The usefulness of stereotactic radiosurgery for radioresistant brain metastases

Repeated Stereotactic Radiotherapy for Local Brain Metastases Failure or Distant Brain Recurrent: A Retrospective Study of 184 Patients

BACKGROUND

The main advantages of stereotactic radiotherapy (SRT) are to delay whole-brain radiotherapy (WBRT) and to deliver ablative doses. Despite this efficacy, the risk of distant brain metastases (BM) one year after SRT ranges from 26% to 77% and 20 to 40% of patients required salvage treatment. The role and consequences of reirradiation remain unclear, particularly in terms of survival. The objective was to study overall survival (OS) and neurological death-free survival (NDFS) and to specify the prognostic factors of long-term survival.

METHODS

we retrospectively reviewed the data of patients treated between 2010 and 2020 with at least two courses of SRT without previous WBRT.

RESULTS

In total, 184 patients were treated for 915 BMs with two-to-six SRT sessions. Additional SRT sessions were provided for local (5.6%) or distant (94.4%) BM recurrence. The median number of BMs treated per SRT was one with a median of four BMs in total. The mean time between the two SRT sessions was 8.9 months (95%CI 7.7-10.1) and there was no significant difference in the delay between the two sessions. The 6-, 12- and 24-month NDFS rates were 97%, 82% and 52%, respectively. The 6-, 12- and 24-month OS rates were 91%, 70% and 38%, respectively. OS was statistically related to the number of SRT sessions (HR = 0.48; p < 0.01), recursive partitioning analysis (HR = 1.84; p = 0.01), salvage WBRT (HR = 0.48; p = 0.01) and brain metastasis velocity (high: HR = 13.83; p < 0.01; intermediate: HR = 4.93; p < 0.01).

CONCLUSIONS

Lung cancer and melanoma were associated with a lower NDFS compared to breast cancer. A low KPS, a low number of SRT sessions, synchronous extracerebral metastases, synchronous BMs, extracerebral progression at SRT1, a high BMV grade, no WBRT and local recurrence were also associated with a lower NDFS. A high KPS at SRT1 and low BMV grade are prognostic factors for better OS, regardless of the number of BM recurrence events.

Analysis of Demographics and Outcomes of Surgical Resection in the Central Nervous System of Patients With Metastatic Melanoma

Background

Patients with melanoma frequently develop central nervous system metastases. Oligometastatic disease is often treated either by surgical resection or by stereotactic radiotherapy. This study investigates the trends and clinical outcomes of patients with melanoma who have undergone surgical procedures on the central nervous system during their hospitalization.

Methods

A retrospective study was performed based on admissions of adult patients who underwent craniotomy for metastatic melanoma from 2000 to 2014 using the Nationwide Inpatient Sample database. The primary outcome measure was all-cause in-hospital mortality. Secondary outcomes included hospital length of stay (LOS) and discharge disposition (home/home with health care and skilled nursing facilities/long-term acute care (SNFs/LTAC)). Factors associated with in-hospital mortality were examined by multivariable logistic regression. We adjusted for patient and hospital characteristics, payer, and comorbid conditions. We also examined trends of mortality for the study years.

Results

There were an estimated 1,216 discharges of patients with melanoma undergoing craniotomy during the study period. Patients undergoing surgical interventions were typically males (69%) and whites (79%). Ninety-eight percent of procedures were performed at teaching hospitals. Unadjusted all-cause in-hospital mortality was 3.1%. There was no significant difference in mortality over 13 years. Age, gender, and race were not associated with increased in-hospital mortality. LOS was longer in elderly and those with higher Charlson Comorbidity Index. Of the survivors, 76% were discharged to home or with home healthcare while 24% were discharged to SNFs/LTAC. Patients with age > 65 (odds ratio (OR): 2.9; 95% confidence interval (CI): 2.2 - 3.9, P < 0.001) and those with higher Charlson Comorbidity Index (OR: 1.2; 95% CI: 1.1 - 1.3) had higher odds for being discharged to SNFs/LTAC.

