Purpose This study aimed to develop and validate a tool to predict the primary tumor site in patients with metastatic cancer of unknown primary using demographic and clinical variables, including imaging-derived sites of metastasis, without pathology or laboratory data. Methods In this population-based study, data were extracted from the SEER database. Patients diagnosed between 2010 and 2020 with a known primary cancer site, metastatic staging, and metastasis in the bone, liver, brain, and lungs were included. Patients were randomly split into training (70%) and/or testing (30%) sets. A total of 27 primary tumor sites were included. A gradient boosting model was trained to predict the primary tumor site, with random forest and classification tree models evaluated as comparators. Random guess and frequency-weighted guessing models were used for baseline comparison. Results A total of 689,715 patients were included from 9,208,295 queried. The most common primary cancer sites were non–small cell lung cancer (NSCLC) (n = 211,338), intestines (n = 64,187), and pancreas (n = 60,310). The baseline models achieved Top-5 accuracies of 0.179 for a random guess and 0.476 for a frequency-weighted guess. The gradient boosting model achieved Top-1, Top-3, and Top-5 accuracies of 0.40 ± 0.001, 0.680 ± 0.001, and 0.790 ± 0.001, respectively, across 100 Monte-Carlo replicates. Top-5 accuracy was highest for primary NSCLC (0.990 ± 0.001) and intestinal cancer (0.900 ± 0.003). Our model was most influenced by sex (gain = 0.27) and metastasis to bone (gain = 0.20). A web app was constructed: primarycancerpredictor.netlify.app. Conclusion This study developed and evaluated a gradient boosting machine learning model and a user-friendly web tool to aid in the diagnosis of cancer of unknown primary.
Modern molecular profiling recontextualizes the NRG/RTOG 0539 trial and reveals hidden high-risk and radiotherapy-resistant meningiomas
Abstract Background Meningiomas exhibit clinical heterogeneity. Radiotherapy (RT) remains the only adjuvant therapy, but tumor-control is variable, and biomarkers are limited. NRG/RTOG-0539 is the first prospective phase 2 trial to stratify meningioma patients for adjuvant RT based on clinical risk. Here, we apply modern molecular tools to this cohort and identify correlates of RT response. Methods Tumor tissue from 100 RTOG-0539 patients was profiled using DNA methylation arrays, RNA sequencing, and whole-exome sequencing. Recurrence scores, Molecular Groups, gene expression, and copy number alterations were compared across clinical groups and between RT responders and non-responders; non-response was defined as progression or death within 3 years. Results Modern grading criteria, including brain invasion, TERT mutation, CDKN2A/B deletion, and 1p/1q status, would reclassify 10% of tumors and alter treatment group assignment in 7%. Non-responders to RT exhibited more frequent 1p and 14q loss, and more copy number alterations. Transcriptomic and epigenetic profiling revealed immune-related signatures in responders and cell cycle–related pathways in non-responders, several of which overlapped with targets of vorinostat, a histone deacetylase inhibitor previously validated in aggressive meningioma models. The Proliferative Molecular Group was an independent predictor of post-RT recurrence in multivariable analysis, outperforming WHO grade. Conclusion Multi-omic analysis of the NRG/RTOG-0539 cohort shows that updated WHO grading criteria, incorporating molecular and cytogenetic features, improve risk stratification. However, molecular classification, particularly the Proliferative group, remains an independent and stronger predictor of RT response. These findings support integrating molecular biomarkers alongside modern grading frameworks to guide treatment and trial design in meningioma. Clinical Trial Information NCT00895622.
Local control and patient survival after stereotactic radiosurgery for esophageal cancer brain metastases: an international multicenter analysis
OBJECTIVE This study aimed to evaluate local control (LC) of tumors, patient overall survival (OS), and the safety of stereotactic radiosurgery (SRS) for esophageal cancer brain metastases (EBMs). METHODS This retrospective cohort study used data from 15 International Radiosurgery Research Foundation facilities encompassing 67 patients with 185 EBMs managed using SRS between January 2000 and May 2022. The median patient age was 63 years, with a male predominance (92.5%). Most patients (64.2%) had a single brain metastasis, while 7.5% had more than 5 metastases. The median tumor volume was 0.9 cm 3 , and the median margin dose delivered to the tumor was 20 Gy. RESULTS The median OS post-SRS was 15.2 months, with 1- and 2-year OS rates of 65.7% and 32.3%, respectively. A significant inverse correlation was found between the number of EBMs and OS in the univariable analysis. LC rates at 1 and 2 years were 89% and 76%, respectively. Adverse radiation effects (AREs) were observed in 17.9% of patients, with 13.4% being mild and transient and 4.5% severely symptomatic (Common Terminology Criteria for Adverse Events grade 3). New intracranial disease developed in 58.2% of patients, with 1- and 2-year rates of 58% and 73%, respectively. CONCLUSIONS SRS for EBMs demonstrated high survival rates and effective tumor control, with a low incidence of severe AREs. These findings highlight the potential role of SRS in the multidisciplinary multimodality management paradigm of EBM.
