities (oral mucositis and odynophagia), and 1 grade 4 toxicity (necrotizing fasciitis). The composite s-BED distributions provided a means of better understanding the effective biological dose being delivered to both the target and nearby OARs spatially. Future utilization of this method during the treatment planning process may allow for more personalized treatment prescriptions for the SFRT course and the follow-up combination therapy, potentially enhancing therapeutic benefits in managing large and bulky unresectable tumors.

Use of Magnetic Resonance Imaging for Postoperative Radiation Therapy Planning in Patients with Carbon Fiber-Reinforced Polyetheretherketone Instrumentation

PURPOSE

Carbon fiber-reinforced polyetheretherketone (CFR-PEEK) instrumentation is being used more frequently in the spinal oncology landscape. Better visualization with this material allows for more precise postoperative stereotactic body radiation therapy (SBRT) planning using either computed tomography (CT)-myelography or magnetic resonance imaging (MRI) studies. We compared the dosimetric planning equivalencies and outcomes.

METHODS AND MATERIALS

Thirty-six consecutively treated patients were reviewed who underwent spinal fusion using CFR-PEEK instrumentation for spine metastases followed by postoperative SBRT between January 1, 2022, and April 3, 2023. Patients were divided into 2 cohorts based on the imaging modality, MRI versus CT-myelogram, used for postoperative SBRT planning. Surgical, demographic, postoperative radiation dosimetry, complication, and survival data were collected. Statistical analysis was performed in SPSS (v29.0.1.0).

RESULTS

Eleven patients underwent CT-myelograms, and 25 patients underwent MR-spine imaging for SBRT planning. The median follow-up was 145.5 days (13-530). There were no significant differences between baseline demographic, surgical characteristics, or SBRT dosimetry between the MRI spine and CT-myelogram groups. There was no significant difference between the cohorts for survival (P = .402).

CONCLUSIONS

MR scans are an effective choice for postoperative SBRT contouring patients using CFR-PEEK instrumentation for oncologic spinal fusions. Avoidance of CT-myelography reduces the need for an invasive procedure and potential risks including cerebrospinal fluid (CSF) leak, nerve root injury, and increased procedural burden.

Safety and Efficacy of Stereotactic Radiosurgery in the Management of Primary Spinal Cord Glioblastoma: A Case Report

Objective

Primary spinal cord Glioblastoma multiforme (IV grade WHO), also known as Primary Spinal Cord Astrocytoma (SCA), accounts for 6-8% of primary spinal cord tumors and up to 1.5% of all spinal cord tumors. However, owing to their rarity, no large studies or management consensus are available. Gross total resection (GTR) is the best advisable approach; however, in primary spinal tumors, this procedure is not always safe or feasible. Higher radiation doses with conventional radiotherapy (RT) are limited by the spinal cord's radiation tolerance. Stereotactic radiosurgery (SRS) is an effective and safe alternative when administered with adequate real-time simulation and planning to minimize setup errors with risks to the normal spinal cord.

Case Presentation

Herein we present the case of a 32-year-old woman with primary grade IV glioblastoma (GBM) of the spinal cord at cervical C3-C6 (C3-C6) vertebrae level who underwent subtotal resection. The patient presented with neurological impairment in the neck, shoulder, and limbs. Sphincteric dysfunction and hyperaesthesia on the chest were also recorded. As adjuvant therapy, SRS with a dose of 14 Gy to the PTV was administered, ensuring a Dmax of 12 Gy to the spinal cord. Patient was treated in the same day of simulation and planning; hence, no set-up discrepancies were recorded on Cone Beam CT (CBCT) images during the RT delivery. Two days after SRS, the patient's neurological symptoms improved with recovery of neck and shoulder motor functions followed by weak upper limb activity. Afterwards, 6 cycles of temozolomide were administered.

Conclusion

We described a case of grade IV glioblastoma multiforme after partial resection, that was safely treated with adjuvant SRS in real-time with simulation and planning. This modality could improve the safety of SRS in the treatment of such tumors.

SPECT/CT Dosimetry of Bronchial Artery 99mTc Macroaggregated Albumin Injection in Pulmonary Malignancies: Feasibility Evaluation of Bronchial Artery 90Y Radioembolization

Background External beam radiation therapy for primary and secondary pulmonary malignancies has limited utility for treating ultracentral tumors (ie, adjacent to the proximal bronchial tree or heart) or multiple metastases due to either radiation to central organs at risk (OARs) or extensive lung tissue exposure. Bronchial artery yttrium 90 (90Y) radioembolization may be a therapeutic option for these patients. Purpose To evaluate the feasibility of bronchial artery 90Y radioembolization using technetium 99m (99mTc) macroaggregated albumin (MAA) injection as a surrogate for 90Y microspheres and to use SPECT/CT dosimetry to assess 99mTc-MAA distribution and calculated anticipated 90Y doses to tumors and OARs. Materials and Methods In this prospective clinical trial, study participants with either primary lung cancer or pulmonary metastases were enrolled between August 2020 and October 2023 from a single academic medical center. All participants underwent bronchial artery embolization for malignancy-induced hemoptysis prophylaxis. 99mTc-MAA was injected via bronchial arteries, followed by bland embolization. SPECT/CT imaging and Monte Carlo simulations were used to evaluate 99mTc-MAA distribution and predict 90Y doses. Predicted 90Y doses to tumors and OARs are reported as means ± SDs. Results Eight participants (mean age, 63.0 years ± 13.58; six [75%] male participants) were included. All had ultracentral tumors, and four had four or more tumors. SPECT/CT revealed a concentrated 99mTc-MAA accumulation in tumors, with a mean tumor-to-normal tissue ratio of 22.71 ± 20.17. Simulations indicated that a 90Y biologically effective dose (α/β ratio of 10 Gy) of 175.7-3173.6 Gy (mean, 778.8 Gy ± 981.9) could be delivered to all tumors while remaining under OAR toxicity thresholds. Conclusion SPECT/CT dosimetric analysis of 99mTc-MAA injected via the bronchial artery for pulmonary malignancy suggests that bronchial artery 90Y radioembolization is feasible and could be an alternative treatment for patients unable to receive external beam radiation therapy. ClinicalTrials.gov Identifier: NCT04105283 © RSNA, 2025 Supplemental material is available for this article.

Optimising (re-)irradiation for locally recurrent head and neck cancer: impact of dose-escalation, salvage surgery, PEG tube and biomarkers on oncological outcomes-a single centre analysis

INTRODUCTION

Locoregional recurrence (LR) is common in locally advanced head and neck cancer (HNSCC), posing challenges for treatment. We analysed outcome parameters and toxicities for patients being treated with radiotherapy (RT) for LR-HNSCC and investigated patient and disease related prognostic factors in this prognostically unfavourable group.

METHODS

This analysis includes 101 LR-HNSCC patients treated with RT, radio-chemotherapy (RCT) or radio-immunotherapy (RIT) between 2010 and 2018 at a high-volume tertiary centre. Patient characteristics, tumour and treatment details were retrospectively collected. Overall survival (OS), progression-free survival (PFS) and toxicities according to Common Terminology Criteria for Adverse Events (CTCAE) v5.0 were assessed.

RESULTS

62% of patients were radiotherapy-naïve (initial RT group) while 38% were re-irradiated at site of LR (re-RT group). Median OS for initial RT was 24 months, for re-RT 12 months (p < 0.01). In the RCT subgroup, patients with initial RT had significantly longer OS with 35 months compared to re-RT 12 months (p < 0.05). Patients with UICC grade IV tumours and percutaneous endoscopic gastrostomy (PEG) tube had significantly shorter OS in multivariate analysis: initial RT 13 vs. re-RT 32 months and initial RT 12 vs. re-RT 32 months respectively. Salvage surgery before RT at recurrence was a positive prognostic factor for OS (initial RT 35 vs. re-RT 12 months). Other significant factors for longer OS in univariate analysis included low inflammatory status (Glasgow Prognostic Score 0) and radiation doses ≥ 50 Gy. We detected 37 (15%) ≥ CTCAE Grade 3 events for initial RT and 19 (15%) for re-RT patients.

CONCLUSION

In this analysis, we identified key prognostic factors including PEG tube and inflammation status that could guide treatment decision. Our findings suggest salvage surgery as preferred treatment option with postoperative RT at LR. Adverse events due to re-RT were acceptable. A radiation dose of ≥ 50 Gy should be administered to achieve better outcomes.

Dosimetric consequences of adapting the craniocaudal isocenter distance to daily patient position in craniospinal irradiation using volumetric modulated arc therapy

PURPOSE

In craniospinal irradiation, two or three isocenter groups along the craniocaudal axis are required to cover the long treatment target. Adapting the isocenter distance according to daily deviations in patient position is challenging because dosimetric hot or cold spots may occur in the field junction. The aim of this study was to quantify the effect of adapting the isocenter distance to patient position on the dose distribution of the field overlap region in craniospinal irradiation using partial-arc volumetric modulated arc therapy.

METHODS

The magnitude of isocenter distance deviations in craniocaudal direction was quantified by registering the setup images of 204 fractions of 12 patients to the planning images. The dosimetric effect of these deviations was determined by shifting the isocenters of the original treatment plan and calculating the resulting dose distribution.

RESULTS

On fraction-level, deviations larger than 3 mm caused more than 5 percentage point changes in the doses covering 2% (D2%) and 98% (D98%) of the junction volume in several patients. On treatment course-level, the changes in D2% and D98% of the junction volume were less than 5 percentage points in all cases except for one patient.

CONCLUSIONS

Craniocaudal isocenter distance adaptation can be conducted provided that the mean isocenter distance deviation over the treatment course is within 3 mm.

