Hypofractionated Radiation Therapy: A Cross-sectional Survey Study of US Radiation Oncologists.

OBJECTIVES: For many malignancies, hypofractionated radiotherapy (HFRT) is an accepted standard associated with decreased treatment time and costs. United States provider beliefs regarding HFRT likely impact its adoption but are poorly studied. We surveyed US-based radiation oncologists (ROs) to gauge HFRT utilization rates for prostate (PC), breast (BC), and rectal cancer (RC) and to characterize the beliefs governing these decisions. METHODS: From July to October 2021, an anonymized, online survey was electronically distributed to ROs actively practicing in the United States. Demographic and practice characteristic information was collected. Questions assessing rates of offering HFRT for PC, BC, and RC and perceived limitations towards using HFRT were administered. RESULTS: A total of 203 eligible respondents (72% male, 72% White, 53% nonacademic practice, 69% with 11+ years in practice) were identified. Approximately 50% offered stereotactic body radiation therapy (SBRT) for early/favorable intermediate risk PC. Although >90% of ROs offered whole-breast HFRT for early-stage BC, only 33% offered accelerated partial-breast irradiation (APBI). Overall, 41% of ROs offered short-course neoadjuvant RT for RC. The primary reported barriers to HFRT utilization were lack of data, inexperience, and referring provider concerns. CONCLUSIONS: HFRT is safe, effective, and beneficial, yet underutilized-particularly prostate SBRT, APBI, and short-course RT for RC. Skills retraining and education of ROs and referring providers may increase utilization rates.

Advancing Beyond the Hippocampus to Preserve Cognition for Patients With Brain Metastases: Dosimetric Results From a Phase 2 Trial of Memory-Avoidance Whole Brain Radiation Therapy.

Purpose: Recent advances to preserve neurocognitive function in patients treated for brain metastases include stereotactic radiosurgery, hippocampal avoidance whole brain radiation therapy (WBRT), and memantine administration. The hippocampus, corpus callosum, fornix, and amygdala are key neurocognitive substructures with a low propensity for brain metastases. Herein, we report our preliminary experience using a "memory-avoidance" WBRT (MA-WBRT) approach that spares these substructures for patients with >15 brain metastases. Methods and Materials: Ten consecutive patients treated with MA-WBRT on a phase 2 clinical trial were reviewed. In each patient, the hippocampi, amygdalae, corpus callosum, and fornix were contoured. Patients were not eligible for MA-WBRT if they had metastases in these substructures. A memory-avoidance region was created using a 5-mm volumetric expansion around these substructures. Hotspots were avoided in the hypothalamus and pituitary gland. Coverage of brain metastases was prioritized over memory avoidance dose constraints. Dose constraints for these avoidance structures included a D100% ≤ 9 Gy and D0.03 cm3 ≤ 16 Gy (variation acceptable to 20 Gy). LINAC-based volumetric modulated arc therapy plans were generated for a prescription dose of 30 Gy in 10 fractions. Results: On average, the memory avoidance structure volume was 37.1 cm3 (range, 25.2-44.6 cm3), occupying 2.5% of the entire whole brain target volume. All treatment plans met the D100% dose constraint, and 8 of 10 plans met the D0.03 cm3 constraint, with priority given to tumor coverage for the remaining 2 cases. Target coverage (D98% > 25 Gy) and homogeneity (D2% ≤ 37.5 Gy) were achieved for all plans. Conclusions: Modern volumetric modulated arc therapy techniques allow for sparing of the hippocampus, amygdala, corpus callosum, and fornix with good target coverage and homogeneity. After enrollment is completed, quality of life and cognitive data will be evaluated to assess the efficacy of MA-WBRT to mitigate declines in quality of life and cognition after whole brain radiation.

Intraoperative Radiation Therapy for Gastrointestinal Malignancies.

Despite improvements in definitive therapy, many patients with gastrointestinal malignancies experience local recurrences or have unresectable disease making subsequent management often challenging and morbid. Although higher doses of radiation may offer improved local control, the ability for dose escalation of external beam radiation therapy is often limited by adjacent radiosensitive structures. Intraoperative radiation therapy allows for additional radiotherapy to be delivered directly to the tumor or areas at highest risk for local recurrence while minimizing toxicity to adjacent structures, offering potentially improved outcomes for patients with unresectable disease or those with a high risk of local recurrence.

Prostate brachytherapy utilization in the COVID-19 era: A cross-sectional study of radiation oncologists in the United States.

PURPOSE: Despite advantages such as abbreviated treatment course, brachytherapy (BT) utilization rates for prostate cancer (PC) in the United States (US) are declining. We surveyed practicing US radiation oncologists (ROs) to determine the proportion who offer BT for PC and whether the COVID-19 pandemic influenced practice patterns. MATERIALS AND METHODS: From July-October 2021, we surveyed practicing US ROs. Provider demographic and practice characteristics were collected. Questions assessing utilization of BT and external beam (EBRT) for patients of varying risk groups and the effect of the pandemic on practice patterns were administered. Descriptive statistics were reported. The bivariate relationships between provider characteristics and likelihood of offering BT were assessed using the Chi-square test (α < 0.05). RESULTS: Six percent of surveyed ROs responded, with 203 meeting inclusion criteria (72% male, 72% white, 53% non-academic, 69% >10 years in practice) and 156 (77%) treating PC. For low-risk, fewer providers offered BT (41% total; 25% low dose rate [LDR], 10% high dose rate [HDR], 6% both) than stereotactic body (SBRT) (54%) and moderately hypofractionated radiation therapy (MHFRT) (83%). For favorable intermediate risk, fewer offered BT (37% total; 21% LDR, 10% HDR, 6% both) than SBRT (48%), MHFRT (87%), and conventionally fractionated EBRT (38%). For high (44%) and very-high (37%) risk, fewer offered EBRT+BT than EBRT alone. For every risk group, academic ROs were significantly more likely to offer BT (all p-values<0.05). <1% of respondents reported increased pandemic-related BT usage. CONCLUSIONS: US ROs, particularly in non-academic settings, do not routinely offer BT monotherapy or boost (<50%). Practice patterns were unaffected by COVID-19. Retraining may be critical to increasing utilization.