Conclusions

Patients who undergo craniotomy for metastatic melanoma have a low in-hospital mortality rate. One quarter of patients were discharged to SNFs/LTAC.

Brain metastases in endometrial cancer: A systematic review of the surgical prognostic factors

CONTEXT

Although endometrial cancer is the fourth most common malignancy in women, dissemination to the brain is an exceptional event in the course of the disease. The aim of this review is to determine the important surgical prognostic factors for patients with endometrial cancer metastatic to the brain.

MATERIALS AND METHODS

Report of two cases. Medline database was used to conduct a systematic literature review from inception to December 2020 looking for English-language articles focused on brain metastases from endometrial cancer.

RESULTS

The research yielded 108 articles, among which 23 articles were retained for a total of 87 patients. Mean age was 60 years-old ±11 at the time of diagnosis of endometrial cancer, and most of the tumors were aggressive (grade 3) with an advanced-stage disease (FIGO III-IV). At the time of diagnosis of cerebral disease, a single brain metastasis (p < 0.0001) and no extra-cerebral metastatic site (p = 0.0011) were significant good prognostic factors for the median overall survival. Surgical excision of brain metastasis followed by radiotherapy provided the longest median overall survival compared to radiotherapy and/or chemotherapy, and surgery alone (respectively 32, 5.4 and 4.8 months, p < 0.0001). An age of 60-year-old or less was not associated with a better prognosis.

CONCLUSION

This review confirms that surgical excision followed by radiotherapy is a reliable option in patients with a single brain metastasis from endometrial cancer and no extra-cerebral metastatic site. This work could help to adapt the Graded Prognostic Assessment for brain metastases in endometrial cancer.

Tumor Control Probability of Radiosurgery and Fractionated Stereotactic Radiosurgery for Brain Metastases

PURPOSE

As part of the American Association of Physicists in Medicine Working Group on Stereotactic Body Radiotherapy, tumor control probability (TCP) after stereotactic radiosurgery (SRS) and fractionated stereotactic radiosurgery (fSRS) for brain metastases was modeled based on pooled dosimetric and clinical data from published English-language literature.

METHODS AND MATERIALS

PubMed-indexed studies published between January 1995 and September 2017 were used to evaluate dosimetric and clinical predictors of TCP after SRS or fSRS for brain metastases. Eligible studies had ≥10 patients and included detailed dose-fractionation data with corresponding ≥1-year local control (LC) data, typically evaluated as a >20% increase in diameter of the targeted lesion using the pre-SRS diameter as a reference.

RESULTS

Of 2951 potentially eligible manuscripts, 56 included sufficient dose-volume data for analyses. Accepting that necrosis and pseudoprogression can complicate the assessment of LC, for tumors ≤20 mm, single-fraction doses of 18 and 24 Gy corresponded with >85% and 95% 1-year LC rates, respectively. For tumors 21 to 30 mm, an 18 Gy single-fraction dose was associated with 75% LC. For tumors 31 to 40 mm, a 15 Gy single-fraction dose yielded ∼69% LC. For 3- to 5-fraction fSRS using doses in the range of 27 to 35 Gy, 80% 1-year LC has been achieved for tumors of 21 to 40 mm in diameter.

CONCLUSIONS

TCP for SRS and fSRS are presented. For small lesions ≤20 mm, single doses of ≈18 Gy appear generally associated with excellent rates of LC; for melanoma, higher doses seem warranted. For larger lesions >20 mm, local control rates appear to be ≈ 70% to 75% with usual doses of 15 to 18 Gy, and in this setting, fSRS regimens should be considered. Greater consistency in reporting of dosimetric and LC data is needed to facilitate future pooled analyses. As systemic and biologic therapies evolve, updated analyses will be needed to further assess the necessity, efficacy, and toxicity of SRS and fSRS.

Malignant Melanoma: Diagnostic and Management Update

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Summarize the changes to the American Joint Committee on Cancer Eighth Edition Melanoma Staging System. 2. List advances in genetic, molecular, and histopathologic melanoma diagnosis and prognostication. 3. Recommend sentinel lymph node biopsy and appropriate surgical margins based on individualized patient needs. 4. Recognize the currently available treatments for in-transit metastasis and advanced melanoma. 5. Describe current and future therapies for melanoma with distant visceral or brain metastases.

