A Multi-institutional Study of Factors Influencing the Use of Stereotactic Radiosurgery for Brain Metastases

Real-world data on patterns and outcomes of radiation therapy for brain metastases in a population-based cohort of lung cancer patients in Victoria

INTRODUCTION

We evaluated real-world data on the patterns and outcomes of radiotherapy (RT) for brain metastases (BM) in a population-based cohort of patients with lung cancer (LC) in Victoria.

METHODS

The Victorian Radiotherapy Minimum Data set (VRMDS) and the Victorian Cancer Registry (VCR) were linked to identify patients with LC who underwent RT for BM between 2013 and 2016. We determined: (i) proportion of patients treated with stereotactic radiosurgery (SRS); (ii) overall survival (OS); and (iii) 30-day mortality (30M) following RT for BM.

RESULTS

Of the 1001 patients included in the study, 193 (19%) had SRS. There was no significant increase in SRS use over time - from 18% in 2013 to 21% in 2016 (P-trend = 0.8). In multivariate analyses, increased age (P = 0.03) and treatment in regional centres (P < 0.001) were independently associated with lower likelihood of SRS treatment. The median OS following RT for BM was 3.6 months. Patients who had SRS had better OS than those who did not have SRS (median OS 8.9 months vs. 3 months, P < 0.01). SRS use, age, sex and year of treatment were independently associated with OS in multivariate analyses. A total of 184 (18%) patients died within 30 days of RT for BM, and the proportion was higher in older (P = 0.001) and male patients (P = 0.004).

CONCLUSION

One-in-five LC patients who received RT for BM had SRS. The improved OS with SRS is likely confounded by patient selection. It is important to reduce 30M by better selecting patients who may not benefit from RT for BM.

Simultaneous radiosurgery for multiple brain metastases: technical overview of the UCLA experience

PURPOSE/OBJECTIVE(S)

To communicate our institutional experience with single isocenter radiosurgery treatments for multiple brain metastases, including challenges with determining planning target volume (PTV) margins and resulting consequences, image-guidance translational and rotational tolerances, intra-fraction patient motion, and prescription considerations with larger PTV margins.

MATERIALS/METHODS

Eight patient treatments with 51 targets were planned with various margins using Elements Multiple Brain Mets SRS treatment planning software (Brainlab, Munich, Germany). Forty-eight plans with 0 mm, 1 mm and 2 mm margins were created, including plans with variable margins, where targets more than 6 cm away from the isocenter were planned with larger margins. The dosimetric impact of the margins were analyzed with V5Gy, V8Gy, V10Gy, V12Gy values. Additionally, 12 patient motion data were analyzed to determine both the impact of the repositioning threshold and the distributions of the patient translational and rotational movements.

RESULTS

The V5Gy, V8Gy, V10Gy, V12Gy volumes approximately doubled when margins change from 0 to 1 mm and tripled when change from 0 to 2 mm. With variable margins, the aggregated results are similar to results from plans using the lower of two margins, since only 12.2% of the targets were more than 6 cm away from the isocenter. With 0.5 mm re-positioning threshold, 57.4% of the time the patients are repositioned. Reducing the threshold to 0.25 mm results in 91.7% repositioning rate, due to limitations of the fusion algorithm and actual patient motion. The 90th percentile of translational movements in all directions is 0.7 mm, while the 90th percentile of rotational movements in all directions is 0.6 degrees. Median translations and rotations are 0.2 mm and 0.2 degrees, respectively.

CONCLUSIONS

Based on the data presented, we have switched our modus operandi from 2 to 1 mm PTV margins, with an eventual goal of using 0.5 and 1.0 mm variable margins when an automated margin assignment method becomes available. The 0.5 mm and 0.5 degrees repositioning thresholds are clinically appropriate with small residual patient movements.

Radiotherapy for brain metastases from small-cell lung cancer in distinct clinical indications and scenarios

Management of brain metastases (BM) from small-cell lung cancer (SCLC) is complex and not supported by a strong evidence from prospective clinical trials. Owing to the different clinical and pathological characteristics of SCLC, patients with this histology were not included in the prospective studies on the value of whole-brain radiotherapy (WBRT) and local surgical or ablative radiation treatment like stereotactic radiosurgery (SRS). Chemotherapy also represents a major part of the armamentarium against BM from SCLC due to the well-recognized chemoresponsiveness of this cancer and the frequent presentation of BM with extracranial progression. WBRT in combination with chemotherapy has long been a standard approach in this setting. However, data on the neurocognitive toxicity and the lack of documented impact on overall survival of WBRT in the management of BM from other solid tumors, as well as the increasing availability of the stereotactic radiotherapy technologies, has led to the increasing use of SRS with omission of WBRT also in SCLC. In the current review the use of different modalities of radiotherapy and ways of combining radiotherapy with chemotherapy for BM from SCLC will be presented for distinct clinical situations: presentation of BM synchronous with primary, metachronous presentation of BM-without previous prophylactic cranial irradiation (PCI) vs. after PCI, and asymptomatic BM found at the staging before PCI.