Novel radiotherapeutic strategies in the management of brain metastases: Challenging the dogma
Abstract The role of radiation therapy in the management of brain metastasis is evolving. Advancements in machine learning techniques have improved our ability to both detect brain metastasis and our ability to contour substructures of the brain as critical organs at risk. Advanced imaging with PET tracers and magnetic resonance imaging-based artificial intelligence models can now predict tumor control and differentiate tumor progression from radiation necrosis. These advancements will help to optimize dose and fractionation for each patient’s lesion based on tumor size, histology, systemic therapy, medical comorbidities/patient genetics, and tumor molecular features. This review will discuss the current state of brain directed radiation for brain metastasis. We will also discuss future directions to improve the precision of stereotactic radiosurgery and optimize whole brain radiation techniques to improve local tumor control and prevent cognitive decline without forming necrosis.
Local control and survival after stereotactic radiosurgery for colorectal cancer brain metastases: an international multicenter analysis
OBJECTIVE The goal of this study was to characterize local tumor control (LC), overall survival (OS), and safety of stereotactic radiosurgery for colorectal brain metastasis (CRBM). METHODS Ten international institutions participating in the International Radiosurgery Research Foundation provided data for this retrospective case series. This study included 187 patients with CRBM (281 tumors), with a median age of 62 years and 56.7% being male. Most patients (53.5%) had solitary tumors, although 10.7% had > 5 tumors. The median tumor volume was 2.7 cm3 (IQR 0.22–8.1 cm3), and the median margin dose was 20 Gy (IQR 18–22 Gy). RESULTS The 3-year LC and OS rates were 72% and 20%, respectively. Symptomatic adverse radiation effects occurred in 1.6% of patients. In the multivariate analysis, age > 65 years and tumor volume > 4.0 cm3 were significant predictors of tumor progression (hazard ratio [HR] 2.6, 95% CI 1.4–4.9; p = 0.003 and HR 3.4, 95% CI 1.7–6.9; p < 0.001, respectively). Better performance status (Karnofsky Performance Scale score > 80) was associated with a reduced risk of tumor progression (HR 0.38, 95% CI 0.19–0.73; p = 0.004). Patient age > 62 years (HR 1.6, 95% CI 1.1–2.3; p = 0.03) and the presence of active extracranial disease (HR 1.7, 95% CI 1.1–2.4; p = 0.009) were significantly associated with worse OS. CONCLUSIONS Stereotactic radiosurgery offers a high LC rate and a low rate of symptomatic adverse radiation effects for the majority of CRBMs. The OS and LC favored younger patients with high functional performance scores and inactive extracranial disease.
Local Control and Survival Outcomes After Stereotactic Radiosurgery for Brain Metastases From Gastrointestinal Primaries: An International Multicenter Analysis
BACKGROUND: There are limited data regarding outcomes for patients with gastrointestinal (GI) primaries and brain metastases treated with stereotactic radiosurgery (SRS). OBJECTIVE: To examine clinical outcomes after SRS for patients with brain metastases from GI primaries and evaluate potential prognostic factors. METHODS: The International Radiosurgery Research Foundation centers were queried for patients with brain metastases from GI primaries managed with SRS. Primary outcomes were local control (LC) and overall survival (OS). Kaplan-Meier analysis was used for univariate analysis (UVA) of prognostic factors. Factors significant on UVA were evaluated with a Cox multivariate analysis proportional hazards model. Logistic regressions were used to examine correlations with RN. RESULTS: We identified 263 eligible patients with 543 brain metastases. Common primary sites were rectal (31.2%), colon (31.2%), and esophagus (25.5%) with a median age of 61.6 years (range: 37-91.4 years) and a median Karnofsky performance status (KPS) of 90% (range: 40%-100%). One-year and 2-year LC rates were 83.5% (95% CI: 78.9%-87.1%) and 73.0% (95% CI: 66.4%-78.5%), respectively. On UVA, age >65 years ( P = .001), dose <20 Gy ( P = .006) for single-fraction plans, KPS <90% ( P < .001), and planning target volume ≥2cc ( P = .007) were associated with inferior LC. All factors other than dose were significant on multivariate analysis ( P ≤ .002). One-year and 2-year OS rates were 68.0% (95% CI: 61.5%-73.6%) and 31.2% (95% CI: 24.6%-37.9%), respectively. Age > 65 years ( P = .006), KPS <90% ( P = .005), and extracranial metastases ( P = .05) were associated with inferior OS. CONCLUSION: SRS resulted in comparable LC with common primaries. Age and KPS were associated with both LC and OS with planning target volume and extracranial metastases correlating with LC and OS, respectively. These factors should be considered in GI cancer patient selection for SRS.
