Phase I trial of dose escalation for preoperative stereotactic radiosurgery for patients with large brain metastases

BACKGROUND

Single session stereotactic radiosurgery (SRS) or surgical resection alone for brain metastases larger than 2 cm results in unsatisfactory local control. We conducted a phase I trial for brain metastases(>2cm) to determine the safety of preoperative SRS at escalating doses.

METHODS

Radiosurgery dose was escalated at 3 Gy increments for 3 cohorts based on maximum tumor dimension starting at: 18 Gy for >2-3 cm, 15 Gy for >3-4 cm, and 12 Gy for >4-6 cm. Dose limiting toxicity (DLT) was defined as grade III or greater acute toxicity.

RESULTS

A total of 35 patients/36 lesions were enrolled. For tumor size >2-3 cm, patients were enrolled up to the second dose level (21 Gy); for >3-4 cm and >4-6 cm cohorts the third dose level (21 Gy and 18 Gy, respectively) was reached. There were 2 DLTs in the >3-4 cm arm at 21Gy. The maximum tolerated dose (MTD) of SRS for >2-3 cm was not reached; and was 18 Gy for both >3-4 cm arm and >4-6 cm arm. With a median follow-up of 64.0 months, the 6- and 12-month local control rates were 85.9% and 76.6%, respectively. One patient developed grade 3 radiation necrosis at 5 months. The 2-year rate of leptomeningeal disease (LMD) was 0%.

CONCLUSION

Preoperative SRS with dose escalation followed by surgical resection for brain metastases greater than 2 cm in size demonstrates acceptable acute toxicity. The phase II portion of the trial will be conducted at the maximum tolerated SRS doses.

Clinical Outcomes for Patients with Brain Metastases from Upper Gastrointestinal Cancer Treated with Stereotactic Radiosurgery

PURPOSE/OBJECTIVE(S)

Prior studies have reported outcomes for brain metastases from gastrointestinal (GI) primary cancers treated with stereotactic radiosurgery (SRS); however, most include a majority of colorectal cancer. Few studies specifically evaluate SRS treatment response for brain metastases from upper GI cancers. We report our institutional outcomes for patients with upper GI cancers who were treated with SRS for brain metastases.

MATERIALS/METHODS

Patients with an upper GI cancer who underwent SRS for brain metastases between 1991 and 2021 were retrospectively reviewed from a single institution IRB-approved database. The primary endpoint was local failure (LF) and secondary endpoint was overall survival (OS). LF was estimated using the Cumulative Incidence Function with death as a competing risk. Survival analysis was performed with the Kaplan-Meier Method. Predictors of cumulative incidence of LF were assessed using competing risk regression.

RESULTS

Forty-nine patients with 107 brain metastases were analyzed. Forty-two (86%) patients were male. The median follow-up time was 6.7 months (range: 0.4-61.7 months) and median OS was 7.5 months (range: 0.9-61.7 months). The median Karnofsky Performance Score (KPS) was 80 (range: 40-100). The primary disease site was esophagus in 87 (81%) lesions, pancreas in 10 (9.3%) lesions, stomach in 5 (4.7%) lesions, liver in 2 (1.9%) lesions, gallbladder in 2 (1.9%) lesions, and small intestine in 1 (0.9%) lesion. The median metastasis size was 1.4 cm (range: 0.3-6.7 cm). The median prescription dose and fraction number were 24 Gy (range: 14-30 Gy) and 1 fraction (range: 1-2 fractions), respectively. The cumulative incidence of LF at 6 and 12 months was 5.6% (95% CI: 2.3-11%) and 12% (95% CI: 6.9-20%), respectively. Overall survival at 6 and 12 months was 59% (95% CI: 50-69%) and 35% (95% CI: 27-46%), respectively. On univariate analysis, female gender (HR = 0.19, 95% CI: 0.06-0.61, p = 0.005), Black race (HR = 0.09, 95% CI: 0.03-0.23, p = <0.001), and larger tumors (HR = 1.35, 95% CI: 1.03-1.78, p = 0.03) were significantly associated with local failure.

CONCLUSION

SRS for brain metastases from upper GI cancers is an appropriate treatment option and provides excellent local control. Unlike prior studies that have reported lower local control rates for all GI cancers with brain metastases treated with SRS, our data show that local failure rates in brain metastases from upper GI cancers specifically are more consistent with previously published data from other disease sites. Further studies evaluating SRS treatment response for brain metastases from GI cancers should separate upper GI and lower GI cancers.

Adjuvant Stereotactic Radiosurgery With or Without Postresection Fractionated Radiation Therapy for the Management of Clival Chordomas in Adults: An International Multicenter Case Series

BACKGROUND

Clival chordomas are challenging because of their proximity to critical neurovascular structures. Stereotactic radiosurgery (SRS) has been proven effective with minimal adverse effects.

OBJECTIVE

To compare the outcomes of histologically confirmed primary clival chordomas in adults who underwent SRS alone (SRS group) vs SRS after fractionated radiotherapy (FRT+SRS group).

METHODS

We collected patient data from 10 institutions affiliated with the International Radiosurgery Research Foundation. We evaluated overall survival, tumor control, and freedom from additional treatment (FFAT).

RESULTS

Fifty-seven (77%) patients were included in the SRS group and 17 (23%) in the FRT+SRS group. The median radiological follow-up was 48 months (IQR, 24-85) in the SRS group and 36 months (IQR, 25-41) in the FRT+SRS group. During the follow-up, 8 SRS and 2 FRT+SRS patients died ( P = .80). The groups had comparable 10-year overall survival (SRS: 76% vs FRT+SRS: 80%; logrank test, P = .75) and tumor control rates (SRS: 34% vs FRT+SRS: 45%; logrank test, P = .29). The SRS group had a superior 10-year FFAT rate (40%) compared with FRT+SRS (23%; logrank test, P = .02). This finding persisted in the multivariate analysis of the Cox proportional hazards illustrating a 2.40-fold increase in the relative risk of requiring additional treatment among the FRT+SRS group ( P = .04).

CONCLUSION

Adjuvant FRT with subsequent boost SRS did not provide superior overall survival or tumor control compared with patients who underwent adjuvant SRS alone. Further studies are required to refine management guidelines among adults with clival chordomas.

Results of a Phase I Trial of Dose Escalation for Preoperative Stereotactic Radiosurgery for Patients with Large Brain Metastases

PURPOSE/OBJECTIVE(S)

Single session stereotactic radiosurgery (SRS) alone for brain metastases larger than 2 cm in diameter results in unsatisfactory local control. Surgical resection alone also produces unreliable local control and perioperative radiation is required. We conducted a prospective phase I trial (NCT01891318) for brain metastases greater than 2 cm to determine the safety of preoperative SRS at escalating doses followed by surgical resection.

MATERIALS/METHODS

Radiosurgery dose started at RTOG 9005 dose levels for the 3 cohorts based on maximum tumor diameter of the index lesion: 18 Gy for >2-3 cm, 15 Gy for >3-4 cm, and 12 Gy >4-6 cm. Concurrent SRS alone to other smaller lesions was allowed using standard RTOG dose. Dose limiting toxicity (DLT) was defined as grade 3 or greater acute toxicity within 3 to 4 months after SRS. Patients underwent surgical resection within 2 weeks and were followed with imaging and neurological evaluations every 3 months.

RESULTS

A total of 35 patients were enrolled into the trial (see Table 1 below). The median age was 63, and median interval between SRS and surgery was 2 days. The most common histology was non-small cell lung cancer (57.1%), followed by breast cancer (14.3%). For tumor size >2-3 cm, patients were enrolled up to the 2nd dose level (21 Gy); for >3-4 cm and >4-6 cm cohorts the 3rd dose level (21 Gy and 18 Gy, respectively) was reached. There was a total of 3 DLTs: 2 in the >3-4 cm cohort and 1 in the >4-6 cm cohort (Table 1). The maximum tolerable dose (MTD) was 18 Gy (2nd dose level) for >3-4 cm, and 18 Gy (3rd dose level) for >4-6 cm. With a median follow-up of 64 months, the 6- and 12-month local control rates were 88.8% and 79.1%, respectively. The 6- and 12-month distant brain control was 63.1% and 55.3%, respectively. Overall survival at 6 and 12 months was 82.9% and 59.0%. The rate of leptomeningeal disease (LMD) at 2 years was 0%.

CONCLUSION

Preoperative SRS with dose escalation followed by surgical resection for brain metastases greater than 2 cm in size results in local control comparable to postoperative SRS or whole-brain radiation therapy and demonstrates acceptable acute toxicity. The Phase II portion of the trial will be conducted at the maximum tolerated SRS doses.

Development of an RPA for Prediction of Radiation Necrosis Following Single Fraction Gamma Knife Radiosurgery for Brain Metastases

PURPOSE/OBJECTIVE(S)

Radiation necrosis (RN) is a potential complication following treatment of brain metastases with stereotactic radiosurgery (SRS). Several risk factors for RN have been reported, but to our knowledge there are no recursive partitioning analysis (RPA) models to identify patients at highest risk for RN. We therefore sought to develop a predictive tool to identify patients at highest risk for the development of RN following single fraction SRS.

