Efficacy and limitations of salvage gamma knife radiosurgery for brain metastases of small-cell lung cancer after whole-brain radiotherapy

Overall survival following stereotactic radiosurgery for ten or more brain metastases: a systematic review and meta-analysis

BACKGROUND

Brain metastases are the most common intracranial tumours. Variation exists in the use of stereotactic radiosurgery for patients with 10 or more brain metastases. Concerns include an increasing number of brain metastases being associated with poor survival, the lack of prospective, randomised data and an increased risk of toxicity.

METHODS

We performed a systematic review and meta-analysis to assess overall survival of patients with ten or more brain metastases treated with stereotactic radiosurgery as primary therapy. The search strings were applied to MEDLINE, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL). Log hazard ratios and standard errors were estimated from each included study. A random-effects meta-analysis using the DerSimonian and Laird method was applied using the derived log hazard ratios and standard errors on studies which included a control group.

RESULTS

15 studies were included for systematic review. 12 studies were used for pooled analysis for overall survival at set time points, with a predicted 12 month survival of 20-40%. The random-effects meta-analysis in five studies of overall survival comparing ten or greater metastases against control showed statistically worse overall survival in the 10 + metastases group (1.10, 95% confidence interval 1.03-1.18, p-value = < 0.01, I2 = 6%). A funnel plot showed no evidence of bias. There was insufficient information for a meta-analysis of toxicity.

DISCUSSION

Overall survival outcomes of patients with ten or more brain metastases treated with SRS is acceptable and should not be a deterrent for its use. There is a lack of prospective data and insufficient real-world data to draw conclusions on toxicity.

PROSPERO ID

CRD42021246115.

Long‑term survival in a patient with extensive‑stage small cell lung cancer treated with multiple courses of salvage stereotactic radiation after whole brain radiotherapy: A case report

Intracranial recurrence following initial cranial irradiation for extensive-stage small cell lung cancer (ES-SCLC) can often be a treatment dilemma given the aggressive nature of the disease, the overall poor prognosis and concerns regarding re-treatment toxicity. The present report describes the case of a 62-year-old man diagnosed with ES-SCLC and synchronous brain metastases who initially underwent whole brain radiotherapy, chemotherapy and consolidative thoracic radiotherapy. The patient was found to have a solitary intracranial recurrence at both 3.5 and 6 years after his diagnosis. On both occasions, the patient received salvage stereotactic radiation, 30 Gy in 5 fractions, and continues to remain functionally independent. Overall, the present case demonstrates that with the appropriate patient selection, aggressive local salvage of recurrent intracranial ES-SCLC with stereotactic radiation can yield excellent and durable clinical outcomes.

Cerebral metastases

Brain metastases are common and deadly. Over the last 25 years GKNS has been established as an invaluable treatment. It may be used as a primary treatment or after either surgery or WBRT. Patients are assessed using one of a number of available scales. GKNS may be repeated for new metastases and for unresponsive tumors. Prescription doses are usually between 18 and 20Gy. The use of advanced MR techniques to highlight sensitive structures like the hippocampi have extended the efficacy of the treatment. More recently GKNS has been used with different target therapies with improved results. More recently frameless treatments have become more popular in this group of very sick patients. GKNS controls tumors in between 80% and over 95% of cases and may even be used for brainstem tumors.

Stereotactic radiosurgery for brain metastases from small cell lung cancer without prior whole-brain radiotherapy: A meta-analysis

OBJECTIVES

Assess upfront Stereotactic radiosurgery (SRS) effectiveness for small cell lung cancer (SCLC) brain metastases (BM). Where possible, a comparison with whole-brain radiotherapy (WBRT) was performed.

METHODS

Following PRISMA and MOOSE guidelines, eligible studies were identified on Medline, Embase, Cochrane Library, and proceedings of annual meetings between inception and July 01, 2020.