Time-Driven Activity-Based Costing Comparison of Stereotactic Radiosurgery to Multiple Brain Lesions Using Single-Isocenter Versus Multiple-Isocenter Technique

PURPOSE

Stereotactic radiosurgery (SRS) historically has been used to treat multiple brain lesions using a multiple-isocenter technique-frequently associated with significant complexity in treatment planning and long treatment times. Recently, given innovations in planning algorithms, patients with multiple brain lesions may now be treated with a single-isocenter technique using fewer total arcs and less time spent during image guidance (though with stricter image guided radiation therapy tolerances). This study used time-driven activity-based costing to determine the difference in cost to a provider for delivering SRS to multiple brain lesions using single-isocenter versus multiple-isocenter techniques.

METHODS AND MATERIALS

Process maps, consisting of discrete steps, were created for each phase of the SRS care cycle and were based on interviews with department personnel. Actual treatment times (including image guidance) were extracted from treatment record and verify software. Additional sources of data to determine costs included salary/benefit data of personnel and average list price/maintenance costs for equipment.

RESULTS

Data were collected for 22 patients who underwent single-isocenter SRS (mean lesions treated, 5.2; mean treatment time, 30.2 minutes) and 51 patients who underwent multiple-isocenter SRS (mean lesions treated, 4.4; mean treatment time, 75.2 minutes). Treatment time for multiple-isocenter SRS varied substantially with increasing number of lesions (11.8 minutes/lesion; P < .001), but to a much lesser degree in single-isocenter SRS (1.8 minutes/lesion; P = .029). The resulting cost savings from single-isocenter SRS based on number of lesions treated ranged from $296 to $3878 for 2 to 10 lesions treated. The 2-mm planning treatment volume margin used with single-isocenter SRS resulted in a mean 43% increase of total volume treated compared with a 1-mm planning treatment volume expansion.

CONCLUSIONS

In a comparison of time-driven activity-based costing assessment of single-isocenter versus multiple-isocenter SRS for multiple brain lesions, single-isocenter SRS appears to save time and resources for as few as 2 lesions, with incremental benefits for additional lesions treated.

Association of Innovations in Radiotherapy and Systemic Treatments With Clinical Outcomes in Patients With Melanoma Brain Metastasis From 2007 to 2016

IMPORTANCE

Treatments for melanoma brain metastasis changed between 2007 and 2016 with the advent of new radiotherapy techniques, targeted therapeutic agents, and immunotherapy. Changes in clinical outcomes over time have not been systematically investigated in large population-based studies.

OBJECTIVE

To investigate the association of innovations in radiotherapy techniques and systemic therapies with clinical outcomes among patients with melanoma brain metastasis.

DESIGN, SETTING AND PARTICIPANTS

This population-based cohort study included all patients who received radiotherapy and/or surgery for the treatment of melanoma brain metastasis in Ontario, Canada, between January 1, 2007, and June 30, 2016. Brain treatment patterns and clinical outcomes were described by period (2007-2009, 2010-2012, and 2013-2016). Provincial administrative records were used to obtain data on surgery, radiotherapy, and drugs. Follow-up data were censored on August 31, 2016. A Kaplan-Meier analysis and multivariable Cox regression analyses were performed. Data were analyzed between November 8, 2017 and May 13, 2020.

MAIN OUTCOMES AND MEASURES

Overall survival, whole-brain radiotherapy-free survival, and time to subsequent brain treatment.

RESULTS

A total of 1096 patients (mean [SD] age, 61.7 [14.0] years; 751 men [68.5%]) with melanoma brain metastasis received treatment in Ontario between January 1, 2007, and June 30, 2016. Of those, 326 patients received treatment from 2007 to 2009 (period 1), 310 patients received treatment from 2010 to 2012 (period 2), and 460 patients received treatment from 2013 to 2016 (period 3). Patient age, other sociodemographic characteristics, and disease factors were similar between periods. Whole-brain radiotherapy was the first local brain-directed treatment used in 246 patients (75.5%; 95% CI, 70.8%-80.1%) in period 1, decreasing to 239 patients (52.0%; 95% CI, 47.4%-56.5%) in period 3. The use of partial-brain radiotherapy techniques as the first treatment increased from 11 patients (3.4%; 95% CI, 1.4%-5.3%) in period 1 to 98 patients (21.3%; 95% CI, 17.6%-25.0%) in period 3. After the first treatment for melanoma brain metastasis, the use of BRAF and MEK inhibitors and immunotherapy increased from less than 6 patients (<1.8%; 95% CI, <0.4% to <3.3%) in period 1 to 188 patients (40.9%; 95% CI, 36.4%-45.4%) in period 3. Overall survival was greater in period 3 (1-year survival, 21.8% [95% CI, 17.9%-25.9%] and 2-year survival, 13.8% [95% CI, 10.4%-17.8%]; Wilcoxon P = .001) compared with period 1 (1-year survival, 12.3% [95% CI, 9.0%-16.1%] and 2-year survival, 6.4% [95% CI, 4.1%-9.5%]), with an adjusted hazard ratio (aHR) of 0.65 (95% CI, 0.56-0.77). The findings were unchanged after accounting for the variation in imaging practice between periods. Between period 1 and period 3, the use of whole-brain radiotherapy decreased (aHR, 0.32; 95% CI, 0.22-0.46), and the use of multiple brain-directed treatments increased (aHR, 2.16; 95% CI, 1.48-3.14).