MATERIALS/METHODS

Patients who underwent single fraction SRS for brain metastases from 2017-2021 were identified from a single institutional IRB-approved database. Patients with concern for RN were discussed in a multi-disciplinary setting and a diagnosis of RN was made based on pathologic or radiographic findings. Cox proportional hazards regression was done to identify factors associated with RN. RPA was performed to categorize patients into distinct risk groups for RN. Variables with p<0.1 on univariate analysis from the Cox regression analysis were included in the RPA. Patients with staged SRS, incomplete treatment records, or < 3 months radiographic follow-up were excluded from the analysis.

RESULTS

The study population comprised 1,011 lesions from 283 patients with a median follow-up of 9.7 months. The majority of lesions had non-small cell lung cancer (NSCLC) (49%) as the primary site followed by breast (12%) and melanoma (11%). The median prescription dose was 24 Gy (range: 12-24 Gy). RN was diagnosed in 12.2% of lesions, of which 28% (35/123) were symptomatic RN. The median time to RN was 4.9 months. Variables identified for inclusion in the RPA included primary tumor site, use of targeted therapy, tumor location, pre-SRS hemorrhage, post-SRS hemorrhage, prior SRS to other lesions, number of SRS targets, maximum dose, maximum lesion diameter, 70% isodose line, heterogeneity index, conformality index, and gradient index. RPA identified four distinct groups. Group 1 was defined as maximum lesion diameter (MLD) <0.8 cm with primary tumor site other than breast, colorectal (CRC) or NSCLC (n = 174); group 2 was MLD <0.8 cm with breast, CRC, or NSCLC (n = 372). Group 3 was defined as MLD ≥ 0.8 cm without post-SRS hemorrhage (n = 336) and group 4 was MLD ≥0.8 cm with post-SRS hemorrhage (n = 129). Two-year RN free survival for all lesions was 82%, 100% for group 1, 89% for group 2, 76% for group 3, and 58% for group 4.

CONCLUSION

We created the first RPA predictive model for RN following single fraction SRS and identified a subgroup of patients at highest risk. This RPA can help guide clinicians when educating patients on RN risk for brain metastases.

Clinical Outcomes of Patients with Brain Metastases from Colorectal Cancer Treated with Stereotactic Radiosurgery

PURPOSE/OBJECTIVE(S)

Prior studies have demonstrated that brain metastases from gastrointestinal (GI) primary cancers have a poorer response to stereotactic radiosurgery (SRS) when compared to patients with other primary sites, with reported local control of 62-74%. We report our institutional outcomes for patients with colorectal primary cancer who were treated with SRS for brain metastases.

MATERIALS/METHODS

Patients with colorectal primary cancer who underwent SRS for brain metastases between 1989 and 2021 were retrospectively reviewed from a single institutional IRB-approved database. The primary endpoint was local failure (LF) and secondary endpoint was overall survival (OS). LF was estimated using the Cumulative Incidence Function with death as a competing risk. Survival analysis was performed using the Kaplan-Meier Method. Predictors of cumulative incidence of LF were assessed using competing risk regression.

RESULTS

The study population comprised of 109 patients with primary colorectal adenocarcinoma with 207 brain metastases. The median follow-up was 5.2 months (range: 0.4-124 months) and median OS was 5.8 months (range: 0.5-71.2 months). Fifty-two patients (48%) were male and median Karnofsky Performance Status at the time of treatment was 80 (range: 40-100). The median tumor diameter was 1.55 cm (range: 0.17-5.48 cm). The median prescription dose and number of fractions were 24 Gy (range: 11-36 Gy) and 1 fraction (range: 1-3 fractions), respectively. The cumulative incidence of LF at 3, 6, and 12 months was 9.7% (95% CI: 6.1-14%), 22% (95% CI: 16-28%), and 25% (95% CI: 20-31%), respectively. Overall survival at 3, 6, and 12 months was 81% (95% CI: 76-87%), 49% (95% CI: 42-56%) and 24% (95% CI: 18-31%), respectively. On univariate analysis, age was a significant predictor (HR = 0.96, 95% CI: 0.94-0.98), p < 0.001) of LF. Tumor size (HR = 0.80, p = 0.13) and prescription dose (HR = 1.02, p = 0.54) did not predict for LF.

CONCLUSION

To our knowledge, this is the largest series of patients with brain metastases from colorectal primary cancer treated with SRS. Compared to historical data, LF and OS in our cohort of patients was favorable. Our data confirms relatively higher rates of LF when compared to brain metastases from other primary disease sites. Further studies are warranted to identify factors that predict for LF following SRS and to develop models that predict which patients with colorectal brain metastases may be at higher risk of failure.

Frameless Fractionated Stereotactic Radiosurgery for Brain Metastases: An Institutional Series of 145 Cases

PURPOSE/OBJECTIVE(S)

Cobalt-60 stereotactic radiosurgery (SRS) typically involves single fraction treatment with frame immobilization. However, large tumor size, proximity to critical structures, and prior radiation treatment sometimes necessitate fractionated SRS with mask immobilization. We present a large institutional experience with fractionated mask-based SRS for brain metastases.

MATERIALS/METHODS

In this single-institution, IRB-approved study, all patients treated with mask-based fractionated SRS for brain metastases from March 2017 to January 2023 were identified. The primary outcomes were 1- and 2-year local control (LC) by Kaplan-Meier method.

RESULTS

A total of 118 patients with a total of 145 metastases were treated. The median follow-up time was seven months. The median age at treatment was 64.1 years (range: 26-95 years). 55.9% of patients were female. The most common primary tumors were breast (25.5%), non-small cell lung (23.4%), small-cell lung (8.3%), and melanoma (8.3%). For most cases (59.3%), the indication for fractionation was retreatment. Large size (28.3%), critical location (9.7%), and medical comorbidity (2.1%) were other indications. For all cases, the mean maximal linear size was 34.9 mm and mean target volume was 15.6 cc. For cases fractionated due to size, the mean size was 43.9 mm and mean target volume was 23.8 cc. Median total dose was 2,700 cGy (range: 1,620-3,000), and median dose per fraction (fx) was 600 cGy (range: 405-900). The most common prescriptions were 3,000 cGy/5 fx (40.0% of patients) and 2500 cGy in 500 cGy per fraction (37.2% of patients). Mean maximum dose was 4,833 cGy (range: 2,920-7,500). For 75.2% of treatments, the prescription isodose line was 50 to 59% (mean, 56.9%). Target coverage was 100% in all but one case (99%). For lesions near the brainstem, mean brainstem maximum point dose (MPD) was 9.3 Gy ± 9.8 Gy and brainstem mean dose was 3.3 Gy ± 3.3 Gy. For lesions near the optic pathway, mean optic nerve MPD was 14.4 Gy ± 9.2, optic nerve mean dose was 6.4 Gy ± 5.4 Gy, mean optic chiasm MPD was 11.7 Gy ± 7.9 Gy, and optic chiasm mean dose was 5.4 Gy ± 4.7 Gy. 1-year LC was 88.2% and 2-year LC was 80.4%. When retreatments were excluded, 1-year LC was 98.0% and 2-year LC was 98.0%. 18% of patients had acute grade 1-2 toxicities (fatigue, headache, nausea, and/or alopecia), and one patient had acute grade 3 fatigue. There was no other grade 3+ acute toxicities. 14% of patients had grade 1-2 radiation necrosis (RN); there were no cases of grade 3+ RN.

CONCLUSION

Cobalt-60 frameless fractionated SRS for brain metastases offers excellent local control, rigorous sparing of critical structures, and minimal toxicity. Frameless fractionated SRS should be considered for large, retreated, or critically located metastases.

The impact of opioid administration for post gamma knife radiosurgery frame removal: a prospective quality-improvement study

PURPOSE

In our center, five Gamma Knife proceduralists differed in opioid administration practices prior to Leksell frame removal, providing the opportunity to improve the care of patients with brain metastases by studying whether opioid medications improve pain scores and patient satisfaction during Gamma Knife treatment in a prospective, pseudorandomized fashion.

METHODS

We prospectively administered a questionnaire to patients undergoing Gamma Knife Radiosurgery for metastases between November, 2017 and July, 2018. Using multivariable methods, we assessed whether opioid pain medication administration influenced the change in pain scores after frame removal, and whether they influenced patient satisfaction on how often their pain was controlled, and their overall satisfaction.

RESULTS

We included 142 patients. Mean age was 65.2 ± 10.8 years and 52.7% were female. Morphine was the most commonly administered medication. Pain increases were greater around frame removal than placement. Opioids were not associated with any difference in the change in pain scores before and after frame removal, or patient satisfaction. Patients with higher pre-removal pain scores had smaller increases in pain scores after removal; they also had worse pain control and overall satisfaction with their treatment.

CONCLUSION

Morphine administration prior to frame removal did not improve pain scores or pain control satisfaction. Absence of efficacy may be related to delayed onset of action, and stronger and faster-acting agents should be explored. Pre-removal pain scores were associated with decreased pain control and overall satisfaction, further identifying earlier and stronger pain treatment as a potential area for improvement.

The Impact of Extent of Ablation on Survival of Patients With Newly Diagnosed Glioblastoma Treated With Laser Interstitial Thermal Therapy: A Large Single-Institutional Cohort

BACKGROUND

Upfront laser interstitial thermal therapy (LITT) can be used as part of the treatment paradigm in difficult-to-access newly diagnosed glioblastoma multiforme (ndGBM) cases. The extent of ablation, though, is not routinely quantified; thus, its specific effect on patients' oncological outcomes is unclear.

