Treatment of Brain Metastases in Lung Cancer: Strategies to Avoid/Reduce Late Complications of Whole Brain Radiation Therapy

Central nervous system metastases in advanced non-small cell lung cancer: A review of the therapeutic landscape

Up to 40% of patients with non-small cell lung cancer (NSCLC) develop central nervous system (CNS) metastases. Current treatments for this subgroup of patients with advanced NSCLC include local therapies (surgery, stereotactic radiosurgery, and, less frequently, whole-brain radiotherapy), targeted therapies for oncogene-addicted NSCLC (small molecules, such as tyrosine kinase inhibitors, and antibody-drug conjugates), and immune checkpoint inhibitors (as monotherapy or combination therapy), with multiple new drugs in development. However, confirming the intracranial activity of these treatments has proven to be challenging, given that most lung cancer clinical trials exclude patients with untreated and/or progressing CNS metastases, or do not include prespecified CNS-related endpoints. Here we review progress in the treatment of patients with CNS metastases originating from NSCLC, examining local treatment options, systemic therapies, and multimodal therapeutic strategies. We also consider challenges regarding assessment of treatment response and provide thoughts around future directions for managing CNS disease in patients with advanced NSCLC.

Hippocampal region avoidance in whole brain radiotherapy in brain metastases: For all or for some? A real-world feasibility report

PURPOSE

Hippocampal sparing whole-brain radiotherapy (HS-WBRT) showed significantly lower long-term side effects compared to standard WBRT. Aim of this study is to describe a HS-WBRT real-world monoinstitutional experience within a retrospective cohort.

METHODS

Patients who completed HS-WBRT course, with Karnofsky Performance Status ⩾ 60 and radiological diagnosis of brain metastases (BMs) were enrolled. Treatment was performed using helical Tomotherapy scheduled in 30 Gy in 10 or 12 fractions or 25 Gy in 10 fractions. Oncological outcomes were clinically and radiologically assessed every three months. Toxicity was graded according to the National Cancer Institute Common Terminology Criteria for Adverse Events 4.3.

RESULTS

One hundred and nineteen patients from 2016 to 2020 met inclusion criteria; after a median follow-up of 18 months, 29 patients were alive; 6- and 12-months overall survival rates were 66% and 41%, respectively. HS-WBRT response was assessed for 72 patients. Median time to any progression and intracranial failure (IF) was 4.5 and 13.7 months, respectively. The 6- and 12-month IF rates were 85% and 57%. Among 40 patients (34%) who experienced IF, 17 (42%) were oligometastatic, 23 (58%) polymetastatic and 15/40 developed IF within the hippocampi avoidance zone. No grade (G) ⩾ 2 acute toxicities were reported and one G2 (dizziness) late toxicity was described.

CONCLUSIONS

HS-WBRT is well tolerated, and despite the hippocampal sparing region, the oncological control is satisfying. Further investigation is warranted to find patients who could most benefit from a HS-WBRT approach.

Evaluation of Potential Predictive Biomarkers for Defining Brain Radiotherapy Efficacy in Non-Small Cell Lung Cancer Patients with Brain Metastases: A Case Report and a Narrative Review

Non-small cell lung cancer (NSCLC) is the second most common cancer worldwide, resulting in 1.8 million deaths per year. Most patients are diagnosed with a metastatic disease. Brain metastases are one of the most common metastatic sites and are associated with severe neurological symptoms, shorter survival, and the worst clinical outcomes. Brain radiotherapy and systemic oncological therapies are currently used for controlling both cancer progression and neurological symptoms. Brain radiotherapy includes stereotactic brain ablative radiotherapy (SBRT) or whole brain radiotherapy (WBRT). SBRT is applied for single or multiple (up to ten) small (diameter less than 4 cm) lesions, whereas WBRT is usually applied for multiple (more than ten) and large (diameter greater than 4 cm) brain metastases. In both cases, radiotherapy application may be viewed as an overtreatment which causes severe toxicities without achieving a significant clinical benefit. Thus far, a number of scoring systems to define the potential clinical benefits derived from brain radiotherapy have been proposed. However, most are not well established in clinical practice. In this article, we present a clinical case of a patient with advanced NSCLC carrying a BRAFV600E mutation and brain metastases. We review the variables in addition to applicable scoring systems considered to have potential for predicting clinical outcomes and benefits of brain radiotherapy in patients with advanced NSCLC and brain metastases. Lastly, we highlight the unmet need of specific scoring systems for advanced NSCLC patients with brain metastases carrying oncogene alterations including BRAFV600E mutations.

