Gamma knife radiosurgery for brainstem metastases: the UCSF experience

Accelerator-based stereotactic radiosurgery for brainstem metastases

BACKGROUND

Stereotactic radiosurgery represents a noninvasive alternative treatment for intracranial metastases.

OBJECTIVE

To investigate the treatment outcome of linear accelerator-based stereotactic radiosurgery (linac-SRS) for brainstem metastases.

METHODS

We retrospectively reviewed our database of patients who were diagnosed with brainstem metastases and underwent linac-SRS between 1997 and 2008 at the University of California, Los Angeles.

RESULTS

A total of 45 patients with 48 brainstem metastases were treated. The median target volume was 0.40 mL (range, 0.02-5.70 mL), and median prescription dose was 14 Gy (range, 10-17 Gy) at 90% isodose curve. The median survival time was 11.6 months. Longer survival time was associated with higher Karnofsky performance status. The local control rate was 92% at 6 months and 88% at 1 year. Univariate analysis demonstrated a significant relationship between local control and tumor volume (≤0.4 mL vs >0.4 mL, P = .023) and SRS mode (conventional circular arc vs dynamic conformal arc, P = .044). There was a trend toward improved local control and prescription dose >14 Gy (P = .059). Two patients had brainstem complications following treatment, and the complication rate was 4.7% at 2 years. Serious morbidity occurred with 17 Gy.

CONCLUSION

Linac-SRS using a median dose of 14 Gy provided excellent local control in patients with brainstem metastases less than 0.4 mL with relatively low serious morbidity. The results of the study support the use of linac-SRS for patients with brainstem metastases. We advocate 14 to 16 Gy, given the high local control rate and low complication rate with this dose.

Diagnosis and treatment of melanoma. European consensus-based interdisciplinary guideline--Update 2012

Cutaneous melanoma (CM) is potentially the most dangerous form of skin tumour and causes 90% of skin cancer mortality. A unique collaboration of multi-disciplinary experts from the European Dermatology Forum (EDF), the European Association of Dermato-Oncology (EADO) and the European Organization of Research and Treatment of Cancer (EORTC) was formed to make recommendations on CM diagnosis and treatment, based on systematic literature reviews and the experts' experience. Diagnosis is made clinically and staging is based upon the AJCC system. CMs are excised with one to two centimetre safety margins. Sentinel lymph node dissection (SLND) is routinely offered as a staging procedure in patients with tumours more than 1mm in thickness, although there is as yet no clear survival benefit for this approach. Interferon-α treatment may be offered to patients with stage II and III melanoma as an adjuvant therapy, as this treatment increases at least the disease-free survival (DFS) and less clear the overall survival (OS) time. The treatment is however associated with significant toxicity. In distant metastasis, all options of surgical therapy have to be considered thoroughly. In the absence of surgical options, systemic treatment is indicated. BRAF inhibitors like vemurafenib for BRAF mutated patients as well as the CTLA-4 antibody ipilimumab offer new therapeutic opportunities apart from conventional chemotherapy. Therapeutic decisions in stage IV patients should be primarily made by an interdisciplinary oncology team ('tumour board').

Prescription dose and fractionation predict improved survival after stereotactic radiotherapy for brainstem metastases

Background

Brainstem metastases represent an uncommon clinical presentation that is associated with a poor prognosis. Treatment options are limited given the unacceptable risks associated with surgical resection in this location. However, without local control, symptoms including progressive cranial nerve dysfunction are frequently observed. The objective of this study was to determine the outcomes associated with linear accelerator-based stereotactic radiotherapy or radiosurgery (SRT/SRS) of brainstem metastases.

Methods

We retrospectively reviewed 38 tumors in 36 patients treated with SRT/SRS between February 2003 and December 2011. Treatment was delivered with the Cyberknife™ or Trilogy™ radiosurgical systems. The median age of patients was 62 (range: 28–89). Primary pathologies included 14 lung, 7 breast, 4 colon and 11 others. Sixteen patients (44%) had received whole brain radiation therapy (WBRT) prior to SRT/SRS; ten had received prior SRT/SRS at a different site (28%). The median tumor volume was 0.94 cm³ (range: 0.01-4.2) with a median prescription dose of 17 Gy (range: 12–24) delivered in 1–5 fractions.

