A comprehensive evaluation of advanced dose calculation algorithms for brain stereotactic radiosurgery.

PURPOSE: Accurate dose calculation is important in both target and low dose normal tissue regions for brain stereotactic radiosurgery (SRS). In this study, we aim to evaluate the dosimetric accuracy of the two advanced dose calculation algorithms for brain SRS. METHODS: Retrospective clinical case study and phantom study were performed. For the clinical study, 138 SRS patient plans (443 targets) were generated using BrainLab Elements Voxel Monte Carlo (VMC). To evaluate the dose calculation accuracy, the plans were exported into Eclipse and recalculated with Acuros XB (AXB) algorithm with identical beam parameters. The calculated dose at the target center (Dref), dose to 95% target volume (D95), and the average dose to target (Dmean) were compared. Also, the distance from the skull was analyzed. For the phantom study, a cylindrical phantom and a head phantom were used, and the delivered dose was measured by an ion chamber and EBT3 film, respectively, at various locations. The measurement was compared with the calculated doses from VMC and AXB. RESULTS: In clinical cases, VMC dose calculations tended to be higher than AXB. It was found that the difference in Dref showed > 5% in some cases for smaller volumes < 0.3 cm3 . Dmean and D95 differences were also higher for small targets. No obvious trend was found between the dose difference and the distance from the skull. In phantom studies, VMC dose was also higher than AXB for smaller targets, and VMC showed better agreement with the measurements than AXB for both point dose and high dose spread. CONCLUSION: The two advanced calculation algorithms were extensively compared. For brain SRS, AXB sometimes calculates a noticeable lower target dose for small targets than VMC, and VMC tends to have a slightly closer agreement with measurements than AXB.

Patient Exposure from Radiologic and Nuclear Medicine Procedures in the United States: Procedure Volume and Effective Dose for the Period 2006-2016.

Background Comprehensive assessments of the frequency and associated doses from radiologic and nuclear medicine procedures are rarely conducted. The use of these procedures and the population-based radiation dose increased remarkably from 1980 to 2006. Purpose To determine the change in per capita radiation exposure in the United States from 2006 to 2016. Materials and Methods The U.S. National Council on Radiation Protection and Measurements conducted a retrospective assessment for 2016 and compared the results to previously published data for the year 2006. Effective dose values for procedures were obtained from the literature, and frequency data were obtained from commercial, governmental, and professional society data. Results In the United States in 2006, an estimated 377 million diagnostic and interventional radiologic examinations were performed. This value remained essentially the same for 2016 even though the U.S. population had increased by about 24 million people. The number of CT scans performed increased from 67 million to 84 million, but the number of other procedures (eg, diagnostic fluoroscopy) and nuclear medicine procedures decreased from 17 million to 13.5 million. The number of dental radiographic and dental CT examinations performed was estimated to be about 320 million in 2016. Using the tissue-weighting factors from Publication 60 of the International Commission on Radiological Protection, the U.S. annual individual (per capita) effective dose from diagnostic and interventional medical procedures was estimated to have been 2.9 mSv in 2006 and 2.3 mSv in 2016, with the collective doses being 885 000 and 755 000 person-sievert, respectively. Conclusion The trend from 1980 to 2006 of increasing dose from medical radiation has reversed. Estimated 2016 total collective effective dose and radiation dose per capita dose are lower than in 2006. © RSNA, 2020 See also the editorial by Einstein in this issue.

Myxopapillary ependymoma: a SEER analysis of epidemiology and outcomes.