Fractionated reirradiation of recurrent high-grade gliomas: Safety with higher reirradiation dose and larger targets

Background

The optimal regimen, normal tissue tolerances, and appropriate indications for reirradiation for recurrent high-grade glioma (HGG) are uncertain. The aim of this study was to determine whether higher reirradiation dose was associated with toxicity or survival.

Methods

Patients with HGG treated with fractionated reirradiation at a single institution from 2007 to 2022 were retrospectively reviewed. Metrics evaluated included overall survival (OS), prognostic factors for survival, and treatment-related toxicity.

Results

Two hundred and thirty patients with recurrent HGG were reviewed. Median follow-up was 8.8 months. Median reirradiation dose was 41.4 Gy with 80.4% receiving concurrent systemic therapy. Median cumulative maximum doses to brainstem and optic structures were 77.9 Gy (range: 4.6-146.0 Gy) and 55.1 Gy (3.3-106.3 Gy), respectively. No injuries to these structures were identified. Radiation necrosis (RN) was identified in 9.4%. There were no significant associations between RN and target size, systemic therapy use, or reirradiation dose. Median OS was 10.2 months from reirradiation start. On multivariate analysis, improved OS was associated with better KPS, longer interval between radiotherapy sessions, reirradiation at first recurrence, and reirradiation dose ≥ 41.4 Gy. Median OS for those with IDH wildtype glioblastoma was 8.7 months. On multivariate analysis of an IDH wildtype disease subanalysis, improved OS was associated with longer interval between radiotherapy sessions and higher reirradiation dose.

Conclusions

These data support the safety and efficacy of fractionated reirradiation for recurrent HGG. They suggest higher reirradiation dose may be feasible, including for large treatment volumes and for tumors near the brainstem or optic structures.

Multicriteria optimization achieves superior normal tissue sparing in volumetric modulated arc therapy for gastric cancer

OBJECTIVE

To evaluate the benefits of volumetric modulated arc therapy (VMAT) based on multicriteria optimization (MCO) for gastric cancer patients, particularly the protection of serial organs at risk (OARs) that overlap with the target volume.

METHODS

MCO and single-criterion optimization (SCO) VMAT plans were conducted among 30 gastric cancer patients, with a prescription dose of 50.4 Gy delivered in 28 fractions. All treatment plans underwent review, and a comparison was made between the active planning time and different dose-volume parameters.

RESULTS

Both the MCO and SCO VMAT plans achieved the target dose coverage, with no significant difference in the conformity index (CI) for the planning target volume (PTV), at median CI values of 0.887 and 0.891, respectively (P = 0.417). The MCO plans showed a slight but significant increase in the homogeneity index of the PTV, with a median increase of 0.029 (P < 0.001). Additionally, the MCO plans resulted in a lower D2% to the small intestine and duodenum, with reductions of 3.43 Gy and 0.3 Gy, respectively (P < 0.05). Furthermore, the Dmax to the small intestine correlated moderately with the overlapping volume between the small intestine and the target volume (ρ = 0.42, P = 0.023). Except for the mean dose to the liver, the MCO plans performed better in terms of dose indicators for other OARs. Moreover, compared to the SCO plans, the median active planning time in the MCO plans was significantly reduced by 53.2 min (P < 0.0001).

CONCLUSIONS

MCO can effectively help the physicians to quickly select an optimal treatment plan for patients with gastric cancer. It has been shown that MCO VMAT plans can significantly reduce the dose to OARs and shorten the active planning time, with acceptable target coverage. In addition, these plans take less dosimetric time, thereby streamlining the treatment planning process.

Surgical options for metastatic spine tumors: WFNS spine committee recommendations

Surgical treatments for metastatic spine tumors have evolved tremendously over the last decade. Improvements in immunotherapies and other medical treatments have led to longer life expectancy in cancer patients. This, in turn, has led to an increase in the incidence of metastatic spine tumors. Spine metastases remain the most common type of spine tumor. In this study, we systematically reviewed all available literature on metastatic spine tumors and spinal instability within the last decade. We also performed further systematic reviews on cervical metastatic tumors, thoracolumbar metastatic tumors, and minimally invasive surgery in metastatic spine tumors. Lastly, the results from the systematic reviews were presented to an expert panel at the World Federation of Neurosurgical Societies (WFNS) meeting, and their consensus was also presented.

Recurrence of Solitary Fibrous Tumor in the Spinal Cord Following Gross Total and Subtotal Resection: A Case Report of Recurrence 19 Years of Post-total Resection and Systematic Literature Review

Spinal cord solitary fibrous tumors (SFTs), previously known as hemangiopericytoma (HPC), represent exceedingly rare neoplasms. Strategies for their management, such as appropriate follow-up duration, remain controversial due to their propensity for recurrence despite extended periods of quiescence. We report a 51-year-old male presenting with new-onset back pain and gait disturbances, who had undergone gross total resection (GTR) of an SFT within the thoracic spinal cord 19 years ago. Magnetic resonance imaging of the thoracic spine revealed recurrent tumors at the T7 level within the spinal cord. Subsequent resection achieved GTR. A comprehensive literature review was undertaken to assess the benefits of different resection extents (gross total removal (GTR) vs. subtotal removal (STR)), adjuvant radiation therapy, and the optimal duration of postoperative follow-up. Since 1960, 46 cases, including the present one, have reported recurrent spinal SFT/HPC following GTR and STR. Statistical analyses demonstrated that neither the type of resection nor adjuvant radiation therapy significantly impacted median recurrence-free survival in this cohort. Given their unpredictable behavior, meticulous lifelong follow-up following successful resection appears crucial for managing these tumors effectively.

Evaluation of Radiation Therapy Treatment Plans in a Randomized Phase 2 Trial Comparing 2 Schedules of Twice-Daily Thoracic Radiation Therapy in Limited Stage Small Cell Lung Cancer

PURPOSE

There is limited clinical data for recommendations on how to deliver thoracic radiation therapy (TRT) concurrently with chemotherapy in limited-stage small cell lung cancer. We reviewed radiation therapy treatment plans in a randomized phase 2 trial comparing high-dose with standard-dose twice-daily TRT to assess treatment planning techniques, dose-volume data for target volumes and organs at risk (OARs), evaluate compliance with the protocol, associations with radiation-induced toxicity, and whether an imbalance in treatment planning parameters might be a reason for the large survival benefit of the higher dose (median overall survival 43.6 vs 22.6 months).

METHODS AND MATERIALS

In the study, 170 patients were to receive 4 courses of platinum/etoposide and were randomized to receive twice-daily TRT of 60 Gy/40 fractions (fx) or 45 Gy/30 fx. TRT treatment plans for those who received 1 or more fx of TRT (n = 166) were analyzed.

RESULTS

The most common treatment planning technique was 3-dimensional conformal radiation therapy (67%). The 75th percentile of the reported dose-volume parameters for the OARs were within the protocol-recommended limits for both groups. Mean doses to the esophagus of 25.5 Gy (IQR, 20.2-31.3; 60 Gy/40 fx) and 24.3 Gy (IQR, 20.3-27.5; 45 Gy/30 fx) were associated with 21% and 18% ≥ grade 3 acute esophagitis, respectively. In the 60 Gy/40 fx group, a mean dose to the lungs of 16.5 Gy (IQR, 15.8-16.9), V20 Gy of 29.5% (IQR, 28.8-30.4), and V5 Gy of 65.6% (IQR, 61.5-68.7) led to ≥ grade 3 pneumonitis in 4% of the patients. There was no ≥ grade 3 pneumonitis in the 45 Gy/30 fx group. The treatment planning techniques, the percentage change in volumes between original and redelineated OARs, planning target volumes, relative doses, and laterality were well balanced between the randomly assigned groups.

CONCLUSIONS

Considering the incidences of severe radiation-induced toxicities were within the range of other recent trials, the reported doses to the OARs appear to be safe. Treatment planning parameters were well balanced between the randomly assigned groups, supporting that the survival benefit of the twice-daily 60 Gy/40 fx TRT schedule was due to the higher dose.

Fractionated radiotherapy for spinal tumors: A literature review regarding spinal glioma, ependymoma, and meningioma

Radiation therapy plays a vital role in the management of primary spinal tumors in adults. However, due to the rarity of these tumor types, the literature on optimal treatment indications and radiation doses is limited. Many treatment recommendations are extrapolated from their cranial counterparts, where more data are available. Despite the absence of prospective data, numerous retrospective studies have provided valuable insights to guide treatment decisions until more comprehensive data become available. This review provides an overview of the most relevant literature, with a specific focus on spinal gliomas, ependymomas, and meningiomas, in the context of the role of radiation therapy.

Primary spinal cord glioblastoma multiforme: a single-center experience

INTRODUCTION

Primary spinal glioblastoma (GBM) are very rare tumors of the spinal cord, with dismal prognosis and their exact management is controversial. We attempt to formulate treatment guidelines for these extremely rare tumors based on our institutional experience and a comprehensive review of the literature.

MATERIALS AND METHODS

In this retrospective study from 2008 to 2020, all the patients diagnosed with primary spinal GBM who underwent surgery at our institution were included. Clinical data were retrieved from case files, outpatient records and telephonic follow-up. Data on postoperative chemoradiation was noted in all the patients. The final diagnosis of spinal GBM was confirmed as per the histopathology reports. Patients who could not be followed up and those with prior history of cranial GBM were excluded from the study.

RESULTS

Nine patients were followed up and a median survival of 11 months was noted. Chemotherapy with TMZ and radiotherapy to the whole craniospinal axis significantly improved survival in these patients. The extent of surgical resection was not shown to be significant. Intracranial metastasis was the leading cause of mortality in such patients. Three patients developed documented intracranial metastasis during the course of the disease.

