External radiation of brain metastases from renal carcinoma: a retrospective study of 119 patients from the M. D. Anderson Cancer Center

Brain metastases from renal cell carcinoma: Effects of novel systemic agents on brain metastasis outcomes

OBJECTIVE

The objective of this study was to examine survival outcomes in 136 patients with renal cell carcinoma with metastases to the brain who were treated with radiation combined with immunotherapy or tyrosine kinase inhibitor compared to those who were treated with radiation therapy alone.

METHODS

The Wake Forest Gamma Knife prospective database was searched for all patients with renal cell carcinoma brain metastases. Outcome measurements included overall survival, determined via the Kaplan-Meier Method, and cumulative incidence of local and distant failure, determined using the Fine Gray competing risks analysis with death as a competing risk for the 136 patients included.

RESULTS

Overall survival for the entire population at 6 months, 12 months, and 24 months was 67%, 47% and 30%, respectively. For the TKI (non-immunotherapy-treated) population (n = 37), overall survival was 75%, 61%, and 40% at 6 months, 12 months, and 24 months, respectively. For the immunotherapy-treated population (n = 35), overall survival was 85%, 64%, and 50% at 6 months, 12 months, and 24 months, respectively. Overall survival was significantly increased for patients who received radiation with either immunotherapy or TKI (p < 0.0001).

CONCLUSION

Prior series of patients with brain metastases of multiple histologies have demonstrated an improvement in the local efficacy of stereotactic radiosurgery when combined with systemic agents. We found that patients treated with targeted agents and patients treated with immunotherapy demonstrated a trend towards improvement over patients treated in the era prior to the advent of either classes of novel therapies.

Local Control in Patients with Metastatic Renal Cell Carcinoma to the Spine: The Experience of an Institution with a Multidisciplinary Spine Oncology Program

BACKGROUND

The outcomes for patients with metastatic renal cell carcinoma (RCC) to the spine who underwent stereotactic body radiotherapy (SBRT) through a multidisciplinary spine oncology program are not well described. We sought to describe the clinical course and local control rates at 1 and 2 years for these patients.

METHODS

A retrospective analysis of a prospectively maintained database of adult oncologic patients receiving SBRT to the spine through a multidisciplinary spine oncology program at a single institution from 2010 to 2021 was performed. Patients with a pathologic diagnosis of RCC were included.

RESULTS

A total of 75 spinal sites were treated in 60 patients. Of the 60 patients, 75.0% were men, and the mean patient age was 59.2 ± 11.3 years. At 1 year after treatment, 6 of the 60 patients were lost to follow-up. Of the remaining 54 patients, 18 were censored by death and 7 treatment sites showed local recurrence, for 37 of 44 treatment sites with local control (87.8%). At 2 years, 1 additional local recurrence had developed, 15 patients were censored by death, and no additional patients had been lost to follow-up, resulting in 28 of 36 treatment sites with local control (83.2%). None of the patients who had undergone repeat SBRT had local recurrence at 1 or 2 years. For those with local recurrence, the average time from treatment to progression was 6.6 ± 6.5 months.

CONCLUSIONS

In this cohort, one of the largest reported studies of spine SBRT for metastatic RCC, local control was high at 1 and 2 years. Our findings support the role of coordinated, algorithmic treatment for these patients.

Efficacy and Safety of a Second Course of Stereotactic Radiation Therapy for Locally Recurrent Brain Metastases: A Systematic Review

Recent advances in cancer treatments have increased overall survival and consequently, local failures (LFs) after stereotactic radiotherapy/radiosurgery (SRS/SRT) have become more frequent. LF following SRS or SRT may be treated with a second course of SRS (SRS2) or SRT (SRT2). However, there is no consensus on whenever to consider reirradiation. A literature search was conducted according to PRISMA guidelines. Analysis included 13 studies: 329 patients (388 metastases) with a SRS2 and 135 patients (161 metastases) with a SRT2. The 1-year local control rate ranged from 46.5% to 88.3%. Factors leading to poorer LC were histology (melanoma) and lack of prior whole-brain radiation therapy, large tumor size and lower dose at SRS2/SRT2, poorer response at first SRS/SRT, poorer performance status, and no controlled extracranial disease. The rate of radionecrosis (RN) ranged from 2% to 36%. Patients who had a large tumor volume, higher dose and higher value of prescription isodose line at SRS2/SRT2, and large overlap between brain volume irradiated at SRS1/SRT1 and SRS2/SRT2 at doses of 18 and 12 Gy had a higher risk of developing RN. Prospective studies involving a larger number of patients are still needed to determine the best management of patients with local recurrence of brain metastases.

Radiotherapy and Renal Cell Carcinoma: A Continuing Saga

Renal cell carcinoma (RCC) is one of the most aggressive malignancies of the genito-urinary tract, having a poor prognosis especially in patients with metastasis. Surgical resection remains the gold standard for localized renal cancer disease, with radiotherapy (RT) receiving much skepticism during the last decades. However, many studies have evaluated the role of RT, and although renal cancer is traditionally considered radio-resistant, technological advances in the RT field with regards to modern linear accelerators, as well as advanced RT techniques have resulted in breakthrough therapeutic outcomes. Additionally, the combination of RT with immune checkpoint inhibitors and targeted agents may maximize the clinical benefit. This review article focuses on the role of RT in the therapeutic management of renal cell carcinoma.

The promising role of radiotherapy in the treatment of advanced or metastatic renal cell carcinoma: a narrative review

Traditionally, renal cell carcinoma (RCC) has been regarded to be “radioresistant”. Conventional fractionated radiation (CFRT) has played a limited role in RCC as a palliative treatment to relieve pain and bleeding. Succeed to the rapid development of precise radiotherapy techniques, realizing safe delivery of high-dose radiotherapy, an increasing amount of convincing data suggests that the delivery of high-dose-per-fraction radiation through stereotactic radiosurgery (SRS) or stereotactic body radiation therapy (SBRT), also known as stereotactic ablative radiotherapy (SABR) can help to overcome resistance to radiotherapy. Herein, we summarized and analyzed the data from randomized controlled trials, retrospective and prospective studies, and meta-analyses relating to the treatment of advanced and metastatic RCC (mRCC) with CFRT, SBRT, or SBRT combined with systemic therapy. CFRT has a limited effect on local control (LC) of advanced RCC and mRCC, but it is a major palliative treatment which could obviously relieve pain caused by cancer. SBRT and SRS have the significant advantage of being able to precisely deliver a high dose of radiation to the target tissues. SBRT could cause a higher LC for advanced and metastatic RCC and could be used as an alternative to surgery for patients with oligometastatic RCC. The combination of SBRT with systemic therapy, such as targeted therapy or immunotherapy, is safe and tolerable. Concurrent immunotherapy and SBRT is a promising treatment strategy for patients with advanced or metastatic RCC. However, research on radiotherapy combined with systemic therapy is still limited and further studies to explore this treatment for RCC are urgently needed.

