Whole-brain radiotherapy with or without efaproxiral for the treatment of brain metastases: Determinants of response and its prognostic value for subsequent survival

Evolution of the Management of Brain Metastases: A Bibliometric Analysis

A systematic review of the published literature was conducted to analyze the management evolution of brain metastases from different cancers. Using the keywords "brain metastasis", "brain metastases", "CNS metastasis", "CNS metastases", "phase III" AND/OR "Randomized Controlled Trial" (RCT), relevant articles were searched for on the SCOPUS database. A total of 1986 articles were retrieved, published over a 45-year period (1977-2022). Relevant articles were defined as clinical studies describing the treatment or prevention of brain metastases from any cancer. Articles on imaging, quality of life, cognitive impairment after treatment, or primary brain tumors were excluded. After a secondary analysis, reviewing the abstracts and/or full texts, 724 articles were found to be relevant. Publications significantly increased in the last 10 years. A total of 252 articles (34.8%) were published in 12 core journals, receiving 50% of the citations. The number of publications in Frontiers in Oncology, BMC Cancer, and Radiotherapy and Oncology have increased considerably over the last few years. There were 111 randomized controlled trials, 128 review articles, and 63 meta-analyses. Most randomized trials reported on brain metastases management from unselected tumors (49), lung cancer (47), or breast cancer (11). In the last 5 years (2017 to 2022), management of brain metastasis has moved on from WBRT, the use of chemotherapy, and radio-sensitization to three directions. First, Radiosurgery or Radiotherapy (SRS/SRT), or hippocampal-sparing WBRT is employed to reduce radiation toxicity. Second, it has moved to the use of novel agents, such as tyrosine kinase inhibitors (TKI) and immune checkpoint inhibitors (ICI) and third, to the use of molecularly directed therapy such as TKIs, in asymptomatic low volume metastasis, obviating the need for WBRT.

X-ray crystallography and sickle cell disease drug discovery-a tribute to Donald Abraham

X-ray crystallography and structure-based drug discovery have played a major role in the discovery of antisickling agents that target hemoglobin (Hb) for the treatment of sickle cell disease (SCD). Sickle cell disease, the most common inherited hematologic disorder, occurs as a result of a single point mutation of βGlu6 in normal human adult hemoglobin (HbA) to βVal6 in sickle hemoglobin (HbS). The disease is characterized by polymerization of HbS and sickling of red blood cells (RBCs), leading to several secondary pathophysiologies, including but not limited to vaso-occlusion, hemolytic anemia, oxidative stress, inflammation, stroke, pain crisis, and organ damage. Despite the fact that SCD was the first disease to have its molecular basis established, the development of therapies was for a very long time a challenge and took several decades to find therapeutic agents. The determination of the crystal structure of Hb by Max Perutz in the early 60s, and the pioneering X-ray crystallography research by Donald J. Abraham in the early 80s, which resulted in the first structures of Hb in complex with small molecule allosteric effectors of Hb, gave much hope that structure-based drug discovery (SBDD) could be used to accelerate development of antisickling drugs that target the primary pathophysiology of hypoxia-induced HbS polymerization to treat SCD. This article, which is dedicated to Donald J. Abraham, briefly reviews structural biology, X-ray crystallography and structure-based drug discovery from the perspective of Hb. The review also presents the impact of X-ray crystallography in SCD drug development using Hb as a target, emphasizing the major and important contributions by Don Abraham in this field.