Myxopapillary ependymoma (MPE) is an exceedingly rare tumor histology. While surgery is clearly the treatment of choice, controversy exists regarding the role of adjuvant radiotherapy (RT). Using the Surveillence, epidemiology, and end results (SEER) database, we aimed to determine the epidemiology, prognostic factors, and treatment-related outcomes for MPE. A total of 773 cases were found in the SEER database. The incidence in the American population was found to be 1.00 per million person-years. On multivariate analysis, receipt of surgery (HR = 0.14, CI = 0.06-0.35, p < 0.001), receipt of RT (HR = 4.06, CI = 1.87-8.81, p < 0.001), age less than 30 (HR = 0.24, CI = 0.08-0.72, p = 0.01), and Caucasian race (HR = 0.37, CI = 0.13-0.996, p = 0.049) were statistically significant prognostic factors. The mean tumor size among those receiving RT (4.6 cm) was significantly larger than among those not receiving RT (3.2 cm, p = 0.0002). Those who lived in metropolitan areas were more likely to receive RT than those who did not. Given multiple previous studies show that RT improves PFS and the discrepancy in tumor size, selection bias is likely a significant contributor to the apparent negative impact of RT on OS. Regardless, surgery remains the most crucial aspect in the care of patients with MPE.

Second primary head and neck cancer after Hodgkin lymphoma: a population-based study of 44,879 survivors of Hodgkin lymphoma.

BACKGROUND: Survivors of Hodgkin lymphoma (HL) are at an increased risk of developing second malignancies. To the authors' knowledge, the risks of head and neck cancer (HNC) after HL and subsequent survival have not been thoroughly investigated. METHODS: From the US population-based Surveillance, Epidemiology, and End Results (SEER) database for 1973 through 2011, survivors of HL who developed HNC as a second cancer were analyzed. Patients with a first primary HNC were used as a comparison group. Observed-to-expected ratios and summary statistics were performed on patients with HL with squamous cell carcinoma (HL-SCC) and salivary gland cancer (HL-SGC). The impact of HL history on overall survival was assessed using a multivariate Cox proportional hazards model. RESULTS: The observed-to-expected ratio for SCC among patients with HL was 1.73 (95% confidence interval [95% CI], 1.36-2.16; P<.05), whereas it was 8.56 for SGC (95% CI, 5.82-12.15; P<.05). Using Cox proportional hazards modeling, a history of HL was found to be an adverse prognostic factor for overall survival for SCC (hazard ratio, 1.37; 95% CI, 1.08-1.73 [P = .009]) but not SGC (hazard ratio, 1.21; 95% CI, 0.82-1.79 [P = .34]). The inferior survival of the patients in the HL-SCC cohort appears to be attributable to more deaths from HL and other malignancies diagnosed after SCC. CONCLUSIONS: There is a significantly increased risk of salivary and nonsalivary HNC after HL, and worse survival for patients with HL-SCC versus those with a first primary SCC. Clinicians should be aware of the risks of HNC after HL. In the absence of evidence-based criteria, the authors recommend that survivors of HL undergo periodic head and neck examination.

Brain metastasis from melanoma: the prognostic value of varying sites of extracranial disease.

Patients with brain metastasis from melanoma have poor outcomes. Radiation is used both for prognostic and symptomatic value. We aimed to further clarify the role of stereotactic radiosurgery (SRS) and whole brain radiotherapy (WBRT) as well as the prognostic implication of various sites of extracranial disease. The records of 73 consecutive patients treated at the University of Rochester Medical Center for brain-metastatic melanoma from January 2004 to October 2013 were reviewed. The median overall survival (OS) was 3.0 months. Patients treated with WBRT alone had decreased OS compared to those treated with SRS alone (HR = 0.38, p = 0.001) or WBRT and SRS (HR = 0.51, p = 0.039). The mean number of brain metastasis differed (p = 0.002) in patients in patients who received WBRT (4.0) compared to those who did not (2.0). Among patients with extracranial disease (n = 63), bone metastasis (HR = 1.86, p = 0.047, n = 15) was a negative prognostic factor; liver (HR = 1.59, p = 0.113, n = 17), lung (HR = 1.51, p = 0.23, n = 51) and adrenal metastasis (HR = 1.70, p = 0.15, n = 10) were not. In patients with concurrent brain and lung metastasis, those with disease limited to those two sites (OS = 8.7 mo, n = 13) had improved OS (HR = 0.44, p = 0.014) compared to those with additional disease (OS = 1.8 mo, n = 50). Based on this hypothesis-generating retrospective analysis, SRS may offer survival benefit compared to WBRT alone in patients with brain metastatic melanoma. Bone metastasis appears to confer a particularly poor prognosis. Those with disease confined to the lung and brain may represent a population with improved prognosis.