SUMMARY

Strides in melanoma surveillance, detection, and treatment continue to be made. The American Joint Committee on Cancer Eighth Edition Cancer Staging System has improved risk stratification of patients, introduced new staging categories, and resulted in stage migration of patients with improved outcomes. This review summarizes melanoma advances of the recent years with an emphasis on the surgical advances, including techniques and utility of sentinel node biopsy, controversies in melanoma margin selection, and the survival impact of time-to-treatment metrics. Once a disease manageable only with surgery, a therapeutic paradigm shift has given a more promising outlook to melanoma patients at any stage. Indeed, a myriad of novel, survival-improving immunotherapies have been introduced for metastatic melanoma and more recently in the high-risk adjuvant setting.

Stereotactic Radiosurgery and Ipilimumab Versus Stereotactic Radiosurgery Alone in Melanoma Brain Metastases

Benefits of stereotactic radiosurgery (SRS) have been well established in melanoma brain metastases (MBM). Immunotherapy agents such as ipilimumab (ipi) have recently demonstrated clinical efficacy in advanced disease as well. The theoretical synergistic effects of combining these therapies in MBM have not been explored in detail, however, we conducted a systematic review with meta-analysis of studies that compared combined SRS and ipi versus SRS alone in MBM. Medical Literature Analysis and Retrieval System Online (MEDLINE) and Central databases were used for our literature search, which was conducted by three reviewers. We included studies that examined SRS and ipilimumab compared to SRS alone in MBM. Pertinent results were tabulated in a standardized spreadsheet. Newcastle-Ottawa Scale (NOS) Risk of Bias Assessment and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) method for rating evidence quality were used for qualitative analysis. Review Manager was used for statistical analysis. We identified four cohort studies that compared SRS plus ipi versus SRS alone in MBM. As per the GRADE criteria, we found low-quality evidence for survival benefits associated with combined treatment. Meta-analysis confirmed a significant benefit in survival for SRS and ipilimumab (hazard ratio 0.38, 95% confidence interval 0.28 – 0.52, p < 0.01). There were no significant differences between comparison groups for local control, distant brain control, radiation necrosis, or intracranial bleeding. We conclude that low-quality evidence exists for superior overall survival in MBM treated with SRS and ipilimumab compared to SRS without ipilimumab. There is also no increased risk of radiation necrosis and/or intracranial bleeding with combining radiation and immunotherapy in this setting.

Role of stereotactic body radiation therapy for lung metastases from radio-resistant primary tumours

OBJECTIVES

A retrospective analysis was performed on patients treated for lung oligo-metastatic disease from radio-resistant histology groups.

METHODS

The primary end point was local control (LC), secondary end points were overall survival (OS) and progression free survival (PFS). Toxicity was scored according to CTCAE 4.03.

RESULTS

200 patients were analyzed: 49.5% of the cases derived from colorectal primary tumors, 20.5% from sarcomas, 12.0% from renal cell carcinoma and the rest from other mixed origin. The mean follow-up was 24.2 months. LC at 1 and 2 years was 91, 84.9%. Primary histology and the presence of extra-pulmonary disease had a significant impact on LC. OS at 1 and 2 years was 88.7, 65.4%. Primary histology, disease free interval, presence of extra-pulmonary disease, number of irradiated lung lesions and age showed a correlation with prognosis at univariate analysis. PFS at 1 and 2 years was 84, 57.7%. The presence of extra-pulmonary disease and the number of irradiated lung lesions correlated with prognosis. Treatment was well tolerated with no G3-4 acute or late toxicity recorded.

CONCLUSION

Colorectal metastases showed a higher rate of local relapse. However, the factors mostly influencing prognosis were the presence of extra-pulmonary disease and the number of lung lesions.