Hemoglobin allostery and pharmacology

The oxygen demands of the human body require the constant circulation of blood carrying an enormous concentration of hemoglobin (Hb). Oxygen transport depends not only on the amount of Hb, but also on the control over the affinity of the protein for the gas, which can be optimized for the environmental conditions by changes in the concentration of effectors (hydrogen ions, chloride, CO2, and DPG) inside the red cell. Some pathological conditions affecting Hb may benefit from pharmacological interventions to increase or decrease its affinity for oxygen, or otherwise modify its properties, or alter its biosynthesis. Examples of such conditions include sickle cell anemia, thalassemias and inherited hemoglobinopathies. Effective and safe drugs such as voxelotor, bezafibrate and efaproxiral are available that significantly increase or decrease Hb oxygen affinity. Some medical conditions not directly affecting the blood or its oxygen carrying capacity may also be relieved by the manipulation of Hb. For example, the standard treatment of acute cyanide poisoning requires the oxidation of a fraction of the Hb in the bloodstream so that it efficiently scavenges cyanide. Tumors are often extremely hypoxic and therefore strongly resistant to radiotherapy; the sensitivity of cancerous tissue to X-rays may be increased by improved oxygenation through drugs binding Hb. This review attempts to provide a systematic exploration of the pharmacology of Hb, its molecular basis, and its intended and possible uses.

Whole brain radiotherapy for the treatment of newly diagnosed multiple brain metastases

BACKGROUND

This is an update to the review published in the Cochrane Library (2012, Issue 4).It is estimated that 20% to 40% of people with cancer will develop brain metastases during the course of their illness. The burden of brain metastases impacts quality and length of survival.

OBJECTIVES

To assess the effectiveness and adverse effects of whole brain radiotherapy (WBRT) given alone or in combination with other therapies to adults with newly diagnosed multiple brain metastases.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, and Embase to May 2017 and the National Cancer Institute Physicians Data Query for ongoing trials.

SELECTION CRITERIA

We included phase III randomised controlled trials (RCTs) comparing WBRT versus other treatments for adults with newly diagnosed multiple brain metastases.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and abstracted information in accordance with Cochrane methods.

MAIN RESULTS

We added 10 RCTs to this updated review. The review now includes 54 published trials (45 fully published reports, four abstracts, and five subsets of data from previously published RCTs) involving 11,898 participants.Lower biological WBRT doses versus controlThe hazard ratio (HR) for overall survival (OS) with lower biological WBRT doses as compared with control (3000 cGy in 10 daily fractions) was 1.21 (95% confidence interval (CI) 1.04 to 1.40; P = 0.01; moderate-certainty evidence) in favour of control. The HR for neurological function improvement (NFI) was 1.74 (95% CI 1.06 to 2.84; P = 0.03; moderate-certainty evidence) in favour of control fractionation.Higher biological WBRT doses versus controlThe HR for OS with higher biological WBRT doses as compared with control (3000 cGy in 10 daily fractions) was 0.97 (95% CI 0.83 to 1.12; P = 0.65; moderate-certainty evidence). The HR for NFI was 1.14 (95% CI 0.92 to 1.42; P = 0.23; moderate-certainty evidence).WBRT and radiosensitisersThe addition of radiosensitisers to WBRT did not confer additional benefit for OS (HR 1.05, 95% CI 0.99 to 1.12; P = 0.12; moderate-certainty evidence) or for brain tumour response rates (odds ratio (OR) 0.84, 95% CI 0.63 to 1.11; P = 0.22; high-certainty evidence).Radiosurgery and WBRT versus WBRT aloneThe HR for OS with use of WBRT and radiosurgery boost as compared with WBRT alone for selected participants was 0.61 (95% CI 0.27 to 1.39; P = 0.24; moderate-certainty evidence). For overall brain control at one year, the HR was 0.39 (95% CI 0.25 to 0.60; P < 0.0001; high-certainty evidence) favouring the WBRT and radiosurgery boost group.Radiosurgery alone versus radiosurgery and WBRTThe HR for local brain control was 2.73 (95% CI 1.87 to 3.99; P < 0.00001; high-certainty evidence)favouring the addition of WBRT to radiosurgery. The HR for distant brain control was 2.34 (95% CI 1.73 to 3.18; P < 0.00001; high-certainty evidence) favouring WBRT and radiosurgery. The HR for OS was 1.00 (95% CI 0.80 to 1.25; P = 0.99; moderate-certainty evidence). Two trials reported worse neurocognitive outcomes and one trial reported worse quality of life outcomes when WBRT was added to radiosurgery.We could not pool data from trials related to chemotherapy, optimal supportive care (OSC), molecular targeted agents, neurocognitive protective agents, and hippocampal sparing WBRT. However, one trial reported no differences in quality-adjusted life-years for selected participants with brain metastases from non-small-cell lung cancer randomised to OSC and WBRT versus OSC alone.

