Gamma knife surgery for brain metastases in patients harboring four or more lesions: survival and prognostic factors

Outcomes in Patients With 4 to 10 Brain Metastases Treated With Dose-Adapted Single-Isocenter Multitarget Stereotactic Radiosurgery: A Prospective Study

Purpose

To examine the effectiveness and safety of single-isocenter multitarget stereotactic radiosurgery using a volume-adapted dosing strategy in patients with 4 to 10 brain metastases.

Methods and Materials

Adult patients with 4 to 10 brain metastases were eligible for this prospective trial. The primary endpoint was overall survival. Secondary endpoints were local recurrence, distant brain failure, neurologic death, and rate of adverse events. Exploratory objectives were neurocognition, quality of life, dosimetric data, salvage rate, and radionecrosis. Dose was prescribed in a single fraction per RTOG 90-05 or as 5 Gy × 5 fractions for lesions ≥3 cm diameter, lesions involving critical structures, or single-fraction brain V_12Gy >20 mL.

Results

Forty patients were treated with median age of 61 years, Karnofsky performance status 90, and 6 brain metastases. Twenty-two patients survived longer than expected from the time of protocol SRS, with 1 living patient who has not reached that milestone. Median overall survival was 8.1 months with a 1-year overall survival of 35.7%. The 1-year local recurrence rate was 5% (10 of 204 of evaluable lesions) in 12.5% (4 of 32) of the patients. Distant brain failure was observed in 19 of 32 patients with a 1-year rate of 35.8%. Grade 1-2 headache was the most common complaint, with no grade 3-5 treatment-related adverse events. Radionecrosis was observed in only 5 lesions, with a 1-year rate of 1.5%. Rate of neurologic death was 20%. Neurocognition and quality of life did not significantly change 3 months after SRS compared with pretreatment.

Conclusions

These results suggest that volume-adapted dosing single-isocenter multitarget stereotactic radiosurgery is an effective and safe treatment for patients with 4 to 10 brain metastases.

Management of multiple brain metastases: a patterns of care survey within the German Society for Radiation Oncology

PURPOSE

The treatment of brain metastases (BM) has changed considerably in recent years and in particular, the management of multiple BM is currently undergoing a paradigm shift and treatment may differ from current guidelines. This survey was designed to analyze the patterns of care in the management of multiple BM.

METHODS

An online survey consisting of 36 questions was distributed to the members of the German Society for Radiation Oncology (DEGRO).

RESULTS

In total, 193 physicians out of 111 institutions within the German Society for Radiation oncology responded to the survey. Prognostic scores for decision making were not used regularly. Whole brain radiotherapy approaches (WBRT) are the preferred treatment option for patients with multiple BM, although stereotactic radiotherapy treatments are chosen by one third depending on prognostic scores and overall number of BM. Routine hippocampal avoidance (HA) in WBRT is only used by a minority. In multiple BM of driver-mutated non-small cell lung cancer origin up to 30% favor sole TKI therapy as upfront treatment and would defer upfront radiotherapy.

CONCLUSION

In multiple BM WBRT without hippocampal avoidance is still the preferred treatment modality of choice regardless of GPA and mutational status, while SRT is only used in patients with good prognosis. Evidence for both, SRS and hippocampal avoidance radiotherapy, is growing albeit the debate over the appropriate treatment in multiple BM is yet not fully clarified. Further prospective assessment of BM management-ideally as randomized trials-is required to align evolving concepts with the proper evidence and to update current guidelines.

Radiosurgery and stereotactic irradiation of multiple and contiguous brain metastases: A practical proposal of dose prescription methods and a literature review

PURPOSE

In literature, there are no guidelines on how to prescribe dose in the case of radiosurgery (SRS) or stereotactic irradiation of multiple and adjacent BM. Aim of this work is to furnish practical proposals of dosimetric methods for multiple neighboring BM, and to make a literature review about the SRS treatment of multiple BM, comparing radiotherapy techniques on the basis of different dosimetric parameters.

MATERIALS AND METHODS

A theoretical proposal of dosimetric approaches to prescribe dose in case of multiple contiguous BM is done. A literature review between 2010 and 2020 was performed on MEDLINE and Cochrane databases according to the PRISMA methodology, with the following keywords dose prescription, radiosurgery, multiple BM. Papers not reporting dosimetric solutions to irradiate multiple BM were excluded.