OBJECTIVE

To methodically measure the extent of ablation in the cohort of patients with ndGBM and its effect, and other treatment-related parameters, on patients' progression-free survival (PFS) and overall survival (OS).

METHODS

A retrospective study was conducted on 56 isocitrate dehydrogenase 1/2 wild-type patients with ndGBM treated with upfront LITT between 2011 and 2021. Patient data including demographics, oncological course, and LITT-associated parameters were analyzed.

RESULTS

Patient median age was 62.3 years (31-84), and the median follow-up duration was 11.4 months. As expected, the subgroup of patients receiving full chemoradiation was found to have the most beneficial PFS and OS (n = 34). Further analysis showed that 10 of them underwent near-total ablation and had a significantly improved PFS (10.3 months) and OS (22.7 months). Notably, 84% excess ablation was detected which was not related to a higher rate of neurological deficits. Tumor volume was also found to influence PFS and OS, but it was not possible to further corroborate this finding because of low numbers.

CONCLUSION

This study presents data analysis of the largest series of ndGBM treated with upfront LITT. Near-total ablation was shown to significantly benefit patients' PFS and OS. Importantly, it was shown to be safe, even in cases of excess ablation and therefore could be considered when using this modality to treat ndGBM.

Percutaneous Rhizotomy of the Gasserian Ganglion in Patients With Mass Lesion-Associated Trigeminal Neuralgia: A Case Series

BACKGROUND

Patients with trigeminal neuralgia (TN) secondary to mass lesions are typically treated by directly addressing the underlying pathology. In cases of TN not alleviated by treatment of the pathology, percutaneous balloon compression (PBC) and glycerol rhizotomy (Gly) are simple and effective ways to alleviate pain. However, there is limited literature on the use of these techniques for patients with TN caused by mass lesions.

OBJECTIVE

To describe the use of PBC/Gly to treat mass lesion-related TN.

METHODS

We report a retrospective, single-institution, descriptive case series of patients who presented with TN secondary to tumor or mass-like inflammatory lesion from 1999 to 2021. Patients with primary, idiopathic, or multiple sclerosis-related TN were excluded. Outcomes included Barrow Neurological Institute (BNI) pain intensity and hypesthesia scores, pain persistence, and postoperative complications.

RESULTS

A total of 459 procedures were identified, of which 16 patients met the inclusion criterion (14 PBC and 2 Gly). Of the 15 patients with tumors, 12 had TN pain despite prior tumor-targeted radiation. Short-term (<3 months) BNI pain intensity improvement occurred in 15 (93.8%) patients. The mean follow-up was 54.4 months. Thirteen (81.3%) patients were pain-free (Barrow Neurological Institute pain intensity scale: IIIa-50%; I-25.0%; II-6.3%) for a mean of 23.8 (range 1-137) months. Ten patients (62.5%) had pain relief for ≥6 months from first procedure. New facial numbness developed immediately postprocedure in 8 (50%) patients. Transient, partial abducens nerve palsy occurred in 1 patient.

CONCLUSION

PBC/Gly is an effective option for medically refractory TN in patients with mass-associated TN and is a viable option for repeat treatment.

18F-fluciclovine PET/CT to distinguish radiation necrosis from tumor progression for brain metastases treated with radiosurgery: results of a prospective pilot study

PURPOSE

Distinguishing radiation necrosis from tumor progression among patients with brain metastases previously treated with stereotactic radiosurgery represents a common diagnostic challenge. We performed a prospective pilot study to determine whether PET/CT with 18F-fluciclovine, a widely available amino acid PET radiotracer, repurposed intracranially, can accurately diagnose equivocal lesions.

METHODS

Adults with brain metastases previously treated with radiosurgery presenting with a follow-up tumor-protocol MRI brain equivocal for radiation necrosis versus tumor progression underwent an 18F-fluciclovine PET/CT of the brain within 30 days. The reference standard for final diagnosis consisted of clinical follow-up until multidisciplinary consensus or tissue confirmation.

RESULTS

Of 16 patients imaged from 7/2019 to 11/2020, 15 subjects were evaluable with 20 lesions (radiation necrosis, n = 16; tumor progression, n = 4). Higher SUVmax statistically significantly predicted tumor progression (AUC = 0.875; p = 0.011). Lesion SUVmean (AUC = 0.875; p = 0.018), SUVpeak (AUC = 0.813; p = 0.007), and SUVpeak-to-normal-brain (AUC = 0.859; p = 0.002) also predicted tumor progression, whereas SUVmax-to-normal-brain (p = 0.1) and SUVmean-to-normal-brain (p = 0.5) did not. Qualitative visual scores were significant predictors for readers 1 (AUC = 0.750; p < 0.001) and 3 (AUC = 0.781; p = 0.045), but not for reader 2 (p = 0.3). Visual interpretations were significant predictors for reader 1 (AUC = 0.898; p = 0.012) but not for reader 2 (p = 0.3) or 3 (p = 0.2).

CONCLUSIONS

In this prospective pilot study of patients with brain metastases previously treated with radiosurgery presenting with a contemporary MRI brain with a lesion equivocal for radiation necrosis versus tumor progression, 18F-fluciclovine PET/CT repurposed intracranially demonstrated encouraging diagnostic accuracy, supporting the pursuit of larger clinical trials which will be necessary to establish diagnostic criteria and performance.

Magnetic resonance imaging-guided stereotactic laser ablation therapy for the treatment of pediatric epilepsy: a retrospective multiinstitutional study

OBJECTIVE

The authors of this study evaluated the safety and efficacy of stereotactic laser ablation (SLA) for the treatment of drug-resistant epilepsy (DRE) in children.

METHODS

Seventeen North American centers were enrolled in the study. Data for pediatric patients with DRE who had been treated with SLA between 2008 and 2018 were retrospectively reviewed.

RESULTS

A total of 225 patients, mean age 12.8 ± 5.8 years, were identified. Target-of-interest (TOI) locations included extratemporal (44.4%), temporal neocortical (8.4%), mesiotemporal (23.1%), hypothalamic (14.2%), and callosal (9.8%). Visualase and NeuroBlate SLA systems were used in 199 and 26 cases, respectively. Procedure goals included ablation (149 cases), disconnection (63), or both (13). The mean follow-up was 27 ± 20.4 months. Improvement in targeted seizure type (TST) was seen in 179 (84.0%) patients. Engel classification was reported for 167 (74.2%) patients; excluding the palliative cases, 74 (49.7%), 35 (23.5%), 10 (6.7%), and 30 (20.1%) patients had Engel class I, II, III, and IV outcomes, respectively. For patients with a follow-up ≥ 12 months, 25 (51.0%), 18 (36.7%), 3 (6.1%), and 3 (6.1%) had Engel class I, II, III, and IV outcomes, respectively. Patients with a history of pre-SLA surgery related to the TOI, a pathology of malformation of cortical development, and 2+ trajectories per TOI were more likely to experience no improvement in seizure frequency and/or to have an unfavorable outcome. A greater number of smaller thermal lesions was associated with greater improvement in TST. Thirty (13.3%) patients experienced 51 short-term complications including malpositioned catheter (3 cases), intracranial hemorrhage (2), transient neurological deficit (19), permanent neurological deficit (3), symptomatic perilesional edema (6), hydrocephalus (1), CSF leakage (1), wound infection (2), unplanned ICU stay (5), and unplanned 30-day readmission (9). The relative incidence of complications was higher in the hypothalamic target location. Target volume, number of laser trajectories, number or size of thermal lesions, or use of perioperative steroids did not have a significant effect on short-term complications.

CONCLUSIONS

SLA appears to be an effective and well-tolerated treatment option for children with DRE. Large-volume prospective studies are needed to better understand the indications for treatment and demonstrate the long-term efficacy of SLA in this population.

Immediate Titanium Mesh Cranioplasty After Debridement and Craniectomy for Postcraniotomy Surgical Site Infections and Risk Factors for Reoperation

BACKGROUND

We previously published a novel strategy for management of postcraniotomy bone flap infection consisting of single stage debridement, bone flap removal, and immediate titanium mesh cranioplasty.

METHODS

Postcraniotomy patients with surgical site infections treated with surgical debridement, bone flap removal, and immediate titanium mesh cranioplasty were retrospectively reviewed. The primary outcome measure was reoperation due to persistent infection or wound healing complications from the titanium mesh.

RESULTS

We included 48 patients, of which 15 (31.3%) were female. The most common primary diagnoses were glioblastoma (31.3%), meningioma (18.8%), and vascular/trauma (16.7%). Most patients had a history of same-site craniotomy prior to the surgery complicated by surgical site infection and 47.9% had prior cranial radiation. Thirty-six (75.0%) patients achieved resolution of their infection and did not require a second operation. Twelve (25.0%) patients required reoperation: 6 (12.5%) patients were found to have frank intraoperative purulence on reoperation, whereas 6 (12.5%) had reoperation for poor wound healing without any evidence of persistent infection. Cochran Armitage trend test revealed that patients with increasing number of wound healing risk factors had significantly higher risk of reoperation (P = 0.001). Prior intensity modulated radiotherapy alone was a significant risk factor for reoperation (6.5 [1.40-30.31], P = 0.002). Median follow-up time was 20.5 weeks.