The Reintroduction of Radiotherapy Into the Integrated Management of Kidney Cancer

The incidence of renal cell carcinoma (RCC) has been increasing, with a moderate subgroup of individuals who later develop metastatic disease. Historically, metastatic RCC has been managed with systemic therapy because RCC was believed to be radioresistant. Local therapies, such as stereotactic body radiation therapy, also known as stereotactic ablative radiotherapy, which utilize focused high-dose-rate radiation delivered over a limited number of treatments, have been successful in controlling local disease and, in some cases, extending survival in patients with intracranial and extracranial metastatic RCC. Stereotactic ablative radiotherapy is highly effective in treating intact disease when patients are not surgical candidates. Stereotactic ablative radiotherapy is well tolerated when used in conjunction with systemic therapy such as tyrosine kinase inhibitors and immune checkpoint inhibitors. These successes have prompted investigators to evaluate the efficacy of stereotactic body radiation therapy in novel settings such as neoadjuvant treatment of advanced RCC with tumor thrombus and oligometastatic/oligoprogressive disease states.

Characteristics of Patients and Treatment Recommendations from a Multidisciplinary Spinal Tumor Program

Objective: We describe characteristics of patient and treatment recommendations from a spinal tumor board at one institution, including representation from palliative care.

Background: The impact of prospective multidisciplinary input for patients with spinal tumors is poorly understood despite their increasing complexity.

Methods: We retrospectively reviewed 622 cases sequentially discussed at a weekly spinal tumor board, and abstracted patient and treatment information from the medical record and meeting minutes.

Results: From April 2017 to February 2019, 622 cases representing 438 unique patients were discussed. The median age was 62 years (range 21–92). Most patients had spinal tumors originating from metastases (91.78%), including breast (14.3%), nonsmall cell lung cancer (13.4%), prostate (10.9%), and renal cell cancer (8.8%), and the remainder had primary central nervous system (4.3%) or benign tumors (3.9%). Sixty-five percent of patients were alive at last follow-up. Conventional external beam radiotherapy was the most common treatment recommendation (33.8%) followed by surgery (26.2%), stereotactic body radiation therapy (17.8%), imaging follow-up (16.6%), and vertebroplasty (15.9%). Palliative care was the primary treatment recommended for 4.5%, and no therapy recommended for 4.0%. Treatment recommendation involved two modalities for 29% of cases, and three in 1.3% of cases. In four cases, biopsy to confirm pathology changed management due to unexpected findings of osteomyelitis, hematopoiesis, or new diagnosis of plasmacytoma.

Conclusions: Multidisciplinary input is integral to the optimal care of spinal tumor patients. The high risk of death highlights the need to prioritize modalities that optimize quality of life in the context of a patient's individual prognosis.

Impact of Tyrosine Kinase Inhibitors (TKIs) Combined With Radiation Therapy for the Management of Brain Metastases From Renal Cell Carcinoma

Background: Targeted therapy has transformed the outcome for patients with metastatic renal cell carcinoma. Their efficacy and safety have also been demonstrated in brain metastatic RCC. Preclinical evidence suggests synergism of radiation and tyrosine kinase inhibitors. Consequently, several studies have compared their efficacy in the treatment of RCC brain metastases to the era of brain management with surgery/radiation only.

Objectives: We seek to systematically review and meta-analyze the results of those studies that involved comparative intervention groups of brain management; TKIs, and never used TKIs.

Methods and Materials: Online databases (PubMed, EMBASE, Cochrane library, and ClinicalTrials.gov) were searched for comparative studies. Overall survival as the primary outcome of interest, and local brain control, distant control, and adverse events as secondary outcomes of interest were recorded for meta-analysis. Hazard ratios were pooled together using Review Manager 5.3. Fixed effects or random effects model were adopted according to the level of heterogeneity. Subgroup analysis included studies that involved SRS as the local treatment of management.

Results: Overall 7 studies (n = 897) were included for meta-analysis. TKI use was associated with better survival (HR 0.60 [0.52, 0.69], p < 0.00001) and local brain control (HR 0.34 [0.11, 0.98], p = 0.05). SRS subgroup also revealed significantly better survival (HR 0.61 [0.44, 0.83], p = 0.002) and local brain control (HR 0.19 [0.08, 0.45], p = 0.0002). Distant brain control (HR 0.95 [0.67, 1.35], p = 0.79) and brain progression free survival were unaffected (HR 0.94 [0.56, 1.56], p = 0.80). Only one study (n = 376) reported significantly greater 12-months cumulative incidence of radiation necrosis with TKI use within 30 days of SRS (10.9 vs. 6.4%, p = 0.04).

Conclusions: TKIs use in combination with SRS is safe and effective for treating RCC brain metastases. Larger randomized controlled trials are warranted to validate the results.

Tumor Primary Site and Histology Subtypes Role in Radiotherapeutic Management of Brain Metastases

Randomized controlled trials have failed to report any survival advantage for WBRT combined with SRS in the management of brain metastases, despite the enhanced local and distant control in comparison to each treatment alone. Literature review have revealed important role of primary histology of the tumor when dealing with brain metastases. NSCLC responds better to combined approach even when there was only single brain metastasis present while breast cancer has registered better survival with SRS alone probably due to better response of primary tumor to advancement in surgical and chemotherapeutic agents. Furthermore, mutation status (EGFR/ALK) in lung cancer and receptor status (ER/PR/HER2) in breast cancer also exhibit diversity in their response to radiotherapy. Radioresistant tumors like renal cell carcinoma and melanoma brain metastases have achieved better results when treated with SRS alone. Secondly, single brain metastasis may benefit from local and distant brain control achieved with combined treatment. These diverse outcomes suggest a primary histology-based analysis of the radiotherapy regimens (WBRT, SRS, or their combination) would more ideally establish the role of radiotherapy in the management of brain metastases. Molecularly targeted therapeutic and immunotherapeutic agents have revealed synergism with radiation therapy particularly SRS in treating cancer patients with brain metastases. Clinical updates in this regard have also been reviewed.

