Risk and survival outcomes of radiation-induced CNS tumors.

Patients treated with cranial radiation are at risk of developing secondary CNS tumors. Understanding the incidence, treatment, and long-term outcomes of radiation-induced CNS tumors plays a role in clinical decision-making and patient education. Additionally, as meningiomas and pituitary tumors have been detected at increasing rates across all ages and may potentially be treated with radiation, it is important to know and communicate the risk of secondary tumors in children and adults. After conducting an extensive literature search, we identified publications that report incidence and long-term outcomes of radiation-induced CNS tumors. We reviewed 14 studies in children, which reported that radiation confers a 7- to 10-fold increase in subsequent CNS tumors, with a 20-year cumulative incidence ranging from 1.03 to 28.9 %. The latency period for secondary tumors ranged from 5.5 to 30 years, with gliomas developing in 5-10 years and meningiomas developing around 15 years after radiation. We also reviewed seven studies in adults, where the two strongest studies showed no increased risk while the remaining studies found a higher risk compared to the general population. The latency period for secondary CNS tumors in adults ranged from 5 to 34 years. Treatment and long-term outcomes of radiation-induced CNS tumors have been documented in four case series, which did not conclusively demonstrate that secondary CNS tumors fared worse than primary CNS tumors. Radiation-induced CNS tumors remain a rare occurrence that should not by itself impede radiation treatment. Additional investigation is needed on the risk of radiation-induced tumors in adults and the long-term outcomes of these tumors.

Stress-induced changes in gene interactions in human cells.

Cells respond to variable environments by changing gene expression and gene interactions. To study how human cells response to stress, we analyzed the expression of >5000 genes in cultured B cells from nearly 100 normal individuals following endoplasmic reticulum stress and exposure to ionizing radiation. We identified thousands of genes that are induced or repressed. Then, we constructed coexpression networks and inferred interactions among genes. We used coexpression and machine learning analyses to study how genes interact with each other in response to stress. The results showed that for most genes, their interactions with each other are the same at baseline and in response to different stresses; however, a small set of genes acquired new interacting partners to engage in stress-specific responses. These genes with altered interacting partners are associated with diseases in which endoplasmic reticulum stress response or sensitivity to radiation has been implicated. Thus, our findings showed that to understand disease-specific pathways, it is important to identify not only genes that change expression levels but also those that alter interactions with other genes.

Imaging Assessment of Radiation Therapy-Related Normal Tissue Injury in Children: A PENTEC Visionary Statement.

The Pediatric Normal Tissue Effects in the Clinic (PENTEC) consortium has made significant contributions to understanding and mitigating the adverse effects of childhood cancer therapy. This review addresses the role of diagnostic imaging in detecting, screening, and comprehending radiation therapy-related late effects in children, drawing insights from individual organ-specific PENTEC reports. We further explore how the development of imaging biomarkers for key organ systems, alongside technical advancements and translational imaging approaches, may enhance the systematic application of imaging evaluations in childhood cancer survivors. Moreover, the review critically examines knowledge gaps and identifies technical and practical limitations of existing imaging modalities in the pediatric population. Addressing these challenges may expand access to, minimize the risk of, and optimize the real-world application of, new imaging techniques. The PENTEC team envisions this document as a roadmap for the future development of imaging strategies in childhood cancer survivors, with the overarching goal of improving long-term health outcomes and quality of life for this vulnerable population.

Systematic Review and Meta-analysis for Surgery Versus Stereotactic Radiosurgery for Jugular Paragangliomas.