Results

Median follow-up for the cohort was 3.2 months (range: 0.4-20.6). Nineteen patients (52%) had an MRI follow-up available for review. Of these, one patient experienced local failure corresponding to an actuarial 6-month local control of 93%. Fifteen of the patients with available follow-up imaging (79%) experienced intracranial failure outside of the treatment volume. The median time to distant intracranial failure was 2.1 months. Six of the 15 patients with distant intracranial failure (40%) had received previous WBRT. The actuarial overall survival rates at 6- and 12-months were 27% and 8%, respectively. Predictors of survival included Graded Prognostic Assessment (GPA) score, greater number of treatment fractions, and higher prescription dose. Three patients experienced acute treatment-related toxicity consisting of nausea (n = 1) and headaches (n = 2) that resolved with a short-course of dexamethasone.

Conclusion

SRT/SRS for brainstem metastases is safe and achieves a high rate of local control. We found higher GPA as well as greater number of treatment fractions and higher prescription dose to be correlated with improved overall survival. Despite this approach, prognosis remains poor and distant intracranial control remains an issue, even in patients previously treated with WBRT.

Outcomes and prognostic factors for patients with brainstem metastases undergoing stereotactic radiosurgery

BACKGROUND

Treatment of tumors metastatic to the brainstem with stereotactic radiosurgery (SRS) has not been widely studied.

OBJECTIVE

To identify the effects of SRS on patients with brainstem metastases by assessing duration of local progression-free survival (LPFS) and overall survival.

METHODS

We retrospectively reviewed clinical data collected from 60 patients undergoing linear accelerator-based SRS for tumors metastatic to the brainstem between August 1994 and December 2007. The LPFS and overall survival were calculated with the Kaplan-Meier method. Prognostic factors were evaluated with the log-rank test and Cox proportional hazards model.

RESULTS

The median age of patients was 61 years (range, 39-85 years); the median treated lesion volume was 1.0 mL (range, 0.1-8.7 mL); and the median SRS dose was 15 Gy (range, 8-18 Gy). The median overall survival interval after SRS was 4 months (95% confidence interval, 3.4-4.9 months); crude local tumor control was 76%; and median LPFS was 5.7 months (95% confidence interval, 3.0-8.4 months). Shorter overall survival was associated with a pretreatment tumor volume ≥4 mL (P < .001) and male sex (P = .03). Shorter LPFS was associated with a pretreatment tumor volume ≥4 mL (P = .008), a melanoma primary tumor (P = .002), and the presence of necrosis in pre-SRS magnetic resonance imaging (P = .04). A Basic Score for Brain Metastases of 2 to 3 vs 1 (P = .007) and a Score Index for Radiosurgery >5 (P = .003) were significantly associated with longer survival. Twelve patients (20%) developed SRS-related complications.

CONCLUSION

Stereotactic radiosurgery provides noninvasive treatment and favorable local tumor control for patients with brainstem metastases.

Gamma knife radiosurgery for brainstem metastasis

OBJECTIVE

Brainstem metastases are rarely operable and generally unresponsive to conventional radiation therapy or chemotherapy. Recently, Gamma Knife Radiosurgery (GKRS) was used as feasible treatment option for brainstem metastasis. The present study evaluated our experience of brainstem metastasis which was treated with GKRS.

METHODS

Between November 1992 and June 2010, 32 patients (23 men and 9 women, mean age 56.1 years, range 39-73) were treated with GKRS for brainstem metastases. There were metastatic lesions in pons in 23, the midbrain in 6, and the medulla oblongata in 3 patients, respectively. The primary tumor site was lung in 21, breast in 3, kidney in 2 and other locations in 6 patients. The mean tumor volume was 1,517 mm(3) (range, 9-6,000), and the mean marginal dose was 15.9 Gy (range, 6-23). Magnetic Resonance Imaging (MRI) was obtained every 2-3 months following GKRS. Follow-up MRI was possible in 24 patients at a mean follow-up duration of 12.0 months (range, 1-45). Kaplan-Meier survival analysis was used to evaluate the prognostic factors.