AUTHORS' CONCLUSIONS

None of the trials with altered higher biological WBRT dose-fractionation schemes reported benefit for OS, NFI, or symptom control compared with standard care. However, OS and NFI were worse for lower biological WBRT dose-fractionation schemes than for standard dose schedules.The addition of WBRT to radiosurgery improved local and distant brain control in selected people with brain metastases, but data show worse neurocognitive outcomes and no differences in OS.Selected people with multiple brain metastases from non-small-cell lung cancer may show no difference in OS when OSC is given and WBRT is omitted.Use of radiosensitisers, chemotherapy, or molecular targeted agents in conjunction with WBRT remains experimental.Further trials are needed to evaluate the use of neurocognitive protective agents and hippocampal sparing with WBRT. As well, future trials should examine homogeneous participants with brain metastases with focus on prognostic features and molecular markers.

Lapatinib with whole brain radiotherapy in patients with brain metastases from breast and non-small cell lung cancer: a phase II study of the Hellenic Cooperative Oncology Group (HeCOG)

Small molecules, mainly tyrosine kinase inhibitors, are currently used in various malignancies. Lapatinib, a dual inhibitor of EGFR/HER2 tyrosine kinases, has demonstrated effectiveness in brain metastases from HER2-overexpressing breast cancer. It also appears to sensitize EGFR-expressing cell lines to radiation. To evaluate the efficacy of lapatinib in combination with whole brain radiotherapy (WBRT) in patients with brain metastases from non-small cell lung cancer (NSCLC) and breast cancer, as assessed by volumetric analysis by MRI. 81 patients were treated with WBRT (30 Gy in ten fractions) in combination with lapatinib 1250 mg once daily, followed by lapatinib 1500 mg once daily for a total 6 weeks. 21 patients had primary breast cancer and 60 patients NSCLC. Pre- and post-treatment MRI scans in a compact disk for central volumetric assessment were available for 43 patients. 27 patients (62.8%) achieved partial response, 15 patients (34.9%) had stable disease and only one patient (2.3%) had disease progression. Response was not associated to EGFR protein expression. All 81 patients were assessed for safety. The large majority of the adverse events were mild. Eight deaths occurred, four of which were considered related to the study drugs but there were also other contributing factors. Nine cases of serious infections were observed in eight patients, but they were also receiving dexamethasone. Lapatinib in combination with WBRT in patients with brain metastases from breast cancer and NSCLC is a feasible approach that can be further studied in larger clinical trials.

Aryloxyalkanoic Acids as Non-Covalent Modifiers of the Allosteric Properties of Hemoglobin

Hemoglobin (Hb) modifiers that stereospecifically inhibit sickle hemoglobin polymer formation and/or allosterically increase Hb affinity for oxygen have been shown to prevent the primary pathophysiology of sickle cell disease (SCD), specifically, Hb polymerization and red blood cell sickling. Several such compounds are currently being clinically studied for the treatment of SCD. Based on the previously reported non-covalent Hb binding characteristics of substituted aryloxyalkanoic acids that exhibited antisickling properties, we designed, synthesized and evaluated 18 new compounds (KAUS II series) for enhanced antisickling activities. Surprisingly, select test compounds showed no antisickling effects or promoted erythrocyte sickling. Additionally, the compounds showed no significant effect on Hb oxygen affinity (or in some cases, even decreased the affinity for oxygen). The X-ray structure of deoxygenated Hb in complex with a prototype compound, KAUS-23, revealed that the effector bound in the central water cavity of the protein, providing atomic level explanations for the observed functional and biological activities. Although the structural modification did not lead to the anticipated biological effects, the findings provide important direction for designing candidate antisickling agents, as well as a framework for novel Hb allosteric effectors that conversely, decrease the protein affinity for oxygen for potential therapeutic use for hypoxic- and/or ischemic-related diseases.