Optimization of diagnostic performance for differentiation of recurrence from radiation necrosis in patients with metastatic brain tumors using tumor volume-corrected 11C-methionine uptake

Background

Tumor to normal tissue ratio (T/N ratio) on ¹¹C-methionine (¹¹C-MET) positron emission tomography/computed tomography (PET/CT) is affected by variable factors. We investigated whether T/N ratio cutoff values corrected according to metabolic tumor volume (MTV) could improve the diagnostic performance of ¹¹C-MET PET/CT for diagnosis of recurrence in patients with metastatic brain tumor.

Forty-eight patients with metastatic brain tumors underwent ¹¹C-MET PET/CT for differential diagnosis between recurrence and radiation necrosis after gamma knife radiosurgery (GKR). Both T/N ratio and MTV were estimated in each lesion on ¹¹C-MET PET/CT. The lesions were classified into three groups based on MTV criteria (≤ 0.5 cm³; > 0.5, ≤ 4.0 cm³; and > 4.0 cm³). The optimal cutoff values of the T/N ratio from receiver operating characteristic (ROC) curve were determined in each group (MTV-corrected) as well as total lesions (non-corrected). Finally, diagnostic performance of ¹¹C-MET PET/CT was compared with the MTV-corrected cutoff values.

Results

Among 77 lesions, 51 were diagnosed with recurrence. The mean T/N ratio was 2.25 (± 1.12) for recurrent lesions and 1.44 (± 0.22) for radiation necrosis (P < 0.001). T/N ratio of 1.61 (non-corrected) provided the best sensitivity, specificity, and diagnostic accuracy (70.6, 80.8, and 74.0%, respectively). Using the MTV criteria, optimal cutoff values of the T/N ratios in each group were 1.23 (MTV ≤ 0.5 cm³), 1.54 (0.5 cm³ < MTV ≤ 4.0 cm³), and 1.85 (MTV > 4.0 cm³). In small-sized lesions (MTV ≤ 0.5 cm³), MTV-corrected cutoff values (1.23) could maintain favorable diagnostic performance with sensitivity, specificity, and diagnostic accuracy (70.0, 80.0, and 73.3%, respectively), compared to non-corrected cutoff values.

Conclusions

MTV-corrected cutoff values of T/N ratio could maintain the diagnostic performance of ¹¹C-MET PET/CT in small sized, metastatic brain tumors. We expect our results to contribute to reproducible and standardized interpretation of ¹¹C-MET PET/CT.

Prognostic Factors for Survival of Patients With Synchronous or Metachronous Brain Metastasis of Renal Cell Carcinoma

INTRODUCTION

We evaluated the oncological outcomes of synchronous or metachronous brain metastasis (BM) of metastatic renal cell carcinoma (RCC) according to clinicopathologic factors.

PATIENTS AND METHODS

Patients with metastatic RCC (n = 93) with synchronous and metachronous BM were retrospectively identified. We analyzed patients and tumor characteristics, treatment methods, prognostic factors, BM progression, and overall survival (OS).

RESULTS

Seventy-six patients (81.7%) received local therapy (stereotactic radiosurgery [60.2%], radiation therapy [22.6%], and neurosurgery [10.8%]), and 54 patients (58.1%) were treated with systemic medical therapy. In multivariable analysis, poor Memorial Sloan-Kettering Cancer Center (MSKCC) risk (hazard ratio [HR] 3.672; 95% confidence interval [CI], 1.441-9.36; P = .0064), sarcomatoid component (HR 4.264; 95% CI, 2.062-8.820; P = .0001), and multiple BMs (HR 2.838; 95% CI, 1.690-4.767; P = .0001) were prognostic indicators of a poorer OS outcome. Local (HR 0.436; 95% CI, 0.237-0.802; P = .0076) and systemic treatment (HR 0.322; 95% CI, 0.190-0.548; P < .0001) were independent factors for a better OS. Although OS from initial RCC diagnosis in patients with metachronous BM was better than that for patients with synchronous BM, there were no differences found between synchronous and metachronous patients in terms of BM progression and OS after the diagnosis of BM.

