The role of prophylactic brain irradiation in limited stage small cell lung cancer: clinical, neuropsychologic, and CT sequelae

The Cognitive Effects of Radiotherapy for Brain Metastases

Brain metastases are the most common intracranial neoplasm and are seen in upwards of 10-30% of patients with cancer. For decades, whole brain radiation therapy (WBRT) was the mainstay of treatment in these patients. While WBRT is associated with excellent rates of intracranial tumor control, studies have demonstrated a lack of survival benefit, and WBRT is associated with higher rates of cognitive deterioration and detrimental effects on quality of life. In recent years, strategies to mitigate this risk, such as the incorporation of memantine and hippocampal avoidance have been employed with improved results. Furthermore, stereotactic radiosurgery (SRS) has emerged as an appealing treatment option over the last decade in the management of brain metastases and is associated with superior cognitive preservation and quality of life when compared to WBRT. This review article evaluates the pathogenesis and impact of cranial irradiation on cognition in patients with brain metastases, as well as current and future risk mitigation techniques.

Intracranial failure after hippocampal-avoidance prophylactic cranial irradiation in limited-stage small-cell lung cancer patients

We evaluated intracranial failure after hippocampus-avoidance-prophylactic cranial irradiation (HA-PCI) for limited-stage small-cell lung cancer (SCLC). Data of 106 patients who received PCI with 25 Gy were retrospectively reviewed. The patients were divided into two groups based on whether they underwent HA-PCI: the HA-PCI group (n = 48) and the conventional PCI (C-PCI) group (n = 58). Twenty-one patients experienced intracranial failure: 11 and 10 patients in the C-PCI and HA-PCI groups, respectively. Using the log-rank test, the intracranial failure rate was not significantly different between the groups (p = 0.215). No clinical factor was significantly associated with intracranial failure in multivariate Cox regression analysis, but HA-PCI tended to be associated with increased incidence of intracranial failure (HR 2.87, 95% CI 0.86–9.58, p = 0.087). Among patients who received HA-PCI, two developed peri-hippocampal recurrence. A higher thoracic radiotherapy dose (≥ 60 Gy) was significantly associated with DFS (HR 0.52, p = 0.048) and OS (HR 0.35, p = 0.003). However, HA-PCI was associated with neither DFS nor OS. Although HA-PCI may be associated with an increased risk of intracranial failure, HA-PCI did not impair disease control or survival. Future prospective randomized trials are needed to reach a definite conclusion.

Human Brain Functional Network Organization Is Disrupted After Whole-Brain Radiation Therapy

Radiation therapy (RT) plays a vital role in the treatment of brain cancers, but it frequently results in cognitive decline in the patients who receive it. Because the underlying mechanisms for this decline remain poorly understood, the brain is typically treated as a single, uniform volume when evaluating the toxic effects of RT plans. This ignorance represents a significant deficit in the field of radiation oncology, as the technology exists to manipulate dose distributions to spare regions of the brain, but there exists no body of knowledge regarding what is critical to spare. This deficit exists due to the numerous confounding factors that are frequently associated with radiotherapy, including the tumors themselves, other treatments such as surgery and chemotherapy, and dose gradients across the brain. Here, we present a case in which a 57-year-old male patient received a uniform dose of radiation across the whole brain, did not receive concurrent chemotherapy, had minimal surgical intervention and a small tumor burden, and received resting-state functional magnetic resonance imaging (fMRI) scans both before and after RT. To our knowledge, this is the first study on the effects of whole-brain radiotherapy on functional network organization, and this patient's treatment regimen represents a rare and non-replicable opportunity to isolate the effects of radiation on functional connectivity. We observed substantial changes in the subject's behavior and functional network organization over a 12-month timeframe. Interestingly, the homogenous radiation dose to the brain had a heterogeneous effect on cortical networks, and the functional networks most affected correspond with observed cognitive behavioral deficits. This novel study suggests that the cognitive decline that occurs after whole-brain radiation therapy may be network specific and related to the disruption of large-scale distributed functional systems, and it indicates that fMRI is a promising avenue of study for optimizing cognitive outcomes after RT.