Factors Associated with Total Laryngectomy Utilization in Patients with cT4a Laryngeal Cancer.

BACKGROUND: Despite recommendations for upfront total laryngectomy (TL), many patients with cT4a laryngeal cancer (LC) instead undergo definitive chemoradiation, which is associated with inferior survival. Sociodemographic and oncologic characteristics associated with TL utilization in this population are understudied. METHODS: This retrospective cohort study utilized hospital registry data from the National Cancer Database to analyze patients diagnosed with cT4a LC from 2004 to 2017. Patients were stratified by receipt of TL, and patient and facility characteristics were compared between the two groups. Logistic regression analyses and Cox proportional hazards methodology were performed to determine variables associated with receipt of TL and with overall survival (OS), respectively. OS was estimated using the Kaplan-Meier method and compared between treatment groups using log-rank testing. TL usage over time was assessed. RESULTS: There were 11,149 patients identified. TL utilization increased from 36% in 2004 to 55% in 2017. Treatment at an academic/research program (OR 3.06) or integrated network cancer program (OR 1.50), male sex (OR 1.19), and Medicaid insurance (OR 1.31) were associated with increased likelihood of undergoing TL on multivariate analysis (MVA), whereas age > 61 (OR 0.81), Charlson-Deyo comorbidity score ≥ 3 (OR 0.74), and clinically positive regional nodes (OR 0.78 [cN1], OR 0.67 [cN2], OR 0.21 [cN3]) were associated with decreased likelihood. Those undergoing TL with post-operative radiotherapy (+/- chemotherapy) had better survival than those receiving chemoradiation (median OS 121 vs. 97 months; p = 0.003), and TL + PORT was associated with lower risk of death compared to chemoradiation on MVA (HR 0.72; p = 0.024). CONCLUSIONS: Usage of TL for cT4a LC is increasing over time but remains below 60%. Patients seeking care at academic/research centers are significantly more likely to undergo TL, highlighting the importance of decreasing barriers to accessing these centers. Increased focus should be placed on understanding and addressing the additional patient-, physician-, and system-level factors that lead to decreased utilization of surgery.

Novel Intrafraction Motion Tracking During Postoperative Spine Stereotactic Irradiation for a Patient With Carbon Fiber Fixation Hardware.

Carbon-fiber reinforced (CFR) polyetheretherketone hardware is an alternative to traditional metal hardware used for spinal fixation surgeries before postoperative radiation therapy for patients with spinal metastases. CFR hardware's radiolucency decreases metal artifact, improving visualization and accuracy of treatment planning. We present the first clinical use and proof of principle of CFR spinal hardware with tantalum markers used for successful tracking of intrafraction motion (IM) using Varian TrueBeam IMR (Intrafraction Motion Review) software module during postoperative spine stereotactic radiation. A 63-year-old woman with history of endometrial cancer presented with acute back pain. Imaging demonstrated pathologic T12 vertebral fracture with cord compression. She underwent T12 vertebrectomy with circumferential decompression and posterior instrumented T10-L2 fusion at our facility using CFR-polyetheretherketone hardware with tantalum screw markers followed by postoperative stereotactic body radiation therapy to 3000 cGy in 5 fractions delivered to T11-T12. Tantalum screw markers were used for IMR tracking. During irradiation, 260 kV images were acquired, and IMR software was able to identify and track markers. During the entire treatment, the IM motions were less than 3 mm. This is the first presented case of CFR spinal hardware with tantalum markers used for successful IMR tracking of IM during daily spine stereotactic treatment. Future work will be needed to improve workflow and create a spine-specific IMR protocol.

Small Molecules and Immunotherapy Agents for Enhancing Radiotherapy in Glioblastoma.

Glioblastoma (GBM) is an aggressive primary brain tumor that is associated with a poor prognosis and quality of life. The standard of care has changed minimally over the past two decades and currently consists of surgery followed by radiotherapy (RT), concomitant and adjuvant temozolomide, and tumor treating fields (TTF). Factors such as tumor hypoxia and the presence of glioma stem cells contribute to the radioresistant nature of GBM. In this review, we discuss the current treatment modalities, mechanisms of radioresistance, and studies that have evaluated promising radiosensitizers. Specifically, we highlight small molecules and immunotherapy agents that have been studied in conjunction with RT in clinical trials. Recent preclinical studies involving GBM radiosensitizers are also discussed.

Quality of Life and Cognitive Function Evaluations and Interventions for Patients with Brain Metastases in the Radiation Oncology Clinic.

Brain metastases (BMs) account for a disproportionately high percentage of cancer morbidity and mortality. Historically, studies have focused on improving survival outcomes, and recent radiation oncology clinical trials have incorporated HRQOL and cognitive assessments. We are now equipped with a battery of assessments in the radiation oncology clinic, but there is a lack of consensus regarding how to incorporate them in modern clinical practice. Herein, we present validated assessments for BM patients, current recommendations for future clinical studies, and treatment advances that have improved HRQOL and cognitive outcomes for BM patients.