CONCLUSIONS

Low threshold must be kept in mind in diagnosing patients with high-grade spinal cord intramedullary tumors in view of the rapidly progressing nature of the disease. In case of positive histopathological diagnosis of spinal GBM, the whole craniospinal axis should be imaged and any cranial metastasis which was originally missed during initial workup could be given appropriate radiotherapy.

Stereotactic Body Radiotherapy for Centrally Located Inoperable Early-Stage NSCLC: EORTC 22113-08113 LungTech Phase II Trial Results

INTRODUCTION

The international phase II single-arm LungTech trial 22113-08113 of the European Organization for Research and Treatment of Cancer assessed the safety and efficacy of stereotactic body radiotherapy (SBRT) in patients with centrally located early-stage NSCLC.

METHODS

Patients with inoperable non-metastatic central NSCLC (T1-T3 N0 M0, ≤7cm) were included. After prospective central imaging review and radiation therapy quality assurance for any eligible patient, SBRT (8 × 7.5 Gy) was delivered. The primary endpoint was freedom from local progression probability three years after the start of SBRT.

RESULTS

The trial was closed early due to poor accrual related to repeated safety-related pauses in recruitment. Between August 2015 and December 2017, 39 patients from six European countries were included and 31 were treated per protocol and analyzed. Patients were mainly male (58%) with a median age of 75 years. Baseline comorbidities were mainly respiratory (68%) and cardiac (48%). Median tumor size was 2.6 cm (range 1.2-5.5) and most cancers were T1 (51.6%) or T2a (38.7%) N0 M0 and of squamous cell origin (48.4%). Six patients (19.4%) had an ultracentral tumor location. The median follow-up was 3.6 years. The rates of 3-year freedom from local progression and overall survival were 81.5% (90% confidence interval [CI]: 62.7%-91.4%) and 61.1% (90% CI: 44.1%-74.4%), respectively. Cumulative incidence rates of local, regional, and distant progression at three years were 6.7% (90% CI: 1.6%-17.1%), 3.3% (90% CI: 0.4%-12.4%), and 29.8% (90% CI: 16.8%-44.1%), respectively. SBRT-related acute adverse events and late adverse events ≥ G3 were reported in 6.5% (n = 2, including one G5 pneumonitis in a patient with prior interstitial lung disease) and 19.4% (n = 6, including one lethal hemoptysis after a lung biopsy in a patient receiving anticoagulants), respectively.

CONCLUSIONS

The LungTech trial suggests that SBRT with 8 × 7.5Gy for central lung tumors in inoperable patients is associated with acceptable local control rates. However, late severe adverse events may occur after completion of treatment. This SBRT regimen is a viable treatment option after a thorough risk-benefit discussion with patients. To minimize potentially fatal toxicity, careful management of dose constraints, and post-SBRT interventions is crucial.

Assessment of Organ-at-risk Sparing in Esophageal Cancer: A Comparative Dosimetric Evaluation of Hybrid, Noncoplanar, and Coplanar RapidArc Plans

Aim

The purpose of this study is to improve the precision of radiation treatment and sparing of organ-at-risk (OAR) in patients with thoracic esophageal cancer (EC) affecting the heart, lung, and spinal cord. To improve and personalize cancer treatment plans, it assesses the dosimetric benefits of coplanar RapidArc (RAc), hybrid arc (RAHyb), and noncoplanar RapidArc (RAnc).

Materials and Methods

Fourteen patients with EC were chosen for our investigation from our hospital's database. RapidArc (RA) plan patients had already received treatment. Retrospectively, additional RAnc and RAHyb plans were made with a prescription dose of 50.4 Gy in 28 fractions for the planning target volume (PTV). A prescription dose of 95% of PTV was used, so that three different treatment planning procedures could be compared. The cumulative dose-volume histogram was used to analyze the plan quality indices homogeneity index (HI), conformity index (CI), conformation number (CN) as well as the OARs doses to the lung, heart, and spinal cord.

Results

In comparison to RAc and RAnc techniques, the study indicated that RAHyb plans significantly increased D95%, CI and HI; Dmax and CN did not differ substantially. In addition, compared to RAc (lung: 16.15 ± 0.03 Gy and heart: 23.91 ± 4.67 Gy) and RAnc (lung: 15.24 ± 0.03 Gy and heart 23.82 ± 5.10 Gy) plans, RAHyb resulted in significantly lower mean lung doses (15.10 ± 0.03 Gy) and heart doses (21.33 ± 6.99 Gy). Moreover, the RAHyb strategy showed a statistically significant (P < 0.05) lower average MU (452.7) than both the RAc (517.5) and RAnc (566.2) plans.

Conclusion

The D95%, conformity, and homogeneity indices were better for hybrid arc plans compared to RAc and RAnc plans. They also successfully managed to reduce the lung and heart doses as well as the mean MU per fraction.

Feasibility and flexibility of a novel multi-dose level avoidance reirradiation technical methodology in recurrent head and neck cancer

Reirradiation in recurrent head and neck cancer presents a considerable clinical challenge in radiation oncology. Though technically feasible due to advanced treatment delivery and planning techniques, confidence in delivering such treatments is not universal and patient selection is critical. Radiotherapy planning in reirradiation cases presents a complex technical challenge owing to the often-considerable overlap of dose from a patient's first treatment plan. This technical note describes three clinical case studies of recurrent head and neck cancer and the technical details of how their multidose level reirradiation was planned. Each patient had confirmed recurrence of squamous cell carcinoma and was referred for reirradiation to a previously irradiated area. The clinical details for each patient are provided before a detailed description of the treatment planning methodology is presented, which specifies how to approach such complex overlapping treatment volumes. The patient outcomes are described and a discussion is presented outlining the clinical challenges associated with these cases and the variables that must be accounted for when considering patients for potential reirradiation.

Comparison of Risks of Late Effects From Radiation Therapy in Children Versus Adults: Insights From the QUANTEC, HyTEC, and PENTEC Efforts

Pediatric Normal Tissue Effects in the Clinic (PENTEC) seeks to refine quantitative radiation dose-volume relationships for normal-tissue complication probabilities (NTCPs) in survivors of pediatric cancer. This article summarizes the evolution of PENTEC and compares it with similar adult-focused efforts (eg, Quantitative Analysis of Normal Tissue Effects in the Clinic [QUANTEC] and Hypofractionated Treatment Effects in the Clinic [HyTEC]) with respect to content, oversight, support, scope, and methodology of literature review. It then summarizes key organ-specific findings from PENTEC in an attempt to compare NTCP estimates in children versus adults. In brief, select normal-tissue risks within developing organs and tissues (eg, maldevelopment of musculoskeletal tissue, teeth, breasts, and reproductive organs) are primarily relevant only in children. For some organs and tissues, children appear to have similar (eg, brain for necrosis, optic apparatus, parotid gland, liver), greater (eg, brain for neurocognition, cerebrovascular, breast for lactation), less (ovary), or perhaps slightly less (eg, lung) risks of toxicity versus adults. Similarly, even within the broad pediatric age range (including adolescence), for some endpoints, younger children have greater (eg, hearing and brain for neurocognition) or lesser (eg, ovary, thyroid) risks of radiation-associated toxicities. NTCP comparisons in adults versus children are often confounded by marked differences in treatment paradigms that expose normal tissues to radiation (ie, cancer types, prescribed radiation therapy dose and fields, and chemotherapy agents used). To add to the complexity, it is unclear if age is best analyzed as a continuous variable versus with age groupings (eg, infants, young children, adolescents, young adults, middle-aged adults, older adults). Further work is needed to better understand the complex manner in which age and developmental status affect risk.

Brain and Brain Stem Necrosis After Reirradiation for Recurrent Childhood Primary Central Nervous System Tumors: A PENTEC Comprehensive Review

PURPOSE

Reirradiation is increasingly used in children and adolescents/young adults (AYA) with recurrent primary central nervous system tumors. The Pediatric Normal Tissue Effects in the Clinic (PENTEC) reirradiation task force aimed to quantify risks of brain and brain stem necrosis after reirradiation.

METHODS AND MATERIALS

A systematic literature search using the PubMed and Cochrane databases for peer-reviewed articles from 1975 to 2021 identified 92 studies on reirradiation for recurrent tumors in children/AYA. Seventeen studies representing 449 patients who reported brain and brain stem necrosis after reirradiation contained sufficient data for analysis. While all 17 studies described techniques and doses used for reirradiation, they lacked essential details on clinically significant dose-volume metrics necessary for dose-response modeling on late effects. We, therefore, estimated incidences of necrosis with an exact 95% CI and qualitatively described data. Results from multiple studies were pooled by taking the weighted average of the reported crude rates from individual studies.

RESULTS

Treated cancers included ependymoma (n = 279 patients; 7 studies), medulloblastoma (n = 98 patients; 6 studies), any CNS tumors (n = 62 patients; 3 studies), and supratentorial high-grade gliomas (n = 10 patients; 1 study). The median interval between initial and reirradiation was 2.3 years (range, 1.2-4.75 years). The median cumulative prescription dose in equivalent dose in 2-Gy fractions (EQD22; assuming α/β value = 2 Gy) was 103.8 Gy (range, 55.8-141.3 Gy). Among 449 reirradiated children/AYA, 22 (4.9%; 95% CI, 3.1%-7.3%) developed brain necrosis and 14 (3.1%; 95% CI, 1.7%-5.2%) developed brain stem necrosis with a weighted median follow-up of 1.6 years (range, 0.5-7.4 years). The median cumulative prescription EQD22 was 111.4 Gy (range, 55.8-141.3 Gy) for development of any necrosis, 107.7 Gy (range, 55.8-141.3 Gy) for brain necrosis, and 112.1 Gy (range, 100.2-117 Gy) for brain stem necrosis. The median latent period between reirradiation and the development of necrosis was 5.7 months (range, 4.3-24 months). Though there were more events among children/AYA undergoing hypofractionated versus conventionally fractionated reirradiation, the differences were not statistically significant (P = .46).