OBJECTIVE: Comprehensively analyze tumor control and treatment complications for jugular paraganglioma patients undergoing surgery versus stereotactic radiosurgery (SRS). DATABASES REVIEWED: EMBASE, Medline, and Scopus. METHODS: The databases were searched for English and Spanish articles from January 1, 1995, to January, 1, 2019, for studies reporting tumor control and treatment side effects regarding patients with jugular paraganglioma treated with surgery or SRS. Main outcome measures included short-term and long-term tumor recurrence, as well as postintervention complications. RESULTS: We identified 10,952 original abstracts, 705 eligible studies, and 107 studies for final data extraction. There were 3,498 patients-2,215 surgical patients and 1,283 SRS patients. Bayesian meta-analysis was applied to the extracted data, with tau measurements for study heterogeneity. SRS tumors were larger (3.9 cm 3 versus 8.1 cm 3 ). Meta-analysis results demonstrated low rates of long-term recurrence for both modalities (surgery, 15%; SRS, 7%), with SRS demonstrating lower rates of postintervention cerebrospinal fluid leak, dysphagia, and cranial nerve Vll, lX, X, Xl, or Xll palsies. CONCLUSIONS: This study demonstrates excellent control of jugular paragangiomas with both surgery and SRS, with higher rates of lower cranial neuropathies, dysphagia, and cerebrospinal fluid leaks among surgical patients.

Characterization of cardiovascular injury in mice following partial-heart irradiation with clinically relevant dose and fractionation.

BACKGROUND AND PURPOSE: Late cardiac toxicity is a major side effect of radiation therapy (RT) for breast cancer. We developed and characterized a mouse model of radiation-induced heart disease that mimics the dose, fractionation, and beam arrangement of left breast and chest wall RT. MATERIAL AND METHODS: Female wild-type (C57BL6/J) and atherosclerosis-prone apolipoprotein E-deficient (ApoE-/-) mice (on a C57BL/6J background) on regular chow were treated with 2 Gy × 25 fractions of partial-heart irradiation via opposed tangential beams to the left chest wall. The changes in myocardial perfusion and cardiac function of C57BL/6J mice were examined by single-photon emission computed tomography (SPECT) and echocardiography, respectively. In addition to SPECT and echocardiography, the formation of calcified plaques and changes in cardiac function of ApoE-/- mice were examined by dual-energy microCT (DE-CT) and pressure-volume (PV) loop analysis, respectively. The development of myocardial fibrosis was examined by histopathology. RESULTS: Compared to unirradiated controls, irradiated C57BL/6J mice showed no significant changes by SPECT or echocardiography up to 18 months after 2 Gy × 25 partial-heart irradiation even though irradiated mice exhibited a modest increase in myocardial fibrosis. For ApoE-/- mice, 2 Gy × 25 partial-heart irradiation did not cause significant changes by SPECT, DE-CT, or echocardiography. However, PV loop analysis revealed a significant decrease in load-dependent systolic and diastolic function measures including cardiac output, dV/dtmax and dV/dt min 12 months after RT. CONCLUSIONS: Following clinically relevant doses of partial-heart irradiation in C57BL/6J and ApoE-/- mice, assessment with noninvasive imaging modalities such as echocardiography, SPECT, and DE-CT yielded no evidence of decreased myocardial perfusion and cardiac dysfunction related to RT. However, invasive hemodynamic assessment with PV loop analysis indicated subtle, but significant, changes in cardiac function of irradiated ApoE-/- mice. PV loop analysis may be useful for future preclinical studies of radiation-induced heart disease, especially if subtle changes in cardiac function are expected.

Adjuvant Radiation in Older Patients With Glioblastoma: A Retrospective Single Institution Analysis.

OBJECTIVES: Standard 6-week and hypofractionated 3-week courses of adjuvant radiation therapy (RT) are both options for older patients with glioblastoma (GBM), but deciding the optimal regimen can be challenging. This analysis explores clinical factors associated with selection of RT course, completion of RT, and outcomes following RT. MATERIALS AND METHODS: This IRB-approved retrospective analysis identified patients ≥70 years old with GBM who initiated adjuvant RT at our institution between 2004 and 2016. We identified factors associated with standard or hypofractionated RT using the Cochran-Armitage trend test, estimated time-to-event endpoints using the Kaplan-Meier method, and found predictors of overall survival (OS) using Cox proportional hazards models. RESULTS: Sixty-two patients with a median age of 74 (range 70-90) initiated adjuvant RT, with 43 (69%) receiving standard RT and 19 (31%) receiving hypofractionated RT. Selection of short-course RT was associated with older age (p = 0.04) and poor KPS (p = 0.03). Eight (13%) patients did not complete RT, primarily for hospice care due to worsening symptoms. After a median follow-up of 37 months, median OS was 12.3 months (95% CI 9.0-15.1). Increased age (p < 0.05), poor KPS (p < 0.0001), lack of MGMT methylation (p < 0.05), and lack of RT completion (p < 0.0001) were associated with worse OS on multivariate analysis. In this small cohort, GTV size and receipt of standard or hypofractionated RT were not associated with OS. CONCLUSIONS: In this cohort of older patients with GBM, age and KPS was associated with selection of short-course or standard RT. These regimens had similar OS, though a subset of patients experienced worsening symptoms during RT and discontinued treatment. Further investigation into predictors of RT completion and survival may help guide adjuvant therapies and supportive care for older patients.