Long-term cause-specific mortality in survivors of adolescent and young adult bone and soft tissue sarcoma: a population-based study of 28,844 patients.

BACKGROUND: Despite improved cure rates for bone and soft tissue sarcomas, to the authors' knowledge, no large population-based study to date has evaluated long-term cause-specific mortality in patients diagnosed in the adolescent and young adult (AYA) age range (15 years-39 years). METHODS: A total of 28,844 survivors of AYA bone and soft tissue sarcoma, who accrued 113,206 person-years of follow-up, were identified in the population-based Surveillance, Epidemiology, and End Results program. Standardized mortality ratios (SMR) and absolute excess risks (AER) (per 10,000 person-years) were calculated to evaluate associations with histology (chemotherapy-sensitive subtypes: Ewing sarcoma, osteosarcoma, and rhabdomyosarcoma vs all other subtypes), age, and initial therapy. RESULTS: All-cause mortality in survivors of AYA sarcoma was found to be significantly increased compared with that of the general population (SMR, 1.76; 95% confidence interval [95% CI], 1.60-1.92 [AER of 19]), and persisted for > 20 years (SMR, 1.39; 95% CI, 1.04-1.82 [AER of 20]). Significant excess mortality was observed for both second malignant neoplasms (SMR, 2.05; 95% CI, 1.71-2.43 [AER of 7]) and noncancer causes (SMR, 1.66; 95% CI, 1.49-1.85 [AER of 19]). Significant excess deaths occurred among patients with chemotherapy-sensitive (SMR, 2.76; 95% CI, 2.20-3.41 [AER of 32]) and nonchemosensitive (SMR, 1.63; 95% CI, 1.47-1.80 [AER of 17]) subtypes. Significantly elevated noncancer mortality in the former group included cardiovascular disease (SMR, 2.33) and infections (SMR, 15.6), whereas significant excess deaths in the latter group included diabetes (SMR, 2.40) and infections (SMR, 2.77). CONCLUSIONS: Survivors of AYA bone and soft tissue sarcoma experience significant long-term mortality due to second malignant neoplasms and noncancer causes. Further research is needed to develop preventive and surveillance guidelines in this understudied population to prevent and reduce long-term excess mortality.

Correlation between progression free survival and dynamic susceptibility contrast MRI perfusion in WHO grade III glioma subtypes.

The purpose of this study was to determine whether dynamic susceptibility contrast MR perfusion relative cerebral blood volume (rCBV) correlates with prognosis of World Health Organization (WHO) grade III glial tumors and their different subtypes. Retrospective evaluation of pre-treatment tumor rCBV derived from dynamic susceptibility contrast MR perfusion was performed in 34 patients with histopathologically diagnosed WHO grade III glial tumors (anaplastic astrocytomas (n = 20), oligodendrogliomas (n = 4), and oligoastrocytomas (n = 10)). Progression free survival was correlated with rCBV using Spearman rank analysis. ROC curve analysis was performed to determine the operating point for rCBV in patients with anaplastic astrocytomas dichotomized at the median progression free survival time. For all grade III tumors (n = 34) the mean rCBV was 2.51 with a progression free survival of 705.5 days. The mean rCBV of anaplastic astrocytomas was 2.47 with progression free survival 495.2 days. In contrast, the mean rCBV for oligodendroglial tumors was 2.56 with a progression free survival of 1005.6 days. Although there was no significant correlation between rCBV and progression free survival among all types of grade III gliomas (P = 0.12), among anaplastic astrocytomas there was a significant correlation between pretreatment rCBV and progression free survival with correlation coefficient of -0.51 (P = 0.02). The operating point for rCBV in patients with anaplastic astrocytomas dichotomized at the median progression free survival time (446.5 days) was 2.86 with 78 % accuracy and there was a significant difference between the survival of patients with anaplastic astrocytomas in the dichotomized groups (P = 0.0009). Pre-treatment rCBV may serve as a prognostic imaging biomarker for anaplastic astrocytomas, but not grade III oligodendroglioma tumors.