CONCLUSIONS

Existing reports suggest that in children/AYA with recurrent brain tumors, reirradiation with a total EQD22 of about 112 Gy is associated with an approximate 5% to 7% incidence of brain/brain stem necrosis after a median follow-up of 1.6 years (with the initial course of radiation therapy being given with conventional prescription doses of ≤2 Gy per fraction and the second course with variable fractionations). We recommend a uniform approach for reporting dosimetric endpoints to derive robust predictive models of late toxicities following reirradiation.

Re-irradiation spine stereotactic body radiotherapy following high-dose conventional radiotherapy for metastatic epidural spinal cord compression: a retrospective study

PURPOSE

 We aimed to evaluate the efficacy and safety of re-irradiation stereotactic body radiation therapy (SBRT) in patients with metastatic epidural spinal cord compression (MESCC) following high-dose conventional radiotherapy.

MATERIALS AND METHODS

 Twenty-one patients met the following eligibility criteria: with an irradiation history of 50 Gy2 equivalent dose in 2-Gy fractions (EQD2) or more, diagnosed MESCC in the cervical or thoracic spines, and treated with re-irradiation SBRT of 24 Gy in 2 fractions between April 2018 and March 2023. Prior treatment was radiotherapy alone, not including surgery. The primary endpoint was a 1-year local failure rate. Overall survival (OS) and treatment-related adverse events were assessed as the secondary endpoints. Since our cohort includes one treatment-related death (TRD) of esophageal perforation, the cumulative esophageal dose was evaluated to find the dose constraints related to severe toxicities.

RESULTS

 The median age was 68, and 14 males were included. The primary tumor sites (esophagus/lung/head and neck/others) were 6/6/7/2, and the median initial radiotherapy dose was 60 Gy2 EQD2 (range: 50-105 Gy2, 60-70/ > 70 Gy2 were 11/4). Ten patients underwent surgery followed by SBRT and 11 SBRT alone. At the median follow-up time of 10.4 months, 17 patients died of systemic disease progression including one TRD. No radiation-induced myelopathy or nerve root injuries occurred. Local failure occurred in six patients, with a 1-year local failure rate of 29.3% and a 1-year OS of 55.0%. Other toxicities included five cases of vertebral compression fractures (23.8%) and one radiation pneumonitis. The cumulative esophageal dose was recommended as follows: Dmax < 203, D0.035 cc < 187, and D1cc < 167 (Gy3 in biological effective dose).

CONCLUSION

 Re-irradiation spine SBRT may be effective for selected patients with cervical or thoracic MESCC, even with high-dose irradiation histories. The cumulative dose assessment across the original and re-irradiated esophagus was recommended to decrease the risk of severe esophageal toxicities.

Predictive Factors Associated With Radiation Myelopathy in Pediatric Patients With Cancer: A PENTEC Comprehensive Review

PURPOSE

Radiation myelitis (RM) is a rare complication of radiation therapy (RT). The Pediatric Normal Tissue Effects in the Clinic spinal cord task force aimed to identify RT dose effects and assess risk factors for RM in children. Through systematic review, we analyzed RT dose, fraction size, latency between completion of RT and toxicity, chemotherapy use, age when irradiated, and sex.

METHODS AND MATERIALS

We conducted literature searches of peer-reviewed manuscripts published from 1964 to June 2017 evaluating RM among children. Normality of variables was assessed with Kolmogorov-Smirnov or Shapiro-Wilk tests. Spearman's rank correlation coefficients were used to test correlations between RT dose/fraction size and latency between RT and development of toxicity.

RESULTS

Of 1329 identified and screened reports, 144 reports were fully reviewed and determined to have adequate data for analysis; 16 of these reports had a total of 33 cases of RM with a median age of 13 years (range, 0.2-18) at the time of RT. The most common primary tumor histologies were rhabdomyosarcoma (n = 9), medulloblastoma (n = 5), and Hodgkin lymphoma (n = 2); the most common chemotherapy agents given were vincristine (n = 15), intrathecal methotrexate (n = 12), and intrathecal cytarabine (n = 10). The median RT dose and fraction size were 40 Gy (range, 24-57.4 Gy) and 1.8 Gy (range, 1.3-2.6 Gy), respectively. RT dose resulting in RM in patients who also received chemotherapy was lower than in those not receiving chemotherapy (mean 39.6 vs 49.7 Gy; P = .04). There was no association of age with RT dose. The median latency period was 7 months (range, 1-29). Higher RT dose was correlated with longer latency periods (P = .03) to RM whereas sex, age, fraction size, and chemotherapy use were not. Two of 17 patients with adequate follow-up recovered from RM; unfortunately, it was fatal in 6 of 15 evaluable patients. Complication probability modeling was not possible because of the rarity of events.

CONCLUSIONS

This report demonstrates a relatively short latency from RT (with or without chemotherapy) to RM and a wide range of doses (including fraction sizes) associated with RM. No apparent association with age at the time of RT could be discerned. Chemotherapy appears to reduce spinal cord tolerance. Recovery from RM is rare, and it is often fatal.

Neurological complications of modern radiotherapy for head and neck cancer

Radiotherapy is one of the mainstay treatment modalities for the management of non-metastatic head and neck cancer (HNC). Notable improvements in treatment outcomes have been observed in the recent decades. Modern radiotherapy techniques, such as intensity-modulated radiotherapy and charged particle therapy, have significantly improved tumor target conformity and enabled better preservation of normal structures. However, because of the intricate anatomy of the head and neck region, multiple critical neurological structures such as the brain, brainstem, spinal cord, cranial nerves, nerve plexuses, autonomic pathways, brain vasculature, and neurosensory organs, are variably irradiated during treatment, particularly when tumor targets are in close proximity. Consequently, a diverse spectrum of late neurological sequelae may manifest in HNC survivors. These neurological complications commonly result in irreversible symptoms, impair patients' quality of life, and contribute to a substantial proportion of non-cancer deaths. Although the relationship between radiation dose and toxicity has not been fully elucidated for all complications, appropriate application of dosimetric constraints during radiotherapy planning may reduce their incidence. Vigilant surveillance during the course of survivorship also enables early detection and intervention. This article endeavors to provide a comprehensive review of the various neurological complications of modern radiotherapy for HNC, summarize the current incidence data, discuss methods to minimize their risks during radiotherapy planning, and highlight potential strategies for managing these debilitating toxicities.

Brain Re-Irradiation Or Chemotherapy: a phase II randomised trial of re-irradiation and chemotherapy in patients with recurrent glioblastoma (BRIOChe) - protocol for a multi-centre open-label randomised trial

INTRODUCTION

Glioblastoma (GBM) is the most common adult primary malignant brain tumour. The condition is incurable and, despite aggressive treatment at first presentation, almost all tumours recur after a median of 7 months. The aim of treatment at recurrence is to prolong survival and maintain health-related quality of life (HRQoL). Chemotherapy is typically employed for recurrent GBM, often using nitrosourea-based regimens. However, efficacy is limited, with reported median survivals between 5 and 9 months from recurrence. Although less commonly used in the UK, there is growing evidence that re-irradiation may produce survival outcomes at least similar to nitrosourea-based chemotherapy. However, there remains uncertainty as to the optimum approach and there is a paucity of available data, especially with regards to HRQoL. Brain Re-Irradiation Or Chemotherapy (BRIOChe) aims to assess re-irradiation, as an acceptable treatment option for recurrent IDH-wild-type GBM.

METHODS AND ANALYSIS

BRIOChe is a phase II, multi-centre, open-label, randomised trial in patients with recurrent GBM. The trial uses Sargent's three-outcome design and will recruit approximately 55 participants from 10 to 15 UK radiotherapy sites, allocated (2:1) to receive re-irradiation (35 Gy in 10 daily fractions) or nitrosourea-based chemotherapy (up to six, 6-weekly cycles). The primary endpoint is overall survival rate for re-irradiation patients at 9 months. There will be no formal statistical comparison between treatment arms for the decision-making primary analysis. The chemotherapy arm will be used for calibration purposes, to collect concurrent data to aid interpretation of results. Secondary outcomes include HRQoL, dexamethasone requirement, anti-epileptic drug requirement, radiological response, treatment compliance, acute and late toxicities, progression-free survival.

ETHICS AND DISSEMINATION

BRIOChe obtained ethical approval from Office for Research Ethics Committees Northern Ireland (reference no. 20/NI/0070). Final trial results will be published in peer-reviewed journals and adhere to the ICMJE guidelines.

TRIAL REGISTRATION NUMBER

ISRCTN60524.