RESULTS

Nine observational studies with 1638 patients were included. The median overall survival (OS) was 8.3 months (95% CI 7.1-9.5 months, I2 = 0%). OS rate at 12 months was 39% (95% CI 31-44%, I2 = 0%). The relative risk between SRS and WBRT for the OS at 12 months was 1.33 (95% CI 1.13-1.51, P = 0.0001). The projected OS for 6, 12, 18- and 24-months comparing SRS with WBRT was 67% vs. 57%, 39% vs. 29%, 22% vs. 15% and 15% vs 9%, favoring SRS (P < 0.001). The LC rate at 12 months was 93% (95% CI 91-94%, I2 = 0%). The distant brain failure rate (DBFR) at 12 months was 41% (95% CI 33-48%, I2 = 52%, P = 0.08). The SRS or WBRT as salvage treatment after upfront SRS was 32% and 19%, respectively. The freedom from neurologic death at 12 months was 87% (95% CI 84-89%).

CONCLUSION

Based on the pooling of a large sample of retrospective studies our meta-analysis suggests that for high selected SCLC patients with limited BM upfront SRS produces favorable lesion control and survival outcomes. These findings support the design of randomized clinical trial to confirm the role of SRS in this clinical scenario.

Management of brain metastases in elderly patients with lung cancer

The incidence of brain metastases (BM) is continuing to grow in the elderly population with lung cancer, but these patients are seriously under-represented in clinical trials. Thus, their treatment is not based on the evidence from randomized prospective studies. Age is a well recognized poor prognostic factor for survival in patients with BM from lung cancer, which is reflected in prognostic scales, but its impact on the patients' prognosis reflected by its value in gradually updated grading indices seems to decrease. The reason for poorer outcomes in the elderly is unknown—it may result from the influence of the age per se, simplified staging work-up and suboptimal treatment in this patient subgroup or the excess toxicity of the aggressive anticancer treatment secondary to the impaired physiological regulation mechanisms and comorbidities. The main goal of treatment of BM is to ameliorate neurological symptoms and delay neurological progression, with the focus on the improvement and maintenance of the patients’ quality of life. The possible treatment options for BM from lung cancer are whole-brain radiotherapy, stereotactic radiosurgery, surgery, chemotherapy, targeted therapies and best supportive care. The aim of this review is to summarize the problems related to the management of BM in elderly patients with lung cancer, to analyze the value of the above mentioned treatment options, and to provide an insight into the influence of age-related clinical factors on the patients’ outcomes.

Radiotherapy for brain metastases from small-cell lung cancer in distinct clinical indications and scenarios

Management of brain metastases (BM) from small-cell lung cancer (SCLC) is complex and not supported by a strong evidence from prospective clinical trials. Owing to the different clinical and pathological characteristics of SCLC, patients with this histology were not included in the prospective studies on the value of whole-brain radiotherapy (WBRT) and local surgical or ablative radiation treatment like stereotactic radiosurgery (SRS). Chemotherapy also represents a major part of the armamentarium against BM from SCLC due to the well-recognized chemoresponsiveness of this cancer and the frequent presentation of BM with extracranial progression. WBRT in combination with chemotherapy has long been a standard approach in this setting. However, data on the neurocognitive toxicity and the lack of documented impact on overall survival of WBRT in the management of BM from other solid tumors, as well as the increasing availability of the stereotactic radiotherapy technologies, has led to the increasing use of SRS with omission of WBRT also in SCLC. In the current review the use of different modalities of radiotherapy and ways of combining radiotherapy with chemotherapy for BM from SCLC will be presented for distinct clinical situations: presentation of BM synchronous with primary, metachronous presentation of BM-without previous prophylactic cranial irradiation (PCI) vs. after PCI, and asymptomatic BM found at the staging before PCI.

Role of Gamma Knife Radiosurgery in Small Cell Lung Cancer: A Multi-Institutional Retrospective Study of the International Radiosurgery Research Foundation (IRRF)

BACKGROUND

Despite a high incidence of brain metastases in patients with small-cell lung cancer (SCLC), limited data exist on the use of stereotactic radiosurgery (SRS), specifically Gamma Knife™ radiosurgery (Elekta AB), for SCLC brain metastases.