RESULTS

Follow-up MRI showed tumor disappearance in 6, tumor shrinkage in 14, no change in tumor size in 1, and tumor growth in 3 patients, which translated into a local tumor control rate of 87.5% (21 of 24 tumors). The mean progression free survival was 12.2 months (range, 2-45) after GKRS. Nine patients were alive at the completion of the study, and the overall mean survival time after GKRS was 7.7 months (range, 1-22). One patient with metastatic melanoma experienced intratumoral hemorrhage during the follow-up period. Survival was found to be associated with score of more than 70 on Karnofsky performance status and low recursive partitioning analysis class (class 1 or 2), in terms of favorable prognostic factors.

CONCLUSION

GKRS was found to be safe and effective for management of brainstem metastasis. The integral clinical status of patient seems to be important in determining the overall survival time.

Minimized doses for linear accelerator radiosurgery of brainstem metastasis

PURPOSE

Treatment of cerebral metastases located inside the brainstem remains a challenge, as the brainstem is considered to be a neurological organ at risk, whatever the treatment strategy. We report a retrospective study of 30 consecutive patients treated in our institution between 2005 and 2007 with micromultileaf linear accelerator (LINAC)-radiosurgery for brainstem metastases, with reduced doses compared to those usually reported in the literature.

METHODS AND MATERIALS

Mean follow-up was 311 days (range, 41-1351). Median age was 57 years (range, 37-82), Mean Karnofsky Index (KI) was 80. Primary tumor site was lung (n = 13), breast (n = 4), kidney (n = 4), skin (melanoma; n = 3), and others (n = 6). Primary tumor was controlled in 17 cases; extracranial metastases were controlled in 12 cases. Mean number of metastases was 1.46 (one to three); median volume was 2.82 cc (0.06-18). Dose was delivered by a micromultileaf collimator 6-MV LINAC .

RESULTS

Dose administered at the 70% isodose was 13.4 Gy (range, 8.2-15). Median survival was 10 months. Local control rates at 3, 6, and 12 months were 100%, 100%, and 79% respectively. Median neurological control duration was 5 months. Neurological control rates at 3, 6, and 12 months were 73%, 42%, and 25%, respectively. No parameter was found to significantly correlate with survival, local, or cerebral control. No patients had severe side effects (Grade III-IV), according to the Radiation Therapy Oncology Group (RTOG) scale.

CONCLUSION

Lower doses than previously reported can achieve the same local control and survival rates in brain metastases, with minimal side effects.

Linear accelerator-based stereotactic radiosurgery for brainstem metastases: the Dana-Farber/Brigham and Women's Cancer Center experience

To review the safety and efficacy of linear accelerator-based stereotactic radiosurgery (SRS) for brainstem metastases. We reviewed all patients with brain metastases treated with SRS at DF/BWCC from 2001 to 2009 to identify patients who had SRS to a single brainstem metastasis. Overall survival and freedom-from-local failure rates were calculated from the date of SRS using the Kaplan-Meier method. Prognostic factors were evaluated using the log-rank test and Cox proportional hazards model. A total of 24 consecutive patients with brainstem metastases had SRS. At the time of SRS, 21/24 had metastatic lesions elsewhere within the brain. 23/24 had undergone prior WBRT. Primary diagnoses included eight NSCLC, eight breast cancer, three melanoma, three renal cell carcinoma and two others. Median dose was 13 Gy (range, 8-16). One patient had fractionated SRS 5 Gy ×5. Median target volume was 0.2 cc (range, 0.02-2.39). The median age was 57 years (range, 42-92). Follow-up information was available in 22/24 cases. At the time of analysis, 18/22 patients (82%) had died. The median overall survival time was 5.3 months (range, 0.8-21.1 months). The only prognostic factor that trended toward statistical significance for overall survival was the absence of synchronous brain metastasis at the time of SRS; 1-year overall survival was 31% with versus 67% without synchronous brain metastasis (log rank P = 0.11). Non-significant factors included primary tumor histology and status of extracranial disease (progressing vs. stable/absent). Local failure occurred in 4/22 cases (18%). Actuarial freedom from local failure for all cases was 78.6% at 1 year. RTOG grade 3 toxicities were recorded in two patients (ataxia, confusion). Linac-based SRS for small volume brainstem metastases using a median dose of 13 Gy is associated with acceptable local control and low morbidity.

