Linear accelerator-based stereotactic radiosurgery in 140 brain metastases from malignant melanoma

Radiation therapy for melanoma brain metastases: a systematic review

BACKGROUND

Radiation therapy (RT) for melanoma brain metastases, delivered either as whole brain radiation therapy (WBRT) or as stereotactic radiosurgery (SRS), is an established component of treatment for this condition. However, evidence allowing comparison of the outcomes, advantages and disadvantages of the two RT modalities is scant, with very few randomised controlled trials having been conducted. This has led to considerable uncertainty and inconsistent guideline recommendations. The present systematic review identified 112 studies reporting outcomes for patients with melanoma brain metastases treated with RT. Three were randomised controlled trials but only one was of sufficient size to be considered informative. Most of the evidence was from non-randomised studies, either specific treatment series or disease cohorts. Criteria for determining treatment choice were reported in only 32 studies and the quality of these studies was variable. From the time of diagnosis of brain metastasis, the median survival after WBRT alone was 3.5 months (IQR 2.4-4.0 months) and for SRS alone it was 7.5 months (IQR 6.7-9.0 months). Overall patient survival increased over time (pre-1989 to 2015) but this was not apparent within specific treatment groups.

CONCLUSIONS

These survival estimates provide a baseline for determining the incremental benefits of recently introduced systemic treatments using targeted therapy or immunotherapy for melanoma brain metastases.

Frameless Stereotactic Radiosurgery With Linear Accelerator (LINAC)-Based Technology for Brain Metastases: Outcomes Analysis in 141 Patients

Objectives Brain metastases (BM) are the most common intracranial tumors in adults. Surgery and frame-based stereotactic radiosurgery (SRS) are well-described treatment options. Frameless SRS is an emerging BM treatment option offering fewer side effects. The aim of this study was to describe the therapeutic outcomes and toxicity of frameless SRS with linear accelerator (LINAC)-based technology for BM treatment in our institution. Materials and methods We performed a retrospective study including all adult patients treated with frameless SRS with LINAC-based technology for BM between October 2010 and July 2016. Patients were followed routinely with MRI scans at three-month intervals. Primary endpoints were progression-free survival, local control, overall survival, and toxicity related to the treatment. All survival times were computed with the Kaplan-Meier method. All cumulative incidences were computed using competing risk analyses. Results A total of 194 metastatic lesions in 141 patients were treated in a 69-month interval. At the time of analysis, 33 patients were still alive, with a median follow-up time of 25.1 months. The overall median survival was 8.7 months. The median progression-free survival was 5.3 months. Local recurrence as a first event was 25% and 38% at one and two years, respectively, while distant brain recurrence as a first event was 18% and 21%. Death before any brain event occurred in 31% of patients. The cumulative incidence of radiation necrosis as a first brain event was 2% at one and two years. Conclusions The treatment of BM with LINAC-based frameless SRS in our institution had an overall and progression-free survival comparable with the literature for frameless SRS and for conventional frame-based SRS while being less invasive and more comfortable for the patient. In our study, frameless SRS with LINAC technology seems to be safe for BM treatment with minimal rates of radiation necrosis.

Predictive value of a nomogram for melanomas with brain metastases at initial diagnosis

BACKGROUND

Estimation of incidence and prognosis of melanomas with brain metastases (MBM) at initial diagnosis based on a large cohort is lacking in current research. This study aims to construct an effective prognostic nomogram for newly diagnosed MBM.

MATERIALS AND METHODS

Patients diagnosed with melanomas from Surveillance, Epidemiology, and End Results program between 2010 and 2014 were enrolled in our study. Risk factors predicting brain metastases (BM) were identified using logistic regression analysis. Cox regression analysis was performed to identify prognostic factors of overall survival (OS). Nomogram for estimating 6-, 9-, and 12-month OS was established based on Cox regression analysis. The discriminative ability and calibration of the nomogram were tested using C statistics, calibration plots, and Kaplan-Meier curves.

RESULTS

Sixty-two thousand three hundred and sixty-nine melanoma patients were enrolled, including 928 with BM. Sex, marital status, insurance status, subsite, surgery of primary sites, radiation, chemotherapy, bone metastases, liver metastases, and lung metastases were associated with MBM at initial diagnosis. On multivariable Cox regression, the following eight variables were incorporated in the prediction of OS: age, unmarried status, absence of surgery to primary sites or unknown, absence of radiation or unknown, absence of chemotherapy or unknown, with bone metastases, with liver metastases, and with lung metastases. The nomogram showed good predictive ability as indicated by discriminative ability and calibration, with the C statistics of 0.716 (95% CI, 0.695-0.737).

CONCLUSIONS

The incidence and prognosis of MBM patients were well estimated in this study based on a large cohort. The nomogram performed well and could be a useful tool to predict prognosis.