CONCLUSIONS

Immediate titanium mesh cranioplasty at the time of debridement and bone flap removal is an acceptable option in the management of post-craniotomy bone flap infection. Patients with multiple wound healing risk factors are at higher risk for reoperation.

Stereotactic radiosurgery for Koos grade IV vestibular schwannoma: a multi-institutional study

OBJECTIVE

Though stereotactic radiosurgery (SRS) is an established safe treatment for small- and medium-sized vestibular schwannomas (VSs), its role in the management of Koos grade IV VS is still unclear. In this retrospective multicenter study, the authors evaluated tumor control and the patient outcomes of primary, single-session SRS treatment for Koos grade IV VS.

METHODS

This study included patients treated with primary, single-session SRS for Koos grade IV VS at 10 participating centers. Only those patients presenting with non-life-threatening or incapacitating symptoms and at least 12 months of clinical and neuroimaging follow-up were eligible for inclusion. Relevant data were collected, and the Kaplan-Meier method was used to perform time-dependent analysis for post-SRS tumor control, hearing preservation, and facial nerve function preservation. Univariate and multivariate analyses were performed for outcome measures using Cox regression analysis.

RESULTS

Six hundred twenty-seven patients (344 females, median patient age 54 [IQR 22] years) treated with primary SRS were included in this study. The median tumor volume was 8.7 (IQR 5) cm3. Before SRS, serviceable hearing, facial nerve weakness (House-Brackmann grade > I), and trigeminal neuropathy were present in 205 (33%), 48 (7.7%), and 203 (32.4%) patients, respectively. The median prescription dose was 12 (IQR 1) Gy. At a median radiological follow-up of 38 (IQR 54) months, tumor control was achieved in 94.1% of patients. Early tumor expansion occurred in 67 (10.7%) patients and was associated with a loss of tumor control at the last follow-up (p = 0.001). Serviceable hearing preservation rates at the 5- and 10-year follow-ups were 65% and 44.6%, respectively. Gardner-Robertson class > 1 (p = 0.003) and cochlear dose ≥ 4 Gy (p = 0.02) were risk factors for hearing loss. Facial nerve function deterioration occurred in 19 (3.0%) patients at the last follow-up and was associated with margin doses ≥ 13 Gy (p = 0.03) and early tumor expansion (p = 0.04). Post-SRS, 33 patients developed hydrocephalus requiring shunting. Adverse radiation effects occurred in 92 patients and were managed medically or surgically in 34 and 18 cases, respectively.

CONCLUSIONS

SRS is a safe and effective method of obtaining tumor control in patients with Koos grade IV VS presenting with non-life-threatening or debilitating symptoms, especially those with surgical comorbidities that contraindicate resection. To decrease the incidence of post-SRS facial palsy, a prescription dose < 13 Gy is recommended.

Stereotactic radiosurgery for Koos grade IV vestibular schwannoma in patients ≥ 65 years old: a multi-institutional retrospective study

BACKGROUND

Surgery is the preferred treatment for large vestibular schwannomas (VS). Good tumor control and cranial nerve outcomes were described in selected Koos IV VS after single-session stereotactic radiosurgery (SRS), but outcomes in elderly patients have never been specifically studied. The aim of this study is to report clinical and radiological outcomes after single-session SRS for Koos IV VS in patients ≥ 65 years old.

METHOD

This multicenter, retrospective study included patients ≥ 65 years old, treated with primary, single-session SRS for a Koos IV VS, and at least 12 months of follow-up. Patients with life-threatening or incapacitating symptoms were excluded. Tumor control rate, hearing, trigeminal, and facial nerve function were studied at last follow-up.

RESULTS

One-hundred and fifty patients (median age of 71.0 (IQR 9.0) years old with a median tumor volume of 8.3 cc (IQR 4.4)) were included. The median prescription dose was 12.0 Gy (IQR 1.4). The local tumor control rate was 96.0% and 86.2% at 5 and 10 years, respectively. Early tumor expansion occurred in 6.7% and was symptomatic in 40% of cases. A serviceable hearing was present in 16.1% prior to SRS and in 7.4% at a last follow-up of 46.5 months (IQR 55.8). The actuarial serviceable hearing preservation rate was 69.3% and 50.9% at 5 and 10 years, respectively. Facial nerve function preservation or improvement rates at 5 and 10 years were 98.7% and 91.0%, respectively. At last follow-up, the trigeminal nerve function was improved in 14.0%, stable in 80.7%, and worsened in 5.3% of the patients. ARE were noted in 12.7%. New hydrocephalus was seen in 8.0% of patients.

CONCLUSION

SRS can be a safe alternative to surgery for selected Koos IV VS in patients ≥ 65 years old. Further follow-up is warranted.

Radiation necrosis or tumor progression? A review of the radiographic modalities used in the diagnosis of cerebral radiation necrosis

PURPOSE

Cerebral radiation necrosis is a complication of radiation therapy that can be seen months to years following radiation treatment. Differentiating radiation necrosis from tumor progression on standard magnetic resonance imaging (MRI) is often difficult and advanced imaging techniques may be needed to make an accurate diagnosis. The purpose of this article is to review the imaging modalities used in differentiating radiation necrosis from tumor progression following radiation therapy for brain metastases.

METHODS

We performed a review of the literature addressing the radiographic modalities used in the diagnosis of radiation necrosis.

RESULTS

Differentiating radiation necrosis from tumor progression remains a diagnostic challenge and advanced imaging modalities are often required to make a definitive diagnosis. If diagnostic uncertainty remains following conventional imaging, a multi-modality diagnostic approach with perfusion MRI, magnetic resonance spectroscopy (MRS), positron emission tomography (PET), single photon emission spectroscopy (SPECT), and radiomics may be used to improve diagnosis.

CONCLUSION

Several imaging modalities exist to aid in the diagnosis of radiation necrosis. Future studies developing advanced imaging techniques are needed.

Stereotactic radiosurgery for intracranial chordomas: an international multiinstitutional study

OBJECTIVE

The object of this study was to evaluate the safety, efficacy, and long-term outcomes of stereotactic radiosurgery (SRS) in the management of intracranial chordomas.

METHODS

This retrospective multicenter study involved consecutive patients managed with single-session SRS for an intracranial chordoma at 10 participating centers. Radiological and neurological outcomes were assessed after SRS, and predictive factors were evaluated via statistical methodology.

RESULTS

A total of 93 patients (56 males [60.2%], mean age 44.8 years [SD 16.6]) underwent single-session SRS for intracranial chordoma. SRS was utilized as adjuvant treatment in 77 (82.8%) cases, at recurrence in 13 (14.0%) cases, and as primary treatment in 3 (3.2%) cases. The mean tumor volume was 8 cm3 (SD 7.3), and the mean prescription volume was 9.1 cm3 (SD 8.7). The mean margin and maximum radiosurgical doses utilized were 17 Gy (SD 3.6) and 34.2 Gy (SD 6.4), respectively. On multivariate analysis, treatment failure due to tumor progression (p = 0.001) was associated with an increased risk for post-SRS neurological deterioration, and a maximum dose > 29 Gy (p = 0.006) was associated with a decreased risk. A maximum dose > 29 Gy was also associated with improved local tumor control (p = 0.02), whereas the presence of neurological deficits prior to SRS (p = 0.04) and an age > 65 years at SRS (p = 0.03) were associated with worse local tumor control. The 5- and 10-year tumor progression-free survival rates were 54.7% and 34.7%, respectively. An age > 65 years at SRS (p = 0.01) was associated with decreased overall survival. The 5- and 10-year overall survival rates were 83% and 70%, respectively.

CONCLUSIONS

SRS appears to be a safe and relatively effective adjuvant management option for intracranial chordomas. The best outcomes were obtained in younger patients without significant neurological deficits. Further well-designed studies are necessary to define the best timing for the use of SRS in the multidisciplinary management of intracranial chordomas.

Stereotactic radiosurgery for Koos grade IV vestibular schwannoma in young patients: a multi-institutional study

PURPOSE

Surgery is the treatment of choice for large vestibular schwannomas (VS). Stereotactic radiosurgery (SRS) has been suggested as an alternative to resection in selected patients. However, the safety and efficacy of SRS in Koos grade IV patients ≤ 45 years old has not been evaluated. The aim of this study is to describe the clinical and radiological outcomes of Koos grade IV in young patient managed with a single-session SRS.

METHODS

This retrospective, multicenter analysis included SRS-treated patients, ≤ 45 years old presenting with non-life threatening or incapacitating symptoms due to a Koos Grade IV VS and with follow-up ≥ 12 months. Tumor control and neurological outcomes were evaluated.

RESULTS

176 patients [median age of 36.0 (IQR 9) and median tumor volume of 9.3 cm³ (IQR 4.7)] were included. The median prescription dose was 12 Gy (IQR 0.5). Median follow-up period was 37.5 (IQR 53.5) months. The 5- and 10-year progression-free survival was 90.9% and 86.7%. Early tumor enlargement occurred in 10.9% of cases and was associated with tumor progression at the last follow-up. The probability of serviceable hearing preservation at 5- and 10-years was 56.8% and 45.2%, respectively. The probability of improvement or preservation of facial nerve function was 95.7% at 5 and 10-years. Adverse radiation effects were noted in 19.9%. New-onset hydrocephalus occurred in 4.0%.