A comparative dose-escalation analysis for reirradiated cancer patients with and without appropriate dose mapping

This study aims to compare dose escalation between two groups of reirradiated cancer patients, one with the previous contour and radiotherapy plan available on the treatment planning system and the other without. First group is identified as DICOM-group, while the other one is called non-DICOM group. The current study included 89 patients, 57 in the DICOM, and 32 in the non-DICOM group, who received reirradiation for recurrent or second primary tumours between 2019 and 2021. For the DICOM group, doses to 0.2cc volume for spine, brainstem, and optic apparatus from first radiation were converted into structures and transferred to reirradiation CT using deformable registration. First, one radiotherapy plan was created using the doctor prescribed dose (baseline prescription RxD_B); further an escalated dose (RxD_E) plan, taking into account all the dose volume parameters from previous radiation, was created only for DICOM group. In non-DICOM group patients were planned only for RxD_B. The maximum accepted dose escalation was 21 Gy. Radiotherapy prescription dose during earlier (first) treatment in DICOM and non-DICOM groups were 61 ± 5.6 Gy and 30-66 Gy, respectively. DICOM and non-DICOM groups had nearly identical baseline doses: 52.5 ± 10.7 Gy and 50.6 ± 6.9 Gy (difference 1.9 ± 12.7 Gy). Dose escalation was possible for 51 out of 57 patients in the DICOM-group. Average escalated dose in DICOM-group was 59.2 ± 6.2 Gy, with an incremental dose of 6.7 ± 12.4 Gy from the baseline prescription. No dose escalation was opted for in the non-DICOM group due to the unavailability of dose volume information from previous radiation. Reirradiation for head and neck cases allowed for a moderate to high dose escalation, facilitated by the presence of pertinent DICOM information from the initial radiotherapy.

Practice and principles of stereotactic body radiation therapy for spine and non-spine bone metastases

Radiotherapy is the dominant treatment modality for painful spine and non-spine bone metastases (NSBM). Historically, this was achieved with conventional low dose external beam radiotherapy, however, stereotactic body radiotherapy (SBRT) is increasingly applied for these indications. Meta-analyses and randomized clinical trials have demonstrated improved pain response and more durable tumor control with SBRT for spine metastases. However, in the setting of NSBM, there is limited evidence supporting global adoption and large scale randomized clinical trials are in need. SBRT is technically demanding requiring careful consideration of organ at risk tolerance, and strict adherence to technical requirements including immobilization, simulation, contouring and image-guidance procedures. Additional considerations include follow up practices after SBRT, with appropriate imaging playing a critical role in response assessment. Finally, there is renewed research into promising new technologies that may further refine the use of SBRT in both spinal and NSBM in the years to come.

Efficacy of flattening filter-free beams with the acuros XB algorithm in thoracic spine stereotactic body radiation therapy

This study aimed to determine the dosimetric value of flattening filter-free (FFF) beams compared to flattening filter (FF) beams using different algorithms in the treatment planning of thoracic spine stereotactic body radiation therapy (SBRT). A total of 120 plans were created for 15 patients using the Anisotropic Analytical Algorithm (AAA) and the Acuros External Beam (AXB) algorithm with FF and FFF beams at 6 MV and 10 MV energies. Various dosimetric parameters were evaluated, including target coverage, dose spillage, and organs-at-risk sparing of the spinal cord and esophagus. Treatment delivery parameters, such as the monitor units (MUs), modulation factors (MFs), beam-on time (BOT), and dose calculation time (DCT), were also collected. Significant differences were observed in the dosimetric parameters when AXB was used for all energies (P < 0.05). 6 XFFF energy was the best option for target coverage, dose spillage, and organs-at-risk sparing. In contrast, dosimetric parameters had no significant difference when using the AAA. The AAA and AXB calculations showed that the 6 XFFF beam had the shortest DCT. The treatment delivery parameters indicated that 10 XFF beam required the fewest MUs and MFs. In addition, the 10 XFFF beam demonstrated the shortest BOT. For effective treatment of the thoracic spine using SBRT, it is recommended to use the 10 XFFF beam because of the short BOT. Moreover, the AXB algorithm should be used because of its accurate dose calculation in regions with tissue heterogeneity.

Efficacy and safety analysis of stereotactic body radiotherapy for brain multi-metastases in non-small cell lung cancer patients

BACKGROUND

Lung cancer is prone to metastasize to the brain, which is difficult for surgery and leads to poor prognosis due to poor chemotherapy efficacy.

OBJECTIVE

Our aim is to evaluate the efficacy and safety of stereotactic body radiotherapy (SBRT) for brain multi-metastases.

METHODS

In the retrospective study, a total of 51 non-small cell lung cancer (NSCLC) patients with brain multi-metastases (3-5 metastases) receiving SBRT in the local hospital between 2016 and 2019 were enrolled for analyzing the efficacy and safety of SBRT. The primary endpoints included 1-year local control rate, radiotherapy toxicity, overall survival and progression-free survival.

RESULTS

The median follow-up for the enrolled patients was 21 months, and the 1-year and 2-year OS rates were 82.4% and 45.1%, respectively. Demographic analysis showed no significant differences between SBRT alone and combination with whole brain radiotherapy in clinical characteristics including age, gender and Eastern Cooperative Oncology Group performance status. The 1-year local control rate was 77.3% (17/22) for SBRT alone, which was comparable to 79.3% (23/29) of combined radiotherapy. Cox proportional hazard regression demonstrated that the prognostic benefit of combining WBRT was not significantly superior to SBRT alone (HR = 0.851, P= 0.263). Their radiotherapy toxicity rate was lower in SBRT alone group (13.6%, vs. 44.8% for combination; P= 0.017).

CONCLUSION

The current research suggested that SBRT alone could effectively relieve tumor burden and improve the prognosis and quality of life for NSCLC patients with brain multi-metastases, which should be validated in further prospective clinical trials.

In Silico Analysis of Adjuvant Head and Neck Online Adaptive Radiation Therapy

Purpose

Recently developed online adaptive radiation therapy (OnART) systems enable frequent treatment plan adaptation, but data supporting a dosimetric benefit in postoperative head and neck radiation therapy (RT) are sparse. We performed an in silico dosimetric study to assess the potential benefits of a single versus weekly OnART in the treatment of patients with head and neck squamous cell carcinoma in the adjuvant setting.

Methods and Materials

Twelve patients receiving conventionally fractionated RT over 6 weeks and 12 patients receiving hypofractionated RT over 3 weeks on a clinical trial were analyzed. The OnART emulator was used to virtually adapt either once midtreatment or weekly based on the patient's routinely performed cone beam computed tomography. The planning target volume (PTV) coverage, dose heterogeneity, and cumulative dose to the organs at risk for these 2 adaptive approaches were compared with the nonadapted plan.

Results

In total, 13, 8, and 3 patients had oral cavity, oropharynx, and larynx primaries, respectively. In the conventionally fractionated RT cohort, weekly OnART led to a significant improvement in PTV V100% coverage (6.2%), hot spot (-1.2 Gy), and maximum cord dose (-3.1 Gy), whereas the mean ipsilateral parotid dose increased modestly (1.8 Gy) versus the nonadapted plan. When adapting once midtreatment, PTV coverage improved with a smaller magnitude (0.2%-2.5%), whereas dose increased to the ipsilateral parotid (1.0-1.1 Gy) and mandible (0.2-0.7 Gy). For the hypofractionated RT cohort, similar benefit was observed with weekly OnART, including significant improvement in PTV coverage, hot spot, and maximum cord dose, whereas no consistent dosimetric advantage was seen when adapting once midtreatment.

Conclusions

For head and neck squamous cell carcinoma adjuvant RT, there was a limited benefit of single OnART, but weekly adaptations meaningfully improved the dosimetric criteria, predominantly PTV coverage and dose heterogeneity. A prospective study is ongoing to determine the clinical benefit of OnART in this setting.

Obtaining organ-specific radiobiological parameters from clinical data for radiation therapy planning of head and neck cancers

Objective.Different radiation therapy (RT) strategies, e.g. conventional fractionation RT (CFRT), hypofractionation RT (HFRT), stereotactic body RT (SBRT), adaptive RT, and re-irradiation are often used to treat head and neck (HN) cancers. Combining and/or comparing these strategies requires calculating biological effective dose (BED). The purpose of this study is to develop a practical process to estimate organ-specific radiobiologic model parameters that may be used for BED calculations in individualized RT planning for HN cancers.Approach.Clinical dose constraint data for CFRT, HFRT and SBRT for 5 organs at risk (OARs) namely spinal cord, brainstem, brachial plexus, optic pathway, and esophagus obtained from literature were analyzed. These clinical data correspond to a particular endpoint. The linear-quadratic (LQ) and linear-quadratic-linear (LQ-L) models were used to fit these clinical data and extract relevant model parameters (alpha/beta ratio, gamma/alpha,dTand BED) from the iso-effective curve. The dose constraints in terms of equivalent physical dose in 2 Gy-fraction (EQD2) were calculated using the obtained parameters.Main results.The LQ-L and LQ models fitted clinical data well from the CFRT to SBRT with the LQ-L representing a better fit for most of the OARs. The alpha/beta values for LQ-L (LQ) were found to be 2.72 (2.11) Gy, 0.55 (0.30) Gy, 2.82 (2.90) Gy, 6.57 (3.86) Gy, 5.38 (4.71) Gy, and the dose constraint EQD2 were 55.91 (54.90) Gy, 57.35 (56.79) Gy, 57.54 (56.35) Gy, 60.13 (59.72) Gy and 65.66 (64.50) Gy for spinal cord, optic pathway, brainstem, brachial plexus, and esophagus, respectively. Additional two LQ-L parametersdTwere 5.24 Gy, 5.09 Gy, 7.00 Gy, 5.23 Gy, and 6.16 Gy, and gamma/alpha were 7.91, 34.02, 8.67, 5.62 and 4.95.Significance.A practical process was developed to extract organ-specific radiobiological model parameters from clinical data. The obtained parameters can be used for biologically based radiation planning such as calculating dose constraints of different fractionation regimens.