Intracranial Metastatic Disease: Present Challenges, Future Opportunities

Intracranial metastatic disease (IMD) is a prevalent complication of cancer that significantly limits patient survival and quality of life. Over the past half-century, our understanding of the epidemiology and pathogenesis of IMD has improved and enabled the development of surveillance and treatment algorithms based on prognostic factors and tumor biomolecular characteristics. In addition to advances in surgical resection and radiation therapy, the treatment of IMD has evolved to include monoclonal antibodies and small molecule antagonists of tumor-promoting proteins or endogenous immune checkpoint inhibitors. Moreover, improvements in the sensitivity and specificity of imaging as well as the development of new serological assays to detect brain metastases promise to revolutionize IMD diagnosis. In this review, we will explore current treatment principles in patients with IMD, including the emerging role of targeted and immunotherapy in select primary cancers, and discuss potential areas for further investigation.

Low-level whole-brain radiation enhances theranostic potential of single-domain antibody fragments for human epidermal growth factor receptor type 2 (HER2)-positive brain metastases

Background

Single-domain antibody fragments (aka V_HH, ~ 13 kDa) are promising delivery systems for brain tumor theranostics; however, achieving efficient delivery of V_HH to intracranial lesions remains challenging due to the tumor–brain barrier. Here, we evaluate low-dose whole-brain irradiation as a strategy to increase the delivery of an anti- human epidermal growth factor receptor type 2 (HER2) V_HH to breast cancer-derived intracranial tumors in mice.

Methods

Mice with intracranial HER2-positive BT474BrM3 tumors received 10-Gy fractionated cranial irradiation and were evaluated by noninvasive imaging. Anti-HER2 V_HH 5F7 was labeled with ¹⁸F, administered intravenously to irradiated mice and controls, and PET/CT imaging was conducted periodically after irradiation. Tumor uptake of ¹⁸F-labeled 5F7 in irradiated and control mice was compared by PET/CT image analysis and correlated with tumor volumes. In addition, longitudinal dynamic contrast-enhanced MRI (DCE-MRI) was conducted to visualize and quantify the potential effects of radiation on tumor perfusion and permeability.

Results

Increased ¹⁸F-labeled 5F7 intracranial tumor uptake was observed with PET in mice receiving cranial irradiation, with maximum tumor accumulation seen approximately 12 days post initial radiation treatment. No radiation-induced changes in HER2 expression were detected by Western blot, flow cytometry, or on tissue sections. DCE-MRI imaging demonstrated transiently increased tumor perfusion and permeability after irradiation, consistent with the higher tumor uptake of ¹⁸F-labeled anti-HER2 5F7 in irradiated mice.

Conclusion

Low-level brain irradiation induces dynamic changes in tumor vasculature that increase the intracranial tumor delivery of an anti-HER2 V_HH, which could facilitate the use of radiolabeled V_HH to detect, monitor, and treat HER2-expressing brain metastases.

Assessment of Normal Tissue Radiosensitivity by Evaluating DNA Damage and Repair Kinetics in Human Brain Organoids

DNA-double strand break (DSB), detected by immunostaining of key proteins orchestrating repair, like γH2AX and 53BP1, is well established as a surrogate for tissue radiosensitivity. We hypothesized that the generation of normal brain 3D organoids (“mini-brains”) from human induced pluripotent stem cells (hiPSC) combined with detection of DNA damage repair (DDR) may hold the promise towards developing personalized models for the determination of normal tissue radiosensitivity. In this study, cerebral organoids, an in vitro model that stands in its complexity between 2D cellular system and an organ, have been used. To quantify radiation-induced response, immunofluorescent staining with γH2AX and 53BP1 were applied at early (30 min, initial damage), and late time points (18 and 72 h, residual damage), following clinical standard 2 Gy irradiation. Based on our findings, assessment of DDR kinetics as a surrogate for radiosensitivity in hiPSC derived cerebral organoids is feasible. Further development of mini-brains recapitulating mature adult neuronal tissue and implementation of additional signaling and toxicity surrogates may pave the way towards development of next-generation personalized assessment of radiosensitivity in healthy neuronal tissue.