Deoxyribonucleic acid damage-associated biomarkers of ionising radiation: current status and future relevance for radiology and radiotherapy

Diagnostic and therapeutic radiation technology has developed dramatically in recent years, and its use has increased significantly, bringing clinical benefit. The use of diagnostic radiology has become widespread in modern society, particularly in paediatrics where the clinical benefit needs to be balanced with the risk of leukaemia and brain cancer increasing after exposure to low doses of radiation. With improving long-term survival rates of radiotherapy patients and the ever-increasing use of diagnostic and interventional radiology procedures, concern has risen over the long-term risks and side effects from such treatments. Biomarker development in radiology and radiotherapy has progressed significantly in recent years to investigate the effects of such use and optimise treatment. Recent biomarker development has focused on improving the limitations of established techniques by the use of automation, increasing sensitivity and developing novel biomarkers capable of quicker results. The effect of low-dose exposure (0-100 mGy) used in radiology, which is increasingly linked to cancer incidences, is being investigated, as some recent research challenges the linear-no-threshold model. Radiotherapy biomarkers are focused on identifying radiosensitive patients, determining the treatment-associated risk and allowing for a tailored and more successful treatment of cancer patients. For biomarkers in any of these areas to be successfully developed, stringent criteria must be applied in techniques and analysis of data to reduce variation among reports and allow data sets to be accurately compared. Newly developed biomarkers can then be used in combination with the established techniques to better understand and quantify the individual biological response to exposures associated with radiology tests and to personalise treatment plans for patients.

[The role of whole brain radiation therapy for brain metastases]

Brain metastases are the leading cause of intracranial malignancy and a major cause of mortality and morbidity. From 20 to 40% of cancer patients develop brain metastases. The irradiation of the whole brain remains the most commonly undertaken treatment, but should be discussed in relation to other therapeutic alternatives such as stereotactic radiotherapy or the use of new chemotherapy drugs. Its use according to pathology should be discussed. It can lead to a long-term neurocognitive toxicity that should be evaluated more precisely. This literature review aims to highlight the role of whole-brain radiotherapy used alone or in combination with other treatments.

Multidisciplinary care of patients with brain tumors

Patients with brain tumors are some of the most complex patients in the medical system, necessitating treatment teams of multiple subspecialists for optimal care. This article examines the roles of these subspecialists, with the goal of summarizing standard-of-care practices, recent therapeutic advances, and ongoing clinical investigations within each subspecialty.

Whole brain radiotherapy for the treatment of newly diagnosed multiple brain metastases

BACKGROUND

Brain metastases represent a significant healthcare problem. It is estimated that 20% to 40% of patients with cancer will develop metastatic cancer to the brain during the course of their illness. The burden of brain metastases impacts on quality and length of survival. Presenting symptoms include headache (49%), focal weakness (30%), mental disturbances (32%), gait ataxia (21%), seizures (18%), speech difficulty (12%), visual disturbance (6%), sensory disturbance (6%) and limb ataxia (6%).Brain metastases may spread from any primary site. The most common primary site is the lung, followed by the breast then gastrointestinal sites. Eighty-five per cent of brain metastases are found in the cerebral hemispheres, 10% to 15% in the cerebellum and 1% to 3% in the brainstem. Brain radiotherapy is used to treat cancer participants who have brain metastases from various primary malignancies.This is an update to the original review published in Issue 3, 2006.

OBJECTIVES

To assess the effectiveness and adverse effects of whole brain radiotherapy (WBRT) in adult participants with multiple metastases to the brain.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 3, 2011), MEDLINE and EMBASE to July 2011.

SELECTION CRITERIA

Randomized controlled trials (RCTs) comparing WBRT either alone or with other treatments in adults with newly diagnosed multiple metastases to the brain from any primary cancer. Trials of prophylactic WBRT were excluded as well as trials that dealt with surgery or WBRT, or both, for the treatment of single brain metastasis.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and abstracted information. Adverse effects information was also collected from the trials.