Neurologic Complications of Conventional Chemotherapy and Radiation Therapy

OBJECTIVE

Neurologic complications are among the most common and feared outcomes of cancer treatments. This review discusses the signs and symptoms, mechanisms, and management of the most common peripheral and central neurologic complications of chemotherapy, radiation therapy, and antiangiogenic therapy during cancer treatment and in survivors.

LATEST DEVELOPMENTS

The landscape of cancer treatments is evolving to include more targeted and biologic therapies, in addition to more traditional cytotoxic therapies and radiation therapy. With increasingly complex regimens and longer survival for patients with cancer, the early recognition and management of neurologic complications is key to improving the morbidity and mortality of patients living with cancer.

ESSENTIAL POINTS

Neurologists should be familiar with acute central and peripheral toxicities that can occur during cancer treatment and delayed toxicities that can occur years after exposure. Neurologists should be familiar with the clinical and radiologic presentations of these complications and strategies for management.

Conventional fractionated radiotherapy outcomes for young dogs with nephroblastoma of the spinal cord: 5 cases

Published radiotherapy results for spinal nephroblastomas in dogs are limited. In this retrospective longitudinal study (1/2007-1/2022), five dogs with a median age of 2.8 years received post-operative 3D conformal, conventional fractionated radiotherapy (CFRT) with 2-4 fields (parallel-opposed with or without two hinge-angle fields), for an incompletely resected nephroblastoma. Clinical findings prior to surgery included one or more of the following: pelvic limb paresis (5), faecal incontinence (2), flaccid tail (1), non-ambulatory (2) and deep pain loss (1). All masses were located between T11 and L3 and surgically removed via hemilaminectomy. Dogs received 45-50 Gray (Gy) in 18-20 fractions, and no dogs received chemotherapy post-radiation. At analysis, all dogs were deceased, with none lost to follow-up. The median overall survival (OS) from first treatment to death of any cause was 3.4 years (1234 days; 95% CI 68 days-upper limit not reached; range: 68-3607 days). The median planning target volume was 51.3 cc, with a median PTV dose of 51.4 Gy and median D98 = 48.3 Gy. Late complications or recurrence was difficult to fully determine in this small dataset; however, some degree of ataxia persisted throughout life in all dogs. This study provides preliminary evidence that post-operative radiotherapy may result in prolonged survival times dogs with spinal nephroblastomas.

The evolving role of reirradiation in the management of recurrent brain tumors

Despite aggressive management consisting of surgery, radiation therapy (RT), and systemic therapy given alone or in combination, a significant proportion of patients with brain tumors will experience tumor recurrence. For these patients, no standard of care exists and management of either primary or metastatic recurrent tumors remains challenging.Advances in imaging and RT technology have enabled more precise tumor localization and dose delivery, leading to a reduction in the volume of health brain tissue exposed to high radiation doses. Radiation techniques have evolved from three-dimensional (3-D) conformal RT to the development of sophisticated techniques, including intensity modulated radiation therapy (IMRT), volumetric arc therapy (VMAT), and stereotactic techniques, either stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT). Several studies have suggested that a second course of RT is a feasible treatment option in patients with a recurrent tumor; however, survival benefit and treatment related toxicity of reirradiation, given alone or in combination with other focal or systemic therapies, remain a controversial issue.We provide a critical overview of the current clinical status and technical challenges of reirradiation in patients with both recurrent primary brain tumors, such as gliomas, ependymomas, medulloblastomas, and meningiomas, and brain metastases. Relevant clinical questions such as the appropriate radiation technique and patient selection, the optimal radiation dose and fractionation, tolerance of the brain to a second course of RT, and the risk of adverse radiation effects have been critically discussed.

Companion Animals as a Key to Success for Translating Radiation Therapy Research into the Clinic

Many successful preclinical findings fail to be replicated during translation to human studies. This leads to significant resources being spent on large clinical trials, and in some cases, promising therapeutics not being pursued due to the high costs of clinical translation. These translational failures emphasize the need for improved preclinical models of human cancer so that there is a higher probability of successful clinical translation. Companion-animal cancers offer a potential solution. These cancers are more similar to human cancer than other preclinical models, with a natural evolution over time, genetic alterations, intact immune system, and a permanent adaptation to the microenvironment. These advantages have led pioneers in veterinary radiation oncology to aid human medicine by elucidating basic principles of radiation biology. More recently, the veterinary and human radiation oncology fields have increasingly collaborated to achieve advancements in education, radiotherapy techniques, and trial networks. This review describes these advancements, including significant prior research findings and the evolution of the veterinary radiation oncology discipline. It concludes by describing how companion-animal models can help shape the future of human radiotherapy. Taken as a whole, this review suggests companion-animal cancers may become widely used for preclinical radiotherapy research.

Prioritizing sufficient dose to gross tumor volume over normal tissue sparing in intensity-modulated radiotherapy treatment of T4 nasopharyngeal carcinoma

BACKGROUND

In intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC), priority is often given minimize dose to the critical organs at risk (OARs) to avoid potential morbid sequelae. However, in T4 NPC, dosimetric inadequacy enforced by dose constraints on OARs may significantly impact tumor control.

METHODS

This was a single-institute cohort that patients diagnosed between July 2005 and December 2010 with T4 NPC treated with IMRT. All patients were re-classification according to the 7th-AJCC stage.

RESULTS

Overall, the average doses such as Dmax , D1% , D2% and D1cc for various Central nervous system (CNS) OARs including brainstem, optic nerve, chiasm, temporal lobes and spinal cord were found to exceed published guidelines as RTOG0225. However, no clinical toxicities were seen during the follow-up period except for 13% patients with temporal lobe necrosis.

CONCLUSION

Our retrospective review showed that its feasible to maximize gross tumor volume dose coverage while exceeding most CNS OAR constraint standards, with ideal local control and no obvious increase of craniocerebral toxicity.

Treatment plan optimisation for reirradiation

BACKGROUND

The STRIDeR (Support Tool for Re-Irradiation Decisions guided by Radiobiology) project aims to create a clinically viable re-irradiation planning pathway within a commercial treatment planning system (TPS). Such a pathway should account for previously delivered dose, voxel-by-voxel, taking fractionation effects, tissue recovery and anatomical changes into account. This work presents the workflow and technical solutions in the STRIDeR pathway.

METHODS

The pathway was implemented in RayStation (version 9B DTK) to allow an original dose distribution to be used as background dose to guide optimisation of re-irradiation plans. Organ at risk (OAR) planning objectives in equivalent dose in 2 Gy fractions (EQD2) were applied cumulatively across the original and re-irradiation treatments, with optimisation of the re-irradiation plan performed voxel-by-voxel in EQD2. Different approaches to image registration were employed to account for anatomical change. Data from 21 patients who received pelvic Stereotactic Ablative Radiotherapy (SABR) re-irradiation were used to illustrate the use of the STRIDeR workflow. STRIDeR plans were compared to those produced using a standard manual method.

RESULTS

The STRIDeR pathway resulted in clinically acceptable plans in 20/21 cases. Compared to plans produced using the laborious manual method, less constraint relaxation was required or higher re-irradiation doses could be prescribed in 3/21.

CONCLUSION

The STRIDeR pathway used background dose to guide radiobiologically meaningful, anatomically-appropriate re-irradiation treatment planning within a commercial TPS. This provides a standardised and transparent approach, offering more informed re-irradiation and improved cumulative OAR dose evaluation.

Re-irradiation Using Stereotactic Radiotherapy: A Bibliometric Analysis of Research Trends

The objective of this research is to conduct a comprehensive bibliometric analysis using the Web of Science Core Collection (WoSCC) to examine the current research topics and trends pertaining to stereotactic-based re-irradiation. A bibliometric search was conducted for re-irradiation-related literature published in English from the WoSCC database from 1991 to 2022, using VOSviewer to visualize the results. The extracted information comprises the publication year, overall citation count, average citation rate, keywords, and research domains. We conducted a literature review to identify trends in research on re-irradiation. A total of 19,891 citations were found in 924 qualifying papers that came from 48 different nations. The number of publications and citations has grown steadily since 2008 with the highest number of publications in the year 2018. Similarly, a substantial increase in the number of citations has increased since 2004 and the citation growth rate has been positive between 2004 and 2019 with a peak in 2013. The top authorship patterns were six authors (111 publications and 2498 citations), whereas the highest number of citations per publication was attained with an authorship pattern of 17 authors (C/P = 41.1). The collaboration patterns analysis showed that the largest proportion of publications emanated from the United States with 363 publications (30.9%), followed by Germany with 102 publications (8.7%), and France with 92 publications (7.8%). The majority of the analyzed studies were focused on the brain (30%), head and neck (13%), lung (12%), and spine (10%) and there have been emerging studies on the use of re-irradiation for lung, prostate, pelvic and liver utilizing stereotactic radiotherapy. The main areas of interest have changed over time and are now based on a multidisciplinary approach that integrates advanced imaging techniques, stereotactic treatment delivery, the toxicity of organs at risk, quality of life, and treatment outcomes.

Occupational history associates with ALS survival and onset segment

OBJECTIVE

To identify associations between occupational settings and self-reported occupational exposures on amyotrophic lateral sclerosis (ALS) survival and phenotypes.

METHODS

All patients seen in the University of Michigan Pranger ALS Clinic were invited to complete an exposure assessment querying past occupations and exposures. Standard occupational classification (SOC) codes for each job and the severity of various exposure types were derived. Cox proportional hazards models associated all-cause mortality with occupational settings and the self-reported exposures after adjusting for sex, diagnosis age, revised El Escorial criteria, onset segment, revised ALS Functional Rating Scale (ALSFRS-R), and time from symptom onset to diagnosis. Multinomial logistic regression models with three categories, adjusted for age, assessed the association between occupational settings and exposures to onset segment.