CONCLUSIONS AND RELEVANCE

These findings suggest that innovations in systemic therapy and radiotherapy are associated with improvements in clinical outcomes among patients with melanoma brain metastasis, even in population-wide routine practice. Overall survival improved over time, and the use of whole-brain radiotherapy decreased. However, many patients continued to receive whole-brain radiotherapy in the last period (2013-2016) examined.

Radiation Therapy Practice Patterns for Brain Metastases in the United States in the Stereotactic Radiosurgery Era

PURPOSE

Utilization of stereotactic radiosurgery (SRS) for brain metastases (BM) has increased, prompting reassessment of whole brain radiation therapy (WBRT). A pattern of care analysis of SRS and WBRT dose-fractionations was performed in patients presenting with BM at the time of cancer diagnosis.

METHODS AND MATERIALS

Adults with BM at cancer diagnosis between 2010 to 2015 and no prior malignancy were identified in the National Cancer Database. SRS was defined using published thresholds. Short (ShWBRT), standard (StWBRT), and extended (ExWBRT) dose-fractionations were defined as 4 to 9, 10 to 15, and >15 fractions. Radioresistant histology was defined as melanoma, renal cell carcinoma, sarcoma or spindle cell, or gastrointestinal primary.

RESULTS

Of 4,087,967 adults with their first lifetime cancer, 90,388 (2.2%) had BM at initial diagnosis. Of these, 11,486 (12.7%) received SRS and 24,262 (26.8%) WBRT as first-course radiation therapy. The proportion of annual WBRT use decreased from 27.8% to 23.5% of newly diagnosed patients, and SRS increased from 8.7% to 17.9%. Common dose-fractionations were 30 Gy in 10 fractions (56.8%) for WBRT and 20 Gy in 1 fraction (13.0%) for SRS. On multivariate analysis, factors significantly associated with SRS versus WBRT included later year of diagnosis (2015 vs 2010, adjusted odds ratio [aOR] = 2.4), radioresistance (aOR = 2.0), academic facility (aOR = 1.9), highest income quartile (aOR = 1.6), chemotherapy administration (aOR = 1.4), and longer travel distance (>15 vs < 5 miles, aOR = 1.4). Linear regression revealed significant ExWBRT reductions (-22.4%/y, R2 = 0.97, P < .001) and no significant change for ShWBRT or StWBRT. Patients were significantly more likely to receive ShWBRT than StWBRT if not treated with chemotherapy (aOR = 3.5).

CONCLUSIONS

Utilization of WBRT, particularly ExWBRT, decreased while SRS utilization doubled as the first radiation therapy course in patients with BM at diagnosis. Patients with radioresistant histologies were more likely to receive SRS. Those not receiving chemotherapy, potentially owing to poor performance status, were less likely to receive SRS and more likely to receive ShWBRT.

Stereotactic radiosurgery for brain metastases from newly diagnosed small cell lung cancer: practice patterns and outcomes

BACKGROUND

Up-front stereotactic radiosurgery (SRS) has been historically thought of as inadequate for brain metastases (BM) from newly diagnosed small cell lung cancer (SCLC). This study evaluates national practice patterns and clinical outcomes for BM from SCLC.

MATERIAL AND METHODS

The National Cancer Database was queried (2004-2013) for patients with newly diagnosed metastatic SCLC receiving intracranial radiotherapy. Patients were grouped into three categories: upfront SRS, whole-brain radiotherapy (WBRT) alone, or WBRT with boost (SRS or fractionated radiotherapy). Statistics included temporal trend assessment by annual percent change (APC), logistic regression, exploratory Kaplan-Meier overall survival (OS) analysis without and with propensity matching, and Cox proportional hazards modeling.