A systematic review: Role of systemic therapy on treatment and prevention of brain metastasis in renal cell carcinoma

AIM

To define the inclusion/exclusion status of patients with brain metastasis in phase-III clinical trials and the effect of systemic therapies in metastatic renal cell cancer patients with brain metastasis.

METHODS

"kidney neoplasms"[MeSH Terms] OR ("kidney"[All Fields] AND "neoplasms"[All Fields]) OR "kidney neoplasms"[All Fields] OR ("kidney"[All Fields] AND "cancer"[All Fields]) OR "kidney cancer"[All Fields] AND "brain metastasis" were used for searching "PubMed" electronic database and "clinicaltrials.gov" website.

RESULTS

Five of 19 landmark phase-III clinical trials included patients with stable or asymptomatic brain metastasis and there was no data about outcomes of brain metastasis. The effect of systemic therapy on prevention of brain metastasis in renal cell cancer was evaluated in four studies. Two studies showed that the incidence of brain metastasis decreased, while the other two studies showed no effect of antiangiogenic agents on the prevention of brain metastasis in patients with renal cell cancer. There were 10 trials regarding systemic therapy of renal cell cancer brain metastasis. The overall response rate improved through a combination of targeted therapies and local treatment. The results of the trials studying the effect of tyrosine kinase inhibitors without local treatment were controversial. None of the ongoing clinical trials included patients with active brain metastasis.

CONCLUSION

In metastatic renal cell cancer patients with brain metastasis, the overall response rate improved with the combination of targeted agents and local treatment. Further trials are needed to evaluate the effect of systemic treatment on the prevention or treatment of brain metastasis in patients with renal cell cancer.

Overall survival and response to radiation and targeted therapies among patients with renal cell carcinoma brain metastases

OBJECTIVE

The object of this retrospective study was to investigate the impact of targeted therapies on overall survival (OS), distant intracranial failure, local failure, and radiation necrosis among patients treated with radiation therapy for renal cell carcinoma (RCC) metastases to the brain.

METHODS

All patients diagnosed with RCC brain metastasis (BM) between 1998 and 2015 at a single institution were included in this study. The primary outcome was OS, and secondary outcomes included local failure, distant intracranial failure, and radiation necrosis. The timing of targeted therapies was recorded. Multivariate Cox proportional-hazards regression was used to model OS, while multivariate competing-risks regression was used to model local failure, distant intracranial failure, and radiation necrosis, with death as a competing risk.

RESULTS

Three hundred seventy-six patients presented with 912 RCC BMs. Median OS was 9.7 months. Consistent with the previously validated diagnosis-specific graded prognostic assessment (DS-GPA) for RCC BM, Karnofsky Performance Status (KPS) and number of BMs were the only factors prognostic for OS. One hundred forty-seven patients (39%) received vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKIs). Median OS was significantly greater among patients receiving TKIs (16.8 vs 7.3 months, p < 0.001). Following multivariate analysis, KPS, number of metastases, and TKI use remained significantly associated with OS.The crude incidence of local failure was 14.9%, with a 12-month cumulative incidence of 13.4%. TKIs did not significantly decrease the 12-month cumulative incidence of local failure (11.4% vs 14.5%, p = 0.11). Following multivariate analysis, age, number of BMs, and lesion size remained associated with local failure. The 12-month cumulative incidence of radiation necrosis was 8.0%. Use of TKIs within 30 days of SRS was associated with a significantly increased 12-month cumulative incidence of radiation necrosis (10.9% vs 6.4%, p = 0.04).

CONCLUSIONS

Use of targeted therapies in patients with RCC BM treated with intracranial SRS was associated with improved OS. However, the use of TKIs within 30 days of SRS increases the rate of radiation necrosis without improving local control or reducing distant intracranial failure. Prospective studies are warranted to determine the optimal timing to reduce the rate of necrosis without detracting from survival.

Evaluation of response to stereotactic radiosurgery in patients with radioresistant brain metastases

PURPOSE

Renal cell carcinoma (RCC) and melanoma have been considered 'radioresistant' due to the fact that they do not respond to conventionally fractionated radiation therapy. Stereotactic radiosurgery (SRS) provides high-dose radiation to a defined target volume and a limited number of studies have suggested the potential effectiveness of SRS in radioresistant histologies. We sought to determine the effectiveness of SRS for the treatment of patients with radioresistant brain metastases.

MATERIALS AND METHODS

We performed a retrospective review of our institutional database to identify patients with RCC or melanoma brain metastases treated with SRS. Treatment response were determined in accordance with the Response Evaluation Criteria in Solid Tumors.

RESULTS

We identified 53 radioresistant brain metastases (28% RCC and 72% melanoma) treated in 18 patients. The mean target volume and coverage was 6.2 ± 9.5 mL and 95.5% ± 2.9%, respectively. The mean prescription dose was 20 ± 4.9 Gy. Forty lesions (75%) demonstrated a complete/partial response and 13 lesions (24%) with progressive/stable disease. Smaller target volume (p < 0.001), larger SRS dose (p < 0.001), and coverage (p = 0.008) were found to be positive predictors of complete response to SRS.

CONCLUSION

SRS is an effective management option with up to 75% response rate for radioresistant brain metastases. Tumor volume and radiation dose are predictors of response and can be used to guide the decision-making for patients with radioresistant brain metastases.

Is there a role for stereotactic radiotherapy in the treatment of renal cell carcinoma?