The role of radiotherapy in immunotherapy strategies in the central nervous system.

The clinical efficacy and relative tolerability of adverse effects of immune checkpoint immunotherapy have led to its increasingly routine use in the management of multiple advanced solid malignancies. Radiation therapy (RT) is well-known to have both local and distant immunomodulatory effects, which has led to extensive investigation into the synergism of these 2 therapies. While the central nervous system (CNS) has historically been thought to be a sanctuary site, well-protected by the blood-brain barrier from the effects of immunotherapy, over the last several years studies have shown the benefits of these drugs, particularly in metastatic disease involving the CNS. This review explores current progress and the future of combination therapy with immune checkpoint inhibitors and RT.

Hypofractionated Stereotactic Radiation Therapy Dosimetric Tolerances for the Inferior Aspect of the Brachial Plexus: A Systematic Review.

We sought to systematically review and summarize dosimetric factors associated with radiation-induced brachial plexopathy (RIBP) after stereotactic body radiation therapy (SBRT) or hypofractionated image guided radiation therapy (HIGRT). From published studies identified from searches of PubMed and Embase databases, data quantifying risks of RIBP after 1- to 10-fraction SBRT/HIGRT were extracted and summarized. Published studies have reported <10% risks of RIBP with maximum doses (Dmax) to the inferior aspect of the brachial plexus of 32 Gy in 5 fractions and 25 Gy in 3 fractions. For 10-fraction HIGRT, risks of RIBP appear to be low with Dmax < 40 to 50 Gy. For a given dose value, greater risks are anticipated with point volume-based metrics (ie, D0.03-0.035cc: minimum dose to hottest 0.03-0.035 cc) versus Dmax. With SBRT/HIGRT, there were insufficient published data to predict risks of RIBP relative to brachial plexus dose-volume exposure. Minimizing maximum doses and possibly volume exposure of the brachial plexus can reduce risks of RIBP after SBRT/HIGRT. Further study is needed to better understand the effect of volume exposure on the brachial plexus and whether there are location-specific susceptibilities along or within the brachial plexus structure.

How Does the Number of Brain Metastases Correlate With Normal Brain Exposure in Single-Isocenter Multitarget Multifraction Stereotactic Radiosurgery.

Purpose: To investigate the relationship between normal brain exposure in LINAC-based single-isocenter multitarget multifraction stereotactic radiosurgery or stereotactic radiation therapy (SRT) and the number or volume of treated brain metastases, especially for high numbers of metastases. Methods and Materials: A cohort of 44 SRT patients with 709 brain metastases was studied. Renormalizing to a uniform prescription of 27 Gy in 3 fractions, normal brain dose volume indices, including V23 Gy (volume receiving >23 Gy), V18 Gy (volume receiving >18 Gy), and mean dose, were evaluated on these plans against the number and the total volume of targets for each plan. To compare with exposures from whole-brain radiation therapy (WBRT), the SRT dose distributions were converted to equivalent dose in 3 Gy fractions (EQD3) using an alpha-beta ratio of 2 Gy. Results: With increasing number of targets and increasing total target volume, normal brain exposures to dose ≥18 Gy increases, and so does the mean normal brain dose. The factors of the number of targets and the total target volume are both significant, although the number of targets has a larger effect on the mean normal brain dose and the total target volume has a larger effect on V23 Gy and V18 Gy. The EQD3 mean normal brain dose with SRT planning is lower than conventional WBRT. On the other hand, SRT results in higher hot spot (ie, maximum dose outside of tumor) EQD3 dose than WBRT. Conclusions: Based on clinical SRT plans, our study provides information on correlations between normal brain exposure and the number and total volume of targets. As SRT becomes more greatly used for patients with increasingly extensive brain metastases, more clinical data on outcomes and toxicities is necessary to better define the normal brain dose constraints for high-exposure cases and to optimize the SRT management for those patients.