RESULTS

A total of 14,722 patients met selection criteria, of whom 487 (3.3%), 13,657 (92.8%), and 578 (3.9%) received upfront SRS, WBRT and WBRT with boost, respectively. Utilization of SRS showed a slight increasing trend from 2004 to 2013 (2.7-4.3%). In addition to socioeconomic factors, other variables associated with SRS use included diagnosis after 2010, treatment at academic centers, and residing in higher-educated regions. SRS was less often delivered to patients with node-positive disease (p < .05). On exploratory analysis, SRS cohort was observed to have a higher overall survival (OS) than WBRT-based groups (p < .001), namely in patients without extracranial metastases.

CONCLUSIONS

Utilization of up-front SRS for SCLC BM has been increasing over time but is driven by socioeconomic disparities. Although there are likely numerous biases associated with the OS findings herein, further research is needed to validate this finding as well as the role of SRS on patients with brain metastases due to SCLC.

National trends in radiotherapy for brain metastases at time of diagnosis of non-small cell lung cancer

BACKGROUND

To analyze the national trends of patients treated radiotherapy for brain metastases from non-small cell lung cancer (NSCLC) that were found at diagnosis.

METHODS

The National Cancer Database was queried for patients with NSCLC diagnosed from 2004 to 2013 that received brain irradiation for metastases and patients grouped into having had received fractionated brain radiotherapy (5-15 fractions with or without radiosurgery) or intracranial radiosurgery alone (1-5 fractions). Univariable and multivariable (MVA) analyses were performed to investigate factors associated with the receipt of SRS alone, and temporal/regional trends.

RESULTS

47,746 patients met inclusion criteria, of which 42,148 received fractionated brain irradiation (88%) and 5,598 received radiosurgery (12%). 345 patients received fractioned brain irradiation with a radiosurgical boost (0.8%). The utilization of radiosurgery-alone increased over time owing to increases in each radiosurgery modality. On MVA, several factors were associated with increased odds of receiving intracranial radiosurgery-alone over fractionated brain radiotherapy including more recent year of diagnosis, increased median income, eastern U.S. regions, further distance to the hospital, and the receipt of chemotherapy (each p<0.001). Patients of Asian descent were less likely to receive radiosurgery alone (p=0.044).

CONCLUSIONS

In the management of brain metastases from NSCLC, overall utilization of an intracranial radiosurgery alone treatment strategy has increased over the past decade. Despite this, there appear to be significant geographic variations and disparities remain based on patient income level and race. Further study is needed to define the reasons for these disparities and appropriate actions to mitigate them.

Assessment of function and quality of life in a phase II multi-institutional clinical trial of fractionated simultaneous in-field boost radiotherapy for patients with 1-3 metastases

We examined functional outcomes and quality of life of whole brain radiotherapy (WBRT) with integrated fractionated stereotactic radiotherapy boost (FSRT) for brain metastases treatment. Eighty seven people with 1-3 brain metastases (54/87 lung primary, 42/87 single brain metastases) were enrolled on this Phase II trial of WBRT (30 Gy/10) + simultaneous FSRT, (60 Gy/10). Median overall follow-up and survival was 5.4 months, 6 month actuarial intra-lesional control was 78 %; only 1 patient exhibited grade 4 toxicity (worsened seizures); most treatment related toxicity was grade 1 or 2; 2/87 patients demonstrated asymptomatic radiation necrosis on follow-up imaging. Mean (Min-Max) baseline KPS, Mini Mental Status Exam (MMSE) and FACT-BR quality of life were 83 (70-100), 28 (21-30) and 143 (98-153). Lower baseline MMSE (but not KPS or FACT-Br) was associated with worse survival after adjusting for age, number of metastases, primary and extra-cranial disease status. Crude rates of deterioration (>10 points decrease from baseline for KPS and FACT-Br, MMSE fall to <27) ranged from 26 to 38 % for KPS, 32-59 % for FACT-Br and 0-16 % for MMSE depending on the time-point assessed with higher rates generally noted at earlier time points (≤6 months post-treatment). Using a linear mixed models analysis, significant declines from baseline were noted for KPS and FACT-Br (largest effects at 6 weeks to 3 months) with no significant change in MMSE. The effects on function and quality of life of this integrated treatment of WBRT + simultaneous FSRT were similar to other published series combining WBRT + radiosurgery.

New developments in intracranial stereotactic radiotherapy for metastases

Brain metastases are common and the prognosis for patients with multiple brain metastases treated with whole brain radiotherapy is limited. As systemic disease control continues to improve, the expectations of radiotherapy for brain metastases are growing. Stereotactic radiosurgery (SRS) as a high precision localised irradiation given in a single fraction prolongs survival in patients with a single brain metastasis and functional independence in those with up to three brain metastases. SRS technology has become commonplace and is available in many radiation oncology and neurosurgery departments. With increasing use there is a need for appropriate patient selection, refinement of dose-fractionation and safe integration of SRS with other treatment modalities. We review the evidence for current practice and new developments in the field, with a specific focus on patient-relevant outcomes.