Long-Term Intracranial Outcomes With Combination Dual Immune-Checkpoint Blockade and Stereotactic Radiosurgery in Patients With Melanoma and Non-Small Cell Lung Cancer Brain Metastases

Exploratory Evaluation of Personalized Ultrafractionated Stereotactic Adaptive Radiation Therapy (PULSAR) With Central Nervous System-Active Drugs in Brain Metastases Treatment

PURPOSE

Brain metastases (BMs) affect an increasing number of cancer patients and are typically managed with stereotactic radiosurgery (SRS). Our institution advocates the use of Personalized Ultrafractionated Stereotactic Adaptive Radiation Therapy (PULSAR), where radiation is delivered in high-dose pulses at extended intervals allowing for treatment adaptation and easy concurrent systemic therapy integration. We explore the integration of PULSAR with central nervous system (CNS)-active drugs (CNS-aDs).

METHODS AND MATERIALS

This study involved a retrospective evaluation of patients treated with PULSAR using Gamma Knife from 2018 to 2024. We collected demographic, clinical, and specific treatment details, as well as outcomes such as local failure (LF) and toxicity rates. Cumulative incidence analysis for LF and toxicity, considering death a competing risk, and Kaplan-Meier survival analysis for overall survival (OS) were conducted.

RESULTS

Analysis included 109 lesions treated with PULSAR, predominantly in patients with lung and breast cancer. The median follow-up was 1.72. The median OS was not reached. The 1- and 2-year LF rates were 5% and 8.9%, respectively, and 3.4% and 5.5% with concurrent CNS-aDs (cCNS-aDs). BMs >2 cm had LF rates of 9.4% at 2 years. No LFs were observed in BMs >2 cm treated with the combined PULSAR+CNS-aDs approach at 2.5 years. Univariate analysis indicated CNS-aD and radioresponsive histologies were associated with decreased LF rates. The 2-year grade 3+ toxicity rate for PULSAR was 8.7%, with no increase in toxicity with cCNS-aDs.

CONCLUSIONS

The integration of PULSAR with CNS-aDs appears to offer excellent local control for larger BMs with limited toxicity. These promising results merit further prospective investigation to validate the findings and potentially establish new treatment protocols.

Improved Survival and Prognostication in Melanoma Patients With Brain Metastases: An Update of the Melanoma Graded Prognostic Assessment

PURPOSE

Survival for patients with melanoma has recently improved. The propensity of melanoma to metastasize to the brain remains a common and serious feature of this disease. The purposes of this study were to evaluate prognostic factors for patients with newly diagnosed melanoma brain metastases (MBMs) in a large cohort treated with modern multimodal therapies, compare those results with those in prior eras, and update the Melanoma Graded Prognostic Assessment (GPA).

METHODS

Univariable and multivariable (MVA) analyses of prognostic factors and treatments associated with survival were performed on 1,796 patients with newly diagnosed MBM treated between January 01, 2015, and December 31, 2021, using a multi-institutional retrospective database. Multiple imputation was used to address missingness of potential predictors. Significant variables in combined MVA were used to update the Melanoma GPA. Comparisons were made with legacy cohorts.

RESULTS

Median survivals for cohorts A (1985-2007, n = 481), B (2006-2015, n = 823), and C (2015-2021, n = 1,796) were 6.7, 9.8, and 16.6 months and median follow-up times were 40.1, 43.6, and 48.8 months, respectively. In combined MVA, significant prognostic factors for survival were higher Karnofsky Performance Status, fewer MBMs, absence of extracranial metastases, lower serum lactate dehydrogenase, and no immunotherapy before MBM. These factors were incorporated into the updated Melanoma GPA. The combined median and 3-year survivals for patients with GPA 0-1, 1.5-2, and 2.5-4.0 were 5.4, 13.2, and 43.2 months and 12.4%, 28.8%, and 51.6%, respectively.

CONCLUSION

Prognostic factors have changed and survival has improved for patients with MBM but varies widely by GPA. The updated Melanoma GPA calculator (BrainMetGPA), available free online, can be used to estimate survival, individualize treatment, stratify clinical trials, guide surveillance, and augment clinical trial eligibility. Multidisciplinary treatment is essential. Trials are needed to elucidate the optimal sequencing of various therapeutic modalities.

Symptomatic Necrosis With Dual Immune-Checkpoint Inhibition and Radiosurgery for Brain Metastases

This cohort study evaluates whether immune-checkpoint inhibition therapy concurrent with radiosurgery is associated with risk of symptomatic radionecrosis among US patients with brain metastases.

Radiogenomic explainable AI with neural ordinary differential equation for identifying post-SRS brain metastasis radionecrosis

BACKGROUND

Stereotactic radiosurgery (SRS) is widely used for managing brain metastases (BMs), but an adverse effect, radionecrosis, complicates post-SRS management. Differentiating radionecrosis from tumor recurrence non-invasively remains a major clinical challenge, as conventional imaging techniques often necessitate surgical biopsy for accurate diagnosis. Machine learning and deep learning models have shown potential in distinguishing radionecrosis from tumor recurrence. However, their clinical adoption is hindered by a lack of explainability, limiting understanding and trust in their diagnostic decisions.