RESULTS

Only one article in the literature reports a practical modality of dose prescription for multiple adjacent BM. Thus, we proposed other five practical solutions to prescribe radiation dose in case of two or more neighboring BM, describing advantages and drawbacks of each method in terms of different dosimetric parameters. The literature review about dosimetric solutions to irradiate multiple BM led to 56 titles; 14 articles met the chosen criteria and we reported their results in terms of dosimetric indexes and low doses to the normal brain tissue.

CONCLUSIONS

The six dosimetric approaches here described can be used by physicians for multiple contiguous BM, depending on the clinical situation. These methods may be applied in clinical studies to better evaluate their usefulness in practice.

Stereotactic Radiosurgery for Multiple Brain Metastases

PURPOSE OF REVIEW

To give an overview on the current evidence for stereotactic radiosurgery of brain metastases with a special focus on multiple brain metastases.

RECENT FINDINGS

While the use of stereotactic radiosurgery in patients with limited brain metastases has been clearly defined, its role in patients with multiple lesions (> 4) is still a matter of controversy. Whole-brain radiation therapy (WBRT) has been the standard treatment approach for patients with multiple brain lesions and is still the most commonly used treatment approach worldwide. Although distant brain failure is improved by WBRT, the overall survival is not readily impacted. As WBRT is associated with significant neurocognitive decline compared to stereotactic radiosurgery (SRS), SRS has been explored and increasingly utilized for selected patients with multiple brain metastases. Recent clinical data indicated the feasibility of stereotactic radiosurgery to multiple brain metastases with a similar survival in patients with more than 4 brain metastases versus patients with a maximum of 4 brain metastases. Also, neurocognitive function and quality of life was maintained after stereotactic radiosurgery which is essential in a palliative setting. The application of stereotactic radiosurgery with Gamma Knife, Cyberknife, or LINAC-based equipment has emerged as an effective and widely available treatment option for patients with limited brain metastases. Although not formally proven in prospective studies, SRS may also be considered as a safe and effective treatment option in selected patients with multiple brain metastases. Especially in patients with a favorable prognosis, survival over several years is observed also in the setting of multiple BM. For these patients, avoidance of the neurocognitive damage of WBRT is desirable, and SRS is often a more appropriate treatment in the current multimodality treatment of BM in which systemic treatment is often the cornerstone of the treatment. For patients with an intermediate (3-12 months) and poor prognosis (< 3 months), the application of WBRT becomes more and more controversial, because of its acute side effects, such as hair loss and fatigue and, thereby, detrimental effect on quality of life. For these patients, best supportive care, primary systemic treatment, and even SRS may be preferred over WBRT on an individualized patient basis.

Progress in the biological understanding and management of breast cancer-associated central nervous system metastases

Metastasis to the central nervous system (CNS) is a devastating neurological complication of systemic cancer. Brain metastases from breast cancer have been documented to occur in approximately 10%-16% of cases over the natural course of the disease with leptomeningeal metastases occurring in approximately 2%-5% of cases of breast cancer. CNS metastases among women with breast cancer tend to occur among those who are younger, have larger tumors, and have a more aggressive histological subtype such as the triple negative and HER2-positive subtypes. Treatment of CNS metastases involves various combinations of whole brain radiation therapy, surgery, stereotactic radiosurgery, and chemotherapy. We will discuss the progress made in the treatment and prevention of breast cancer-associated CNS metastases and will delve into the biological underpinnings of CNS metastases including evaluating the role of breast tumor subtype on the incidence, natural history, prognostic outcome, and impact of therapeutic efficacy.

Gamma Knife surgery for the treatment of 5 to 15 metastases to the brain: clinical article

OBJECT

It has been generally accepted that Gamma Knife surgery (GKS) is an effective primary or adjunct treatment for patients with 1-4 metastases to the brain. The number of studies detailing the use of GKS for 5 or more brain metastases, however, remains minimal. The aim of the current retrospective study was to elucidate the utility of GKS in patients with 5-15 brain metastases.

METHODS

Patients were chosen for GKS based on prior MRI of these metastatic lesions and a known primary cancer diagnosis. Magnetic resonance imaging was used post-GKS to assess tumor control; patients were also followed up clinically. Overall survival (OS) from the date of GKS was used as the primary end point. Statistical analysis was performed to identify prognostic factors related to OS.