Reporting Standards for Complication Studies of Radiation Therapy for Pediatric Cancer: Lessons From PENTEC.

The major aim of Pediatric Normal Tissue Effects in the Clinic (PENTEC) was to synthesize quantitative published dose/-volume/toxicity data in pediatric radiation therapy. Such systematic reviews are often challenging because of the lack of standardization and difficulty of reporting outcomes, clinical factors, and treatment details in journal articles. This has clinical consequences: optimization of treatment plans must balance between the risks of toxicity and local failure; counseling patients and their parents requires knowledge of the excess risks encountered after a specific treatment. Studies addressing outcomes after pediatric radiation therapy are particularly challenging because: (a) survivors may live for decades after treatment, and the latency time to toxicity can be very long; (b) children's maturation can be affected by radiation, depending on the developmental status of the organs involved at time of treatment; and (c) treatment regimens frequently involve chemotherapies, possibly modifying and adding to the toxicity of radiation. Here we discuss: basic reporting strategies to account for the actuarial nature of the complications; the reporting of modeling of abnormal development; and the need for standardized, comprehensively reported data sets and multivariate models (ie, accounting for the simultaneous effects of radiation dose, age, developmental status at time of treatment, and chemotherapy dose). We encourage the use of tools that facilitate comprehensive reporting, for example, electronic supplements for journal articles. Finally, we stress the need for clinicians to be able to trust artificial intelligence models of outcome of radiation therapy, which requires transparency, rigor, reproducibility, and comprehensive reporting. Adopting the reporting methods discussed here and in the individual PENTEC articles will increase the clinical and scientific usefulness of individual reports and associated pooled analyses.

Improving Pediatric Normal Tissue Radiation Dose-Response Modeling in Children With Cancer: A PENTEC Initiative.

The development of normal tissue radiation dose-response models for children with cancer has been challenged by many factors, including small sample sizes; the long length of follow-up needed to observe some toxicities; the continuing occurrence of events beyond the time of assessment; the often complex relationship between age at treatment, normal tissue developmental dynamics, and age at assessment; and the need to use retrospective dosimetry. Meta-analyses of published pediatric outcome studies face additional obstacles of incomplete reporting of critical dosimetric, clinical, and statistical information. This report describes general methods used to address some of the pediatric modeling issues. It highlights previous single- and multi-institutional pediatric dose-response studies and summarizes how each PENTEC taskforce addressed the challenges and limitations of the reviewed publications in constructing, when possible, organ-specific dose-effect models.

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.

Distribution characteristics and prognosis of tumor-infiltrating lymphocytes in the brain metastases of small cell lung cancer: a retrospective cohort study.