CONCLUSIONS

Poor MSKCC risk, sarcomatoid component of histology, and multiple BMs are prognostic indicators for poor OS in patients with BM from metastatic RCC. Systemic and/or local treatment improves the OS. Because the type of BM, synchronous or metachronous, does not influence BM progression or the OS outcome, routine evaluation for BM is not recommended.

Choosing a Prescription Isodose in Stereotactic Radiosurgery for Brain Metastases: Implications for Local Control

OBJECTIVE

Stereotactic radiosurgery (SRS) achieves excellent local control (LC) with limited toxicity for most brain metastases. SRS dose prescription variables influence LC; therefore, we evaluated the impact of prescription isodose line (IDL) on LC after SRS.

METHODS

A retrospective analysis of patients with brain metastases treated on a Gamma Knife platform from 2004 to 2014 was conducted. Clinical, toxicity, radiographic, and dosimetric data were collected. Cox proportional hazards regression was used to determine progression-free survival (PFS) and competing risks analysis was used to determine predictive factors for LC.

RESULTS

A total of 134 patients with 374 brain metastases were identified with a median survival of 8.7 months (range, 0.2-64.8). The median tumor maximum dimension was 8 mm (range, 2-62 mm), median margin dose was 20 Gy (range, 5-24 Gy), and 12-month LC rate was 88.7%. On multivariate analysis, PFS improved with increasing IDL (P = 0.003) and decreased with non-non-small-cell lung cancer histology (P = 0.001). Margin dose, tumor size, conformality, and previous whole-brain irradiation failed to independently affect PFS. When adjusting for death as a competing risk, the cumulative likelihood of LC improved with higher IDL (P = 0.04). The rate of SRS-induced radiographic and clinical toxicity was low (16.6% and 1.5%, respectively), and neither was affected by IDL.

CONCLUSIONS

Our results confirm that SRS for brain metastases results in favorable LC, particularly for patients with smaller tumors. We noted that dose delivery to a higher prescription IDL is associated with small but measurable improvements in LC. This finding could be related to higher dose just beyond the radiographically apparent tumor.

The Energy Index Does Not Affect Local Control of Brain Metastases Treated by Gamma Knife Stereotactic Radiosurgery

BACKGROUND

The energy index (EI) is a measure of dose homogeneity within a target volume calculated by the integral dose divided by the product of prescription dose and tumor volume.

OBJECTIVE

To assess whether a higher EI is associated with greater local control for brain metastases (BMs) treated by Gamma Knife radiosurgery (GKRS).

METHODS

We reviewed all patients treated with GKRS for BM at our institution between January 2009 and February 2014. Data on the prescription dose, prescription isodose line, minimum dose, mean dose, integral dose, tumor volume, and EI were collected. Tumor response was assessed by reviewing follow-up brain imaging studies and classified according to the Response Evaluation Criteria in Solid Tumors. Local control per lesion and dosimetric prognostic factors for local control were assessed by univariate and multivariate Cox proportional hazards regression analyses.

RESULTS

Of 213 patients treated, 126 had follow-up imaging available with a median follow-up of 6 months. Three hundred seventy-three individual tumors were analyzed. Of these, 133 showed a complete response, 157 showed a partial response, 46 remained stable, and 37 developed local failure. Tumors with EI ≥1.6 mJ·mL(-1)·Gy(-1) showed a higher rate of complete response. Local control rates at 6, 11, and 17 months were 95.4%, 86.5%, and 81.5%, respectively. On univariate analysis, the following factors were associated with higher rates of local failure: prescription doses of 16 and 18 Gy compared with a prescription dose of 20 Gy. The following factors were associated with a greater rate of local control: maximum dose and mean dose. On multivariate analysis, the only statistically significant factor associated with a greater rate of local failure was prescription dose of 16 Gy compared with 20 Gy.

CONCLUSION

GKRS for BM results in a high rate of local control with an 11-month rate of 86.5%. A higher EI was not significantly associated with a higher rate of local control on multivariate analysis. Prescription dose was found to be the only significant predictor of local control on multivariate analysis.