Treatment of Radiation-Induced Cognitive Decline in Adult Brain Tumor Patients

OPINION STATEMENT

Patients with either primary or metastatic brain tumors quite often have cognitive impairment. Maintaining cognitive function is important to brain tumor patients and a decline in cognitive function is generally accompanied by a decline in functional independence and performance status. Cognitive decline can be a result of tumor progression, depression/anxiety, fatigue/sleep dysfunction, or the treatments they have received. It is our opinion that providers treating brain tumor patients should obtain pre-treatment and serial cognitive testing in their patients and offer mitigating and therapeutic interventions when appropriate. They should also support cognition-focused clinical trials.

Fibronectin Produced by Cerebral Endothelial and Vascular Smooth Muscle Cells Contributes to Perivascular Extracellular Matrix in Late-Delayed Radiation-Induced Brain Injury

Late-delayed radiation-induced brain injury (RIBI) is a major adverse effect of fractionated whole-brain irradiation (fWBI). Characterized by progressive cognitive dysfunction, and associated cerebrovascular and white matter injury, RIBI deleteriously affects quality of life for cancer patients. Despite extensive morphological characterization of the injury, the pathogenesis is unclear, thus limiting the development of effective therapeutics. We previously reported that RIBI is associated with increased gene expression of the extracellular matrix (ECM) protein fibronectin (FN1). We hypothesized that fibronectin contributes to perivascular ECM, which may impair diffusion to the dependent parenchyma, thus contributing to the observed cognitive decline. The goal of this study was to determine the localization of fibronectin in RIBI and further characterize the composition of perivascular ECM, as well as identify the cell of origin for FN1 by in situ hybridization. Briefly, fibronectin localized to the vascular basement membrane of morphologically normal blood vessels from control comparators and animals receiving fWBI, and to the perivascular space of edematous and fibrotic vascular phenotypes of animals receiving fWBI. Additional mild diffuse parenchymal staining in areas of vascular injury suggested blood-brain-barrier disruption and plasma fibronectin extravasation. Perivascular ECM lacked amyloid and contained lesser amounts of collagens I and IV, which localized to the basement membrane. These changes occurred in the absence of alterations in microvascular area fraction or microvessel density. Fibronectin transcripts were rarely expressed in control comparators, and were most strongly induced within cerebrovascular endothelial and vascular smooth muscle cells after fWBI. Our results demonstrate that fibronectin is produced by cerebrovascular endothelial and smooth muscle cells in late-delayed RIBI and contributes to perivascular ECM, which we postulate may contribute to diffusion barrier formation. We propose that pathways that antagonize fibronectin deposition and matrix assembly or enhance degradation may serve as potential therapeutic targets in RIBI.

[Neurocognition: Impact of radiotherapy]

The cognitive evaluation is essential to arrest the impact of brain tumours on brain functions. Radiation therapy on the brain has side effects, which can impact on the cognitive functioning. The cognitive disorders constitute a predictive factor of the quality of life of the patients impacting on their autonomy, as well as on their social and professional life. This problem thus takes a more and more important place in the reflection on the cancer care. A better detection of these cognitive disorders requires a better cognitive evaluation from the diagnosis. What would allow the implementation of preventive actions upstream. This prospect of improvement of the coverage of the cognitive consequences of the irradiation should allow a better social reinstatement after the treatment, as well as a facilitation for the preservation of autonomy and functional independence. However, a complete cognitive evaluation is expensive in time and asks for a qualified personnel, which often slows down the exploration and the follow-up of the disorders.

Resection and Observation for Brain Metastasis without Prompt Postoperative Radiation Therapy

Objective

Total resection without consecutive postoperative whole brain radiation therapy is indicated for patients with a single or two sites of brain metastasis, with close follow-up by serial magnetic resonance imaging (MRI). In this study, we explored the effectiveness, usefulness, and safety of this follow-up regimen.

Methods

From January 2006 to December 2015, a total of 109 patients (76 males, 33 females) underwent tumor resection as the first treatment for brain metastases (97 patients with single metastases, 12 with two metastases). The mean age was 59.8 years (range 27-80). The location of the 121 tumors in the 109 patients was supratentorial (n=98) and in the cerebellum (n=23). The origin of the primary cancers was lung (n=45), breast (n=17), gastrointestinal tract (n=18), hepatobiliary system (n=8), kidney (n=7), others (n=11), and unknown origin (n=3). The 121 tumors were totally resected. Follow-up involved regular clinical and MRI assessments. Recurrence-free survival (RFS) and overall survival (OS) after tumor resection were analyzed by Kaplan-Meier methods based on clinical prognostic factors.