Background: The efficacy of immunotherapy for brain metastases from small cell lung cancer (SCLC) is relatively low, and the tumor microenvironment of SCLC brain metastases is still unknown. Therefore, we investigated the distribution of tumor-infiltrating lymphocytes (TILs) and the expression of programmed cell death-ligand 1 (PD-L1) in patients with brain metastases from SCLC to explore the tumor microenvironment of SCLC brain metastases. Methods: A retrospective analysis was performed on 12 surgical specimens of brain metastases from patients with SCLC treated in the Department of Neurosurgery of The First Affiliated Hospital of Anhui Medical University from June 2017 to June 2022. The inclusion criteria for this study were the following: (I) a pathologically confirmed diagnosis of SCLC brain metastases; (II) surgical resection of brain metastases; (III) age >18 years; (IV) and complete clinical data. Patient-related data were retrieved from the inpatient medical record system, telephone follow-up of patients date of death, and overall survival (OS). The immunofluorescence-based tissue microenvironment analysis panel (MAP) was utilized for the detection of TILs, including CD3, CD8, programmed cell death 1 (PD-1), and PD-L1, in formalin-fixed and paraffin-embedded archival specimens of brain metastases. The expression levels of PD-L1 in tumor cells were detected by immunohistochemistry. The correlation between the OS and the above-mentioned markers was analyzed in the 12 patients. Results: Twelve patients were included in the study. The patients' ages ranged from 51-78 years with a median of 68 years, with 1 female and 11 males. Among 12 patients with SCLC brain metastases: positive rates of CD3+ TILs in the tumor parenchyma vs. tumor stroma were 0.60%±0.94% vs. 1.76%±2.72% (P=0.01), respectively; positive rates of CD8+ TILs in the tumor parenchyma vs. tumor stroma were 0.80%±0.78% vs. 2.46%±3.72% (P=0.02), respectively. There was no co-expression of CD8+ and PD-1+ TILs in the tumor parenchyma of 11 cases, and the infiltration density of coexpressed CD3+ and PD-1+ TILs was more than 10/mm2 in only 1 case. There was no coexpression of CD3+ and PD-1+ TIL in the stroma of 10 cases, and the infiltration density of CD8+ and PD-1+ TILs was more than 10/mm2 in 2 cases. Immunohistochemistry was used to detect the expression of PD-L1 in 12 cases of SCLC metastatic lesions, and 3 cases (25%) were positive. Survival analysis showed that patients with positive intraepithelial CD3+ TILs had significantly longer OS [hazard ratio 3.383, 95% confidence interval (CI): 0.959-11.940; P=0.04]. Conclusions: Our study further demonstrated the immune microenvironment of SCLC brain metastases. The distribution of TILs in SCLC brain metastases is low and mainly distributed in the stroma, with the expression of PD-L1 in these tumor tissues being low. Further exploration of the immune microenvironment of SCLC brain metastases is of great significance for potential treatment.

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/ß 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.

Executive Summary of the American Radium Society Appropriate Use Criteria for Brain Metastases in EGFR-mutated and ALK-fusion Non-Small Cell Lung Cancer.

BACKGROUND: The American Radium Society (ARS) Central Nervous System (CNS) committee reviewed literature on epidermal growth factor receptor mutated (EGFRm) and ALK-fusion (ALK+) tyrosine kinase inhibitors (TKIs) for the treatment of brain metastases (BrMs) from non-small cell lung cancers (NSCLC) to generate appropriate use guidelines addressing use of TKIs in conjunction with or in lieu of radiotherapy (RT). METHODS: The panel developed three key questions to guide systematic review: can radiotherapy be deferred in patients receiving EGFR or ALK TKIs at 1) diagnosis or 2) recurrence? Should TKI be administered concurrently with RT (3)? Two literature searches were performed (May 2019 and December 2023). The panel developed 8 model cases and voted on treatment options using a 9-point scale, with 1-3, 4-6 and 7-9 corresponding to usually not appropriate, may be appropriate, and usually appropriate (respectively), per the UCLA/RAND Appropriateness Method. RESULTS: Consensus was achieved in only 4 treatment scenarios, all consistent with existing ARS-AUC guidelines for multiple BrM. The panel did not reach consensus that RT can be appropriately deferred in patients with BrM receiving CNS penetrant ALK or EGFR TKIs, though median scores indicated deferral may be appropriate under most circumstances. Whole brain RT with concurrent TKI generated broad disagreement except in cases with 2-4 BrM, where it was considered usually not appropriate. CONCLUSIONS: We identified no definitive studies dictating optimal sequencing of TKIs and RT for EGFRm and ALK+ BrM. Until such studies are completed, the committee hopes these cases guide decision-making in this complex clinical space.

Multicentre results of stereotactic body radiotherapy for secondary liver tumours.

BACKGROUND: Surgical resection is the standard treatment for liver metastases, although for the majority of patients this is not possible. Stereotactic body radiotherapy (SBRT) is an alternative local-regional therapy. The purpose of this study was to evaluate the results of SBRT for secondary liver tumours from a combined multicentre database. METHODS: Variables from patients treated with SBRT from four Academic Medical Centres were entered into a common database. Local tumour control and 1-year survival rates were calculated. RESULTS: In total, 153 patients (91 women) 59 ± 8.4 years old with 363 metastatic liver lesions were treated with SBRT. The underlying primary tumour arose from gastrointestinal (GI), retroperitoneal and from extra-abdominal primaries in 56%, 8% and 36% of patients, respectively. Metastases, with a gross tumour volume (GTV) of 138.5 ± 126.8 cm(3) , were treated with a total radiation dose of 37.5 ± 8.2 Gy in 5 ± 3 fractions. The 1-year overall survival was 51% with an overall local control rate of 62% at a mean follow-up of 25.2 ± 5.9 months. A complete tumour response was observed in 32% of patients. Grade 3-5 adverse events were noted in 3% of patients. CONCLUSION: Secondary liver tumours treated with SBRT had a high rate of local control with a low incidence of adverse events.