The role of stereotactic radiosurgery and whole brain radiation therapy as primary treatment in the treatment of patients with brain oligometastases - A systematic review

The management of patients presenting with a limited number of brain metastases (BM) (oligo-metastases, defined as less than 3 BM) has evolved from Whole-Brain Radiotherapy (WBRT) alone to more aggressive strategies adding surgical resection and Stereotactic Radiosurgery (SRS) to the armamentarium. In choosing treatment modalities, the relative importance of the patient's age and clinical parameters, the number or volume of BM and the potential treatment related adverse-effects has been a matter of much debate. For patients with oligometastatic BM, local therapy using SRS in addition to WBRT was shown to improve time to neurologic deterioration, relapse rate and Overall Survival (OS). In patients who receive local therapy (SRS or surgery), adjuvant WBRT was shown to improve regional (brain) relapse rate. In the contemporary era, the beneficial effect of WBRT on lengthening the time of neurologic independence or OS when compared to no further treatment is unclear. One Meta-analysis pooling of information from several reports concluded that for younger patients (<50 years), SRS alone favored survival and that the initial omission of WBRT did not impact distant brain relapse rates. Other recent reports demonstrated on the contrary an OS benefit, more pronounced in good prognosis patients (diagnosis-specific Graded Prognostic Assessment 2.4-4.0) treated with SRS+WBRT compared to those who received SRS alone. As of today, there remains a role for both SRS and WBRT in the management of patients with oligo-metastatic BM but consensus about when to employ one or both is lacking. The exact patient selection criteria to benefit from either or both are still a matter of active research and heated debate.

Local control of melanoma brain metastases treated with stereotactic radiosurgery

PURPOSE

To examine the effectiveness of stereotactic radiosurgery (SRS) for melanoma brain metastases, as the optimal management is unknown.

MATERIALS AND METHODS

Patients with melanoma brain metastases treated between 1999 and 2013 with SRS as initial management were reviewed. Local control (LC), intracranial progression free survival, and overall survival were evaluated using the Kaplan Meier analysis and logistic regression.

RESULTS

185 patients were identified with 435 treated brain metastases. 76% of metastases were controlled, with a median freedom from local failure of 23.4 months. Higher SRS dose (p=0.001) and smaller tumor volume (p=0.0007) were associated with improved LC on univariate analysis, but on multivariate analysis only smaller tumor volume remained significant (p=0.047). At analysis, 7.6% of patients were alive and the median time to death after SRS was 7.8 months.

CONCLUSIONS

SRS is an effective primary treatment for melanoma brain metastases. There was no benefit combining SRS and surgery or whole brain radiotherapy.

Efficacy and Safety of Fractionated Stereotactic Radiosurgery for Large Brain Metastases

Objective

To investigate the efficacy and safety of fractionated stereotactic radiosurgery for large brain metastases (BMs).

Methods

Between June 2011 and December 2013, a total of 38 large BMs >3.0 cm in 37 patients were treated with fractionated Cyberknife radiosurgery. These patients comprised 16 men (43.2%) and 21 women, with a median age of 60 years (range, 38-75 years). BMs originated from the lung (n=19, 51.4%), the gastrointestinal tract (n=10, 27.0%), the breast (n=5, 13.5%), and other tissues (n=3, 8.1%). The median tumor volume was 17.6 cc (range, 9.4-49.6 cc). For Cyberknife treatment, a median peripheral dose of 35 Gy (range, 30-41 Gy) was delivered in 3 to 5 fractions.

Results

With a median follow-up of 10 months (range, 1-37 months), the crude local tumor control (LTC) rate was 86.8% and the estimated LTC rates at 12 and 24 months were 87.0% and 65.2%, respectively. The median overall survival (OS) and progression-free survival (PFS) rates were 16 and 11 months, respectively. The estimated OS and PFS rates at 6, 12, and 18 months were 81.1% and 65.5%, 56.8% and 44.9%, and 40.7% and 25.7%, respectively. Patient performance status and preoperative focal neurologic deficits improved in 20 of 35 (57.1%) and 12 of 17 patients (70.6%), respectively. Radiation necrosis with a toxicity grade of 2 or 3 occurred in 6 lesions (15.8%).