CONCLUSION

Single-session SRS is a safe and effective alternative to surgical resection in selected patients ≤ 45 years old particularly those with medical co-morbidities and those who decline resection. Longer term follow up is warranted.

P15.11.A 18F-Fluciclovine PET/CT to distinguish radiation necrosis from tumour progression in brain metastases treated with stereotactic radiosurgery: results of a prospective pilot study

Background

Amino acid PET radiopharmaceutical, 18F-fluciclovine, shows increased uptake in brain tumors relative to normal tissue and may be a useful tool for detecting recurrent brain metastases. Here, we report results from a prospective pilot study evaluating the use of 18F-fluciclovine PET/CT to distinguish radiation necrosis from tumour progression among patients with brain metastases treated with stereotactic radiosurgery (SRS).

Material and Methods

The primary objective was to estimate the accuracy of 18F-fluciclovine PET/CT in distinguishing radiation necrosis from tumour progression. The trial included adults with brain metastases who underwent SRS and presented with a follow up MRI brain (with DSC MR perfusion) which was equivocal for radiation necrosis versus tumour progression. Within 30 days of equivocal MRI brain, patients underwent an 18F-fluciclovine PET/CT (Siemens mCT) acquired 5-15 min post-injection with images generated by PSF reconstruction. Quantitative metrics for each lesion were documented and lesion to normal brain SUVmean ratios were calculated. The reference standard for diagnosis of radiation necrosis vs tumour progression was clinical follow up with MRI brain every 2-4 months until multidisciplinary consensus or tissue confirmation.

Results

Of 16 patients enrolled between 7/2019-11/2020, 1 patient died prior to diagnosis, allowing 15 evaluable subjects with 20 lesions. Primary histology was NSCLC in 9 (45%) lesions, breast in 7 (35%), melanoma in 3 (15%), and endometrial in 1 (5%). The final diagnosis was radiation necrosis in 16 (80%) lesions and tumour progression in 4 (20%). SUVmax was a statistically significant predictor of tumour progression (P = 0.011), with higher SUVmax values indicative of tumour progression. The area under the ROC curve was 0.833 (95% CI: 0.590, 1.0). A cutoff of 4.3 provided a sensitivity to identify tumour progression of 1.0 (4/4) and specificity to rule out tumour progression of 0.63 (10/16). SUVmean (P = 0.018), SUVpeak (P = 0.007), and SUVpeak/normal (P = 0.002) also reached statistical significance as predictors of tumour progression, with higher SUVmax values indicative of tumour progression. SUVmax/normal (P = 0.1) and SUVmean/normal (P = 0.5) were not statistically significant. The AUC for SUVmax was not significantly higher than the AUCs for the other quantitative variables (P-values &gt; 0.2).

Conclusion

In this prospective pilot study, 18F Fluciclovine PET/CT demonstrated promising accuracy to distinguish radiation necrosis from tumour progression among patients with brain metastases previously treated with SRS. Using SUVmax, a cutpoint of 4.3 provided a sensitivity of 1.0 and specificity of 0.63. Confirmatory phase II and III studies are ongoing.

Sex-Specific Differences in Low Grade Glioma Presentation and Outcome

PURPOSE

In addition to established prognostic factors in low-grade glioma (LGG), studies suggest a sexual dimorphism with male sex portending worse prognosis. Our objective was to identify the impact of sex on presentation and outcomes in LGG.

METHODS

We conducted a retrospective cohort study of adults (aged ≥ 18 years) diagnosed with LGG (WHO 2016 grade 2 glioma). Patients with IDH wildtype tumors were excluded. Patients were matched between male and female sex by age, treatment, and surgery via propensity score matching. Patient, tumor, and treatment characteristics were analyzed by sex. Endpoints included overall survival (OS), next intervention free survival (NIFS), progression free survival (PFS), and malignant transformation free survival (MTFS). Kaplan Meier analyses and Cox proportional hazards regression multivariable analysis (MVA) with backwards elimination was completed.

RESULTS

Of the 532 patients identified, 258 (48%) were male. Males were more likely to present with seizure (69.38% vs. 56.57%, p = 0.002), but no other statistically significant differences between sexes at presentation were identified. 5-year OS was higher in females at 87% (95% CI 83%-91%) versus 78% (95% CI 73-84%) in males (p=0.0045). NIFS was significantly higher in female patients at 68% (95% CI 62-74%) versus 57% (95% CI 51%-64%) in males (p = 0.009). On MVA, female sex was independently associated with improved OS (HR 1.54, 95% CI 1.16-2.05; p= 0.002), NIFS (HR 1.42, 95% CI 1.42; p= 0.004), and MTFS (HR 1.62, 95% CI 1.24-2.12; p= 0.0004). In patients with molecularly defined LGG (IDH and 1p19q status) (n = 291), female sex remained independently associated with improved OS (HR 1.79, 95% CI 1.16-2.77; p = 0.008) and NIFS (HR 1.45, 95% CI 1.07-1.96; p = 0.016).

CONCLUSIONS

In this study, female sex was independently associated with improved outcomes. These findings support intrinsic sex-specific differences in LGG behavior, justifying further studies to optimize management and therapeutics based on sex.

Combination Laser Interstitial Thermal Therapy Plus Stereotactic Radiotherapy (SRT) Increases Time to Progression for Biopsy-Proven Recurrent Brain Metastases

Background

Improved survival for patients with brain metastases has been accompanied by a rise in tumor recurrence after stereotactic radiotherapy (SRT). Laser interstitial thermal therapy (LITT) has emerged as an effective treatment for SRT failures as an alternative to open resection or repeat SRT. We aimed to evaluate the efficacy of LITT followed by SRT (LITT+SRT) in recurrent brain metastases.

Methods

A multicenter, retrospective study was performed of patients who underwent treatment for biopsy-proven brain metastasis recurrence after SRT at an academic medical center. Patients were stratified by “planned LITT+SRT” versus “LITT alone” versus “repeat SRT alone.” Index lesion progression was determined by modified Response Assessment in Neuro-Oncology Brain Metastases (RANO-BM) criteria.

Results

Fifty-five patients met inclusion criteria, with a median follow-up of 7.3 months (range: 1.0–30.5), age of 60 years (range: 37–86), Karnofsky Performance Status (KPS) of 80 (range: 60–100), and pre-LITT/biopsy contrast-enhancing volume of 5.7 cc (range: 0.7–19.4). Thirty-eight percent of patients underwent LITT+SRT, 45% LITT alone, and 16% SRT alone. Median time to index lesion progression (29.8, 7.5, and 3.7 months [P = .022]) was significantly improved with LITT+SRT. When controlling for age in a multivariate analysis, patients treated with LITT+SRT remained significantly less likely to have index lesion progression (P = .004).

Conclusions

These data suggest that LITT+SRT is superior to LITT or repeat SRT alone for treatment of biopsy-proven brain metastasis recurrence after SRT failure. Prospective trials are warranted to validate the efficacy of using combination LITT+SRT for treatment of recurrent brain metastases.

Laser Interstitial Thermal Therapy for Posterior Fossa Lesions: A Systematic Review and Analysis of Multi-Institutional Outcomes

Background: Laser interstitial thermal therapy (LITT) has emerged as a treatment option for deep-seated primary and metastatic brain lesions; however, hardly any data exist regarding LITT for lesions of the posterior fossa. Methods: A quantitative systematic review was performed. Article selection was performed by searching MEDLINE (using PubMed), Scopus, and Cochrane electronic bibliographic databases. Inclusion criteria were studies assessing LITT on posterior fossa tumors. Results: 16 studies comprising 150 patients (76.1% female) with a mean age of 56.47 years between 2014 and 2021 were systematically reviewed for treatment outcomes and efficacy. Morbidity and mortality data could be extracted for 131 of the 150 patients. Death attributed to treatment failure, disease progression, recurrence, or postoperative complications occurred in 6.87% (9/131) of the pooled sample. Procedure-related complications, usually including new neurologic deficits, occurred in approximately 14.5% (19/131) of the pooled sample. Neurologic deficits improved with time in most cases, and 78.6% (103/131) of the pooled sample experienced no complications and progression-free survival at the time of last follow-up. Conclusions: LITT for lesions of the posterior fossa continues to show promising data. Future clinical cohort studies are required to further direct treatment recommendations.

Laser interstitial thermal therapy for brain metastases

Laser interstitial thermal therapy (LITT) is a minimally invasive treatment for intracranial lesions entailing thermal ablation via a stereotactically placed laser probe. In metastatic disease, it has shown the most promise in the treatment of radiographically progressive lesions after initial stereotactic radiosurgery, whether due to recurrent metastatic disease or radiation necrosis. LITT has been demonstrated to provide clinical benefit in both cases, as discussed in the review below. With its minimal surgical footprint and short recovery period, LITT is further advantaged for patients who are otherwise high-risk surgical candidates or with lesions in difficult to access locations. Exploration of the current data on its use in metastatic disease will allow for a better understanding of the indications, benefits, and future directions of LITT for these patients.