OBJECTIVE

To provide a detailed analysis of SCLC patients treated with SRS, focusing on local failure, distant brain failure, and overall survival (OS).

METHODS

A multi-institutional retrospective review was performed on 293 patients undergoing SRS for SCLC brain metastases at 10 medical centers from 1991 to 2017. Data collection was performed according to individual institutional review boards, and analyses were performed using binary logistic regression, Cox-proportional hazard models, Kaplan-Meier survival analysis, and competing risks analysis.

RESULTS

Two hundred thirty-two (79%) patients received SRS as salvage following prior whole-brain irradiation (WBRT) or prophylactic cranial irradiation, with a median marginal dose of 18 Gy. At median follow-up after SRS of 6.4 and 18.0 mo for surviving patients, the 1-yr local failure, distant brain failure, and OS were 31%, 49%, and 28%. The interval between WBRT and SRS was predictive of improved OS for patients receiving SRS more than 1 yr after initial treatment (21%, <1 yr vs 36%, >1 yr, P = .01). On multivariate analysis, older age was the only significant predictor for OS (hazard ratio 1.63, 95% CI 1.16-2.29, P = .005).

CONCLUSION

SRS plays an important role in the management of brain metastases from SCLC, especially in salvage therapy following WBRT. Ongoing prospective trials will better assess the value of radiosurgery in the primary management of SCLC brain metastases and potentially challenge the standard application of WBRT in SCLC patients.

Laser interstitial thermal therapy as an adjunct therapy in brain tumors: A meta-analysis and comparison with stereotactic radiotherapy

BACKGROUND

Minimally invasive procedures are gaining widespread acceptance in difficult-to-access brain tumor treatment. Stereotactic radiosurgery (SRS) is the preferred choice, however, laser interstitial thermal therapy (LITT) has emerged as a tumor cytoreduction technique. The present meta-analysis compared current SRS therapy with LITT in brain tumors.

METHODS

A search was performed in Lilacs, PubMed, and Cochrane database. Patient's demographics, tumor location, therapy used, Karnofsky performance status score before treatment, and patient's outcome (median overall survival, progression-free survival, and adverse events) data were extracted from studies. The risk of bias was assessed by Cochrane collaboration tool.

RESULTS

Twenty-five studies were included in this meta-analysis. LITT and SRS MOS in brain metastasis patients were 12.8 months' versus 9.8 months (ranges 9.3-16.3 and 8.3-9.8; P = 0.02), respectively. In a combined comparison of adverse effects among LITT versus SRS in brain metastasis, we found 15% reduction in absolute risk difference (-0.16; 95% confidence interval P < 0.0001).

CONCLUSION

We could not state that LITT treatment is an optimal alternative therapy for difficult-to-access brain tumors due to the lack of systematic data that were reported in our pooled studies. However, our results identified a positive effect in lowering the absolute risk of adverse events compared with SRS therapy. Therefore, randomized trials are encouraged to ascertain LITT role, as upfront or postoperative/post-SRS therapy for brain tumor treatment.

Current Management and Progress in Radiotherapy for Small Cell Lung Cancer

Radiotherapy (RT) and chemotherapy continue to be widely utilized in small cell lung cancer (SCLC) management. In most limited stage (LS)-SCLC cases, the standard initial therapy remains concurrent chemoradiotherapy (CRT), typically with an etoposide and platinum-based regimen. Hyperfractionated twice daily (BID) RT remains the standard of care, though conventional daily (QD) RT is now a viable alternative supported by randomized evidence. In LS-SCLC patients who experienced good response to CRT, prophylactic cranial irradiation (PCI) remains the standard of care. Brain imaging, ideally with MRI, should be performed prior to PCI to screen for clinically apparent brain metastases that may require a higher dose of cranial irradiation. Platinum doublet chemotherapy alone is the historic standard initial therapy in extensive stage (ES)-SCLC. Addition of immunotherapy such as atezolizumab and durvalumab to chemotherapy is now recommended after their benefits were demonstrated in recent trials. In patients with response to chemotherapy, consolidation thoracic RT and PCI could be considered, though with caveats. Emergence of hippocampal avoidance cranial irradiation and SRS in SCLC patients may supplant whole cranial irradiation as future standards of care. Incorporation of novel systemic therapies such as immunotherapies has changed the treatment paradigm and overall outlook of patients with SCLC. This narrative review summarizes the current state, ongoing trials, and future directions of radiotherapy in management of SCLC.