Results

During the follow-up, MRI scans were done for 85 patients (78%) with 97 tumors. Fifty-six of the 97 tumors showed no recurrence without adjuvant local treatment, representing a numerical tumor recurrence-free rate of 57.7%. Mean and median RFS was 13.6 and 5.3 months, respectively. Kaplan-Meier analysis revealed the cerebellar location of the tumor as the only statistically significant prognostic factor related to RFS (p=0.020). Mean and median OS was 15.2 and 8.1 months, respectively. There were no significant prognostic factors related to OS. The survival rate at one year was 8.2% (9 of 109).

Conclusion

With close and regular clinical and image follow-up, initial postoperative observation without prompt postoperative radiation therapy can be applied in patients of brain metastasi(e)s when both the tumor(s) are completely resected.

Cerebrovascular Remodeling and Neuroinflammation is a Late Effect of Radiation-Induced Brain Injury in Non-Human Primates

Fractionated whole-brain irradiation (fWBI) is a mainstay of treatment for patients with intracranial neoplasia; however late-delayed radiation-induced normal tissue injury remains a major adverse consequence of treatment, with deleterious effects on quality of life for affected patients. We hypothesize that cerebrovascular injury and remodeling after fWBI results in ischemic injury to dependent white matter, which contributes to the observed cognitive dysfunction. To evaluate molecular effectors of radiation-induced brain injury (RIBI), real-time quantitative polymerase chain reaction (RT-qPCR) was performed on the dorsolateral prefrontal cortex (DLPFC, Brodmann area 46), hippocampus and temporal white matter of 4 male Rhesus macaques (age 6-11 years), which had received 40 Gray (Gy) fWBI (8 fractions of 5 Gy each, twice per week), and 3 control comparators. All fWBI animals developed neurologic impairment; humane euthanasia was elected at a median of 6 months. Radiation-induced brain injury was confirmed histopathologically in all animals, characterized by white matter degeneration and necrosis, and multifocal cerebrovascular injury consisting of perivascular edema, abnormal angiogenesis and perivascular extracellular matrix deposition. Herein we demonstrate that RIBI is associated with white matter-specific up-regulation of hypoxia-associated lactate dehydrogenase A (LDHA) and that increased gene expression of fibronectin 1 (FN1), SERPINE1 and matrix metalloprotease 2 (MMP2) may contribute to cerebrovascular remodeling in late-delayed RIBI. Additionally, vascular stability and maturation associated tumor necrosis super family member 15 (TNFSF15) and vascular endothelial growth factor beta (VEGFB) mRNAs were increased within temporal white matter. We also demonstrate that radiation-induced brain injury is associated with decreases in white matter-specific expression of neurotransmitter receptors SYP, GRIN2A and GRIA4. We additionally provide evidence that macrophage/microglial mediated neuroinflammation may contribute to RIBI through increased gene expression of the macrophage chemoattractant CCL2 and macrophage/microglia associated CD68. Global patterns in cerebral gene expression varied significantly between regions examined (P < 0.0001, Friedman's test), with effects most prominent within cerebral white matter.

Neurocognitive Deficits After Radiation Therapy for Brain Malignancies

Radiotherapy (RT) has proven to be an effective therapeutic tool in treatment of a wide variety of brain tumors; however, it has a negative impact on quality of life and neurocognitive function. Cognitive dysfunction associated with both the disease and adverse effects of RT is one of the most concerning complication among long-term survivors. The effects of RT to brain can be divided into acute, early delayed, and late delayed. It is, however, the late delayed effects of RT that lead to severe neurological consequences such as minor-to-severe cognitive deficits due to irreversible focal or diffuse necrosis of brain parenchyma. In this review, we discuss current and emerging data regarding the relationship between RT and neurocognitive outcomes, and therapeutic strategies to prevent/treat postradiation neurocognitive deficits.