Adjuvant radiation versus observation with salvage radiation after gross-total resection of WHO grade II meningiomas: a propensity score-adjusted analysis

OBJECTIVE

After gross-total resection (GTR) of a newly diagnosed WHO grade II meningioma, the decision to treat with radiation upfront or at initial recurrence remains controversial. A comparison of progression-free survival (PFS) between observation and adjuvant radiation fails to account for the potential success of salvage radiation, and a direct comparison of PFS between adjuvant and salvage radiation is hampered by strong selection bias against salvage radiation cohorts in which only more aggressive, recurrent tumors are included. To account for the limitations of traditional PFS measures, the authors evaluated radiation failure-free survival (RFFS) between two treatment strategies after GTR: adjuvant radiation versus observation with salvage radiation, if necessary.

METHODS

The authors performed a retrospective review of patients who underwent GTR of newly diagnosed WHO grade II meningiomas at their institution between 1996 and 2019. They assessed traditional PFS in patients who underwent adjuvant radiation, postoperative observation, and salvage radiation. For RFFS, treatment failure was defined as time from initial surgery to failure of first radiation. To assess the association between treatment strategy and RFFS while accounting for potential confounders, a multivariable Cox regression analysis adjusted for the propensity score (PS) and inverse probability of treatment weighted (IPTW) Cox regression analysis were performed.

RESULTS

A total of 160 patients underwent GTR and were included in this study. Of the 121 patients who underwent observation, 32 (26.4%) developed recurrence and required salvage radiation. PFS at 3, 5, and 10 years after observation was 75.1%, 65.6%, and 45.5%, respectively. PFS at 3 and 5 years after salvage radiation was 81.7% and 61.3%, respectively. Of 160 patients, 39 received adjuvant radiation, and 3- and 5-year PFS/RFFS rates were 86.1% and 59.2%, respectively. In patients who underwent observation with salvage radiation, if necessary, the 3-, 5-, and 10-year RFFS rates were 97.7%, 90.3%, and 87.9%, respectively. Both PS and IPTW Cox regression models demonstrated that patients who underwent observation with salvage radiation treatment, if necessary, had significantly longer RFFS (PS model: hazard ratio [HR] 0.21, p < 0.01; IPTW model: HR 0.21, p < 0.01).

CONCLUSIONS

In this retrospective, nonrandomized study, adjuvant radiation after GTR of a WHO II meningioma did not add significant benefit over a strategy of observation and salvage radiation at initial recurrence, if necessary, but results must be considered in the context of the limitations of the study design.

Laser Interstitial Thermal Therapy in the Treatment of Thalamic Brain Tumors: A Case Series

BACKGROUND

Surgical options for patients with thalamic brain tumors are limited. Traditional surgical resection is associated with a high degree of morbidity and mortality. Laser interstitial thermal therapy (LITT) utilizes a stereotactically placed laser probe to induce thermal damage to tumor tissue. LITT provides a surgical cytoreduction option for this challenging patient population. We present our experience treating thalamic brain tumors with LITT.

OBJECTIVE

To describe our experience and outcomes using LITT on patients with thalamic tumors.

METHODS

We analyzed 13 consecutive patients treated with LITT for thalamic tumors from 2012 to 2017. Radiographic, clinical characteristics, and outcome data were collected via review of electronic medical records.

RESULTS

Thirteen patients with thalamic tumors were treated with LITT. Most had high-grade gliomas, including glioblastoma (n = 9) and anaplastic astrocytoma (n = 2). The average tumor volume was 12.0 cc and shrank by 42.9% at 3 mo. The average hospital stay was 3.0 d. Median ablation coverage as calculated by thermal damage threshold (TDT) lines was 98% and 95% for yellow (>43°C for >2 min) or blue (>10 min), respectively. Median disease-specific progression-free survival calculated for 8 patients in our cohort was 6.1 mo (range: 1.1-15.1 mo). There were 6 patients with perioperative morbidity and 2 perioperative deaths because of intracerebral hematoma.

CONCLUSION

LITT is a feasible treatment for patients with thalamic tumors. LITT offers a cytoreduction option in this challenging population. Patient selection is key. Close attention should be paid to lesion size to minimize morbidity. More studies comparing treatment modalities of thalamic tumors need to be performed.

Impact of KRAS mutation status on the efficacy of immunotherapy in lung cancer brain metastases

Immune checkpoint inhibitors (ICIs) have resulted in improved outcomes in non-small cell lung cancer (NSCLC) patients. However, data demonstrating the efficacy of ICIs in NSCLC brain metastases (NSCLCBM) is limited. We analyzed overall survival (OS) in patients with NSCLCBM treated with ICIs within 90 days of NSCLCBM diagnosis (ICI-90) and compared them to patients who never received ICIs (no-ICI). We reviewed 800 patients with LCBM who were diagnosed between 2010 and 2019 at a major tertiary care institution, 97% of whom received stereotactic radiosurgery (SRS) for local treatment of BM. OS from BM was compared between the ICI-90 and no-ICI groups using the Log-Rank test and Cox proportional-hazards model. Additionally, the impact of KRAS mutational status on the efficacy of ICI was investigated. After accounting for known prognostic factors, ICI-90 in addition to SRS led to significantly improved OS compared to no-ICI (12.5 months vs 9.1, p < 0.001). In the 109 patients who had both a known PD-L1 expression and KRAS status, 80.4% of patients with KRAS mutation had PD-L1 expression vs 61.9% in wild-type KRAS patients (p = 0.04). In patients without a KRAS mutation, there was no difference in OS between the ICI-90 vs no-ICI cohort with a one-year survival of 60.2% vs 54.8% (p = 0.84). However, in patients with a KRAS mutation, ICI-90 led to a one-year survival of 60.4% vs 34.1% (p = 0.004). Patients with NSCLCBM who received ICI-90 had improved OS compared to no-ICI patients. Additionally, this benefit appears to be observed primarily in patients with KRAS mutations that may drive the overall benefit, which should be taken into account in the development of future trials.

Laser thermal therapy in the management of high-grade gliomas

Laser interstitial thermal therapy (LITT) is a minimally invasive therapy that have been used for brain tumors, epilepsy, chronic pain, and other spine pathologies. This therapy is performed under imaging and stereotactic guidance to precisely direct the probe and ablate the area of interest using real-time magnetic resonance (MR) thermography. LITT has gained popularity as a treatment for glioma because of its minimally invasive nature, small skin incision, repeatability, shorter hospital stay, and the possibility of receiving adjuvant therapy shortly after surgery instead of several weeks as required after open surgical resection. Several reports have demonstrated the usefulness of LITT in the treatment of newly-diagnosed and recurrent gliomas. In this review, we will summarize the recent evidence of this therapy in the field of glioma surgery and the future perspectives of the use of LITT combined with other treatment strategies for this devastating disease.

The impact of sequencing PD-1/PD-L1 inhibitors and stereotactic radiosurgery for patients with brain metastasis

BACKGROUND

The response of brain metastases (BM) treated with stereotactic radiosurgery (SRS) and immune checkpoint inhibitors (ICIs; programmed cell death 1 and its ligand) is of significant interest.

METHODS

Patients were divided into cohorts based on ICI sequencing around SRS. The primary outcome was best objective response (BOR) that was lesion specific. Secondary outcomes included overall objective response (OOR), response durability, radiation necrosis (RN), and overall survival (OS).

RESULTS

One hundred fifty patients underwent SRS to 1003 BM and received ICI. Five hundred sixty-four lesions (56%) treated with concurrent ICI (±5 half-lives) demonstrated superior BOR, OOR, and response durability compared with lesions treated with SRS and delayed ICI. Responses were best in those treated with immediate (±1 half-life) ICI (BOR: -100 vs -57%, P < 0.001; complete response: 50 vs 32%; 12-month durable response: 94 vs 71%, P < 0.001). Lesions pre-exposed to ICI and treated with SRS had poorer BOR (-45%) compared with ICI naive lesions (-63%, P < 0.001); best response was observed in ICI naive lesions receiving SRS and immediate ICI (-100%, P < 0.001). The 12-month cumulative incidence of RN with immediate ICI was 3.2% (95% CI: 1.3-5.0%). First radiographic follow-up and best intracranial response were significantly associated with longer OS; steroids were associated with inferior response rates and poorer OS (median 10 vs 25 mo, P = 0.002).

CONCLUSIONS

Sequencing of ICI around SRS is associated with overall response, best response, and response durability, with the most substantial effect in ICI naive BM undergoing immediate combined modality therapy. First intracranial response for patients treated with immediate ICI and SRS may be prognostic for OS, whereas steroids are detrimental.