Salvage gamma knife radiosurgery for active brain metastases from small-cell lung cancer after whole-brain radiation therapy: a retrospective multi-institutional study (JLGK1701)

PURPOSE

To evaluate the efficacy of gamma knife radiosurgery (GKS) for brain metastases (BMs) from small-cell lung cancer after whole-brain radiotherapy (WBRT).

METHODS

We retrospectively analyzed the usefulness and safety of GKS in 163 patients from 15 institutions with 1-10 active BMs after WBRT. The usefulness and safety of GKS were evaluated using statistical methods.

RESULTS

The median age was 66 years, and 79.1% of patients were men. The median number and largest diameter of BM were 2.0 and 1.4 cm, respectively. WBRT was administered prophylactically in 46.6% of patients. The median overall survival (OS) was 9.3 months, and the neurologic mortality was 20.0%. Crude incidences of local control failure and new lesion appearance were 36.6% and 64.9%, respectively. A BM diameter ≥ 1.0 cm was a significant risk factor for local progression (hazard ratio [HR] 2.556, P = 0.039) and neurologic death (HR 4.940, P = 0.031). Leukoencephalopathy at the final follow-up was more prevalent in the therapeutic WBRT group than in the prophylactic group (P = 0.019). The symptom improvement rate was 61.3%, and neurological function was preserved for a median of 7.6 months. Therapeutic WBRT was not a significant risk factor for OS, neurological death, local control, or functional deterioration (P = 0.273, 0.490, 0.779, and 0.560, respectively). Symptomatic radiation-related adverse effects occurred in 7.4% of patients.

CONCLUSIONS

GKS can safely preserve neurological function and prevent neurologic death in patients with 1-10 small, active BMs after prophylactic and therapeutic WBRT.

Stereotactic radiosurgery for brain metastases from newly diagnosed small cell lung cancer: practice patterns and outcomes

BACKGROUND

Up-front stereotactic radiosurgery (SRS) has been historically thought of as inadequate for brain metastases (BM) from newly diagnosed small cell lung cancer (SCLC). This study evaluates national practice patterns and clinical outcomes for BM from SCLC.

MATERIAL AND METHODS

The National Cancer Database was queried (2004-2013) for patients with newly diagnosed metastatic SCLC receiving intracranial radiotherapy. Patients were grouped into three categories: upfront SRS, whole-brain radiotherapy (WBRT) alone, or WBRT with boost (SRS or fractionated radiotherapy). Statistics included temporal trend assessment by annual percent change (APC), logistic regression, exploratory Kaplan-Meier overall survival (OS) analysis without and with propensity matching, and Cox proportional hazards modeling.

RESULTS

A total of 14,722 patients met selection criteria, of whom 487 (3.3%), 13,657 (92.8%), and 578 (3.9%) received upfront SRS, WBRT and WBRT with boost, respectively. Utilization of SRS showed a slight increasing trend from 2004 to 2013 (2.7-4.3%). In addition to socioeconomic factors, other variables associated with SRS use included diagnosis after 2010, treatment at academic centers, and residing in higher-educated regions. SRS was less often delivered to patients with node-positive disease (p < .05). On exploratory analysis, SRS cohort was observed to have a higher overall survival (OS) than WBRT-based groups (p < .001), namely in patients without extracranial metastases.

CONCLUSIONS

Utilization of up-front SRS for SCLC BM has been increasing over time but is driven by socioeconomic disparities. Although there are likely numerous biases associated with the OS findings herein, further research is needed to validate this finding as well as the role of SRS on patients with brain metastases due to SCLC.