Association of different fractionation schedules for prophylactic cranial irradiation with toxicity and brain metastases-free survival in stage III non-small cell lung cancer: A pooled analysis of individual patient data from three randomized trials

We assessed the impact of different PCI fractionation schedules (30 Gy in 10 versus 15 fractions) on brain metastases-free survival (BMFS) and toxicity in stage III NSCLC. Our results suggest that 30 Gy in 10 fractions is associated with increased toxicity, while no conclusive evidence of improving BMFS was seen with this schedule.

Treatment of brain metastases in ALK-positive non-small cell lung cancer

Brain metastases are quite frequent in patients with ALK-translocated non-small cell lung cancer (NSCLC): they are often not amenable to surgical resection and are generally treated with radiotherapy (RT). This however causes severe late toxic side effects that may become invalidating considering the relatively long survival provided by recent medical treatment with target therapies. Several clinical trials have demonstrated that ALK-inhibitors (crizotinib, alectinib, brigatinib) show excellent activity also against brain metastases. It is therefore reasonable, in asymptomatic patients, to start treatment with specific inhibitors: RT will be used at the time of tumor progression or when symptoms appear. This sequence provides the best quality of life for patients.

Prophylactic Cranial Irradiation in Patients With High-Risk Metastatic Non-Small Cell Lung Cancer: Quality of Life and Neurocognitive Analysis of a Randomized Phase II Study

PURPOSE

To this date, studies regarding the use of prophylactic cranial irradiation (PCI) versus standard of care (SoC) for patients with non-small cell lung cancer have shown limited benefit in survival outcomes, in addition to the potential effects on quality of life (QoL) and neurocognitive function (NCF). This randomized, phase II study evaluated the role of PCI in QoL and NCF, in a population comprised of subjects at a high risk for development of brain metastases (BM).

METHODS AND MATERIALS

Eligible patients had histologically confirmed non-small cell lung cancer without baseline BM, harboring epidermal growth factor receptor mutations, anaplastic lymphoma kinase rearrangements, or elevated carcinoembryonic antigen (CEA) at diagnosis. Participants were assigned to receive SoC or SoC plus PCI (25 Gy in 10 fractions). Primary endpoint was BM at 24 months (BM-24), for which the study was powered. Secondary endpoints included QoL assessed using the European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLQ-C30) and the Lung Cancer module (LC13) and NCF assessed using the Mini Mental State Examination (MMSE). Patients were followed every 3 months for a year for QoL and NCF.

RESULTS

From May 2012 to December 2017, 84 patients were enrolled in the study, 41 were allocated to PCI while 43 received SoC. Efficacy outcomes are discussed in a separate article. The global health-QoL scores were similar at 3, 6, 9, and 12 months after randomization between both study arms, with no significant differences when comparing by groups. At 1-year postrandomization, median global health QoL scores were 83 (p25-p75: 75-83) and 83 (p25-p75: 75-83) in the control and experimental arms, respectively. There were no significant changes in terms of the mean differences between subjects in either study arm when analyzing the change between baseline and 12-month scores (16.4 ± 19.9 vs 12.9 ± 14.7; P = .385). Seventeen patients were alive at database lockdown in February 2020, without significant differences in median MMSE (30 [p25-75: 29-30] vs 30 [p25-75: 28-30]) or QLQ-C30 scores (75.0 [p25-75: 50-87.2] vs 67.0 [p25-75: 50.0-100.0]).

CONCLUSIONS

Among a selected high-risk population for developing BM, PCI did not significantly decrease QoL or neurocognitive function as assessed using the MMSE. Future studies are warranted to assess this observation, using more varied and sensitive tools available to date.

Early volume reduction of the hippocampus after whole-brain radiation therapy: an automated brain structure segmentation study

PURPOSE

To assess atrophy differences among brain regions and time-dependent changes after whole-brain radiation therapy (WBRT).

MATERIALS AND METHODS

Twenty patients with lung cancer who underwent both WBRT and chemotherapy (WBRT group) and 18 patients with lung cancer who underwent only chemotherapy (control group) were recruited. Three-dimensional T1WI were analyzed to calculate volume reduction ratio after WBRT in various brain structures. The volume reduction ratio of the hippocampus was compared among following 3 periods: 0-3, 4-7, and 8-11 months after WBRT.