Renal cell carcinoma (RCC) has traditionally been regarded as radioresistant tumor based on preclinical data and negative clinical trials using conventional fractionated radiotherapy. However, there is emerging evidence that radiotherapy delivered in few fractions with high single-fraction and total doses may overcome RCC s radioresistance. Stereotactic radiotherapy (SRT) has been successfully used in the treatment of intra- and extracranial RCC metastases showing high local control rates accompanied by low toxicity. Although surgery is standard of care for non-metastasized RCC, a significant number of patients is medically inoperable or refuse surgery. Alternative local approaches such as radiofrequency ablation or cryoablation are invasive and often restricted to small RCC, so that there is a need for alternative local therapies such as stereotactic body radiotherapy (SBRT). Recently, both retrospective and prospective trials demonstrated that SBRT is an attractive treatment alternative for localized RCC. Here, we present a comprehensive review of the published data regarding SBRT for primary RCC. The radiobiological rationale to use higher radiation doses in few fractions is discussed, and technical aspects enabling the safe delivery of SBRT despite intra- and inter-fraction motion and the proximity to organs at risk are outlined.

Renal cell carcinoma and brain metastasis: Questioning the dogma of role for cytoreductive nephrectomy

INTRODUCTION

Renal cell carcinoma (RCC) brain metastasis is generally viewed as poor prognostic features and often excludes patients from cytoreductive nephrectomy or participation in clinical trials. We aim to evaluate patients presenting with brain metastasis and their outcomes.

METHODS

Surveillance Epidemiology and End Results-18 registries database was queried for all patients with metastatic RCC from 2010 to 2014. Patients with renal cancer as their only malignancy were included. Information was available for metastatic disease to bone, liver, lung, and brain. Patients were then further stratified into those with isolated brain metastases and those with additional metastasis to other sites as well. Overall survival was compared between groups using logrank analysis.

RESULTS

A total of 6,667 patients were identified with metastatic RCC. Among them, 775 (12.1%) had brain metastasis at time of diagnosis. Of these patients with brain metastasis, 152 (20.4%) had isolated brain metastasis. Only 23.8% of all patients with brain metastasis underwent cytoreductive nephrectomy, compared to 40.8% of patients with isolated brain metastasis. Patients with brain and other metastasis and brain metastasis only treated by cytoreductive nephrectomy exhibited a median survival of 11 and 33 months, respectively. Those patients who did not undergo cytoreductive nephrectomy experienced a median survival of 4 and 5 months, respectively.

CONCLUSION

It appears that selected patients with brain metastasis may experience durable long-term survival. This information may be beneficial for patient counseling, surgical planning, and consideration for inclusion in clinical trials.

Outcomes After Hypofractionated Dose-Escalation using a Simultaneous Integrated Boost Technique for Treatment of Spine Metastases Not Amenable to Stereotactic Radiosurgery

PURPOSE

Spine stereotactic radiosurgery delivers an ablative dose of radiation therapy (RT) with high conformity relative to standard fractionated RT. This technique is suboptimal for extended targets (>3 vertebral levels) owing to treatment alignment concerns or for patients with marked epidural extension. In these patients, we hypothesized that use of hypofractionated intensity modulated RT/volumetric modulated arc therapy to dose escalate the gross tumor volume (GTV) to 40 Gy as a spinal simultaneous integrated boost (SSIB) would allow for durable local control and palliation.

METHODS AND MATERIALS

We retrospectively analyzed 15 separate spinal sites (12 patients) that were treated with the SSIB technique between 2012 and 2016. The GTV and clinical target volume were prescribed at 40 Gy and 30 Gy, respectively, in 10 fractions. The spinal cord was allowed a maximum point dose of 34 Gy. The GTV was defined as gross tumor. The clinical target volume encompassed the GTV in addition to the involved vertebral bodies, at-risk paraspinal space, and spinal canal, followed by a planning target volume expansion of 3 to 5 mm.

RESULTS

The median follow-up for patients in our cohort was 17 months. At 1 year, local control was 93%, and overall survival was 58%, with a median time to death after treatment of 7 months. No grade ≥2 neurologic toxicities were reported for any of the patients. Nine of 12 patients had pain at presentation, of which 7 patients (78%) reported improvement and/or complete resolution of their pain after treatment.

CONCLUSIONS

Our early experience using a dose of 40 Gy to the GTV delivered via an SSIB technique, in lieu of spine stereotactic radiation surgery but more aggressive than conventional palliative doses, provides durable local control and pain relief. This technique may allow for improved local control and palliation in patients with radioresistant disease compared with conventional 3-dimensional conformal fractionated RT.

Surgical resection and postoperative radiosurgery versus staged radiosurgery for large brain metastases

PURPOSE

The purpose of this study was to retrospectively evaluate the new treatment paradigm of staged stereotactic radiosurgery (SRS) for the treatment of large brain metastases (BM) compared to the standard of surgical resection followed by SRS.

METHODS

We evaluated 78 patients with large BM treated 2012-2017 with surgical resection and postoperative SRS (surgery + SRS) or staged SRS separated by 1 month. Overall survival (OS) was estimated using the Kaplan Meier method and compared across groups using the log-rank test. Cumulative incidence of neurologic death and local and distant brain failure (LF, DBF) were estimated using competing risk methodology.

RESULTS

Forty patients were treated with surgery + SRS and 38 patients were treated with staged SRS. Median follow-up was 23.2 months (95% CI 20.5-39.3). Median OS was 13.2 months for staged SRS compared to surgery + SRS 9.7 months (p = 0.53). Cumulative incidence of neurologic death at 1 year was 23% after surgery + SRS, 27% after staged SRS (p = 0.69); cumulative incidence of LF at 1 year was 6% and 8% (p = 0.65) and 1-year DBF was 59% and 21% (p ≤ 0.01). Overall rates of leptomeningeal failure and radiation necrosis were similar between the groups (p = 0.63 and p = 1.0).

CONCLUSIONS

Though surgery and postoperative SRS is the standard, staged SRS represents an attractive treatment paradigm for treating large BM without sacrificing LC or survival, and potentially decreases DBF. Prospective studies are needed to validate these findings.

Prognostic factors for survival in metastatic renal cell carcinoma patients with brain metastases receiving targeted therapy

BACKGROUND

The primary objective of our study was to examine the clinical outcomes and prognosis of patients with metastatic renal cell carcinoma (mRCC) with brain metastases (BMs) receiving targeted therapy.

PATIENTS AND METHODS

Fifty-eight patients from 16 oncology centers for whom complete clinical data were available were retrospectively reviewed.