Whole brain radiation therapy alone versus radiosurgery for patients with 1-10 brain metastases from small cell lung cancer (ENCEPHALON Trial): study protocol for a randomized controlled trial

BACKGROUND

Conventional whole brain radiotherapy (WBRT) has been established as the treatment standard in patients with cerebral metastases from small-cell lung cancer (SCLC), however, it has only modest efficacy and limited prospective data is available for WBRT as well as local treatments such as stereotactic radiosurgery (SRS).

METHODS/DESIGN

The present single-center prospective randomized study, conducted at Heidelberg University Hospital, compares neurocognitive function, as objectively measured by significant deterioration in Hopkins Verbal Learning Test - Revised total recall at 3 months. Fifty-six patients will be randomized to receive either SRS of all brain metastases (up to ten lesions) or WBRT. Secondary endpoints include intracranial progression (local tumor progression and number of new cerebral metastases), extracranial progression, overall survival, death due to brain metastases, local (neurological) progression-free survival, progression-free survival, changes in other cognitive performance measures, quality of life and toxicity.

DISCUSSION

Recent evidence suggests that SRS might be a promising treatment option for SCLC patients with brain metastases. The present trial is the first to prospectively investigate the treatment response, toxicity and neurocognition of WBRT and SRS in SCLC patients.

TRIAL REGISTRATION

Clinicaltrials.gov NCT03297788 . Registered September 29, 2017.

Outcomes of stereotactic radiosurgery of brain metastases from neuroendocrine tumors

Background

Stereotactic radiosurgery (SRS) is an established treatment for brain metastases, yet little is known about SRS for neuroendocrine tumors given their unique natural history.

Objective

To determine outcomes and toxicity from SRS in patients with brain metastases arising from neuroendocrine tumors.

Methods

Thirty-three patients with brain metastases from neuroendocrine tumors who underwent SRS were retrospectively reviewed. Median age was 61 years and median Karnofsky performance status was 80. Primary sites were lung (87.9%), cervix (6.1%), esophagus (3%), and prostate (3%). Ten patients (30.3%) received upfront SRS, 7 of whom had neuroendocrine tumors other than small cell lung carcinoma. Kaplan-Meier survival and Cox regression analyses were performed to determine prognostic factors for survival.

Results

With median follow-up after SRS of 5.3 months, local and distant brain recurrence developed in 5 patients (16.7%) and 20 patients (66.7%), respectively. Median overall survival (OS) after SRS was 6.9 months. Patients with progressive disease per Response Assessment in Neuro-Oncology-Brain Metastases (RANO-BM) criteria at 4 to 6 weeks after SRS had shorter median time to developing recurrence at a distant site in the brain and shorter OS than patients without progressive disease: 1.4 months and 3.3 months vs 11.4 months and 12 months, respectively (both P < .001). Toxicity was more likely in lesions of small cell histology than in lesions of other neuroendocrine tumor histology, 15.7% vs 3.3% (P = .021). No cases of grade 3 to 5 necrosis occurred.

Conclusions

SRS is an effective treatment option for patients with brain metastases from neuroendocrine tumors with excellent local control despite slightly higher toxicity rates than expected. Progressive disease at 4 to 6 weeks after SRS portends a poor prognosis.

The role of radiation therapy in the management of small cell lung cancer

Small cell lung cancer (SCLC) is a very aggressive form of lung cancer. SCLC treatment requires multidisciplinary management and timely treatment. Radiation therapy is an important part of management of all stages of SCLC, in the curative as well as in the palliative setting. The role of radiation therapy in all stages of SCLC has changed in recent years; this article describes these changes and highlights the role of radiation therapy in the management of SCLC.