PURPOSE

To utilize a novel neural ordinary differential equation (NODE) model for discerning BM post-SRS radionecrosis from recurrence. This approach integrates image-deep features, genomic biomarkers, and non-image clinical parameters within a synthesized latent feature space. The trajectory of each data sample towards the diagnosis decision can be visualized within this feature space, offering a new angle on radiogenomic data analysis foundational for AI explainability.

METHODS

By hypothesizing that deep feature extraction can be modeled as a spatiotemporally continuous process, we designed a novel model based on heavy ball NODE (HBNODE) in which deep feature extraction was governed by a second-order ODE. This approach enabled tracking of deep neural network (DNN) behavior by solving the HBNODE and observing the stepwise derivative evolution. Consequently, the trajectory of each sample within the Image-Genomic-Clinical (I-G-C) space became traceable. A decision-making field (F) was reconstructed within the feature space, with its gradient vectors directing the data samples' trajectories and intensities showing the potential. The evolution of F reflected the cumulative feature contributions at intermediate states to the final diagnosis, enabling quantitative and dynamic comparisons of the relative contribution of each feature category over time. A velocity curve was designed to determine key intermediate states (locoregional ∇F = 0) that are most predictive. Subsequently, a non-parametric model aggregated the optimal solutions from these key states to predict outcomes. Our dataset included 90 BMs from 62 NSCLC patients, and 3-month post-SRS T1+c MR image features, seven NSCLC genomic features, and seven clinical features were analyzed. An 8:2 train/test assignment was employed, and five independent models were trained to ensure robustness. Performance was benchmarked in sensitivity, specificity, accuracy, and ROCAUC, and results were compared against (1) a DNN using only image-based features, and (2) a combined "I+G+C" features without the HBNODE model.

RESULTS

The temporal evolution of gradient vectors and potential fields in F suggested that clinical features contribute the most during the initial stages of the HBNODE implementation, followed by imagery features taking dominance in the latter ones, while genomic features contribute the least throughout the process. The HBNODE model successfully identified and assembled key intermediate states, exhibiting competitive performance with an ROCAUC of 0.88 ± 0.04, sensitivity of 0.79 ± 0.02, specificity of 0.86 ± 0.01, and accuracy of 0.84 ± 0.01, where the uncertainties represent standard deviations. For comparison, the image-only DNN model achieved an ROCAUC of 0.71 ± 0.05 and sensitivity of 0.66 ± 0.32 (p = 0.086), while the "I+G+C" model without HBNODE reported an ROCAUC of 0.81 ± 0.02 and sensitivity of 0.58 ± 0.11 (p = 0.091).

CONCLUSION

The HBNODE model effectively identifies BM radionecrosis from recurrence, enhancing explainability within XAI frameworks. Its performance encourages further exploration in clinical settings and suggests potential applicability across various XAI domains.

Return to work in younger patients with brain metastases who survived for 2 years or more

PURPOSE

The study's purpose was to analyze return to work and other long-term outcomes in younger patients with newly diagnosed brain metastases, treated before they reached legal retirement age, i.e. younger than 65 years.

METHODS

We included patients who survived greater than 2 years after their first treatment, regardless of approach (systemic therapy, neurosurgical resection, whole-brain or stereotactic radiotherapy). The primary endpoint was the proportion of patients who worked 2 years after their initial treatment for brain metastases. Outcomes beyond the 2-year cut-off were also abstracted from comprehensive electronic health records, throughout the follow-up period.

RESULTS

Of 455 patients who received active therapy for brain metastases, 62 (14%) survived for > 2 years. Twenty-eight were younger than 65 years. The actuarial median survival was 81 months and the 5-year survival rate 53%. For patients alive after 5 years, the 10-year survival rate was 54%. At diagnosis, 25% of patients (7 of 28) were permanently incapacitated for work/retired. Of the remaining 21 patients, 33% did work 2 years later. However, several of these patients went on to receive disability pension afterwards. Eventually, 19% continued working in the longer run. Younger age, absence of extracranial metastases, presence of a single brain metastasis, and Karnofsky performance status 90-100 were common features of patients who worked after 2 years.

CONCLUSION

Long-term survival was achieved after vastly different therapeutic approaches, regarding both upfront and sequential management. Many patients required three or more lines of brain-directed treatment. Few patients continued working in the longer run.

Very early symptomatic metastasis pseudoprogression after stereotactic brain radiosurgery in a melanoma patient treated with BRAF/MEK inhibitors: a case report and review of the literature

Introduction

Significant therapeutic changes have recently occurred in the management of melanoma brain metastases (BMs), both in the field of local treatments, with the rise of stereotactic radiotherapy (RT), as well as in systemic ones, with the advent of immunotherapy and targeted therapies (TT). These advances have brought about new challenges, particularly regarding the potential interactions between new TT (notably BRAF/MEK inhibitors) and irradiation. Through a clinical case, we will discuss a side effect not previously described in the literature: ultra-early pseudoprogression (PP) following brain stereotactic radiosurgery (SRS), in a patient treated with dabrafenib-trametinib.