RESULTS

The volume reduction ratio of the hippocampus was significantly higher in the WBRT group than in the control group (p < 0.05). In WBRT group, the volume reduction ratio of the hippocampus was significantly higher than that of the cortex and white matter (p < 0.05). There were significant differences in the volume reduction ratio between of 0-3 months and that of 4-7 months (p = 0.02) and between 4-7 months and that of 8-11 months (p = 0.01).

CONCLUSION

The hippocampus is more vulnerable to the radiation compared with other brain regions and may become atrophic even in the early stage after WBRT.

Brain metastases in ALK-positive NSCLC - time to adjust current treatment algorithms

The progress in molecular biology has revolutionized systemic treatment of advanced non-small-cell lung cancer (NSCLC) from conventional chemotherapy to a treatment stratified by histology and genetic aberrations. Tumors harboring a translocation of the anaplastic-lymphoma-kinase (ALK) gene constitute a distinct genetic and clinico-pathologic NSCLC subtype with patients with ALK-positive disease being at a higher risk for developing brain metastases. Due to the introduction of effective targeted therapy with ALK-inhibitors, today, patients with advanced ALK-positive NSCLC achieve high overall response rates and remain progression-free for long time intervals. Moreover, ALK-inhibitors seem to exhibit efficacy in the treatment of brain metastases. In the light of this, it needs to be discussed how treatment algorithms for managing patients with brain metastases should be modified. By integrating systemic ALK-inhibitor therapy, radiotherapy, in particular whole brain radiotherapy might be postponed deferring potential long-term impairment by neurocognitive deficits to a later time point in the course of the disease. An early treatment of asymptomatic brain metastases might offer patients a longer time without impairment of cerebral symptoms or radiotherapeutic interventions. Based on an updated extensive review of the literature this article provides an overview on the epidemiology and the treatment of patients’ brain metastases. It describes the specifics of ALK-positive disease and proposes an algorithm for the treatment of patients with advanced ALK-positive NSCLC and brain metastases.

Strategies to Preserve Cognition in Patients With Brain Metastases: A Review

Brain metastases are common to the natural history of many advanced malignancies. Historically, whole brain radiation therapy (WBRT) has played a key role in the management of brain metastases, especially for patients with multiple lesions. However, prospective trials have demonstrated consistent neurocognitive toxicities after WBRT, and various pharmacologic and anatomic strategies designed to mitigate these toxicities have been studied in recent years. Memantine, an NMDA receptor antagonist, taken during and after WBRT improved cognitive preservation in a randomized trial over placebo. Deliberate reductions in radiation dose to the hippocampus, via hippocampal-avoidance (HA)-WBRT, resulted in improved cognition over historic controls in a phase II trial, and follow-up randomized trials are now ongoing to evaluate cognitive outcomes with HA vs. conventional brain radiation techniques. Nevertheless, some of the most promising strategies currently available to reduce the cognitive effects of brain radiation may be found in efforts to avoid or delay WBRT administration altogether. Stereotactic radiosurgery (SRS), involving focused, high-dose radiation to central nervous system (CNS) lesions with maximal sparing of normal brain parenchyma, has become the standard for limited brain metastases (classically 1–3 or 4 lesions) in the wake of multiple randomized trials demonstrating equivalent survival and improved cognition with SRS alone compared to SRS plus WBRT. Today, there is growing evidence to support SRS alone for multiple (≥4) brain metastases, with comparable survival to SRS alone in patients with fewer lesions. In patients with small-cell lung cancer, the routine use of prophylactic cranial irradiation (PCI) for extensive-stage disease has been also been challenged following the results of a randomized trial supporting an alternative strategy of MRI brain surveillance and early salvage radiation for the development of brain metastases. Moreover, new systemic agents are demonstrating increasing CNS penetration and activity, with the potential to offer greater control of widespread and microscopic brain disease that was previously only achievable with WBRT. In this review, we endeavor to put these clinical data on cognition and brain metastases into historical context and to survey the evolving landscape of strategies to improve future outcomes.