Neutrophil to lymphocyte ratio influences impact of steroids on efficacy of immune checkpoint inhibitors in lung cancer brain metastases

Steroids are often utilized to manage patients with non-small cell lung cancer brain metastases (NSCLCBM). Steroids and elevated neutrophil-to-lymphocyte ratio (NLR) have been associated with decreased overall survival (OS) in patients treated with immune checkpoint inhibitors (ICI). We retrospectively investigated patients treated with ICI after the diagnosis of NSCLCBM at a single tertiary care institution examing the impact of steroids and NLR. Overall survival (OS) and intracranial progression-free survival (PFS) were analyzed. 171 patients treated with ICI for NSCLCBM were included. Thirty-six received steroids within 30 days of the start of ICI, and 53 patients had an NLR ≥ 5 before the start of ICI. Upfront steroids was associated with decreased OS on multivariable analysis (median OS 10.5 vs. 17.9 months, p = .03) and intracranial PFS (5.0 vs. 8.7 months, p = .045). NLR ≥ 5 was indicative of worse OS (10.5 vs. 18.4 months, p = .04) but not intracranial PFS (7.2 vs. 7.7 months, p = .61). When NLR and upfront steroids are modeled together, there is a strong interaction (p = .0008) indicating that the impact of steroids depended on the patient’s NLR. In a subgroup analysis, only in patients with NLR < 4 was there a significant difference in OS with upfront steroids (26.1 vs. 15.6 months, p = .032). The impact of steroids on the efficacy of ICI in patients with NSCLCBM is dependent on the patient's NLR underscoring its importance in these patients. Patients with a low NLR, steroid use decreases the efficacy of ICI. These results can inform clinicians about the impact of steroids in patients treated with ICI.

Effect of Anatomic Segment Involvement on Stereotactic Radiosurgery for Facial Nerve Schwannomas: An International Multicenter Cohort Study

BACKGROUND

Facial nerve schwannomas are rare, challenging tumors to manage due to their nerve of origin. Functional outcomes after stereotactic radiosurgery (SRS) are incompletely defined.

OBJECTIVE

To analyze the effect of facial nerve segment involvement on functional outcome for these tumors.

METHODS

Patients who underwent single-session SRS for facial nerve schwannomas with at least 3 mo follow-up at 11 participating centers were included. Preoperative and treatment variables were recorded. Outcome measures included radiological tumor response and neurological function.

RESULTS

A total of 63 patients (34 females) were included in the present study. In total, 75% had preoperative facial weakness. Mean tumor volume and margin dose were 2.0 ± 2.4 cm3 and 12.2 ± 0.54 Gy, respectively. Mean radiological follow-up was 45.5 ± 38.9 mo. Progression-free survival at 2, 5, and 10 yr was 98.1%, 87.2%, and 87.2%, respectively. The cumulative proportion of patients with regressing tumors at 2, 5, and 10 yr was 43.1%, 63.6%, and 63.6%, respectively. The number of involved facial nerve segments significantly predicted tumor progression (P = .04). Facial nerve function was stable or improved in 57 patients (90%). Patients with involvement of the labyrinthine segment of the facial nerve were significantly more likely to have an improvement in facial nerve function after SRS (P = .03). Hearing worsened in at least 6% of patients. Otherwise, adverse radiation effects included facial twitching (3 patients), facial numbness (2 patients), and dizziness (2 patients).

CONCLUSION

SRS for facial nerve schwannomas is effective and spares facial nerve function in most patients. Some patients may have functional improvement after treatment, particularly if the labyrinthine segment is involved.

Outcomes of salvage radiation for recurrent world health organization grade II meningiomas: a retrospective cohort study

PURPOSE

The optimal modality of radiation-intensity-modulated radiation therapy (IMRT) or stereotactic radiosurgery (SRS)-in patients with recurrent WHO grade II meningiomas is not well-established. The purpose of this study was to compare progression-free survival (PFS) in patients undergoing salvage IMRT vs SRS. We compared PFS in those with and without history of prior radiation.

METHODS

Forty-two patients with 71 tumor recurrences treated with IMRT or SRS were retrospectively reviewed. Thirty-two salvage treatments were performed on recurrent tumors never treated with prior radiation ('radiation-naïve' cohort), whereas 39 salvage treatments were performed on recurrent tumors previously treated with radiation ('re-treatment cohort').

RESULTS

In the 'radiation-naïve' cohort, 3-year PFS for IMRT and SRS was 68.8% and 60.7%, respectively (p = 0.61). The median tumor volume for patients treated with IMRT was significantly larger than for patients treated with SRS (5.7 vs 2.2 cm³; p = 0.04). The 3-year PFS for salvage IMRT or SRS in the 're-treatment' cohort was 45.4% vs 65.8% in the 'radiation-naïve' cohort (p = 0.008). When analyzing the outcome of multiple re-treatments, median PFS was 47 months for 1^st or 2nd salvage radiation (IMRT or SRS) compared to 16 months for the 3rd or greater salvage radiation treatment (p = 0.003).

CONCLUSION

For salvage radiation of recurrent grade II tumors that are 'radiation-naïve', comparable 3-year PFS rates were found between IMRT and SRS, despite the IMRT group having significantly larger tumors. Salvage radiation overall was less successful in the 're-treatment' cohort compared with the 'radiation-naïve' cohort. Additionally, the effectiveness of radiation significantly declines with successive salvage radiation treatments.

Impact of EGFR mutation and ALK rearrangement on the outcomes of non-small cell lung cancer patients with brain metastasis

BACKGROUND

The impact of activating alterations in non-small cell lung cancer (NSCLC) (epidermal growth factor receptor [EGFR] mutation/anaplastic lymphoma kinase [ALK] translocation) in prognosticating patients with brain metastasis (BM) is not well defined. This study was sought to identify this impact in NSCLC patients with BM accounting for the known validated variables.

METHODS

Among 1078 NSCLC-BM patients diagnosed/treated between January 1, 2000 and December 31, 2015, three hundred and forty-eight with known EGFR/ALK status were analyzed. Overall survival (OS) and intracranial progression-free survival (PFS) were measured from the time of BM.

RESULTS

Ninety-one patients had either ALK (n = 23) alterations or EGFR (n = 68) mutation and 257 were wild type (WT; negative actionable mutations/alterations). Median age of EGFR/ALK+ NSCLC BM patients was 60 years (range 29.8-82.6 y) and ~50% (n = 44) had Karnofsky performance status (KPS) score >80. Median number of BM was 2 (1 to ≥99). The median OS for the ALK/EGFR+ NSCLC BM was 19.9 versus 10.1 months for the WT (P = 0.028). The number of BM in the EGFR/ALK+ group did not impact OS (BM = 1 with 21.1 months vs 2-3 with 19.1 months and >3 with 23.7 months, P = 0.74), whereas fewer BM in the WT cohort had significantly better OS (BM = 1 with 13.8 mo, 2-3 with 11.0 mo and >3 with 8.1 mo; P = 0.006) with the adjustment of age, KPS, symptoms from BM and synchronicity.

CONCLUSIONS

Number of BM does not impact outcomes in the EGFR/ALK+ NSCLC patients, implying that targeted therapy along with surgery and/or radiation may improve OS irrespective of the number of BM. Number of BM, extracranial metastasis (ECM), and KPS independently affected OS/PFS in WT NSCLC BM, which was consistent with the known literature.

Preclinical Modeling of Surgery and Steroid Therapy for Glioblastoma Reveals Changes in Immunophenotype that are Associated with Tumor Growth and Outcome

PURPOSE

Glioblastoma (GBM) immunotherapy clinical trials are generally initiated after standard-of-care treatment-including surgical resection, perioperative high-dose steroid therapy, chemotherapy, and radiation treatment-has either begun or failed. However, the impact of these interventions on the antitumoral immune response is not well studied. While discoveries regarding the impact of chemotherapy and radiation on immune response have been made and translated into clinical trial design, the impact of surgical resection and steroids on the antitumor immune response has yet to be determined.

EXPERIMENTAL DESIGN

We developed a murine model integrating tumor resection and steroid treatment and used flow cytometry to analyze systemic and local immune changes. These mouse model findings were validated in a cohort of 95 patients with primary GBM.

RESULTS

Using our murine resection model, we observed a systemic reduction in lymphocytes corresponding to increased tumor volume and decreased circulating lymphocytes that was masked by dexamethasone treatment. The reduction in circulating T cells was due to reduced CCR7 expression, resulting in T-cell sequestration in lymphoid organs and the bone marrow. We confirmed these findings in a cohort of patients with primary GBM and found that prior to steroid treatment, circulating lymphocytes inversely correlated with tumor volume. Finally, we demonstrated that peripheral lymphocyte content varies with progression-free survival and overall survival, independent of tumor volume, steroid use, or molecular profiles.

CONCLUSIONS

These data reveal that prior to intervention, increased tumor volume corresponds with reduced systemic immune function and that peripheral lymphocyte counts are prognostic when steroid treatment is taken into account.

Role of Gamma Knife Radiosurgery in Small Cell Lung Cancer: A Multi-Institutional Retrospective Study of the International Radiosurgery Research Foundation (IRRF)

BACKGROUND

Despite a high incidence of brain metastases in patients with small-cell lung cancer (SCLC), limited data exist on the use of stereotactic radiosurgery (SRS), specifically Gamma Knife™ radiosurgery (Elekta AB), for SCLC brain metastases.

OBJECTIVE

To provide a detailed analysis of SCLC patients treated with SRS, focusing on local failure, distant brain failure, and overall survival (OS).

METHODS

A multi-institutional retrospective review was performed on 293 patients undergoing SRS for SCLC brain metastases at 10 medical centers from 1991 to 2017. Data collection was performed according to individual institutional review boards, and analyses were performed using binary logistic regression, Cox-proportional hazard models, Kaplan-Meier survival analysis, and competing risks analysis.