Management of brain metastasis with magnetic resonance imaging and stereotactic irradiation attenuated benefits of prophylactic cranial irradiation in patients with limited-stage small cell lung cancer

Background

Magnetic resonance imaging (MRI) enables a more sensitive detection of brain metastasis and stereotactic irradiation (SRI) efficiently controls brain metastasis. In limited-stage small cell lung cancer (LS-SCLC), prophylactic cranial irradiation (PCI) in patients with good responses to initial treatment is recommended based on the survival benefit shown in previous clinical trials. However, none of these trials evaluated PCI effects using the management of brain metastasis with MRI or SRI. This study aimed to determine the effects of MRI and SRI on the benefits of PCI in patients with LS-SCLC.

Methods

The clinical records of pathologically proven SCLC from January 2006 to June 2013 in facilities equipped with or had access to SRI in Japan were retrospectively reviewed. Patients with LS-SCLC and complete or good partial responses after initial treatment were included in the study and analyzed by the Kaplan-Meier method.

Results

Of 418 patients with SCLC, 124 met criteria and were divided into patients receiving PCI (PCI group; n = 29) and those without PCI (non-PCI groups; n = 95). At baseline, ratios of patients with stage III were significantly advantageous for the non-PCI group, although younger age and high ratios of complete response and MRI confirmed absence of brain metastasis were advantageous for the PCI group. Neither median survival times (25 vs. 34 months; p = 0.256) nor cumulative incidence of brain metastasis during 2 years (45.5 vs. 30.8 %; p = 0.313) significantly differed between the two groups. Moreover, these factors did not significantly differ among patients with stage III disease (25 vs. 26 months; p = 0.680, 42.3 vs. 52.3 %; p = 0.458, respectively).

Conclusion

PCI may be less beneficial in patients with LS-SCLC if the management with MRI and SRI is available.

Controversies in small cell carcinoma of the head and neck: Prophylactic cranial irradiation (PCI) after primary complete initial remission

Small cell carcinoma of head and neck region (SmCCHN) represents a rare entity and its management remains a significant clinical challenge. Complete initial response to primary therapy poses a difficult and controversial scenario for radiation oncologists. Prophylactic cranial irradiation (PCI) has long been established in the management of small cell lung cancer; however, its role in SmCCHN is still called into question. The rationale behind PCI lies in the eradication of possible micro-metastatic brain disease, which is often documented in this type of cancer. No randomized trials on this topic are available. This review, based on 20 retrospective studies, addresses the controversies in the use of PCI in SmCCHN management.

Donepezil for Irradiated Brain Tumor Survivors: A Phase III Randomized Placebo-Controlled Clinical Trial

PURPOSE

Neurotoxic effects of brain irradiation include cognitive impairment in 50% to 90% of patients. Prior studies have suggested that donepezil, a neurotransmitter modulator, may improve cognitive function.

PATIENTS AND METHODS

A total of 198 adult brain tumor survivors ≥ 6 months after partial- or whole-brain irradiation were randomly assigned to receive a single daily dose (5 mg for 6 weeks, 10 mg for 18 weeks) of donepezil or placebo. A cognitive test battery assessing memory, attention, language, visuomotor, verbal fluency, and executive functions was administered before random assignment and at 12 and 24 weeks. A cognitive composite score (primary outcome) and individual cognitive domains were evaluated.

RESULTS

Of this mostly middle-age, married, non-Hispanic white sample, 66% had primary brain tumors, 27% had brain metastases, and 8% underwent prophylactic cranial irradiation. After 24 weeks of treatment, the composite scores did not differ significantly between groups (P = .48); however, significant differences favoring donepezil were observed for memory (recognition, P = .027; discrimination, P = .007) and motor speed and dexterity (P = .016). Significant interactions between pretreatment cognitive function and treatment were found for cognitive composite (P = .01), immediate recall (P = .05), delayed recall (P = .004), attention (P = .01), visuomotor skills (P = .02), and motor speed and dexterity (P < .001), with the benefits of donepezil greater for those who were more cognitively impaired before study treatment.

CONCLUSION

Treatment with donepezil did not significantly improve the overall composite score, but it did result in modest improvements in several cognitive functions, especially among patients with greater pretreatment impairments.