RESULTS

Among the 378 ALS participants (median age, 64.7 years; 54.4% male), poorer survival was associated with work in SOC code "Production Occupations" and marginally with work in "Military Occupation"; poor survival associated with self-reported occupational pesticide exposure in adjusted models. Among onset segments: cervical onset was associated with ALS participants having ever worked in "Buildings and Grounds Cleaning and Maintenance Occupations," "Construction and Extraction Occupations," and "Production Occupations"; bulbar onset with self-reported occupational exposure to radiation; and cervical onset with exposure to particulate matter, volatile organic compounds, metals, combustion and diesel exhaust, electromagnetic radiation, and radiation.

CONCLUSION

Occupational settings and self-reported exposures influence ALS survival and onset segment. Further studies are needed to explore and understand these relationships, most advantageously using prospective cohorts and detailed ALS registries.

Spinal Cord Delineation Based on Computed Tomography Myelogram Versus T2 Magnetic Resonance Imaging in Spinal Stereotactic Body Radiation Therapy

Purpose

Spinal cord delineation is critical to the delivery of stereotactic body radiation therapy (SBRT). Although underestimating the spinal cord can lead to irreversible myelopathy, overestimating the spinal cord may compromise the planning target volume coverage. We compare spinal cord contours based on computed tomography (CT) simulation with a myelogram to spinal cord contours based on fused axial T2 magnetic resonance imaging (MRI).

Methods and Materials

Eight patients with 9 spinal metastases treated with spinal SBRT were contoured by 8 radiation oncologists, neurosurgeons, and physicists, with spinal cord definition based on (1) fused axial T2 MRI and (2) CT-myelogram simulation images, yielding 72 sets of spinal cord contours. The spinal cord volume was contoured at the target vertebral body volume based on both images. The mixed-effect model assessed comparisons of T2 MRI- to myelogram-defined spinal cord in centroid deviations (deviations in the center point of the cord) through the vertebral body target volume, spinal cord volumes, and maximum doses (0.035 cc point) to the spinal cord applying the patient's SBRT treatment plan, in addition to in-between and within-subject variabilities.

Results

The estimate for the fixed effect from the mixed model showed that the mean difference between 72 CT volumes and 72 MRI volumes was 0.06 cc and was not statistically significant (95% confidence interval, -0.034, 0.153; P = .1832). The mixed model showed that the mean dose at 0.035 cc for CT-defined spinal cord contours was 1.24 Gy lower than that of MRI-defined spinal cord contours and was statistically significant (95% confidence interval, -2.292, -0.180; P = .0271). Also, the mixed model indicated no statistical significance for deviations in any of the axes between MRI-defined spinal cord contours and CT-defined spinal cord contours.

Conclusions

CT myelogram may not be required when MRI imaging is feasible, although uncertainty at the cord-to-treatment volume interface may result in overcontouring and hence higher estimated cord dose-maximums with axial T2 MRI-based cord definition.

Stereotactic Body Radiation Therapy for Spinal Metastases: Benefits and Limitations

Progress in biological cancer characterization, targeted systemic therapies and multimodality treatment strategies have shifted the goals of radiotherapy for spinal metastases from short-term palliation to long-term symptom control and prevention of compilations. This article gives an overview of the spine stereotactic body radiotherapy (SBRT) methodology and clinical results of SBRT in cancer patients with painful vertebral metastases, metastatic spinal cord compression, oligometastatic disease and in a reirradiation situation. Outcomes after dose-intensified SBRT are compared with results of conventional radiotherapy and patient selection criteria will be discussed. Though rates of severe toxicity after spinal SBRT are low, strategies to minimize the risk of vertebral compression fracture, radiation induced myelopathy, plexopathy and myositis are summarized, to optimize the use of SBRT in multidisciplinary management of vertebral metastases.

Could conventionally fractionated radiation therapy coupled with stereotactic body radiation therapy improve local control in bone oligometastases?

PURPOSE

To describe clinical outcomes of stereotactic body radiation therapy (SBRT) applied alone or as a boost after a conventionally fractionated radiation therapy (CFRT) for the treatment of bone oligometastases.

MATERIAL AND METHODS

This retrospective cohort study included patients treated with SBRT from January 2007 to December 2015 in the Institut de cancérologie de Lorraine in France. The inclusion criteria involved adults treated with SBRT for one to three bone metastases from a histological proven solid tumor and a primary tumor treated, an Eastern Cooperative Oncology Group (ECOG) score inferior or equal to 2. Local control (LC), overall survival (OS), progression free survival (PFS), bone progression incidence (BPI), skeletal related events free survival (SRE-FS), toxicity and pain response were evaluated.

RESULTS

Forty-six patients and 52 bone metastases were treated. Twenty-three metastases (44.2%) received SBRT alone mainly for non-spine metastases and 29 (55.8%) a combination of CFRT and SBRT mainly for spine metastases. The median follow-up time was 22months (range: 4-89months). Five local failures (9.6%) were observed and the cumulative incidences of local recurrence at 1 and 2years respectively were 4.4% and 8% with a median time of local recurrence of 17months (range: 4-36months). The one- and two-years OS were 90.8% and 87.4%. Visceral metastasis (HR: 3.40, 95% confidence interval [1.10-10.50]) and a time from primary diagnosis (TPD)>30months (HR: 0.22 [0.06-0.82]) were independent prognostic factors of OS. The 1 and 2years PFS were 66.8% and 30.9% with a median PFS time of 18months [13-24]. The one- and two-years BPI were 27.7% and 55.3%. In multivariate analysis, unfavorable histology was associated with worse BPI (HR: 3.19 [1.32-7.76]). The SRE-FS was 93.3% and 78.5% % at 1 and 2years. The overall response rate for pain was 75% in the evaluable patients (9/12). No grade≥3 toxicity nor especially no radiation induced myelopathy (RIM), two patients developed asymptomatic vertebral compression fractures.

CONCLUSION

The sole use of SBRT or its association with CFRT is an efficient and well-tolerated treatment that allows high LC for bone oligometastases.

Efficacy and toxicity of primary re-irradiation for malignant spinal cord compression based on radiobiological modelling: a phase II clinical trial

BACKGROUND

The efficacy and safety of primary re-irradiation for MSCC are not known. Our aim was to establish the efficacy and safety of biologically effective dose-based re-irradiation.

METHODS

Patients presenting with MSCC at a previously irradiated spine segment, and not proceeding with surgical decompression, were eligible. A 3 Gray per fraction experimental schedule (minimum 18 Gy/6 fractions, maximum 30 Gy/10 fractions) was used, delivering a maximum cumulative spinal dose of 100 Gy2 if the interval since the last radiotherapy was within 6 months, or 130 Gy2 if longer. The primary outcome was a change in mobility from week 1 to week 5 post-treatment, as assessed by the Tomita score. The RTOG SOMA score was used to screen for spinal toxicity, and an MRI performed to assess for radiation-induced myelopathy (RIM).

RESULTS

Twenty-two patients were enroled, of whom eleven were evaluable for the primary outcome. Nine of eleven (81.8%) had stable or improved Tomita scores at 5 weeks. One of eight (12.5%) evaluable for late toxicity developed RIM.

CONCLUSIONS

Re-irradiation is an efficacious treatment for MSCC. There is a risk of RIM with a cumulative dose of 120 Gy2.

CLINICAL TRIAL REGISTRATION

Cancer Trials Ireland (ICORG 07-11); NCT00974168.

Percutaneous CT-Guided Microwave Ablation Combined with Pedicle Screw Fixation Followed by Vertebroplasty (MASFVA): Initial Experience of a Minimally Invasive Treatment of Vertebral Metastases with Extension to the Vertebral Pedicle

(1) Background: The aim of this study was to retrospectively evaluate the safety and efficacy of a combined CT-guided percutaneous microwave ablation (MWA) and pedicle screw fixation followed by vertebroplasty (MASFVA) for the treatment and stabilization of painful vertebral metastases with vertebral pedicle involvement. (2) Methods: from January 2013 to January 2017 11 patients with 16 vertebral metastatic lesions (7 men and 5 women; mean age, 65 ± 11 years) with vertebral metastases underwent CT-guided microwave ablation and screw fixation followed by vertebroplasty (MASFVA). Technical success, complication rate, pain evaluation using a visual analogue scale (VAS), Oswestry Disability Index (ODI) and local tumor control were examined. (3) Results: Technical success rate was 100%. No procedure-related major complications occurred. VAS score decreased from 6.8 ± 0.7 to 0.6 ± 0.6. ODI score decreased from 3.1 ± 0.7 to 1.2 ± 0.4. All patients could walk independently without neurological complication after one week from the procedure. No new bone fractures or local disease recurrence occurred during a median follow-up of 12 months. (4) Conclusions: Our results suggest that MWA and percutaneous pedicle screw fixation followed by vertebroplasty for the treatment of painful vertebral metastases is a safe and effective procedure for painful vertebral metastases with vertebral pedicle involvement, allowing pain relief and local tumor control.

Head and Neck Radiation Therapy Patterns of Practice Variability Identified as a Challenge to Real-World Big Data: Results From the Learning from Analysis of Multicentre Big Data Aggregation (LAMBDA) Consortium

Purpose

Outside of randomized clinical trials, it is difficult to develop clinically relevant evidence-based recommendations for radiation therapy (RT) practice guidelines owing to lack of comprehensive real-world data. To address this knowledge gap, we formed the Learning from Analysis of Multicenter Big Data Aggregation consortium to cooperatively implement RT data standardization, develop software solutions for data analysis, and recommend clinical practice change based on real-world data analyzed. The first phase of this "Big Data" study aimed at characterizing variability in clinical practice patterns of dosimetric data for organs at risk (OARs) that would undermine subsequent use of large-scale, electronically aggregated data to characterize associations with outcomes. Evidence from this study was used as the basis for practical recommendations to improve data quality.