Prophylactic cranial irradiation for patients with lung cancer

The incidence of brain metastases in patients with lung cancer has increased as a result of improved local and systemic control and better diagnosis from advances in brain imaging. Because brain metastases are responsible for life-threatening symptoms and serious impairment of quality of life, resulting in shortened survival, prophylactic cranial irradiation has been proposed in both small-cell lung cancer (SCLC) and non-small-cell lung cancer (NSCLC) to try to improve incidence of brain metastasis, survival, and eventually quality of life. Findings from randomised controlled trials and a meta-analysis have shown that prophylactic cranial irradiation not only reduces the incidence of brain metastases in patients with SCLC and with non-metastatic NSCLC, but also improves overall survival in patients with SCLC who respond to first-line treatment. Although prophylactic cranial irradiation is potentially associated with neurocognitive decline, this risk needs to be balanced against the potential benefit in terms of brain metastases incidence and survival. Several strategies to reduce neurotoxicity are being investigated.

A matched-pair analysis comparing whole-brain radiotherapy with and without a stereotactic boost for intracerebral control and overall survival in patients with one to three cerebral metastases

Background

Twelve years ago, a randomized trial demonstrated that a radiosurgery boost added to whole-brain radiotherapy (WBRT) improved intracerebral control (IC) in patients with one to three cerebral metastases. Overall survival (OS) was improved only in the subgroup of patients with a single metastasis but not in the entire cohort. The present study compared both regimens in a different scenario outside a randomized trial.

Methods

A total of 252 patients with one to three cerebral metastases were included. Eighty-four patients receiving WBRT plus a planned stereotactic boost and 168 patients receiving WBRT alone were individually matched 1:2 for nine factors including fractionation of WBRT, age, gender, performance score, primary tumor, number of cerebral metastases, extracerebral metastases, recursive partitioning analysis class, and time between cancer diagnosis and WBRT. Each group of three patients was required to match for all nine factors. Both groups were compared for IC and OS.

Results

IC rates at 6, 12, 18 and 24 months were 88, 71, 45 and 22% after WBRT plus stereotactic boost vs. 75, 48, 38 and 22% after WBRT alone (p = 0.005). OS rates at 6, 12, 18 and 24 months were 76, 53, 32 and 25% after WBRT plus stereotactic boost and 67, 45, 29 and 20% after WBRT alone (p = 0.10). In patients with a single lesion, OS rates were also not significantly different (p = 0.12).

Conclusions

Similar to the previous randomized trial from 2004, this matched-pair study showed that a stereotactic boost in addition to WBRT significantly improved IC but not OS.

Cullin7 is required for lung cancer cell proliferation and is overexpressed in lung cancer

Ubiquitin ligase Cullin7 has been identified as an oncogene in some malignant diseases such as choriocarcinoma and neuroblastoma. However, the role of Cullin7 in lung cancer carcinogenesis remains unclear. In this study, we explored the functional role of Cullin7 in lung cancer cell proliferation and tumorigenesis and determined its expression profile in lung cancer. Knocking down Cullin7 expression by small interfering RNA (siRNA) in lung cancer cells inhibited cell proliferation and elevated the expression of p53, p27, and p21 proteins. The enhanced p53 expression resulted from activation of the DNA damage response pathway. Cullin7 knockdown markedly suppressed xenograft tumor growth in vivo in mice. Moreover, Cullin7 expression was increased in primary lung cancer tissues of humans. Thus, Cullin7 is required for sustained proliferation and survival of tumor cells in vitro and in vivo, and its aberrant expression may contribute to the pathogenesis of lung cancer. Thus, our study provided evidence that Cullin7 functions as a novel oncogene in lung cancer and may be a potential therapeutic target for lung cancer management.

Methods and results of locoregional treatment of brain metastases in patients with non-small cell lung cancer

This article presents methods and results of surgery and radiotherapy of brain metastases from non-small cell lung cancer (BMF-NSCLC). Patients with single BMF-NSCLC, with Karnofsky score ≥ 70 and controlled extracranial disease are the best candidates for surgery. Stereotactic radiosurgery (SRS) is recommended in patients with 1-3 BMF-NSCLC below 3-3.5 cm, with minor neurological symptoms, located in parts of the brain not accessible to surgery, with controlled extracranial disease. Whole brain radiotherapy (WBRT) following SRS reduces the risk of local relapse; in selected patients median survival reaches more than 10 months. Whole brain radiotherapy alone is a treatment in patients with multiple metastases, poor performance status, uncontrolled extracranial disease, disqualified from surgery or SRS with median survival 3 to 6 months. There is no doubt that there are patients with BMF-NSCLC who should receive only the best supportive care. There is a debate in the literature on how to select these patients.