The PPARδ agonist GW0742 inhibits neuroinflammation, but does not restore neurogenesis or prevent early delayed hippocampal-dependent cognitive impairment after whole-brain irradiation

Brain tumor patients often develop cognitive impairment months to years after partial or fractionated whole-brain irradiation (WBI). Studies suggest that neuroinflammation and decreased hippocampal neurogenesis contribute to the pathogenesis of radiation-induced brain injury. In this study, we determined if the peroxisomal proliferator-activated receptor (PPAR) δ agonist GW0742 can prevent radiation-induced brain injury in C57Bl/6 wild-type (WT) and PPARδ knockout (KO) mice. Dietary GW0742 prevented the acute increase in IL-1β mRNA and ERK phosphorylation measured at 3h after a single 10-Gy dose of WBI; it also prevented the increase in the number of activated hippocampal microglia 1 week after WBI. In contrast, dietary GW074 failed to prevent the radiation-induced decrease in hippocampal neurogenesis determined 2 months after WBI in WT mice or to mitigate their hippocampal-dependent spatial memory impairment measured 3 months after WBI using the Barnes maze task. PPARδ KO mice exhibited defects including decreased numbers of astrocytes in the dentate gyrus/hilus of the hippocampus and a failure to exhibit a radiation-induced increase in activated hippocampal microglia. Interestingly, the number of astrocytes in the dentate gyrus/hilus was reduced in WT mice, but not in PPARδ KO mice 2 months after WBI. These results demonstrate that, although dietary GW0742 prevents the increase in inflammatory markers and hippocampal microglial activation in WT mice after WBI, it does not restore hippocampal neurogenesis or prevent early delayed hippocampal-dependent cognitive impairment after WBI. Thus, the exact relationship between radiation-induced neuroinflammation, neurogenesis, and cognitive impairment remains elusive.

Radiation-induced cognitive impairment--from bench to bedside

Approximately 100,000 patients per year in the United States with primary and metastatic brain tumor survive long enough (>6 months) to develop radiation-induced brain injury. Before 1970, the human brain was thought to be radioresistant; the acute central nervous system (CNS) syndrome occurs after single doses of ≥ 30 Gy, and white matter necrosis can occur at fractionated doses of ≥ 60 Gy. Although white matter necrosis is uncommon with modern radiation therapy techniques, functional deficits, including progressive impairments in memory, attention, and executive function have become increasingly important, having profound effects on quality of life. Preclinical studies have provided valuable insights into the pathogenic mechanisms involved in radiation-induced cognitive impairment. Although reductions in hippocampal neurogenesis and hippocampal-dependent cognitive function have been observed in rodent models, it is important to recognize that other brain regions are affected; non-hippocampal-dependent reductions in cognitive function occur. Neuroinflammation is viewed as playing a major role in radiation-induced cognitive impairment. During the past 5 years, several preclinical studies have demonstrated that interventional therapies aimed at modulating neuroinflammation can prevent/ameliorate radiation-induced cognitive impairment independent of changes in neurogenesis. Translating these exciting preclinical findings to the clinic offers the promise of improving the quality of life in patients with brain tumors who receive radiation therapy.

[Present role of prophylactic cranial irradiation]

Prophylactic cranial irradiation (PCI) plays a role in the management of lung cancer patients, especially small cell lung cancer (SCLC) patients. As multimodality treatments are now able to ensure better local control and a lower rate of extracranial metastases, brain relapse has become a major concern in lung cancer. As survival is poor after development of brain metastases (BM) in spite of specific treatment, PCI has been introduced in the 1970's. PCI has been evaluated in randomized trials in both SCLC and non-small cell lung cancer (NSCLC) to reduce the incidence of BM and possibly increase survival. PCI reduces significantly the BM rate in both limited disease (LD) and extensive disease (ED) SCLC and in non-metastatic NSCLC. Considering SCLC, PCI significantly improves overall survival in LD (from 15 to 20% at 3 years) and ED (from 13 to 27% at 1 year) in patients who respond to first-line treatment; it should thus be part of the standard treatment in all responders in ED and in good responders in LD. No dose-effect relationship for PCI was demonstrated in LD SCLC patients so that the recommended dose is 25 Gy in 10 fractions. In NSCLC, even if the risk of brain dissemination is lower than in SCLC, it has become a challenging issue. Studies have identified subgroups at higher risk of brain failure. There are more local treatment possibilities for BM related to NSCLC, but most BM will eventually recur so that PCI should be reconsidered. Few randomized trials have been performed. Most of them could demonstrate a decreased incidence of BM in patients with PCI, but they were not able to show an effect on survival as they were underpowered. New trials are needed. Among long-term survivors, neuro-cognitive toxicity may be observed. Several approaches are being evaluated to reduce this possible toxicity. PCI has no place for other solid tumours at risk such as HER2+ breast cancer patients.