RESULTS

The median age was 57 years (range 30-80). Most patients underwent a nephrectomy (n = 41; 70.7%), were male (n = 42; 72.4%) and had clear-cell (CC) RCC (n = 51; 87.9%). Patients were treated with first-line suni-tinib (n = 45; 77.6%) or pazopanib (n = 13; 22.4%). The median time from the initial RCC diagnosis to the diagnosis of BMs was 9 months. The median time from the first occurrence of metastasis to the development of BMs was 7 months. The median overall survival (OS) of mRCC patients with BMs was 13 months. Time from the initial diagnosis of systemic metastasis to the development of BMs (<12 months; p = 0.001), histological subtype (non-CC; p<0.05) and number of BMs (>2; p<0.05) were significantly associated with OS in multivariate analysis. There were no cases of toxic death. One mRCC patient with BMs (1.7%) experienced treatment-related cerebral necrosis. All other toxicities included those commonly observed with VEGF-TKI therapy.

CONCLUSIONS

The time from the initial diagnosis of systemic metastasis to the development of BMs (<12 months), a non-CC histological subtype, and a greater number of BMs (>2) were independent risk factors for a poor prognosis.

Predictors of neurologic and nonneurologic death in patients with brain metastasis initially treated with upfront stereotactic radiosurgery without whole-brain radiation therapy

Background

In this study we attempted to discern the factors predictive of neurologic death in patients with brain metastasis treated with upfront stereotactic radiosurgery (SRS) without whole brain radiation therapy (WBRT) while accounting for the competing risk of nonneurologic death.

Methods

We performed a retrospective single-institution analysis of patients with brain metastasis treated with upfront SRS without WBRT. Competing risks analysis was performed to estimate the subdistribution hazard ratios (HRs) for neurologic and nonneurologic death for predictor variables of interest.

Results

Of 738 patients treated with upfront SRS alone, neurologic death occurred in 226 (30.6%), while nonneurologic death occurred in 309 (41.9%). Multivariate competing risks analysis identified an increased hazard of neurologic death associated with diagnosis-specific graded prognostic assessment (DS-GPA) ≤ 2 (P = .005), melanoma histology (P = .009), and increased number of brain metastases (P<.001), while there was a decreased hazard associated with higher SRS dose (P = .004). Targeted agents were associated with a decreased HR of neurologic death in the first 1.5 years (P = .04) but not afterwards. An increased hazard of nonneurologic death was seen with increasing age (P =.03), nonmelanoma histology (P<.001), presence of extracranial disease (P<.001), and progressive systemic disease (P =.004).

Conclusions

Melanoma, DS-GPA, number of brain metastases, and SRS dose are predictive of neurologic death, while age, nonmelanoma histology, and more advanced systemic disease are predictive of nonneurologic death. Targeted agents appear to delay neurologic death.

Radiotherapy for Brain Metastases From Renal Cell Carcinoma in the Targeted Therapy Era: The University of Rochester Experience

OBJECTIVES

Radiotherapy remains the standard approach for brain metastases from renal cell carcinoma (RCC). Kinase inhibitors (KI) have become standard of care for metastatic RCC. They also increase the radiosensitivity of various tumor types in preclinical models. Data are lacking regarding the effect of KIs among RCC patients undergoing radiotherapy for brain metastases. We report our experience of radiotherapy for brain metastatic RCC in the era of targeted therapy and analyzed effects of concurrent KI therapy.

METHODS

We retrospectively analyzed 25 consecutive patients who received radiotherapy for brain metastases from RCC with whole-brain radiotherapy (WBRT), stereotactic radiosurgery (SRS), or both. Kaplan-Meier rates of overall survival (OS) and brain progression-free survival (BPFS) were calculated and univariate analyses performed.

RESULTS

Lower diagnosis-specific graded prognostic assessment (DS-GPA) score and multiple intracranial metastases were associated with decreased OS and BPFS on univariate analysis; DS-GPA is also a prognostic factor on multivariate analysis. There was no significant difference in OS or BPFS for SRS compared with WBRT or WBRT and SRS combined. The concurrent use of KI was not associated with any change in OS or BPFS.

CONCLUSIONS

This hypothesis-generating analysis suggests among patients with brain metastatic RCC treated with the most current therapies, those selected to undergo SRS did not experience significantly different survival or control outcomes than those selected to undergo WBRT. From our experience to date, limited in patient numbers, there seems to be neither harm nor benefit in using concurrent KI therapy during radiotherapy. Given that most patients progress systemically, we would recommend considering KI use during brain radiotherapy in these patients.

Heterogeneity in Treatment Response of Spine Metastases to Spine Stereotactic Radiosurgery Within "Radiosensitive" Subtypes

PURPOSE

To characterize outcomes of metastatic colorectal and non-small cell lung cancer (NSCLC) histologies, compared with other radiosensitive histologies, treated with spine stereotactic radiosurgery with regard to local control, overall survival, and predictors of response.

METHODS AND MATERIALS

A total of 127 patients with 148 spine stereotactic radiosurgery-treated metastatic lesions at our institution between 2003 and 2013 were reviewed. We assessed clinical endpoints in relation to histologic type, including local control (LC) and overall survival (OS), using univariate and multivariate analyses.

RESULTS

For all patients, the 1- and 2-year actuarial rates for LC were 82.6% and 75.8%, and rates for OS were 72.9% and 51.5% respectively. Among tumor histologies, 1-year cumulative incidence rates of local failure for thyroid, breast, lung, and colon cancer were 8.7%, 7.0%, 26.6%, and 39.6%, respectively. When analyzed together, NSCLC and colorectal cancers had significantly greater cumulative incidence rates at 1 and 2 years (30.4% and 38.7%, respectively) than other histologies (8.0% and 14.1% respectively, P=.0008). Non-small cell lung cancer/colorectal tumor status was a significant predictor of local failure in a competing risk univariate model (hazard ratio 2.12, 95% confidence interval 1.07-4.17, P=.03) and multivariate model (hazard ratio 2.35, 95% confidence interval 1.12-4.92, P=.024).