RESULTS

Two hundred thirty-two (79%) patients received SRS as salvage following prior whole-brain irradiation (WBRT) or prophylactic cranial irradiation, with a median marginal dose of 18 Gy. At median follow-up after SRS of 6.4 and 18.0 mo for surviving patients, the 1-yr local failure, distant brain failure, and OS were 31%, 49%, and 28%. The interval between WBRT and SRS was predictive of improved OS for patients receiving SRS more than 1 yr after initial treatment (21%, <1 yr vs 36%, >1 yr, P = .01). On multivariate analysis, older age was the only significant predictor for OS (hazard ratio 1.63, 95% CI 1.16-2.29, P = .005).

CONCLUSION

SRS plays an important role in the management of brain metastases from SCLC, especially in salvage therapy following WBRT. Ongoing prospective trials will better assess the value of radiosurgery in the primary management of SCLC brain metastases and potentially challenge the standard application of WBRT in SCLC patients.

Extent of resection and survival outcomes in World Health Organization grade II meningiomas

PURPOSE

WHO grade II meningiomas behave aggressively, with recurrence rates as high as 60%. Although complete resection in low-grade meningiomas is associated with a relatively low recurrence rate, the impact of complete resection for WHO grade II meningiomas is less clear. We studied the association of extent of resection with overall and progression-free survivals in patients with WHO grade II meningiomas.

METHODS

A retrospective database review was performed to identify all patients who underwent surgical resection for intracranial WHO grade II meningiomas at our institution between 1995 and 2019. Kaplan-Meier analysis was used to compare overall and progression-free survivals between patients who underwent gross total resection (GTR) and those who underwent subtotal resection (STR). Multivariable Cox proportional-hazards analysis was used to identify independent predictors of tumor recurrence and mortality.

RESULTS

Of 214 patients who underwent surgical resection for WHO grade II meningiomas (median follow-up 53.4 months), 158 had GTR and 56 had STR. In Kaplan-Meier analysis, patients who underwent GTR had significantly longer progression-free (p = 0.002) and overall (p = 0.006) survivals than those who underwent STR. In multivariable Cox proportional-hazards analysis, GTR independently predicted prolonged progression-free (HR 0.57, p = 0.038) and overall (HR 0.44, p = 0.017) survivals when controlling for age, tumor location, and adjuvant radiation.

CONCLUSIONS

Extent of resection independently predicts progression-free and overall survivals in patients with WHO grade II meningiomas. In an era of increasing support for adjuvant treatment modalities in the management of meningiomas, our data support maximal safe resection as the primary goal in treatment of these patients.

The Meningioma Enhancer Landscape Delineates Novel Subgroups and Drives Druggable Dependencies

Meningiomas are the most common primary intracranial tumor with current classification offering limited therapeutic guidance. Here, we interrogated meningioma enhancer landscapes from 33 tumors to stratify patients based upon prognosis and identify novel meningioma-specific dependencies. Enhancers robustly stratified meningiomas into three biologically distinct groups (adipogenesis/cholesterol, mesodermal, and neural crest) distinguished by distinct hormonal lineage transcriptional regulators. Meningioma landscapes clustered with intrinsic brain tumors and hormonally responsive systemic cancers with meningioma subgroups, reflecting progesterone or androgen hormonal signaling. Enhancer classification identified a subset of tumors with poor prognosis, irrespective of histologic grading. Superenhancer signatures predicted drug dependencies with superior in vitro efficacy to treatment based upon the NF2 genomic profile. Inhibition of DUSP1, a novel and druggable meningioma target, impaired tumor growth in vivo. Collectively, epigenetic landscapes empower meningioma classification and identification of novel therapies. SIGNIFICANCE: Enhancer landscapes inform prognostic classification of aggressive meningiomas, identifying tumors at high risk of recurrence, and reveal previously unknown therapeutic targets. Druggable dependencies discovered through epigenetic profiling potentially guide treatment of intractable meningiomas.This article is highlighted in the In This Issue feature, p. 1611.

Peritumoral Brain Edema and Surgical Outcome in Secretory Meningiomas: A Matched-Cohort Analysis

OBJECTIVE

Secretory meningioma (SM) is a rare subtype of benign meningioma reported to cause significant peritumoral brain edema (PTBE). Therefore, patients with SM may have more severe presenting symptoms and possibly increased postoperative complications. Our aim was to perform a statistically rigorous comparison of patients with SM with other nonsecretory World Health Organization grade I meningiomas and examine PTBE, postsurgical outcomes, and recurrence in a large series of cases.

METHODS

A retrospective review of all patients at our institution with pathologically confirmed SM between 2000 and 2017 was performed. A control group of nonsecretory grade I meningiomas was matched 1:1 according to tumor location and size. Study groups were compared on clinical characteristics and outcomes using logistic, cumulative logit, and normal linear generalized estimating equations regression models.

RESULTS

Fifty-five patients with SM met inclusion criteria and were matched with 55 control patients. After adjusting for size and location, the odds of a patient with SM having a more severe T2 edema grade were 8.9 (95% confidence interval, 3.8-21.1; P < 0.001) times higher, and the odds of any T2 edema were 6.2 (95% confidence interval, 2.2-17.6; P < 0.001) times higher. Significance remained even when adjusting for age. Postoperative complications, Simpson grade resection, neurologic outcome, and recurrence were not significantly different.

CONCLUSIONS

Patients with SM have significantly greater odds of having PTBE compared with patients with nonsecretory World Health Organization grade I meningiomas of a similar size and location. Despite this situation, surgical outcome and recurrence rates are similar.

Fractionated Gamma Knife radiosurgery for skull base meningiomas: a single-institution experience

OBJECTIVEGamma Knife radiosurgery (GKRS) has been successfully used for the treatment of intracranial meningiomas given its steep dose gradients and high-dose conformality. However, treatment of skull base meningiomas (SBMs) may pose significant risk to adjacent radiation-sensitive structures such as the cranial nerves. Fractionated GKRS (fGKRS) may decrease this risk, but until recently it has not been practical with traditional pin-based systems. This study reports the authors' experience in treating SBMs with fGKRS, using a relocatable, noninvasive immobilization system.METHODSThe authors performed a retrospective review of all patients who underwent fGKRS for SBMs between 2013 and 2018 delivered using the Extend relocatable frame system or the Icon system. Patient demographics, pre- and post-GKRS tumor characteristics, perilesional edema, prior treatment details, and clinical symptoms were evaluated. Volumetric analysis of pre-GKRS, post-GKRS, and subsequent follow-up visits was performed.RESULTSTwenty-five patients met inclusion criteria. Nineteen patients were treated with the Icon system, and 6 patients were treated with the Extend system. The mean pre-fGKRS tumor volume was 7.62 cm3 (range 4.57-13.07 cm3). The median margin dose was 25 Gy delivered in 4 (8%) or 5 (92%) fractions. The median follow-up time was 12.4 months (range 4.7-17.4 months). Two patients (9%) experienced new-onset cranial neuropathy at the first follow-up. The mean postoperative tumor volume reduction was 15.9% with 6 patients (27%) experiencing improvement of cranial neuropathy at the first follow-up. Median first follow-up scans were obtained at 3.4 months (range 2.8-4.3 months). Three patients (12%) developed asymptomatic, mild perilesional edema by the first follow-up, which remained stable subsequently.CONCLUSIONSfGKRS with relocatable, noninvasive immobilization systems is well tolerated in patients with SBMs and demonstrated satisfactory tumor control as well as limited radiation toxicity. Future prospective studies with long-term follow-up and comparison to single-session GKRS or fractionated stereotactic radiotherapy are necessary to validate these findings and determine the efficacy of this approach in the management of SBMs.

Stereotactic radiosurgery with concurrent HER2-directed therapy is associated with improved objective response for breast cancer brain metastasis

BACKGROUND

Patients with breast cancer positive for human epidermal growth factor receptor 2 (HER2) remain at high risk of intracranial relapse following treatment and experience increased rates of intracranial failure after stereotactic radiosurgery (SRS). We hypothesized that the addition of concurrent lapatinib to SRS would improve intracranial complete response rates.

METHODS

Patients with newly diagnosed HER2-amplified breast cancer brain metastases from 2005-2014 who underwent SRS were included and divided into 2 cohorts based on timing of treatment with lapatinib. Outcome variables included the proportion of patients who achieved an intracranial complete response or progressive disease according to the RECIST 1.1 criteria, as well as individual lesion response rates, distant intracranial failure, and radiation necrosis.

RESULTS

Eighty-four patients with 487 brain metastases met inclusion criteria during the study period. Over 138 treatment sessions, 132 lesions (27%) were treated with SRS and concurrent lapatinib, while 355 (73%) were treated with SRS without lapatinib. Compared with patients treated with SRS alone, patients treated with concurrent lapatinib had higher rates of complete response (35% vs 11%, P = 0.008). On a per-lesion basis, best objective response was superior in the concurrent lapatinib group (median 100% vs 70% reduction, P < 0.001). Concurrent lapatinib was not associated with an increased risk of grade 2+ radiation necrosis (1.0% with concurrent lapatinib vs 3.5% without, P = 0.27). Lapatinib had no protective effect on distant intracranial failure rates (48% vs 49%, P = 0.91).

CONCLUSION

The addition of concurrent lapatinib to SRS was associated with improved complete response rates among patients with HER2-positive brain metastases.