MAIN RESULTS

Nine RCTs involving 1420 participants were added in this updated review. This updated review now includes a total of 39 trials involving 10,835 participants.Eight published reports (nine RCTs) showed no benefit of altered dose-fractionation schedules as compared to the control fractionation (3000 cGy in 10 fractions daily) of WBRT for overall survival. These studies also showed no improvement in symptom control nor neurologic improvement among the different dose-fractionation schemes as compared to 3000 cGy in 10 daily fractions of WBRT. This updated review includes two trials comparing 4000 cGy in 20 fractions given twice daily versus 2000 cGy in 4 or 5 daily fractions. Overall, there was no survival advantage (hazard ratio (HR) 1.18, 95% confidence interval (CI) 0.89 to 1.56, P = 0.25) with the use of 4000 cGy in 20 fractions given twice daily compared to 2000 cGy in 4 or 5 daily fractions.The addition of radiosensitizers in six RCTs did not confer additional benefit to WBRT in either the overall survival times (HR 1.08, 95% CI 0.98 to 1.18, P = 0.11) or brain tumour response rates (HR 0.87, 95% CI 0.60 to 1.26, P = 0.46).Two RCTs found no benefit in overall survival (HR 0.61, 95% CI 0.27 to 1.39, P = 0.24) with the use of WBRT and radiosurgery boost as compared to WBRT alone for selected participants with multiple brain metastases (up to four brain metastases). Overall, there was a statistically significant improvement in local brain control (HR 0.35, 95% CI 0.20 to 0.61, P = 0.0003) favouring the WBRT and radiosurgery boost arm. Only one trial of radiosurgery boost with WBRT reported an improved Karnofsky performance score outcome and improved ability to reduce the dexamethasone dose.In this updated review, a total of three RCTs reported on selected patients (with up to three or four brain metastases) treated with radiosurgery alone versus WBRT and radiosurgery. Based on two trials, there was no difference in overall survival (HR 0.98, 95% CI 0.71 to 1.35, P = 0.88). The addition of WBRT when added to radiosurgery significantly improved locally treated brain metasatases control (HR 2.61, 95% CI 1.68 to 4.06, P < 0.0001) and distant brain control (HR 2.15, 95% CI 1.55 to 2.99, P < 0.00001). On the other hand, one trial concluded that patients treated with WBRT and radiosurgery boost were significantly more likely to show a decline in learning and memory function as compared to those treated with radiosurgery alone.One RCT examined the use of WBRT and prednisone versus prednisone alone and produced inconclusive results.

AUTHORS' CONCLUSIONS

None of the RCTs with altered WBRT dose-fractionation schemes as compared to standard (3000 cGy in 10 daily fractions or 2000 cGy in 4 or 5 daily fractions) found a benefit in terms of overall survival, neurologic function, or symptom control.The use of radiosensitizers or chemotherapy in conjunction with WBRT remains experimental.Radiosurgery boost with WBRT may improve local disease control in selected participants as compared to WBRT alone, although survival remains unchanged for participants with multiple brain metastases.This updated review now includes a total of three RCTs examining the use of radiosurgery alone versus WBRT and radiosurgery. The addition of WBRT to radiosurgery improves local and distant brain control but there is no difference in overall survival. Patients treated with radiosurgery alone were found to have better neurocognitive outcomes in one trial as compared to patients treated with WBRT and radiosurgery.The benefit of WBRT as compared to supportive care alone has not been studied in RCTs. It may be that supportive care alone, without WBRT, is appropriate for some participants, particularly those with advanced disease and poor performance status.