CONCLUSIONS

Spine stereotactic radiosurgery is an effective strategy in achieving local control of spine metastases, particularly among radiosensitive histologies. However, a subset of these classically defined histologies (NSCLC and colorectal) has a propensity toward local failure. In addition to resulting in poorer OS outcomes, the poor LC rates seen in NSCLC and colorectal cancers in this study are more consistent with a radioresistant phenotype, suggesting the need for optimized dosing regimens in this subgroup.

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.

Surgery for Metastases of Renal Cell Carcinoma

The role of surgery for RCC in the era of emerging effective systemic therapy (usually immunotherapy) is not yet defined except for solitary metastasis. The retrospective analysis of patients subjected to aggressive surgical management after systemic therapy reinforces the need to find better therapeutic modalities in order to achieve complete eradication of metastatic disease. In the meantime, however, we propose these guidelines. First, we would encourage aggressive surgical resection of the clinically solitary metastasis, whether synchronous or metachronous. Continue to follow those patients indefinitely, because relapse is quite likely, but do not give adjuvant systemic therapy unless on protocol. Second, limited metastases in only one organ may behave similarly to a solitary metastasis, and if the metastases are in a site amenable to surgical resection, e.g., lung, initial surgery might be reasonable. Systemic therapy for these patients is highly recommended and need not necessarily wait for recurrence. Third, for patients with multiple metastases, initial systemic therapy followed then by resection of any residual disease in selected patients seems to be supported by the experience at several medical centers. Apparently prolonged survival times have been observed after systemic therapy followed by surgery in highly selected patients, despite finding viable cancer in the overwhelming majority of specimens. One must be mindful of the morbidity of an attempt to remove all known disease, however, and try to weigh this against potential benefit. Only a prospective, randomized trial could ever confirm the value of an aggressive surgical approach to metastatic RCC. In the meantime, however, metastasectomy offers, at the very least, the opportunity to confirm the histologic response to systemic therapy, render some patients disease-free, and possibly promote long-term survival in selected patients.

Multimodality treatment of brain metastases from renal cell carcinoma in the era of targeted therapy

In patients with renal cancer, brain metastasis is associated with poor survival and high morbidity. Poor life expectancy is often associated with widespread extracranial metastases. In such patients, a multidisciplinary approach is paramount. Brain metastases-specific therapies may include surgery, radiosurgery, conventional radiation and targeted therapies (TT) or a combination of these treatments. Some factors are important prognostically when choosing the best strategy: performance status, the number, size and location of brain metastases, the extension of systemic metastases and a well-controlled primary tumour. Failure of chemical therapy has always been attributed to an intact blood-brain barrier and acquired drug resistance by renal cancer cells. Recent studies have demonstrated objective responses with TT in a variety of cancer types, including renal cancer. In most cases, these agents have been used in combination and in conjunction with whole-brain radiation therapy and radiosurgery. Local control appears to be better with the combined method if the patient has a good performance status and may improve overall survival. This review summarizes current literature data on multidisciplinary approach in the management of renal brain metastasis with radiation, surgery and TT with an emphasis on potential better outcomes with a combination of current treatment methods.

Single-fraction versus multifraction spinal stereotactic radiosurgery for spinal metastases from renal cell carcinoma: secondary analysis of Phase I/II trials

OBJECTIVE The objective of this study was to compare fractionation schemes and outcomes of patients with renal cell carcinoma (RCC) treated in institutional prospective spinal stereotactic radiosurgery (SSRS) trials who did not previously undergo radiation treatment at the site of the SSRS. METHODS Patients enrolled in 2 separate institutional prospective protocols and treated with SSRS between 2002 and 2011 were included. A secondary analysis was performed on patients with previously nonirradiated RCC spinal metastases treated with either single-fraction (SF) or multifraction (MF) SSRS. RESULTS SSRS was performed in 47 spinal sites on 43 patients. The median age of the patients was 62 years (range 38-75 years). The most common histological subtype was clear cell (n = 30). Fifteen sites underwent surgery prior to the SSRS, with laminectomy the most common procedure performed (n = 10). All SF SSRS was delivered to a dose of 24 Gy (n = 21) while MF regiments were either 27 Gy in 3 fractions (n = 20) or 30 Gy in 5 fractions (n = 6). The median overall survival duration for the entire cohort was 22.8 months. The median local control (LC) for the entire cohort was 80.6 months with 1-year and 2-year actuarial LC rates of 82% and 68%, respectively. Single-fraction SSRS correlated with improved 1- and 2-year actuarial LC relative to MF SSRS (95% vs 71% and 86% vs 55%, respectively; p = 0.009). On competing risk analysis, SF SSRS showed superior LC to MF SSRS (subhazard ratio [SHR] 6.57, p = 0.014). On multivariate analysis for LC with tumor volume (p = 0.272), number of treated levels (p = 0.819), gross tumor volume (GTV) coverage (p = 0.225), and GTV minimum point dose (p = 0.97) as covariates, MF SSRS remained inferior to SF SSRS (SHR 5.26, p = 0.033) CONCLUSIONS SSRS offers durable LC for spinal metastases from RCC. Single-fraction SSRS is associated with improved LC over MF SSRS for previously nonirradiated RCC spinal metastases.

Stereotactic Radiosurgery for Renal Cancer Brain Metastasis: Prognostic Factors and the Role of Whole-Brain Radiation and Surgical Resection

Background. Renal cell carcinoma is a frequent source of brain metastasis. We present our consecutive series of patients treated with Stereotactic Radiosurgery (SRS) and analyse prognostic factors and the interplay of WBRT and surgical resection. Methods. This is a retrospective study of 66 patients with 207 lesions treated with the Cyberknife radiosurgery system in our institution. The patients were followed up with imaging and clinical examination 1 month and 2-3 months thereafter for the brain metastasis. Patient, treatment, and outcomes characteristics were analysed. Results. 51 male (77.3%) and 15 female (22.7%) patients, with a mean age of 58.9 years (range of 31–85 years) and a median Karnofsky Performance Status (KPS) of 90 (range of 60–100), were included in the study. The overall survival was 13.9 months, 21.9 months, and 5.9 months for the patients treated with SRS only, additional surgery, and WBRT, respectively. The actuarial 1-year Local Control rates were 84%, 94%, and 88% for SRS only, for surgery and SRS, and for WBRT and additional SRS, respectively. Conclusions. Stereotactic radiosurgery is a safe and effective treatment option in patients with brain metastases from RCC. In case of a limited number of brain metastases, surgery and SRS might be appropriate.