Radiation associated brainstem injury

Publications relating brainstem radiation toxicity to quantitative dose and dose-volume measures derived from three-dimensional treatment planning were reviewed. Despite the clinical importance of brainstem toxicity, most studies reporting brainstem effects after irradiation have fewer than 100 patients. There is limited evidence relating toxicity to small volumes receiving doses above 60-64 Gy using conventional fractionation and no definitive criteria regarding more subtle dose-volume effects or effects after hypofractionated treatment. On the basis of the available data, the entire brainstem may be treated to 54 Gy using conventional fractionation using photons with limited risk of severe or permanent neurological effects. Smaller volumes of the brainstem (1-10 mL) may be irradiated to maximum doses of 59 Gy for dose fractions <or=2 Gy; however, the risk appears to increase markedly at doses >64 Gy.

Clinical and pathological characteristics of brain metastasis resected after failed radiosurgery

OBJECTIVE

This study evaluates the tumor histopathology and clinical characteristics of patients who underwent resection of their brain metastasis after failed gamma knife radiosurgery.

METHODS

This study was a retrospective review from a prospective database. A total of 1200 brain metastases in 912 patients were treated by gamma knife radiosurgery during a 7-year period. Fifteen patients (1.6% of patients, 1.2% of all brain metastases) underwent resective surgery for either presumed tumor progression (6 patients) or worsening neurological symptoms associated with increased mass effect (9 patients). Radiographic imaging, radiosurgical and surgical treatment parameters, histopathological findings, and long-term outcomes were reviewed for all patients.

RESULTS

The mean age at the time of radiosurgery was 57 years (age range, 32-65 years). Initial pathological diagnoses included metastatic non-small cell lung carcinoma in 8 patients (53%), melanoma in 4 patients (27%), renal cell carcinoma in 2 patients (13%), and squamous cell carcinoma of the tongue in 1 patient (7%). The mean time interval between radiosurgery and surgical extirpation was 8.5 months (range, 3 weeks to 34 months). The mean treatment volume for the resected lesion at the time of radiosurgery was 4.4 cm(3) (range, 0.6-8.4 cm(3)). The mean dose to the tumor margin was 21Gy (range, 18-24 Gy). In addition to the 15 tumors that were eventually resected, a total of 32 other metastases were treated synchronously, with a 78% control rate. The mean volume immediately before surgery for the 15 resected lesions was 7.5 cm(3) (range, 3.8-10.2 cm(3)). Histological findings after radiosurgery varied from case to case and included viable tumor, necrotic tumor, vascular hyalinization, hemosiderin-laden macrophages, reactive gliosis in surrounding brain tissue, and an elevated MIB-1 proliferation index in cases with viable tumor. The mean survival for patients in whom viable tumor was identified (9.4 months) was significantly lower than that of patients in whom only necrosis was seen (15.1 months; Fisher's exact test, P < 0.05).

CONCLUSION

Radiation necrosis and tumor radioresistance are the most common causes precipitating a need for surgical resection after radiosurgery in patients with brain metastasis.

Stereotactic radiosurgery for single brainstem metastases: the cleveland clinic experience

PURPOSE

To assess the imaging and clinical outcomes of patients with single brainstem metastases treated with stereotactic radiosurgery (SRS).

MATERIALS AND METHODS

We retrospectively reviewed the data from patients with single brainstem metastases treated with SRS. Locoregional control and survival were calculated using the Kaplan-Meier method. Prognostic factors were assessed using a Cox proportional hazards model.