RESULTS

Between 2003 and 2012, 96 patients were treated for a total of 704 metastatic brain lesions. The histology of these lesions varied among non-small cell lung cancer (NSCLC), breast cancer, melanoma, renal cancer, and other more rare carcinomas. At the initial treatment, 18 of the patients (18.8%) were categorized in Recursive Partitioning Analysis (RPA) Class 1 and 77 (80.2%) in RPA Class 2; none were in RPA Class 3. The median number of treated lesions was 7 (mean 7.13), and the median planned treatment volume was 6.12 cm(3) (range 0.42-57.83 cm(3)) per patient. The median clinical follow-up was 4.1 months (range 0.1-40.70 months). Actuarial tumor control was calculated to be 92.4% at 6 months, 84.8% at 12 months, and 74.9% at 24 months post-GKS. The median OS was found to be 4.73 months (range 0.4-41.8 months). Multivariate analysis demonstrated that RPA class was a significant predictor of death (HR = 2.263, p = 0.038). Number of lesions, tumor histology, Graded Prognostic Assessment score, prior whole-brain radiation therapy, prior resection, prior chemotherapy, patient age, patient sex, controlled primary tumor, extracranial metastases, and planned treatment volume were not significant predictors of OS.

CONCLUSIONS

In patients with 5-15 brain metastases at presentation, the number of lesions did not predict survival after GKS; however, the RPA class was predictive of OS in this group of patients. Gamma Knife surgery for such patients offers an excellent rate of local tumor control.

Current therapeutic approaches in patients with brain metastases

The development of brain metastases is often viewed as the end stage of a disease course and engenders skepticism about the efficacy of treatment. Aggressive management of brain metastases is effective in both symptom palliation and the prolongation of life. The majority of patients with controlled intracranial metastases will expire from systemic disease rather than from recurrence of these metastases. Single brain metastases should be treated with surgical resection or stereotactic radiosurgery, though it is unclear at this time if one modality is more effective than the other. Surgical resection is preferred when a pathologic diagnosis is needed, for tumors larger than 3.5 cm, or when immediate tumor mass decompression is required. Stereotactic radiosurgery (SRS) should be applied for single tumors less than 3.5 cm in surgically inaccessible areas and for patients who are not surgical candidates. Small tumors (ie, < 3.5 cm) that cause minimal edema and are surgically accessible may be treated with either surgery or SRS. There is controversy over whether whole brain radiation therapy (WBRT) can be omitted following surgical resection or SRS. Omission of WBRT increases intracranial tumor recurrence; however, this has not been correlated with decreased survival. Clinicians who choose to omit upfront WBRT are obligated to monitor the patient closely for intracranial recurrence, at which time further salvage therapy in the form of surgery, SRS, or WBRT may be considered. Histology is of particular importance when considering WBRT for patients with radioresistant tumors such as melanoma, renal cell carcinoma, or sarcoma. WBRT may be of less clinical benefit in this setting. Chemotherapy has been demonstrated to improve response rates when used as an adjunct to radiation therapy. These improvements in response rates have not been correlated with an improvement in median survival. Noncytotoxic radiosensitizing agents such as motexafin and efaproxiral show promise. Phase III trials to assess the benefit of motexafin in patients with metastatic lung cancer and efaproxiral in patients with metastatic breast cancer are ongoing. Targeted therapies offer promise in achieving therapeutic efficacy while minimizing side effects. Surgical adjuncts such as BCNU (carmustine) wafers and the GliaSite Radiation System (Cytyc Corporation, Marlborough, MA) may be useful in the future in achieving optimal local tumor control.

Prognosis of non-small cell lung cancer with synchronous brain metastases treated with gamma knife radiosurgery

The clinical outcome and prognostic factors of patients with synchronous brain metastases from non-small cell lung cancer (NSCLC) who were treated with gamma knife radiosurgery (GKS) were analyzed. A total of 35 patients with NSCLC underwent GKS as an initial treatment for metastatic brain lesions of synchronous onset. The period of survival and various prognostic factors such as age, gender, performance status, multiplicity of the brain lesions, intracranial tumor volume, and extent of the primary tumor were analyzed. The overall median survival time for this series was 12 months (range 0.75 to 43 months) from the diagnosis. Of the 21 patients who were no longer alive at the conclusion of this study, only 7 (33.3%) died of neurological causes. Multivariate analysis of these data revealed that N stage, whole-brain radiotherapy (WBRT), and chemotherapy were significant predictors for survival (p<0.05). Survival of patients with NSCLC and synchronous brain metastases is mainly dependent upon the progression of the systemic disease, provided that the cerebral lesions are treated adequately with local treatment modalities including radiosurgery. Application of radiosurgery as an initial treatment option and aggressive local and systemic modalities to control extracranial disease may improve survival.