Enhancement of radiosensitivity by inhibition of c-Jun N-terminal kinase activity in a Lewis lung carcinoma‑bearing subcutaneous tumor mouse model

Stereotactic radiosurgery has been recognized as an effective treatment approach for metastatic brain tumors. By increasing the sensitivity of the tumor to radiation and decreasing the marginal dose, it is possible to improve therapeutic efficacy and decrease side-effects. In radiation-induced cells, c-Jun N-terminal kinase (JNK) signaling mediates the phosphorylation of H2AX, which indicates DNA damage sensitivity and modulates the effect of radiation. Lewis lung cancer (LLC) and breast cancer (4T1) cells were irradiated with a Gamma Knife in cell culture tubes. To evaluate the relationship between radiosensitivity and JNK activity, clonogenic assay was performed. DNA damage response was estimated by γH2AX focus formation assay and apoptosis‑related protein levels were assessed by western blotting. The mice were subcutaneously inoculated with LLC cells, and irradiated concomitantly with JNK inhibitor treatment. The effect of the JNK inhibitor was investigated by tumor volumetry and immunohistochemistry. γH2AX expression, which mediates repair of radiation‑induced DNA damage, was reduced in the cancer cell group pretreated with the JNK inhibitor. This finding shows that JNK inhibition may increase the radiosensitivity in radiated lung and breast cancer cells. For the in vivo study, irradiated tumor growth was significantly delayed in the JNK inhibitor-treated mouse group. Blockade of JNK signaling decreased γH2AX expression and increased apoptosis in the radiation-induced cancer cells. JNK inhibitor may be useful for enhancing the radiosensitivity of lung and breast cancer cells and improving the treatment efficacy of radiosurgical approaches for metastatic brain tumors.

Hippocampal-Sparing Whole-Brain Radiotherapy for Lung Cancer

Brain metastases occur in 20% to 40% of lung cancer patients. Whole-brain radiotherapy (WBRT) has long been considered the treatment of choice for many patients with lung cancer, because of its wide availability, ease of delivery, and effectiveness in prolonging survival. However, WBRT is also associated with several side effects, such as decline in memory and other cognitive functions. There exists significant preclinical and clinical evidence that radiation-induced injury to the hippocampus correlates with neurocognitive decline of patients who receive WBRT. Technological advances in treatment planning and delivery facilitate the use of hippocampal-sparing (HS) WBRT as prophylactic cranial irradiation or the primary treatment modality for lung cancer patients with brain metastases. In this review, we provide a detailed and comprehensive discussion of the safety profile, techniques for hippocampus-sparing, and the clinical evidence of HS-WBRT for lung cancer patients.

The IASLC Lung Cancer Staging Project: Proposals for the Revision of the M Descriptors in the Forthcoming Eighth Edition of the TNM Classification of Lung Cancer

INTRODUCTION

The aim of this study is to analyze all metastatic (M) categories of the current tumor, node, and metastasis (TNM) classification of lung cancer with the objective of providing suggestions for modifications of the M component in the next edition of the TNM classification for lung cancer.

METHODS

The new International Association for the Study of Lung Cancer lung cancer database was created from 94,708 patients diagnosed as having lung cancer between 1999 and 2010. Including further patients submitted through the electronic data capture system to Cancer Research and Biostatistics until 2012, all together 1059 non-small-cell lung cancer cases were available for a detailed analysis of the clinical M categories. Overall survival was calculated using the Kaplan-Meier method, and prognosis was assessed using a Cox proportional hazards regression analysis.

RESULTS

No significant differences were found among the M1a (metastases within the chest cavity) descriptors. However, when M1b (distant metastases outside the chest cavity) were assessed according to the number of metastases, tumors with a single metastasis in a single organ had significantly better prognosis than those with multiple metastases in one or several organs.

CONCLUSIONS

In this revision of the TNM classification, cases with pleural/pericardial effusions, contralateral/bilateral lung nodules, contralateral/bilateral pleural nodules, or a combination of multiple of these parameters should continue to be grouped as M1a category. Single metastatic lesions in a single distant organ should be newly designated to the M1b category. Multiple lesions in a single organ or multiple lesions in multiple organs should be reclassified as M1c category. This new division can serve as a first step into providing rational definitions for an oligometastatic disease stage in non-small-cell lung cancer in the future.