Patient Perceptions of Sexual Orientation and Gender Identity Data Collection in an Outpatient Radiation Oncology Setting.

PURPOSE: Sexual and gender minority patients with cancer experience significant health disparities requiring tailored care. Collecting sexual orientation and gender identity (SOGI) data in the electronic medical record (EMR) could allow care to be tailored and is in line with radiation oncology's mission to better serve diverse patients. This article describes a systematic method for collecting SOGI data for all patients starting radiation treatment in a department of radiation oncology (DRO). METHODS AND MATERIALS: During a 3-month experimental period, DRO staff administered a demographic questionnaire and attitude survey to new adult patients. SOGI demographic data, entered into the EMR by nursing staff, were extracted and analyzed for all patients from the experimental period and from the 3 months prior (control period). Descriptive and categorical data completion rates were compared between the experimental and control periods using independent-samples t tests and Pearson χ2 tests. RESULTS: A total of 788 patients were included in this analysis: 368 in the control period and 420 in the experimental period. Of the 420 patients enrolled in the experimental period, 267 (63.6%) were offered a survey, of whom 211 (79.0%) completed the survey. There were higher rates of sexual orientation responses entered into the EMR for the experimental group compared with the control group (56.9% vs 27.1%; P <.001), with the highest response rates for patients who completed a survey (82.9%). Ten patients (2.9%) identified as gay or lesbian and 100% identified as cisgender. The majority of patients were not upset by the form, with only 11 patients (5.2%) stating that any specific question caused them distress. CONCLUSIONS: Collecting SOGI data via a demographic form is feasible in an outpatient DRO. This approach was well received by the majority of patients and could lead to provision of higher-quality, tailored care.

Radiation-induced inferior brachial plexopathy after stereotactic body radiotherapy: Pooled analyses of risks.

INTRODUCTION: Radiation-induced brachial plexopathy (RIBP), resulting in symptomatic motor or sensory deficits of the upper extremity, is a risk after exposure of the brachial plexus to therapeutic doses of radiation. We sought to model dosimetric factors associated with risks of RIBP after stereotactic body radiotherapy (SBRT). METHODS: From a prior systematic review, 4 studies were identified that included individual patient data amenable to normal tissue complication probability (NTCP) modelling after SBRT for apical lung tumors. Two probit NTCP models were derived: one from 4 studies (including 221 patients with 229 targets and 18 events); and another from 3 studies (including 185 patients with 192 targets and 11 events) that similarly contoured the brachial plexus. RESULTS: NTCP models suggest ≈10% risks associated with brachial plexus maximum dose (Dmax) of ∼32-34 Gy in 3 fractions and ∼40-43 Gy in 5 fractions. RIBP risks increase with increasing brachial plexus Dmax. Compared to previously published data from conventionally-fractionated or moderately-hypofractionated radiotherapy for breast, lung and head and neck cancers (which tend to utilize radiation fields that circumferentially irradiate the brachial plexus), SBRT (characterized by steep dose gradients outside of the target volume) exhibits a much less steep dose-response with brachial plexus Dmax > 90-100 Gy in 2-Gy equivalents. CONCLUSIONS: A dose-response for risk of RIBP after SBRT is observed relative to brachial plexus Dmax. Comparisons to data from less conformal radiotherapy suggests potential dose-volume dependences of RIBP risks, though published data were not amenable to NTCP modelling of dose-volume measures associated with RIBP after SBRT.

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.