Prophylactic Cranial Irradiation (PCI) versus Active MRI Surveillance for Small Cell Lung Cancer: The Case for Equipoise

Prophylactic cranial irradiation (PCI) for SCLC offers a consistent reduction in the incidence of brain metastases at the cost of measurable toxicity to neurocognitive function and quality of life, in the setting of characteristic pathologic changes to the brain. The sequelae of PCI have historically been justified by the perception of an overall survival advantage specific to SCLC. This rationale has now been challenged by a randomized trial in extensive-stage SCLC demonstrating equivalent progression-free survival and a trend toward improved overall survival with PCI omission in the context of modern magnetic resonance imaging (MRI) staging and surveillance. In this article, we critically examine the randomized trials of PCI in extensive-stage SCLC and discuss their implications on the historical data supporting PCI for limited-stage SCLC from the pre-MRI era. Further, we review the toxicity of moderate doses of radiation to the entire brain that underlie the growing interest in active MRI surveillance and PCI omission. Finally, the evidence supporting prospective investigation of radiosurgery for limited brain metastases in SCLC is reviewed. Overall, our aim is to provide an evidence-based assessment of the debate over PCI versus active MRI surveillance and to highlight the need for contemporary trials evaluating optimal central nervous system management in SCLC.

Is stereotactic radiosurgery a rational treatment option for brain metastases from small cell lung cancer? A retrospective analysis of 70 consecutive patients

Background

Because of the high likelihood of multiple brain metastases (BM) from small cell lung cancer (SCLC), the role of focal treatment using stereotactic radiosurgery (SRS) has yet to be determined. We aimed to evaluate the efficacy and limitations of upfront and salvage SRS for patients with BM from SCLC.

Methods

This was a retrospective and observational study analyzing 70 consecutive patients with BM from SCLC who received SRS. The median age was 68 years, and the median Karnofsky performance status (KPS) was 90. Forty-six (66%) and 24 (34%) patients underwent SRS as the upfront and salvage treatment after prophylactic or therapeutic whole brain radiotherapy (WBRT), respectively. Overall survival (OS), neurological death-free survival, remote and local tumor recurrence rates were analyzed.

Results

None of our patients were lost to follow-up and the median follow-up was 7.8 months. One-and 2-year OS rates were 43% and 15%, respectively. The median OS time was 7.8 months. One-and 2-year neurological death-free survival rates were 94% and 84%, respectively. In total, 219/292 tumors (75%) in 60 patients (86 %) with sufficient radiological follow-up data were evaluated. Six-and 12-month rates of remote BM relapse were 25% and 47%, respectively. Six-and 12-month rates of local control failure were 4% and 23%, respectively. Repeat SRS, salvage WBRT and microsurgery were subsequently required in 30, 8 and one patient, respectively. Symptomatic radiation injury, treated conservatively, developed in 3 patients.

Conclusions

The present study suggested SRS to be a potentially effective and minimally invasive treatment option for BM from SCLC either alone or after failed WBRT. Although repeat salvage treatment was needed in nearly half of patients to achieve control of distant BM, such continuation of radiotherapeutic management might contribute to reducing the rate of neurological death.

Upfront stereotactic radiosurgery in patients with brain metastases from small cell lung cancer: retrospective analysis of 41 patients

BACKGROUND

Although the efficacy of prophylactic or therapeutic whole brain radiotherapy (WBRT) for brain metastases (BM) from small cell lung cancer (SCLC) is well established, the role of stereotactic radiosurgery (SRS) has yet to be determined. In the present retrospective analysis, we investigated whether upfront SRS might be an effective treatment option for patients with BM from SCLC.

METHODS

We analyzed 41 consecutive patients with a limited number of BM (≤ 10) from SCLC who received SRS as the initial treatment. No prophylactic and therapeutic WBRT was given prior to SRS. The median patient age was 69 years and the median Karnofsky performance status (KPS) score was 90. Repeat SRS was given for new distant lesions detected on follow-up neuroradiological imaging, as necessary. Overall survival, neurological death, and local and distant BM recurrence rates were analyzed. The survival results were tested with three prognostic scoring systems validated for SCLC: Diagnosis-specific graded prognostic assessment (DS-GPA), Radiation therapy oncology group -recursive partitioning analysis and Rades's survival score.

