Peter Fecci

Stereotactic radiosurgery (SRS) is a standard of care for many patients with brain metastases. To optimize post-SRS surveillance, this study aimed to validate a previously published nomogram predicting post-SRS intracranial progression (IP). We identified consecutive patients completing an initial course of SRS across two institutions between July 2017 and December 2020. Patients were classified as low- or high-risk for post-SRS IP per a previously published nomogram. Overall survival (OS) and freedom from IP (FFIP) were assessed via the Kaplan-Meier method. Assessment of parameters impacting FFIP was performed with univariable and multivariable Cox proportional hazard models. Among 890 patients, median follow-up was 9.8 months (95% CI 9.1-11.2 months). In total, 47% had NSCLC primary tumors, and 47% had oligometastatic disease (defined as ≤5 metastastic foci) at the time of SRS. Per the IP nomogram, 53% of patients were deemed high-risk. For low- and high-risk patients, median FFIP was 13.9 months (95% CI 11.1-17.1 months) and 7.6 months (95% CI 6.4-9.3 months), respectively, and FFIP was superior in low-risk patients (p < 0.0001). This large multisite BM cohort supports the use of an IP nomogram as a quick and simple means of stratifying patients into low- and high-risk groups for post-SRS IP.

PURPOSE: Stereotactic radiosurgery (SRS) is a highly effective therapy for newly diagnosed brain metastases. Prophylactic antiepileptic drugs are no longer routinely used in current SRS practice, owing to a perceived low overall frequency of new-onset seizures and potential side effects of medications. It is nonetheless desirable to prevent unwanted side effects following SRS. Risk factors for new-onset seizures after SRS have not been well established. As such, we aimed to characterize variables associated with increased seizure risk. METHODS AND MATERIALS: Patients treated with SRS for newly diagnosed brain metastases between 2013 and 2016 were retrospectively reviewed at a single institution. Data on baseline demographics, radiation parameters, and clinical courses were collected. RESULTS: The cohort consisted of 305 patients treated with SRS without prior seizure history. Median age and baseline Karnofsky Performance Scale score were 64 years (interquartile range, 55-70) and 80 (interquartile range, 80-90), respectively. Twenty-six (8.5%) patients developed new-onset seizures within 3 months of SRS. There was no association between new-onset seizures and median baseline Karnofsky Performance Scale score, prior resection, or prior whole brain radiation therapy. There were significant differences in the combined total irradiated volume (12.5 vs 3.7 cm3, P < .001), maximum single lesion volume (8.8 vs 2.8 cm3, P = .003), lesion diameter (3.2 vs 2.0 cm, P = .003), and number of lesions treated (3 vs 1, P = .018) between patients with and without new-onset seizures, respectively. On multivariate logistic regression, total irradiated volume (odds ratio, 1.09 for every 1-cm1 increase in total volume; confidence interval, 1.02-1.17; P = .016) and pre-SRS neurologic symptoms (odds ratio, 3.08; 95% confidence interval, 1.19-7.99; P = .020) were both significantly correlated with odds of seizures following SRS. CONCLUSIONS: Our data suggest that larger total treatment volume and the presence of focal neurologic deficits at presentation are associated with new-onset seizures within 3 months of SRS. High-risk patients undergoing SRS may benefit from counseling or prophylactic antiseizure therapy.

Glioblastoma (GBM) is notorious for its immunosuppressive tumor microenvironment (TME) and is refractory to immune checkpoint blockade (ICB). Here, we identify calmodulin-dependent kinase kinase 2 (CaMKK2) as a driver of ICB resistance. CaMKK2 is highly expressed in pro-tumor cells and is associated with worsened survival in patients with GBM. Host CaMKK2, specifically, reduces survival and promotes ICB resistance. Multimodal profiling of the TME reveals that CaMKK2 is associated with several ICB resistance-associated immune phenotypes. CaMKK2 promotes exhaustion in CD8+ T cells and reduces the expansion of effector CD4+ T cells, additionally limiting their tumor penetrance. CaMKK2 also maintains myeloid cells in a disease-associated microglia-like phenotype. Lastly, neuronal CaMKK2 is required for maintaining the ICB resistance-associated myeloid phenotype, is deleterious to survival, and promotes ICB resistance. Our findings reveal CaMKK2 as a contributor to ICB resistance and identify neurons as a driver of immunotherapeutic resistance in GBM.