Stereotactic Radiosurgery for Intraventricular Metastases: A Multicenter Study
BACKGROUND: Intraventricular metastases (IVMs) are uncommon, and their optimal management remains debatable. OBJECTIVE: To define the safety and efficacy of stereotactic radiosurgery (SRS) in the treatment of IVMs. METHODS: This retrospective, multicenter study included patients managed with SRS for IVMs. SRS-induced adverse events, local tumor or intracranial progression, and the frequency of new-onset hydrocephalus or leptomeningeal spread were documented. Analyses of variables related to patient neuroimaging or clinical outcomes were also performed. RESULTS: The cohort included 160 patients from 11 centers who underwent SRS for treatment of 1045 intracranial metastases, of which 196 were IVMs. The median survival from SRS was 10 months. Of the 154 patients and 190 IVMs with imaging follow-up, 94 patients (61%) experienced distant intracranial disease progression and 16 IVMs (8.4%) progressed locally. The 12- and 24-month local IVM control rates were 91.4% and 86.1%, respectively. Sixteen (10%) and 27 (17.5%) patients developed hydrocephalus and leptomeningeal dissemination post-SRS, respectively. Adverse radiation effects were documented in 24 patients (15%). Eleven patients (6.9%) died because of intracranial disease progression. CONCLUSION: SRS is an effective treatment option for IVMs, with a local IVM control rate comparable with SRS for parenchymal brain metastases. Leptomeningeal spread and hydrocephalus in patients with IVM occur in a minority of patients, but these patients warrant careful follow-up to detect these changes.
Treatment of Brain Metastases: The Synergy of Radiotherapy and Immune Checkpoint Inhibitors
Brain metastases are a devastating sequela of common primary cancers (e.g., lung, breast, and skin) and have limited effective therapeutic options. Previously, systemic chemotherapy failed to demonstrate significant benefit in patients with brain metastases, but in recent decades, targeted therapies and more recently immune checkpoint inhibitors (ICIs) have yielded promising results in preclinical and clinical studies. Furthermore, there is significant interest in harnessing the immunomodulatory effects of radiotherapy (RT) to synergize with ICIs. Herein, we discuss studies evaluating the impact of RT dose and fractionation on the immune response, early studies supporting the synergistic interaction between RT and ICIs, and ongoing clinical trials assessing the benefit of combination therapy in patients with brain metastases.
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.
Exposure to radon and heavy particulate pollution and incidence of brain tumors
Abstract Background Global incidence for brain tumors varies substantially without explanation. Studies correlating radon exposure and incidence are inconclusive. Particulate pollution has been linked to increased tumor incidence. Particulates may disrupt the blood-brain barrier allowing intracranial exposure to oncogenic radon. We investigated the relationship between exposure to residential radon, particulate pollution, and brain tumor incidence in the United States (US). Methods County-level median radon testing results and annual air quality index values were obtained and divided into tertiles. Counties without both values were excluded. Four groups of counties were generated: high particulate/high radon (high/high), high/low, low/high, and low/low. Using incidence data from the Central Brain Tumor Registry of the US (provided by CDC’s National Program of Cancer Registries and NCI’s SEER), annual age-adjusted incidence rates (AAAIRs) by group were generated by behavior. Incidence rate ratios were calculated to examine for significant differences (α = .05). Poisson regression accounting for possible confounders was conducted. Results Counties with available data included 83% of the US population. High/high exposure was significantly associated with increased AAAIR of all non-malignant tumors (up to 26% higher, including most meningiomas) even after accounting for potential confounders. An increased AAAIR was noted for all malignant tumors (up to 10% higher), including glioblastoma, but was negated after accounting for demographic/socioeconomic differences. Conclusions We present the first report suggesting increased non-malignant brain tumor incidence in regions with high particulate and radon exposure. These findings provide insight into unexplained variation in tumor incidence. Future studies are needed to validate these findings in other populations.