Radiation-enhancing effect of sodium glycididazole in patients suffering from non-small cell lung cancer with multiple brain metastases: A randomized, placebo-controlled study

PURPOSE

Median survival of patients with brain metastases from non-small cell lung cancer is poor. This study was to investigate the radiation-enhancing effect of sodium glycididazole combined with whole-brain radiotherapy of multiple brain metastases from non-small cell lung cancer.

PATIENTS AND METHODS

Sixty-four patients with multiple brain metastases from non-small cell lung cancer were included: the study group (n=32) received whole-brain radiotherapy combined with sodium glycididazole at a dose of 700mg/m(2) intravenous infusion 30minutes before radiotherapy, three times a week; the control group (n=32) only received whole-brain radiotherapy. The primary end point was central nervous system (CNS) progression-free survival and overall survival. The treatment-related toxicity was also recorded.

RESULTS

The CNS disease control rate was better (90.6% vs 65.6%, P=0.016) in the study group than in the control group at 3 month of follow-up. The median CNS progression-free survival time was longer in the study group than in the control group (7.0 months vs 4.0 months, P=0.038). There was no significant difference of the median overall survival time between the study group and the control group (11.0 months vs 9.0 months, P=0.418). On the other hand, the treatment-related toxicity showed no statistically significant difference between these two groups (P>0.05).

CONCLUSIONS

The study indicated that sodium glycididazole was an effective, promising radiation-enhancing agent that improved CNS disease control rate, extended the median CNS progression-free survival time and was well tolerated in patients suffering from non-small cell lung cancer with multiple brain metastases.

Total regression of brain metastases in non-small cell lung cancer patients harboring EGFR mutations treated with gefitinib without radiotherapy: two case reports

Background

Gefitinib is an epidermal growth factor receptor tyrosine kinase inhibitor. Clinical trials have reported its effectiveness in the treatment of brain metastases from non-small cell lung cancer by overcoming the blood–brain barrier. Gefitinib is generally regarded as a relatively safe agent, and several reports have described its efficacy in patients with epidermal growth factor receptor mutation-positive non-small cell lung cancer and a poor performance status.

Case presentation

We herein described two patients with brain metastasis from non-small cell lung cancer who achieved the total regression of metastasis with the administration of gefitinib. A 70-year-old Japanese woman was referred to our hospital with a severe cough. Brain magnetic resonance imaging revealed a metastatic lesion in the left temporal lobe. The tumor was positive for an epidermal growth factor receptor L858R mutation in exon 21 using the peptide nucleic acid-locked nucleic acid polymerase chain reaction clamp method. She was treated with 250 mg gefitinib per day, and, 1 month later, the primary lesion and brain metastasis had totally resolved. A 58-year-old Japanese woman was referred to our hospital with nausea and headache. Brain magnetic resonance imaging revealed a metastatic lesion in the left cerebellar hemisphere and meningeal dissemination. The tumor was positive for the epidermal growth factor receptor L858R mutation in exon 21. She was treated with 250 mg gefitinib per day, and, 3 weeks later, the primary lesion, brain metastasis, and meningeal dissemination had completely resolved.

Conclusion

We successfully treated two lung cancer patients with brain metastasis using gefitinib. Gefitinib therapy may be a suitable treatment for brain metastasis in lung cancer with an epidermal growth factor receptor mutation, particularly in elderly patients with a poor performance status.

Hippocampus Avoidance Whole-brain Radiation Therapy: A Practical Intensity-modulated Radiation Therapy Planning and Delivery Approach to RTOG 0933

PURPOSE

The goal of this work was to develop a more practical technique to meet the requirements of the Radiation Therapy Oncology Group (RTOG) 0933 protocol for sparing the hippocampus while irradiating the whole brain. Whole-brain radiation therapy (WBRT) has been linked to a decrease in neurocognitive function and increase in memory loss leading to lower quality of life for patients. Hippocampus avoidance (HA) WBRT may help to mitigate these issues by delaying the decline in neurocognitive function. RTOG 0933 is a phase II clinical trial aimed at HA-WBRT for patients with metastatic brain lesions. Recently published results from this study showed significant benefit in preserving short-term memory function for these patients. Although the trial allows several methods of treatment, including tomotherapy, volumetric arc therapy, and linac-based IMRT, treatment at many cancer centers is limited to linear accelerator (linac) based step-and-shoot IMRT. The linac-based method suggested by RTOG involves nine gantry angles on a number of different planes. Our goal was to find a more practical solution for the planning and delivery of HA-WBRT according to the RTOG 0933 protocol.