Upfront association of carboplatin plus pemetrexed in patients with brain metastases of lung adenocarcinoma

Approximately 10% of patients with non-small cell lung cancer (NSCLC) have brain metastases at the time of diagnosis. When surgical resection is not possible, whole brain radiotherapy is the standard of care, with a cerebral response rate of approximately 30%. We report our experience with an upfront association of carboplatin and pemetrexed (areas under the curve, 5 and 500 mg/m(2), respectively), every 3 weeks, in 30 patients presenting with newly diagnosed brain metastases and NSCLC. Cerebral MRIs were performed every 6-9 weeks. The radiologic response rates were assessed according to Response Evaluation Criteria in Solid Tumors. Overall survival was also determined. Twenty-six patients were evaluable for response, and the objective cerebral response rate (complete and partial response) in the intent-to-treat population was 40% (12 of 30 patients). Event-free survival was 31 weeks, and median overall survival was 39 weeks. The upfront association of carboplatin plus pemetrexed allows simultaneous treatment of cerebral and systemic disease in patients with NSCLC with newly diagnosed brain metastases and appears to be particularly interesting in terms of radiologic response and overall survival. Further clinical studies are warranted.

[Management of brain metastases from non-small cell lung carcinoma]

INTRODUCTION

In France, approximately 30,000 new patients per year develop brain metastases (BM), most of them resulting from a lung cancer.

STATE OF THE ART

Surgery and radiosurgery of all the BM must be considered when possible. In other cases, whole brain radiotherapy remains the standard of care.

PERSPECTIVES

The role of chemotherapy, poorly investigated so far, should be revisited.

CONCLUSION

This review focused on BM secondary to a non-small cell lung carcinoma.

Investigational therapies for brain metastases

Contrary to the incidence of primary cancers, the incidence of brain metastasis has been increasing. This increase is likely because of the effects of an aging population, improved neuroimaging surveillance, and better control of systemic cancer, allowing time for brain metastasis to occur. Unlike systemic cancers, for which chemotherapy is the mainstay of treatment, the therapeutic strategies available to treat brain metastasis have traditionally been limited to surgical resection, whole brain radiation therapy, or stereotactic radiosurgery, either individually or in combination. It is important to put the treatment in the context of the prognosis for patients with brain metastases.

The management of brain metastases in patients with non-small cell lung cancer-is it time to go back to the drawing board?

Unless confirmation of a solitary brain metastasis is made in the context of absent extracranial disease and good performance status, patients with metastatic brain disease from non-small cell lung cancer fare badly. There are no level I recommendations for the management of those with multiple brain metastases. The role of whole brain radiotherapy is not certain in those of poorer performance status. This overview assesses what we know and what we are uncertain of in the context of a changing paradigm for some subsets of patients who may obtain superior palliation with treatments targeted at the histological or molecular level. Once the standard treatment is established (steroids plus or minus whole brain radiotherapy), those who are of better performance status may be considered for comparison of this standard with or without systemic management.

The role of emerging and investigational therapies for metastatic brain tumors: a systematic review and evidence-based clinical practice guideline of selected topics

QUESTION

What evidence is available regarding the emerging and investigational therapies for the treatment of metastatic brain tumors?

TARGET POPULATION

These recommendations apply to adults with brain metastases.

RECOMMENDATIONS

New radiation sensitizers Level 2 A subgroup analysis of a large prospective randomized controlled trial (RCT) suggested a prolongation of time to neurological progression with the early use of motexafin-gadolinium (MGd). Nonetheless this was not borne out in the overall study population and therefore an unequivocal recommendation to use the currently available radiation sensitizers, motexafin-gadolinium and efaproxiral (RSR 13) cannot be provided. Interstitial modalities There is no evidence to support the routine use of new or existing interstitial radiation, interstitial chemotherapy and or other interstitial modalities outside of approved clinical trials. New chemotherapeutic agents Level 2 Treatment of melanoma brain metastases with whole brain radiation therapy and temozolomide is reasonable based on one class II study. Level 3 Depending on individual circumstances there may be patients who benefit from the use of temozolomide or fotemustine in the therapy of their brain metastases. Molecular targeted agents Level 3 The use of epidermal growth factor receptor inhibitors may be of use in the management of brain metastases from non-small cell lung carcinoma.