RESULTS

Between 1997 and 2007, 43 patients with single brainstem metastases were treated with SRS. The median age at treatment was 59 years, the median Karnofsky performance status was 80, and the median follow-up was 5.3 months. The median dose was 15 Gy (range, 9.6-24), and the median conformality and heterogeneity index was 1.7 and 1.9, respectively. The median survival was 5.8 months from the procedure date. Of the 33 patient with post-treatment imaging available, a complete radiographic response was achieved in 2 (4.7%), a partial response in 8 (18.6%), and stable disease in 23 (53.5%). The 1-year actuarial rate of local control, distant brain control, and overall survival was 85%, 38.3%, and 31.5%, respectively. Of the 43 patients, 8 (19%) died within 2 months of undergoing SRS, and 15 (36%) died within 3 months. On multivariate analysis, greater performance status (hazard ratio [HR], 0.95, p = .004), score index for radiosurgery (HR, 0.7; p = .004), graded prognostic assessment score (HR, 0.48; p = .003), and smaller tumor volume (HR, 1.23, p = .002) were associated with improved survival. No Grade 3 or 4 toxicities were observed.

CONCLUSION

The results of our study have shown that SRS is a safe and effective local therapy for patients with brainstem metastases.

Diagnosis and treatment of melanoma: European consensus-based interdisciplinary guideline

Cutaneous melanoma (CM) is potentially the most dangerous form of skin tumour and causes 90% of skin cancer mortality. A unique collaboration of multi-disciplinary experts from the European Dermatology Forum, the European Association of Dermato-Oncology and the European Organization of Research and Treatment of Cancer was formed to make recommendations on CM diagnosis and treatment, based on systematic literature reviews and the experts' experience. Diagnosis is made clinically and staging is based upon the AJCC system. CMs are excised with one to two centimetre safety margins. Sentinel lymph node dissection is routinely offered as a staging procedure in patients with tumours more than 1mm in thickness, although there is as yet no resultant survival benefit. Interferon-alpha treatment can be offered to patients with more than 1.5mm in thickness and stage II to III melanoma as an adjuvant therapy, as this treatment increases the relapse-free survival. The lack of a clear survival benefit and the presence of toxicity however limit its use in practice. In distant metastasis, all options of surgical therapy have to be considered thoroughly. In the absence of surgical options, systemic medical treatment is indicated, but with, to date, low response rates. Therapeutic decisions should be made by the melanoma team and the informed patient after full discussion of the options.

Advances in technology for intracranial stereotactic radiosurgery

Stereotactic radiosurgery (SRS) refers to a single radiation treatment delivering a high dose to an intra-cranial target localized in three-dimensions by CT and/or MRI imaging. Traditionally, immobilization of the patient's head has been achieved using a rigid stereotactic head frame as the key step in allowing for accurate dose delivery. SRS has been delivered by both Cobalt-60 (Gamma Knife) and linear accelerator (linac) technologies for many decades. The focus of this review is to highlight recent advances and major innovations in SRS technologies relevant to clinical practice and developments allowing for non-invasive frame SRS.

Current concepts in stereotactic radiosurgery - a neurosurgical and radiooncological point of view

Stereotactic radiosurgery is related to the history of "radiotherapy" and "stereotactic neurosurgery". The concepts for neurosurgeons and radiooncologists have been changed during the last decade and have also transformed neurosurgery. The gamma knife and the stereotactically modified linear accelerator (LINAC) are radiosurgical equipments to treat predetermined intracranial targets through the intact skull without damaging the surrounding normal brain tissue. These technical developments allow a more precise intracranial lesion control and offer even more conformal dose plans for irregularly shaped lesions. Histological determination by stereotactic biopsy remains the basis for any otherwise undefined intracranial lesion. As a minimal approach, it allows functional preservation, low risk and high sensitivity. Long-term results have been published for various indications. The impact of radiosurgery is presented for the management of gliomas, metastases, brain stem lesions, benign tumours and vascular malformations and selected functional disorders such as trigeminal neuralgia. In AVM's it can be performed as part of a multimodality strategy including resection or endovascular embolisation. Finally, the technological advances in radiation oncology as well as stereotactic neurosurgery have led to significant improvements in radiosurgical treatment opportunities. Novel indications are currently under investigation. The combination of both, the neurosurgical and the radiooncological expertise, will help to minimize the risk for the patient while achieving a greater treatment success.