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.

Heterogeneous drug target expression as possible basis for different clinical and radiological response to the treatment of primary and metastatic renal cell carcinoma: suggestions from bench to bedside

Metastatic disease occurs in a significant percentage of patients with renal cell carcinoma (RCC) and is usually associated with an overall poor prognosis. However, not all of the sites of metastases seem to have the same prognostic significance in patients receiving targeted agents. Indeed, patients with lung-only metastases seem to present a better survival than patients with other sites, whereas liver and bone metastases are associated with a worst prognosis. Some clinical studies suggest that metastatic sites are more responsive than primary tumors. This event may be due to intratumor heterogeneity in terms of somatic mutations, chromosome aberrations, and tumor gene expression, primarily centered around Von Hippel-Lindau (VHL) pathway, such as VHL mutations, HIF levels, vascular endothelial growth factor (VEGF) isoforms, and VEGF receptor levels. Nevertheless, these data do not completely explain the discordant biological behavior between primary tumor and metastatic sites. Understanding the causes of this discordance will have profound consequences on translational research and clinical trials in RCC. In this review, we overview current data on the differences between primary RCC and metastases in terms of drug target expression and clinical/radiological response to targeted agents, thus describing the prognostic role of different metastatic sites in RCC patients.

Safety and efficacy of targeted therapy for renal cell carcinoma with brain metastasis

BACKGROUND

Brain metastases are associated with a poor prognosis in patients with renal cell carcinoma (RCC). The role of targeted therapy in this setting is not well established. The primary objective was to assess overall survival (OS) and neurologic events in patients with brain metastasis treated with targeted agents.

PATIENTS AND METHODS

Patients with RCC treated with targeted agents for brain metastasis between 2002 and 2012 were retrospectively identified. Kaplan-Meier methodology and a Cox proportional hazards model were used to analyze the association between clinical features and OS.

RESULTS

Of 65 patients identified, 52 (80%) were treated with antiangiogenic agents and 13 (20%) received inhibitors of mTOR (mechanistic target of rapamycin [serine/threonine kinase]); 57 (88%) had local therapy for brain metastasis, including surgery in 3 (5%), radiation therapy in 36 (55%), and both surgery and radiotherapy in 18 (28%). Median follow-up was 12.3 months (1.1-58.8). Median treatment duration for targeted therapy as first-line therapy was 3.4 months (0.3-31.9). The median OS was 12.2 months (95% CI, 8.0-15.5). The risk group according to the Memorial Sloan Kettering Cancer Center (MSKCC) stratification (P = .001), the histology subtype (clear vs. other) (P < .0001), and the number of brain lesions (1 vs. ≥ 2) (P = .004) correlated with OS on multivariate analysis. Neurologic complications were identified in 5 patients (8%), including 2 with radiation necrosis and 3 with brain metastasis hemorrhage.

CONCLUSION

The use of targeted agents in the multimodal treatment of patients with RCC and brain metastasis was not associated with excessive neurologic adverse events. Clear cell histology, favorable MSKCC risk status, and solitary brain metastasis are associated with more favorable OS.

Predictive chromosomal clusters of synchronous and metachronous brain metastases in clear cell renal cell carcinoma

Synchronous (early) and metachronous (late) brain metastasis (BM) events of sporadic clear cell renal cell carcinoma (ccRCC) (n = 148) were retrospectively analyzed using comparative genomic hybridization (CGH). Using oncogenetic tree models and cluster analyses, chromosomal imbalances related to recurrence-free survival until BM (RFS-BM) were analyzed. Losses at 9p and 9q appeared to be hallmarks of metachronous BM events, whereas an absence of detectable chromosomal changes at 3p was often associated with synchronous BM events. Correspondingly, k-means clustering showed that cluster 1 cases generally exhibited low copy number chromosomal changes that did not involve 3p. Cluster 2 cases had a high occurrence of -9p/-9q (94-98%) deletions, whereas cluster 3 cases had a higher frequency of copy number changes, including loss at chromosome 14 (80%). The higher number of synchronous cases in cluster 1 was also associated with a significantly shorter RFS-BM compared with clusters 2 and 3 (P = 0.02). Conversely, a significantly longer RFS-BM was observed for cluster 2 versus clusters 1 and 3 (P = 0.02). Taken together, these data suggest that metachronous BM events of ccRCC are characterized by loss of chromosome 9, whereas synchronous BM events may form independently of detectable genetic changes at chromosomes 9 and 3p.

Tumor histology predicts patterns of failure and survival in patients with brain metastases from lung cancer treated with gamma knife radiosurgery

BACKGROUND

We review our experience with lung cancer patients with newly diagnosed brain metastases treated with Gamma Knife radiosurgery (GKRS).

OBJECTIVE

To determine whether tumor histology predicts patient outcomes.

METHODS

Between July 1, 2000, and December 31, 2010, 271 patients with brain metastases from primary lung cancer were treated with GKRS at our institution. Included in our study were 44 squamous cell carcinoma (SCC), 31 small cell carcinoma (SCLC), and 138 adenocarcinoma (ACA) patients; 47 patients with insufficient pathology to determine subtype were excluded. No non-small cell lung cancer (NSCLC) patients received whole-brain radiation therapy (WBRT) before their GKRS, and SCLC patients were allowed to have prophylactic cranial irradiation, but no previously known brain metastases. A median of 2 lesions were treated per patient with median marginal dose of 20 Gy.

RESULTS

Median survival was 10.2 months for ACA, 5.9 months for SCLC, and 5.3 months for SCC patients (P = .008). The 1-year local control rates were 86%, 86%, and 54% for ACA, SCC, and SCLC, respectively (P = .027). The 1-year distant failure rates were 35%, 63%, and 65% for ACA, SCC, and SCLC, respectively (P = .057). The likelihood of dying of neurological death was 29%, 36%, and 55% for ACA, SCC, and SCLC, respectively (P = .027). The median time to WBRT was 11 months for SCC and 24 months for ACA patients (P = .04). Multivariate analysis confirmed SCLC histology as a significant predictor of worsened local control (hazard ratio [HR]: 6.46, P = .025) and distant failure (HR: 3.32, P = .0027). For NSCLC histologies, SCC predicted for earlier time to salvage WBRT (HR: 2.552, P = .01) and worsened overall survival (HR: 1.77, P < .0121).