Prospective evaluation of quality of life and neurocognitive effects in patients with multiple brain metastases receiving whole-brain radiotherapy with or without thalidomide on Radiation Therapy Oncology Group (RTOG) trial 0118

PURPOSE

Radiation Therapy Oncology Group (RTOG) 0118 randomized patients with multiple brain metastases to whole-brain radiotherapy (WBRT) +/- thalidomide. This secondary analysis of 156 patients examined neurocognitive and quality of life (QOL) outcomes.

METHODS AND MATERIALS

Quality of life was determined with the Spitzer Quality of Life Index (SQLI). The Folstein Mini-Mental Status Exam (MMSE) assessed neurocognitive function. SQLI and MMSE were administered at baseline and at 2-month intervals. MMSE was scored with a threshold value associated with neurocognitive functioning (absolute cutoff level of 23) and with the use of corrections for age and educational level.

RESULTS

Baseline SQLI predicted survival. Patients with SQLI of 7-10 vs. <7 had median survival time (MST) of 4.8 vs. 3.1 months, p = 0.05. Both arms showed steady neurocognitive declines, but SQLI scores remained stable. Higher levels of neurocognitive decline were observed with age and education-level corrections. Of patients considered baseline age/educational level neurocognitive failures, 32% died of intracranial progression.

CONCLUSIONS

Quality of life and neuropsychological testing can be prospectively administered on a Phase III cooperative group trial. The MMSE should be evaluated with adjustments for age and educational level. Baseline SQLI is predictive of survival. Despite neurocognitive declines, QOL remained stable during treatment and follow-up. Poor neurocognitive function may predict clinical deterioration. Lack of an untreated control arm makes it difficult to determine the contribution of the respective interventions (i.e., WBRT, thalidomide) to neurocognitive decline. The RTOG has developed a trial to study the role of preventative strategies aimed at forestalling neurocognitive decline in this population.

Chemical radiosensitizers for use in radiotherapy

Radiosensitizers are intended to enhance tumour cell killing while having much less effect on normal tissues. Some drugs target different physiological characteristics of the tumour, particularly hypoxia associated with radioresistance. Oxygen is the definitive hypoxic cell radiosensitizer, the large differential radiosensitivity of oxic vs hypoxic cells being an attractive factor. The combination of nicotinamide to reduce acute hypoxia with normobaric carbogen breathing is showing clinical promise. 'Electron-affinic' chemicals that react with DNA free radicals have the potential for universal activity to combat hypoxia-associated radioresistance; a nitroimidazole, nimorazole, is clinically effective at tolerable doses. Hypoxia-specific cytotoxins, such as tirapazamine, are valuable adjuncts to radiotherapy. Nitric oxide is a potent hypoxic cell radiosensitizer; variations in endogenous levels might have prognostic significance, and routes to deliver nitric oxide specifically to tumours are being developed. In principle, many drugs can be delivered selectively to hypoxic tumours using either reductase enzymes or radiation-produced free radicals to activate drug release from electron-affinic prodrugs. A redox-active agent based on a gadolinium chelate is being evaluated clinically. Pyrimidines substituted with bromine or iodine are incorporated into DNA and enhance free radical damage; fluoropyrimidines act by different mechanisms. A wide variety of drugs that influence the nature or repair of DNA damage are being evaluated in conjunction with radiation; it is often difficult to define the mechanisms underlying chemoradiation regimens. Drugs being evaluated include topoisomerase inhibitors (e.g. camptothecin, topotecan), and the hypoxia-activated anthraquinone AQ4N; alkylating agents include temozolomide. Drugs involved in DNA repair pathways being investigated include the potent poly(ADP ribose)polymerase inhibitor, AG14,361. Proteins involved in cell signalling, such as the Ras family, are attractive targets linked to radioresistance, as are epidermal growth factor receptors and linked kinases (drugs including vandetanib [ZD6,474], cetuximab and gefitinib), and cyclooxygenase-2 (celecoxib). The suppression of radioprotective thiols seems to offer more potential with alkylating agents than with radiotherapy, although it remains a strategy worthy of exploration.