Methods and Materials

Dosimetric details of patients with head and neck cancer treated with radiation therapy between 2014 and 2019 were analyzed. Institutional patterns of practice were characterized, including structure nomenclature, volumes, and frequency of contouring. Dose volume histogram (DVH) distributions were characterized and compared with institutional constraints and literature values.

Results

Plans for 4664 patients treated to a mean plan dose of 64.4 ± 13.2 Gy in 32 ± 4 fractions were aggregated. Before implementation of TG-263 guidelines in each institution, there was variability in OAR nomenclature across institutions and structures. With evidence from this study, we identified a targeted and practical set of recommendations aimed at improving the quality of real-world data.

Conclusions

Quantifying similarities and differences among institutions for OAR structures and DVH metrics is the launching point for next steps to investigate potential relationships between DVH parameters and patient outcomes.

Dose-escalated radiotherapy with simultaneous integrated boost for bone metastases in selected patients with assumed favourable prognosis

BACKGROUND

Stereotactic body radiotherapy (SBRT) concepts for dose escalation are increasingly used for bone metastases in patients with oligometastatic or oligoprogressive disease. For metastases that are not suitable for SBRT-regimens, a treatment with 30/40 Gy with simultaneous integrated boost (SIB) in 10 fractions represents a possible regimen. The aim of this study was to investigate the feasibility of this concept and the acute and subacute toxicities.

PATIENTS AND METHODS

Clinical records for dose-escalated radiotherapy of all consecutive patients treated with this regimen were evaluated retrospectively (24 patients with 28 target volumes for oncologic outcomes and 25 patients with 29 target volumes for treatment feasibility and dose parameters analysis). Analysis of radiotherapy plans included size of target volumes and dosimetric parameter for target volumes and organs at risk (OAR). Acute and subacute toxicities were evaluated according to Common Terminology Criteria for Adverse Events (CTCAE) V4.0.

RESULTS

The most common localization was the spine (71.4%). The most common histology was prostate cancer (45.8%). Oligometastatic or oligoprogressive disease was the indication for dose-escalated radiotherapy in 19/24 patients (79.2%). Treatment was feasible with all patients completing radiotherapy. Acute toxicity grade 1 was documented in 36.0% of the patients. During follow up, one patient underwent surgery due to bone instability. The 1-year local control and patient-related progression-free survival (PFS) were 90.0 ± 6.7% and 33.3 ± 11.6%, respectively.

CONCLUSIONS

Dose-escalated hypofractionated radiotherapy with simultaneous integrated boost for bone metastases resulted in good local control with limited acute toxicities. Only one patient required surgical intervention. The regimen represents an alternative to SBRT in selected patients.

Radiodynamic therapy with acridine orange local administration as a new treatment option for primary and secondary bone tumours

AIMS

Acridine orange (AO) demonstrates several biological activities. When exposed to low doses of X-ray radiation, AO increases the production of reactive radicals (radiodynamic therapy (AO-RDT)). We elucidated the efficacy of AO-RDT in breast and prostate cancer cell lines, which are likely to develop bone metastases.

METHODS

We used the mouse osteosarcoma cell line LM8, the human breast cancer cell line MDA-MB-231, and the human prostate cancer cell line PC-3. Cultured cells were exposed to AO and radiation at various concentrations followed by various doses of irradiation. The cell viability was then measured. In vivo, each cell was inoculated subcutaneously into the backs of mice. In the AO-RDT group, AO (1.0 μg) was locally administered subcutaneously around the tumour followed by 5 Gy of irradiation. In the radiation group, 5 Gy of irradiation alone was administered after macroscopic tumour formation. The mice were killed on the 14th day after treatment. The change in tumour volume by AO-RDT was primarily evaluated.

RESULTS

The viability of LM8, MDA-MB-231, and PC-3 cells strongly decreased at AO concentration of 1.0 μg/ml and a radiation dose of 5 Gy. In xenograft mouse model, the AO-RDT also showed a strong cytocidal effect on tumour at the backside in osteosarcoma, breast cancer, and prostate cancer. AO-RDT treatment was more effective for tumour control than radiotherapy in breast cancer.

CONCLUSION

AO-RDT was effective in preventing the proliferation of osteosarcoma, breast cancer, and prostate cancer cell lines in vitro. The reduction in tumour volume by AO-RDT was also confirmed in vivo.Cite this article: Bone Joint Res 2022;11(10):685-692.

Primary epidural lumbar Ewing sarcoma presenting as cauda equina syndrome in an adult patient who underwent surgical decompression: A case report

Ewing sarcoma (ES) is a rare primary neoplasm in the lumbar adult spine and may mimic a benign tumor. In this case, after a patient's three-month history of lower back pain and rapidly progressing leg numbness and weakness, magnetic resonance imaging (MRI) showed a mass in the third lumbar vertebra. At a two-month follow-up, imaging showed a fracture, compression and lesion enlargement. Decompression and fixation confirmed ES, and the patient began combined radiotherapy and chemotherapy. Two months postoperatively, residual ES was suspected on MRI. The patient underwent a second surgery, and histopathology confirmed necrosis. A six-month follow-up after the first surgery showed no tumor recurrence. This case supports the inclusion of ES in the differential diagnosis of pathologic spinal fracture. Early decompression and spinal fixation are critical for preserving neurologic and spinal functions in ES complicated by a compression fracture. Combined adjuvant radiotherapy and chemotherapy remain the standard therapeutic strategy.

Radiation Therapy for IDH-Mutant Grade 2 and Grade 3 Diffuse Glioma: An ASTRO Clinical Practice Guideline

PURPOSE

This guideline provides evidence-based recommendations for adults with isocitrate dehydrogenase (IDH)-mutant grade 2 and grade 3 diffuse glioma, as classified in the 2021 World Health Organization (WHO) Classification of Tumours. It includes indications for radiation therapy (RT), advanced RT techniques, and clinical management of adverse effects.

METHODS

The American Society for Radiation Oncology convened a multidisciplinary task force to address 4 key questions focused on the RT management of patients with IDH-mutant grade 2 and grade 3 diffuse glioma. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

A strong recommendation for close surveillance alone was made for patients with oligodendroglioma, IDH-mutant, 1p/19q codeleted, WHO grade 2 after gross total resection without high-risk features. For oligodendroglioma, WHO grade 2 with any high-risk features, adjuvant RT was conditionally recommended. However, adjuvant RT was strongly recommended for oligodendroglioma, WHO grade 3. A conditional recommendation for close surveillance alone was made for astrocytoma, IDH-mutant, WHO grade 2 after gross total resection without high-risk features. Adjuvant RT was conditionally recommended for astrocytoma, WHO grade 2, with any high-risk features and strongly recommended for astrocytoma, WHO grade 3. Dose recommendations varied based on histology and grade. Given known adverse long-term effects of RT, consideration for advanced techniques such as intensity modulated radiation therapy/volumetric modulated arc therapy or proton therapy were given as strong and conditional recommendations, respectively. Finally, based on expert opinion, the guideline recommends assessment, surveillance, and management for toxicity management.

CONCLUSIONS

Based on published data, the American Society for Radiation Oncology task force has proposed recommendations to inform the management of adults with IDH-mutant grade 2 and grade 3 diffuse glioma as defined by WHO 2021 classification, based on the highest quality published data, and best translated by our task force of subject matter experts.

Single and multi-fraction spine stereotactic body radiation therapy and the risk of radiation induced myelopathy

Purpose

This study reports on the risk of radiation-induced myelitis (RM) of the spinal cord from a large single-institutional experience with 1 to 5 fraction stereotactic body radiation therapy (SBRT) to the spine.

Methods and Materials

A retrospective review of patients who received spine SBRT to a radiation naïve level at or above the conus medullaris between 2007 and 2019 was performed. Local failure determination was based on SPIne response assessment in Neuro-Oncology criteria. RM was defined as neurologic symptoms consistent with the segment of cord irradiated in the absence of neoplastic disease recurrence and graded by Common Toxicity Criteria for Adverse Events, version 4.0. Rates of adverse events were estimated and dose-volume statistics from delivered treatment plans were extracted for the planning target volumes and spinal cord.

Results

A total of 353 lesions in 277 patients were identified that met the specified criteria, for which 270, 70, and 13 lesions received 1-, 3-, and 5-fraction treatments, respectively, with a median follow-up of 46 months (95% confidence interval [CI], 41-52 months) for all surviving patients. The median overall survival was 33.0 months (95% CI, 29-43). The median D0.03cc to the spinal cord was 11.7 Gy (interquartile range [IQR], 10.5-12.4), 16.7 Gy (IQR, 12.8-20.6), and 26.0 Gy (IQR, 24.1-28.1), for 1-, 3-, 5-fractions. Using an a/b = 2Gy for the spinal cord, the median single-fraction equivalent-dose (SFED₂) was 11.7 Gy (IQR, 10.2-12.5 Gy) and the normalized biological equivalent dose (nBED_2/2) was 19.9 Gy (IQR, 15.4-22.8 Gy). One patient experienced grade 2 RM after a single-fraction treatment. The cumulative probability of RM was 0.3% (95% CI, 0%-2%).

Conclusions

Spine SBRT is safe while limiting the spinal cord (as defined on treatment planning magnetic resonance imaging or computed tomography myelogram) D0.03cc to less than 14 Gy, 21.9 Gy, and 30 Gy, for 1, 3, and 5-fractions, consistent with standard guidelines.