Sensitization of Endothelial Cells to Ionizing Radiation Exacerbates Delayed Radiation Myelopathy in Mice.

Delayed radiation myelopathy is a rare, but significant late side effect from radiation therapy that can lead to paralysis. The cellular and molecular mechanisms leading to delayed radiation myelopathy are not completely understood but may be a consequence of damage to oligodendrocyte progenitor cells and vascular endothelial cells. Here, we aimed to determine the contribution of endothelial cell damage to the development of radiation-induced spinal cord injury using a genetically defined mouse model in which endothelial cells are sensitized to radiation due to loss of the tumor suppressor p53. Tie2Cre; p53FL/+ and Tie2Cre; p53FL/- mice, which lack one and both alleles of p53 in endothelial cells, respectively, were treated with focal irradiation that specifically targeted the lumbosacral region of the spinal cord. The development of hindlimb paralysis was followed for up to 18 weeks after either a 26.7 Gy or 28.4 Gy dose of radiation. During 18 weeks of follow-up, 83% and 100% of Tie2Cre; p53FL/- mice developed hindlimb paralysis after 26.7 and 28.4 Gy, respectively. In contrast, during this period only 8% of Tie2Cre; p53FL/+ mice exhibited paralysis after 28.4 Gy. In addition, 8 weeks after 28.4 Gy the irradiated spinal cord from Tie2Cre; p53FL/- mice showed a significantly higher fractional area positive for the neurological injury marker glial fibrillary acidic protein (GFAP) compared with the irradiated spinal cord from Tie2Cre; p53FL/+ mice. Together, our findings show that deletion of p53 in endothelial cells sensitizes mice to the development of delayed radiation myelopathy indicating that endothelial cells are a critical cellular target of radiation that regulates myelopathy.

Are Higher Doses of Consolidation Radiation Therapy Necessary in Diffuse Large B-cell Lymphoma Involving Osseous Sites?

PURPOSE: This study aimed to evaluate whether higher doses of consolidation radiation therapy (RT), which have been traditionally recommended for osseous sites in diffuse large B-cell lymphoma (DLBCL), are still necessary. METHODS AND MATERIALS: Patients with DLBCL with osseous involvement treated with first-line chemotherapy followed by consolidation RT between 1995 and 2016 were reviewed. The primary endpoint was 5-year freedom from local recurrence, estimated using the Kaplan-Meier method. Outcomes based on the RT dose received were also assessed. RESULTS: A total of 51 patients were identified. The most common chemotherapy regimens were rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (80%) and cyclophosphamide, doxorubicin, vincristine, and prednisone (12%) with a median of 6 cycles (range, 3-8 cycles). After chemotherapy, 82% of patients achieved a complete response (CR), and 18% achieved a partial response (PR). All patients in PR were deemed appropriate for consolidation RT. The median dose was 29 Gy (24 Gy for CR; 36 Gy for PR). After a median follow-up of 86 months, 8 patients relapsed, with 2 relapses in the RT field after consolidation RT of 30 and 39.6 Gy, respectively. Overall, the 5-year freedom from local recurrence was 96% (95% confidence interval [CI], 91%-100%), disease-free survival was 76% (95% CI, 65%-89%), and overall survival was 86% (95% CI, 76%-96%). No dose-response relationship was observed. CONCLUSIONS: In patients with DLBCL with osseous involvement who achieved a CR after first-line chemotherapy, 20 to 30 Gy of consolidation RT led to high rates of local control. Higher doses should be reserved for patients in PR.