Case presentation

A 61-year-old patient with BRAFV600E-mutated melanoma, receiving second-line dabrafenib-trametinib therapy, was referred for SRS on three progressing meningeal implants, without evidence of systemic progression. Four days after the first RT session (1x6 Gy on a fronto-orbital lesion prescribed 5x6 Gy, and 1x20 Gy single fraction on the other lesions), the patient presented with an epileptic seizure. An MRI, compared to the planning MRI ten days earlier, revealed significant progression of the irradiated lesions. The patient's condition improved with dexamethasone and levetiracetam, and RT was halted out of caution. A follow-up MRI at one month demonstrated a size reduction of all treated lesions. Subsequent imaging at five months revealed further shrinking of the two lesions treated with an ablative dose of 20 Gy, while the under-treated fronto-orbital lesion progressed. These dynamics suggest an initial PP in the three irradiated lesions, followed by good response in the ablatively treated lesions and progression in the partially treated lesion.

Conclusion

To our knowledge, this represents the first documented case of ultra-early PP following brain SRS in a patient receiving concomitant dabrafenib-trametinib. It highlights the need for particular vigilance when using tyrosine kinase inhibitors (TKIs) with SRS, and warrants further research into potential treatment interactions between RT and novel systemic agents, as well as the optimal treatment sequence of melanoma BMs.

Dosimetric and Clinical Prognostic Factors in Single-Isocenter Linac-Based Stereotactic Radiotherapy for Brain Metastases

Background/Objectives: To report on predictive factors in Linac-based SRT for single and multiple BM. Methods: Consecutive patients receiving either one or three fractions of single-isocenter coplanar VMAT SRT were retrospectively included. The GTV-PTV margin was 1-2 mm. The delivered target dose was estimated by recalculating the original plans on roto-translated CT according to errors recorded by post-treatment CBCT. The Kaplan-Meier method estimated local progression-free survival (LPFS), intracranial progression-free survival (IPFS), and overall survival (OS). Log-rank and Wilcoxon-Mann-Whitney tests evaluated inter-group differences, whereas Cox regression analysis assessed prognostic factors. Results: Fifty females and fifty males, with a median age of 69 years, received 107 SRTs. A total of 213 BM (range, 1-10 per treatment) with a median volume of 0.22 cc were irradiated with a median minimum BED of 59.5 Gy. The median delivered GTV D95 reduction was -0.3%. The median follow-up was 11 months. Nineteen LP events and a 1-year LC rate of 90.1% were observed. The GTV coverage did not correlate with LC, while the GTV volume was a risk factor for LP, with the 1-year rate dropping to 73% for volumes ≥ 0.88 cc. The median LPFS, IPFS, and OS were 6, 5, and 7 months, respectively. Multivariate analysis showed that patients with melanoma histology and those receiving a second or subsequent systemic therapy line had the worst outcomes, whereas patients with adenocarcinoma histology and mutations showed better results. Conclusions: The accuracy and efficacy of the Linac-based SRT approach for BM were confirmed, but the dose distribution alone failed to predict the treatment response, suggesting that other factors must be considered to maximize SRT outcomes.

Comprehensive analysis of stereotactic Radiosurgery outcomes in triple-negative breast cancer patients with brain metastases: The influence of immunotherapy and prognostic factors

INTRODUCTION

Breast cancer stands as the second most common solid tumors with a propensity for brain metastasis. Among metastatic breast cancer cases, the brain metastasis incidence ranges from 10 % to 30 %, with triple-negative breast cancer (TNBC) displaying a heightened risk and poorer prognosis. SRS has emerged as an effective local treatment modality for brain metastases; however, data on its outcomes specifically in pure triple-negative subtype remain scarce.

METHOD

We retrospectively reviewed the electronic medical records of all brain metastasis (BM) TNBC patients treated with SRS. Patient, tumour characteristics and treatment details data were collected. This retrospective cohort study aimed to evaluate local control (LC), distant brain metastasis free survival (DBMFS), and overall survival (OS) outcomes in TNBC patients undergoing SRS for brain metastases while identifying potential prognostic factors.

RESULT

Forty-three patients with TNBC and brain metastases treated with SRS between January 2017 and 2023 were included. The study found rates of LC (99 % at 1 year) and DBMFS (76 % at 1 year) after SRS, with brain metastasis count (p = 0,003) and systemic treatment modality (p = 0,001) being significant predictors of DBMFS. The median OS following SRS was 19.5 months, with neurological deficit (p = 0.003) and systemic treatment modality (p = 0.019) identified as significant predictors of OS.

CONCLUSION

SRS demonstrates favourable outcomes in terms of local control and distant brain metastasis-free survival in TNBC. Neurological deficit and systemic treatment significantly influence overall survival, emphasizing the importance of personalized treatment approaches and (magnetic resonance imaging) MRI surveillance based on these factors.