CONCLUSION

Histological subtype of lung cancer appears to predict outcomes. Future trials and prognostic indices should take these histology-specific patterns into account.

The impact of tyrosine kinase inhibitors on the multimodality treatment of brain metastases from renal cell carcinoma

OBJECTIVES

This study evaluated the effect of tyrosine kinase inhibitors (TKIs) on the brain metastasis (BM), local control (LC), and overall survival (OS) of patients with renal cell carcinoma (RCC) with BM.

METHODS

A retrospective review of patients with RCC BM was conducted. Eligible patients from 2 eras: pre-TKI, 2002 to 2003 and post-TKI, 2006 to 2007, were identified. Prognostic factors, use, and type of systemic therapy were noted. The timing, number, size, and treatment modality data for each BM were recorded. Use of TKI and BM treatment modality were correlated to LC and OS.

RESULTS

Eighty-one patients with 216 BMs were identified. Thirty-seven patients had BM at diagnosis and the remaining 44 were found to have BM at a later point. Forty-one patients never received a TKI and the remaining 40 received TKIs. Stereotactic radiosurgery, surgery, whole brain radiotherapy, or no local brain treatment was used for 89, 19, 24, and 75 lesions, respectively. The median OS from BM diagnosis was 5.4 months for the whole group: 4.4 versus 6.71 months in the never-TKI versus TKI groups, respectively. Patients who received TKIs post-BM development had a median OS of 23.6 months versus 2.08 and 4.41 months for the patients who received TKIs pre-BM or never-TKI, respectively (P=0.0001). LC was statistically superior in lesions managed with surgery or stereotactic radiosurgery versus the no local therapy.

CONCLUSIONS

In patients with RCC and BM, TKIs are associated with a trend of improved OS, but no significant improvement in LC of BM. They may provide a significant benefit to patients with BM with no prior TKI exposure.

Stereotactic radiosurgery with and without whole-brain radiotherapy for newly diagnosed brain metastases

Brain metastases develop in 20-40% of cancer patients and can cause significant morbidity. In selected patients with one to three lesions, stereotactic radiosurgery may be used to improve local control. However, it is unclear whether whole-brain radiotherapy is necessary for all patients who are candidates for stereotactic radiosurgery. While whole-brain radiotherapy may improve the locoregional control of brain metastases, it may cause long-term side effects and may not improve overall survival in some patients. Its benefits should be evaluated in the context of risks of neurocognitive deterioration, either from whole-brain radiotherapy or from uncontrolled brain metastases, and the possible need for salvage treatments with the omission of initial whole-brain radiotherapy. For certain radioresistant brain metastases, the benefit of whole-brain radiotherapy to patients who have stereotactic radiosurgery is uncertain.

The impact of radiosurgery fractionation and tumor radiobiology on the local control of brain metastases

Object

Experience with whole-brain radiation therapy for metastatic tumors in the brain has identified a subset of tumors that exhibit decreased local control with fractionated regimens and are thus termed radioresistant. With the advent of frameless radiosurgery, fractionated radiosurgery (2–5 fractions) is being used increasingly for metastatic tumors deemed too large or too close to crucial structures to be treated in a single session. The authors retrospectively reviewed metastatic brain tumors treated at 2 centers to analyze the dependency of local control rates on tumor radiobiology and dose fractionation.

Methods

The medical records of 214 patients from 2 institutions with radiation-naive metastatic tumors in the brain treated with radiosurgery given either as a single dose or in 2–5 fractions were analyzed retrospectively. The authors compared the local control rates of the radiosensitive with the radioresistant tumors after either single-fraction or fractionated radiosurgery.

Results

There was no difference in local tumor control rates in patients receiving single-fraction radiosurgery between radioresistant and radiosensitive tumors (p = 0.69). However, after fractionated radiosurgery, treatment for radioresistant tumors failed at a higher rate than for radiosensitive tumors with an OR of 5.37 (95% CI 3.83–6.91, p = 0.032).

Conclusions

Single-fraction radiosurgery is equally effective in the treatment of radioresistant and radiosensitive metastatic tumors in the brain. However, fractionated stereotactic radiosurgery is less effective in radioresistant tumor subtypes. The authors recommend that radioresistant tumors be treated in a single fraction when possible and techniques for facilitating single-fraction treatment or dose escalation be considered for larger radioresistant lesions.

The usefulness of stereotactic radiosurgery for radioresistant brain metastases

Objective

We investigated the effectiveness of stereotactic gamma knife Radiosurgery (GKR) for radioresistant brain metastases with the impact upon histology.

Methods

Between April 2004 and May 2011, a total of 23 patients underwent GKR for 67 metastatic brain tumors from 12 renal cell cancers, 5 sarcomas and 6 melanomas. The mean age was 56 years (range, 18 to 79 years). Most of the patients were classified as the Radiation Therapy Oncology Group recursive partitioning analysis class II (91.3%). The synchronous metastasis was found in 6 patients (26.1%) and metachronous metastasis in 17 patients (73.9%). We analyzed the local control rate, intracranial progression-free survival (PFS) and overall survival (OS).

Results

The mean tumor volume for GKR was 2.24 cc and the mean prescription dose was 19.4 Gy (range, 10 to 24) to the tumor margin. Out of metachronous metastases, the median duration to intracranial metastasis was 3.3 years in renal cell cancer (RCC), 2.4 years in melanoma and 1.1 years in sarcoma (p=0.012). The total local control rate was 89.6% during the mean 12.4 months follow-up. The six-month and one-year local control rate was 90.2% and 83% respectively. Depending on the pathology, the control rate of RCC was 95.7%, sarcoma 91.3% and melanoma 80.5% during the follow-up. The common cause of local failure was the tumor bleeding in melanoma. The median PFS and OS were 5.2 and 8.4 months in RCC patients, 6.5 and 9.8 months in sarcoma, and 3.8 and 5.1 months in melanoma.

Conclusion

The GKR can be one of the effective management options for the intracranial metastatic tumors from the radioresistant tumors. The melanoma showed a poor local control rate compared to other pathologies because of the hemorrhage.