Early imaging radioresponsiveness of melanoma brain metastases as a predictor of patient prognosis

OBJECTIVE The aim of this study was to analyze the early radiological response of melanoma brain metastases to single high-dose irradiation and to reveal possible correlations between tumor radioresponsiveness and patient clinical outcomes. METHODS The authors performed a retrospective analysis of the medical data for all patients with melanoma brain metastases who had undergone Gamma Knife radiosurgery (GKRS) and follow-up MRI examinations with standard protocols at regular 2- to 3-month intervals. Volumetric measurements of the metastases on pretreatment and initial posttreatment images were performed to assess the rate of early radiological response. Patients were divided into 2 groups according to the rate of response, and overall survival, local control, and the appearance of new metastases in the brain were compared in these groups using the long-rank test. Univariate and multivariate analyses were performed to identify predictors of clinical outcomes. RESULTS After retrospective analysis of 298 melanoma brain metastases in 78 patients, the authors determined that early radiological responses of these metastases to GKRS differ considerably and can be divided into 2 distinct groups. One group of tumors underwent rapid shrinkage after radiosurgery, whereas the other showed minor fluctuations in size (rapid- and slow-response groups, respectively). Median survival for patients with a slow response was 15.2 months compared with 6.3 months for those with a rapid response (p < 0.0001). In the multivariate analysis, improved overall survival was associated with a slow response to radiosurgery (p < 0.0001), stable systemic disease (p = 0.001), and a higher Karnofsky Performance Scale score (p = 0.001). Stratification by Recursive Partitioning Analysis, score index for radiosurgery, and diagnosis-specific Graded Prognostic Assessment classes further confirmed the difference in overall survival for patients with a slow versus rapid radiation response. Local recurrence was observed in 11% of patients with a rapid response and in 6% of patients with a slow response, at a median of more than 8 months after radiosurgery. New brain metastases were diagnosed in 67% of patients with a slow response at a median of 8.6 months after radiosurgery and in 82% of patients with a rapid response at a considerably earlier median time of 2.7 months. In the multivariate analysis, a longer time to the development of new brain metastases was associated with a slow response (p = 0.012), stable systemic disease (p = 0.034), and a single brain metastasis (p = 0.030). CONCLUSIONS Melanoma brain metastases show different early radioresponsiveness to radiosurgery. Rapid shrinkage of brain metastases is associated with poor patient prognosis, which may indicate more aggressive biological behavior of this tumor phenotype.

Metastatic melanoma: prognostic factors and survival in patients with brain metastases

Brain metastases from malignant melanoma carry a poor prognosis. Novel systemic agents have improved overall survival (OS), but the value of whole-brain radiotherapy (WBRT) and stereotactic radiosurgery (SRS) remains uncertain. The melanoma-specific graded prognostic assessment (msGPA) provides useful prognostic information, but the relevance to the modern-day population has not been validated. Since 2011, 53 patients received treatment for brain metastases from malignant melanoma at the Rosemere Cancer Centre medical oncology clinic. Data were collated on demographic factors and survival. Survival analyses were performed using Kaplan–Meier methods. Cox regression was used to identify prognostic factors on univariate and multivariate analysis. OS from the date of diagnosis of brain metastases was 4.83 months (range 0.27–30.4 months). On univariate analysis, BRAF, performance status and msGPA were significant prognostic indicators for OS (p = 0.0056, p = 0.0039 and p = 0.0001 respectively). msGPA remained significant on multivariate analysis (p = 0.0006). OS for BRAF-positive patients receiving targeted treatment (n = 22) was significantly better than for BRAF-negative patients (n = 26), with median survival times of 8.2 and 3.7 months respectively (p = 0.0039, HR 2.36). SRS combined with systemic agents (n = 16) produced an OS of 13.5 months. Patients receiving WBRT alone (n = 21) had a poor prognosis (2.2 months). The msGPA remains a valid prognostic indicator in the era of novel systemic treatments for melanoma. BRAF-positive patients receiving targeted agents during their treatment had favorable survival outcomes. WBRT alone should be use with caution in the active management of melanoma brain metastases.

Frameless LINAC-based stereotactic radiation therapy to brain metastasis resection cavity without whole-brain radiation therapy: A systematic review

PURPOSE

The aim of this systematic review was to summarize the findings from the published data of frameless stereotactic radiation therapy (RT) to the resection cavity delivered with nonrobotic linear accelerator in patients with brain metastases.

METHODS

The studies cited in this systematic review were identified through a search of the PubMed database, using the search terms: "stereotactic [Title/Abstract]" and "Brain [Title/Abstract]," and "Metas* [Title/Abstract]." The search was unlimited to language and publication year.

RESULTS

A total of 9 studies were included in our review. Stereotactic RT to the resection cavity appears to provide excellent local control rates that are comparable to framed stereotactic RT. There are various factors that influence local control. Distant intracranial control rates are poor with the use of postoperative stereotactic RT compared with local treatment (surgery or stereotactic RT) plus whole-brain RT.

CONCLUSIONS

Stereotactic RT to the resection cavity appears to provide good local control rates and poor distant intracranial control. Postoperative treatment should be discussed by a multidisciplinary team and tailored to each case individually.