Phase II study of Ginkgo biloba in irradiated brain tumor patients: effect on cognitive function, quality of life, and mood

Ginkgo biloba has been reported to improve cognitive function in older adults and patients with Alzheimer's disease and multi-infarct dementia. We conducted an open-label phase II study of this botanical product in symptomatic irradiated brain tumor survivors. Eligibility criteria included: life expectancy ≥30 weeks, partial or whole brain radiation ≥6 months before enrollment, no imaging evidence of tumor progression in previous 3 months, or stable or decreasing steroid dose, and no brain tumor treatment planned while on study. The Ginkgo biloba dose was 120 mg/day (40 mg t.i.d.) for 24 weeks followed by a 6-week washout period. Assessments performed at baseline, 12, 24 (end of treatment), and 30 weeks (end of washout) included KPS, Functional Assessment of Cancer Therapy-Brain (FACT-Br), Profile of Mood States, Mini-Mental Status Exam, Trail Making Test Parts A (TMT-A) and B (TMT-B), Digit Span Test, Modified Rey Osterrieth Complex Figure (ROCF), California Verbal Learning Test Part II, and the F-A-S Test.

RESULTS

Of the 34 patients enrolled on study, 23 (68 %) completed 12 weeks of treatment and 19 (56 %) completed 24 weeks of treatment. There were significant improvements at 24 weeks in: executive function (TMT-B) (p = 0.007), attention/concentration (TMT-A) (p = 0.002), and non-verbal memory (ROCF-immediate/delayed recall) (p = 0.001/0.002), mood (p = 0.002), FACT-Br subscale (p = 0.001), and the FACT physical subscale (p = 0.003).

CONCLUSIONS

Some improvement in quality of life and cognitive function were noted with Ginkgo biloba. However, treatment with Ginkgo biloba was associated with a high dropout rate.

Radiation-induced brain injury: A review

Approximately 100,000 primary and metastatic brain tumor patients/year in the US survive long enough (>6 months) to experience radiation-induced brain injury. Prior to 1970, the human brain was thought to be highly radioresistant; the acute CNS syndrome occurs after single doses >30 Gy; white matter necrosis occurs at fractionated doses >60 Gy. Although white matter necrosis is uncommon with modern techniques, functional deficits, including progressive impairments in memory, attention, and executive function have become important, because they have profound effects on quality of life. Preclinical studies have provided valuable insights into the pathogenesis of radiation-induced cognitive impairment. Given its central role in memory and neurogenesis, the majority of these studies have focused on the hippocampus. Irradiating pediatric and young adult rodent brains leads to several hippocampal changes including neuroinflammation and a marked reduction in neurogenesis. These data have been interpreted to suggest that shielding the hippocampus will prevent clinical radiation-induced cognitive impairment. However, this interpretation may be overly simplistic. Studies using older rodents, that more closely match the adult human brain tumor population, indicate that, unlike pediatric and young adult rats, older rats fail to show a radiation-induced decrease in neurogenesis or a loss of mature neurons. Nevertheless, older rats still exhibit cognitive impairment. This occurs in the absence of demyelination and/or white matter necrosis similar to what is observed clinically, suggesting that more subtle molecular, cellular and/or microanatomic modifications are involved in this radiation-induced brain injury. Given that radiation-induced cognitive impairment likely reflects damage to both hippocampal- and non-hippocampal-dependent domains, there is a critical need to investigate the microanatomic and functional effects of radiation in various brain regions as well as their integration at clinically relevant doses and schedules. Recently developed techniques in neuroscience and neuroimaging provide not only an opportunity to accomplish this, but they also offer the opportunity to identify new biomarkers and new targets for interventions to prevent or ameliorate these late effects.