RESULTS

One- and 2-year overall survival rates were 44% and 17%, respectively. The median survival time was 8.1 months. Survival results replicated the DS-GPA (P = 0.022) and Rades's survival score (P = 0.034). On multivariate analysis, patients with high KPS (hazard ratio (HR): 0.308, P = 0.009) and post-SRS chemotherapy (HR: 0.324, P = 0.016) had better overall survival. In total, 95/121 tumors (79%) in 34 patients (83%) with sufficient radiological follow-up data were evaluated. Six- and 12-month rates of local control failure were 0% and 14%, respectively. Six- and 12-month distant BM rates were 22% and 44%, respectively. Repeat SRS, salvage WBRT and microsurgery were subsequently required in 18, 7 and one patient, respectively. Symptomatic radiation injury developed in two patients and both were treated conservatively.

CONCLUSIONS

Our survival analyses with the validated prognostic grading systems suggested upfront SRS for limited BM from SCLC to be a potential treatment option, with patient survival being slightly more than eight months after SRS. Although SRS provided durable local tumor control, repeat treatment was needed in nearly half of patients to achieve control of distant BM.

Local recurrence and survival following stereotactic radiosurgery for brain metastases from small cell lung cancer

PURPOSE

Stereotactic radiosurgery (SRS) represents a treatment option for patients with brain metastases from small cell lung cancer (SCLC) following prior cranial radiation. Inferior local control has been described. We reviewed our failure patterns following SRS treatment to evaluate this concern.

METHODS AND MATERIALS

Individuals with SCLC who received SRS for brain metastases from 2004 to 2011 were identified. Central nervous system (CNS) disease was detected and followed by gadolinium-enhanced, high-resolution magnetic resonance (MR) imaging. SRS dose was prescribed to the tumor periphery. Local recurrence was defined by increasing lesion size or enhancement, MR-spectroscopy, and perfusion changes consistent with recurrent disease or pathologic confirmation. Any new enhancing lesion not identified on the SRS planning scan was considered a regional failure. Overall survival (OS) and CNS control were evaluated using the Kaplan-Meier method. Factors predicted to influence outcome were tested by univariate log-rank analysis and Cox regression.

RESULTS

Fifteen males and 25 females (median age of 61 years [range, 36-79]) of which 39 received prior brain irradiation were identified. In all, 132 lesions (3.3 per patient) between 0.4 and 4.7 cm received a median dose of 16 Gy (12-22 Gy). Thirteen metastases (10%) ultimately recurred locally with 6- and 12-month control rates of 81% and 69%, respectively. Only 1 of 110 metastases <2 cm recurred. Local failure was more likely for size >2 cm (P < .001) and dose <16 Gy (P < .001). The median OS was 6.5 months, and the time to regional CNS recurrence was 5.2 months. For patients with single brain metastases, both OS (P = .037) and regional CNS recurrence (P = .003) were improved. CNS control (P = .001), and survival (P = .057), were also longer for patients with controlled systemic disease.

CONCLUSIONS

Local control following SRS for SCLC metastases is achievable for lesions <2 cm. For metastases >2 cm, local failure is more common than expected. Patients with controlled systemic disease and limited CNS involvement would benefit most from aggressive treatment.

Salvage stereotactic radiosurgery for brain metastases

Recurrent or progressive brain metastases after initial treatment represent a common clinical entity mainly due to increased survival of cancer patients. From the various available treatment modalities, salvage stereotactic radiosurgery seems to be the most commonly used. Many clinical studies of class of evidence III have demonstrated satisfied results concerning the local brain control and survival of patients with relapsing brain disease. Also stereotactic radiosurgery is considered a relatively safe modality with low incidence of brain toxicity side effects. It is obvious that well-designed, randomized, prospective studies are necessary for the evaluation of the stereotactic radiosurgery as salvage treatment and for the establishment of guidelines for the selection of patients most suitable for this treatment option. The increasing number of patients with relapsing brain metastatic disease will act as a pressure to this direction.

[Advances in diagnosis and treatment of brain metastases from the primary lung cancer]

肺癌脑转移的发生率为23%-65%，是脑转移性肿瘤中最常见的类型，且预后较差。目前肺癌脑转移的诊治和分子机理已成为众多研究的热点之一。本文就肺癌脑转移的临床特征、诊断和治疗方面的进展以及最新脑转移的机制学研究做了系统的综述。