Conclusion

These results suggest a promising role of fractionated stereotactic radiosurgery in treating large BMs in terms of both efficacy and safety.

Control of brain metastases from radioresistant tumors treated by stereotactic radiosurgery

Renal cell carcinoma, sarcoma, and melanoma are considered to be "radioresistant" tumor histologies. Brain metastases (BM) from these tumors are considered unlikely to be controlled using the relatively low doses used in whole brain radiotherapy (WBRT). Our objective was to analyze the efficacy of stereotactic radiosurgery (SRS) on local control and overall survival of BM from radioresistant primary tumors. We reviewed all patients who received Gamma Knife Radiosurgery (GKRS) for BM at Columbia University Medical Center between January 2009 and April 2014. All patients were treated using the Gamma Knife Perfexion System. Dosimetric data was collected from treatment plans and metastases were categorized as radioresistant or not. Response was assessed by reviewing follow-up brain imaging studies and classified according to RECIST. Local control and median overall survival were calculated using the Kaplan-Meier method. In total, 373 tumors were analyzed from 126 patients. Of these tumors, 49 (13.1 %) originated from radioresistant cancers. The overall local control rate in the radioresistant cohort was 89.8 and 90.1 % in the non-radioresistant cohort. Univariate and multivariate analyses demonstrated that radioresistance status of the primary tumor had no statistically significant effect on local control with hazard ratios of 1.0 (p = 1.0, 95 % CI 0.388-2.576) and 0.954 (p = 0.926, 95 % CI 0.349-2.603) respectively. Median overall survival for both radioresistant and non-radioresistant cohorts was 20.0 months, with a p value of 0.926. There was no significant difference in local control of BM from radioresistant and non-radioresistant primary tumors treated with GKRS. Both cohorts showed excellent response and local control, suggesting that SRS upfront or in addition to WBRT may be an appropriate strategy in the treatment of BM from radioresistant cancers. Median overall survival for both cohorts was equal, suggesting that improved local control may be associated with an improvement in long-term survival.

Factors that determine local control with gamma knife radiosurgery: The role of primary histology

BACKGROUND

Stereotactic radiosurgery for the treatment of brain metastases is commonly delivered without regard to primary cancer histology. This study sought to determine if the primary site of origin for brain metastases affected the propensity for local failure.

METHODS

A total of 83 patients with 200 brain metastases were examined retrospectively for predictors of infield failure. Tumor, patient, and treatment characteristics were analyzed including primary tumor histology, radiosurgical dose and age. Cox proportional hazards models, univariate and multivariate analyses were used to identify predictors of local failure.

RESULTS

Freedom from local failure for the entire population was 83% and 65% at 6 and 12 months, respectively. Multivariate analysis revealed that breast cancer brain metastases have a significantly lower risk of local failure than melanoma (HR = 0.31, p< 0.001). Additionally, multivariate analysis revealed that increasing dose lowered risk for local failure (HR = 0.87, p<0.001).

CONCLUSIONS

Melanoma histology leads to a higher rate of local failure. Higher prescription dose results in higher incidence of local control.

Stereotactic radiosurgery for multiple brain metastases

Stereotactic radiosurgery (SRS) alone has become one of the treatment options for patients with 1-4 metastases as the detrimental effects of whole brain radiation therapy on neurocognition and quality of life are becoming well known. Multiple randomized control trials also failed to show overall survival benefit of adding whole brain radiation therapy to SRS. However, the role of SRS in multiple brain metastases, especially those with ≥ 4 tumors, remains controversial. The literature is emerging, and the limited evidence suggests that the local control benefit is independent of the number of metastases, and that patients with more than four brain metastases have similar overall survival compared to those with 2-4 tumors. This review aims at summarizing the current evidence of SRS for multiple brain metastases, divided into limited (2-3) and multiple (≥ 4) lesions. It also reviews the technical aspects and cost-effectiveness of SRS.