Targeted Therapy for Brain Metastases: Improving the Therapeutic Ratio

Brain metastasis is the most common intracranial malignancy in adults. Improvements in modern imaging techniques are detecting previously occult brain metastases, and more effective therapies are extending the survival of patients with invasive cancer who have historically died from extracranial disease before developing brain metastasis. This combination of factors along with increased life expectancy has led to the increased diagnosis of brain metastases. Conventional treatment has been whole brain radiotherapy, which can improve symptoms, but potentially results in neurocognitive deficits. Several strategies to improve the therapeutic ratio are currently under investigation to either enhance the radiation effect, thereby preventing tumor recurrence or progression as well as reducing collateral treatment-related brain injury. In this review article, we discuss new directions in the management of brain metastases, including the role of chemical modifiers, novel systemic agents, and the management and prevention of neurocognitive deficits.

La radiothérapie des métastases cérébrales

Brain metastases are an important cause of mortality and morbidity. The prognosis is poor with a median survival of less than one year in the majority of cases. From this review, whole-brain irradiation clearly appears as the standard treatment. However, its role could be discussed according to newer treatment modalities, radiosurgery or new chemotherapies. Post irradiation neurocognitive status remains insufficiently known.

Whole brain radiotherapy for the treatment of multiple brain metastases

BACKGROUND

Brain radiotherapy is used to treat cancer patients who have brain metastases resulting from various primary malignancies.

OBJECTIVES

To assess the effectiveness and adverse effects of whole brain radiotherapy (WBRT) in adult patients with multiple metastases to the brain.

SEARCH STRATEGY

CENTRAL (The Cochrane Library), MEDLINE, EMBASE, CANCERLIT, and CINAHL were searched.

SELECTION CRITERIA

Randomized controlled trials (RCTs) in which adult patients with multiple metastases to the brain from any primary cancer and treated with WBRT were included. Trials of prophylactic WBRT were excluded as well as trials that dealt with surgery or WBRT, or both, for the treatment of a single brain metastasis.

DATA COLLECTION AND ANALYSIS

Two review authors independently abstracted information for each predetermined outcome: overall survival at six months, intracranial progression-free duration, local brain response, local brain control, quality of life, symptom control, neurological function, and the proportion of patients able to reduce the daily dexamethasone dose. Adverse effects were also collected.

MAIN RESULTS

Eight published reports (nine trials) showed no benefit of altered dose-fractionation schedules as compared to control fractionation (3000 cGy in 10 fractions) of WBRT on the probability of survival at six months. These studies also showed no difference in symptom control nor neurologic improvement among the different dose-fractionation schemes. The addition of radiosensitizers, in five RCTs, did not confer additional benefit to WBRT in either overall median survival times or brain tumor response rates. The addition of the radiosensitizer motexafin gadolinium did not improve quality of life nor time to neurologic progression overall. For the radiosensitizer misonidazole, there was no improvement in Karnofsky performance score outcomes. Three RCTs found no benefit in overall survival with the use of WBRT and a radiosurgery boost as compared to WBRT alone for selected patients with multiple brain metastases (up to four brain metastases). Overall, however, there was a statistically significant improvement in local brain control favoring the whole brain radiotherapy and radiosurgery boost arm. Only one trial of radiosurgery boost with WBRT reported an improved Karnofsky performance score outcome and improved ability to reduce dexamethasone dose. One RCT examined the use of WBRT and prednisone versus prednisone alone and produced inconclusive results.

AUTHORS' CONCLUSIONS

None of the RCTs with altered dose-fractionation schemes as compared to standard delivery (3000 cGy in ten fractions) found a benefit in terms of overall survival, neurologic function, or symptom control. The use of radiosensitizers or chemotherapy in conjunction with WBRT remains experimental. A radiosurgery boost with WBRT may improve local disease control in selected patients, although survival remains unchanged. The benefit of WBRT as compared to supportive care alone has not been studied in RCTs. It may be that supportive care alone, without WBRT, may be appropriate for some patients, particularly those with advanced disease and poor performance status.