METHODS AND MATERIALS

A total of 14 patients were accrued to 0933 at our center. Patients receive magnetic resonance imaging, which is fused with the planning computed tomographic scan to aid in contouring the hippocampus. Immobilization of the patients is achieved using Mayo Mold and Thermoplast shell (CDR Systems, Calgary, AB). Treatment planning is performed using Pinnacle version 9 (Pinnacle3, Fitchburg, WI) and direct machine parameter optimization. Treatment is delivered using a Varian iX (Varian Medical Systems, Palo Alto, CA), 120-leaf multileaf collimator, 6 MV photon beams. Through an iterative process, we developed a technique using seven gantry angles and no couch rotations. The planning process was aided by the use of dose shaping rings and avoidance structures; the delivery time was further optimized by avoiding split fields and keeping the total number of monitor units and beam segments to the minimum required to meet RTOG 0933 dose constraints. The planning and dosimetry were centrally reviewed for the first five patients according to protocol requirement.

RESULTS

We were able to achieve our goal by developing a technique that requires only seven gantry angles and no couch movements. All of our plans met the protocol requirements and were accepted into the study. We assessed the average delivery time for four patients comparing our technique with the technique proposed by the RTOG. An average time saving of 523 seconds was achieved with the seven gantry angle technique. There was also a modest saving of 102 total monitor units with our technique.

CONCLUSIONS

The technique developed in our center is a practical technique for HA-WBRT. Our process gave reproducible results in the patients we accrued to RTOG 0933 and should allow many more centers to be able to deliver HA-WBRT. Should HA become a standard of care this technique is easier to adopt.

Complete Remission of Brain Metastases in Non-Small Cell Lung Cancer Patients Harboring an EGFR Mutation Treated with Tyrosine Kinase Inhibitor without Radiotherapy: A Report of 3 Cases

Brain parenchymal metastasis from a solid tumor is a serious clinical condition associated with a poor outcome because systemic chemotherapy is usually ineffective for treating brain metastases (BM) due to the blood-brain barrier. Therefore, radiotherapy such as whole brain radiotherapy (WBRT) and stereotactic radiosurgery have taken on a central role in the management of BM. However, WBRT can delay subsequent systemic treatment or cause neurologic complications such as a decline in cognitive function. Therefore, suspending WBRT is worth considering if there is an effective alternative. Although there have been no large prospective studies, many reports are available about the favorable effect of tyrosine kinase inhibitors (TKIs) for treating BM in patients with non-small cell lung cancer (NSCLC). Here, we report 3 NSCLC cases that showed a complete response in BM after TKI treatment without WBRT. Based on these remarkable response rates of BM to a TKI, the potential toxicity of WBRT can be avoided, particularly in patients with small metastatic nodules and an epidermal growth factor receptor activating mutation.

Consequences of cancer treatments on adult hippocampal neurogenesis: implications for cognitive function and depressive symptoms

The human brain is capable of generating new functional neurons throughout life, a phenomenon known as adult neurogenesis. The generation of new neurons is sustained throughout adulthood due to the proliferation and differentiation of adult neural stem cells. This process in humans is uniquely located in the subgranular zone of the dentate gyrus in the hippocampus. Adult hippocampal neurogenesis (AHN) is thought to play a major role in hippocampus-dependent functions, such as spatial awareness, long-term memory, emotionality, and mood. The overall aim of current treatments for cancer (such as radiotherapy and chemotherapy) is to prevent aberrant cell division of cell populations associated with malignancy. However, the treatments in question are absolutist in nature and hence inhibit all cell division. An unintended consequence of this cessation of cell division is the impairment of adult neural stem cell proliferation and AHN. Patients undergoing treatment for cancerous malignancies often display specific forms of memory deficits, as well as depressive symptoms. This review aims to discuss the effects of cancer treatments on AHN and propose a link between the inhibition of the neurogenetic process in the hippocampus and the advent of the cognitive and mood-based deficits observed in patients and animal models undergoing cancer therapies. Possible evidence for coadjuvant interventions aiming to protect neural cells, and subsequently the mood and cognitive functions they regulate, from the ablative effects of cancer treatment are discussed as potential clinical tools to improve mental health among cancer patients.