Neurocognitive function impairment after whole brain radiotherapy for brain metastases: actual assessment

Whole brain radiation therapy (WBRT) is an effective treatment in brain metastases and, when combined with local treatments such as surgery and stereotactic radiosurgery, gives the best brain control. Nonetheless, WBRT is often omitted after local treatment due to its potential late neurocognitive effects. Publications on radiation-induced neurotoxicity have used different assessment methods, time to assessment, and definition of impairment, thus making it difficult to accurately assess the rate and magnitude of the neurocognitive decline that can be expected. In this context, and to help therapeutic decision making, we have conducted this literature review, with the aim of providing an average incidence, magnitude and time to occurrence of radio-induced neurocognitive decline. We reviewed all English language published articles on neurocognitive effects of WBRT for newly diagnosed brain metastases or with a preventive goal in adult patients, with any methodology (MMSE, battery of neurcognitive tests) with which baseline status was provided. We concluded that neurocognitive decline is predominant at 4 months, strongly dependant on brain metastases control, partially solved at later time, graded 1 on a SOMA-LENT scale (only 8% of grade 2 and more), insufficiently assessed in long-term survivors, thus justifying all efforts to reduce it through irradiation modulation.

Gamma knife stereotactic radiosurgery as salvage therapy after failure of whole-brain radiotherapy in patients with small-cell lung cancer

PURPOSE

Radiosurgery has been successfully used in selected cases to avoid repeat whole-brain irradiation (WBI) in patients with multiple brain metastases of most solid tumor histological findings. Few data are available for the use of radiosurgery for small-cell lung cancer (SCLC).

METHODS AND MATERIALS

Between November 1999 and June 2009, 51 patients with SCLC and previous WBI and new brain metastases were treated with GammaKnife stereotactic radiosurgery (GKSRS). A median dose of 18 Gy (range, 10-24 Gy) was prescribed to the margin of each metastasis. Patients were followed with serial imaging. Patient electronic records were reviewed to determine disease-related factors and clinical outcomes after GKSRS. Local and distant brain failure rates, overall survival, and likelihood of neurologic death were determined based on imaging results. The Kaplan-Meier method was used to determine survival and local and distant brain control. Cox proportional hazard regression was performed to determine strength of association between disease-related factors and survival.

RESULTS

Median survival time for the entire cohort was 5.9 months. Local control rates at 1 and 2 years were 57% and 34%, respectively. Distant brain failure rates at 1 and 2 years were 58% and 75%, respectively. Fifty-three percent of patients ultimately died of neurologic death. On multivariate analysis, patients with stable (hazard ratio [HR] = 2.89) or progressive (HR = 6.98) extracranial disease (ECD) had worse overall survival than patients without evidence of ECD (p = 0.00002). Concurrent chemotherapy improved local control (HR = 89; p = 0.006).

CONCLUSIONS

GKSRS represents a feasible salvage option in patients with SCLC and brain metastases for whom previous WBI has failed. The status of patients' ECD is a dominant factor predictive of overall survival. Local control may be inferior to that seen with other cancer histological results, although the use of concurrent chemotherapy may help to improve this.

Incidence, timing, and treatment of new brain metastases after Gamma Knife surgery for limited brain disease: the case for reducing the use of whole-brain radiation therapy

Object

In this paper, the authors' goal was to analyze the incidence, timing, and treatment of new metastases following initial treatment with 20-Gy Gamma Knife surgery (GKS) alone in patients with limited brain metastases without whole-brain radiation therapy (WBRT).

Methods

A retrospective analysis of 114 consecutive adults (75 women and 34 men; median age 61 years) with KPS scores of 60 or higher who received GKS for 1–3 brain metastases ≤ 2 cm was performed (median lesion volume 0.35 cm3). Five patients lacking follow-up data were excluded from analysis. After treatment, patients underwent MR imaging at 6 weeks and every 3 months thereafter. New metastases were preferentially treated with additional GKS. Indications for WBRT included development of numerous metastases, leptomeningeal disease, or diffuse surgical-site recurrence.

Results

The median overall survival from GKS was 13.8 months. Excluding the 3 patients who died before follow-up imaging, 12 patients (11.3%) experienced local failure at a median of 7.4 months. Fifty-three patients (50%) developed new metastases at a median of 5 months. Six (7%) of 86 instances of new lesions were symptomatic. Most patients (67%) with distant failures were successfully treated using salvage GKS alone. Whole-brain radiotherapy was indicated in 20 patients (18.3%). Thirteen patients (11.9%) died of neurological disease.

Conclusions

For patients with limited brain metastases and functional independence, 20-Gy GKS provides excellent disease control and high-functioning survival with minimal morbidity. New metastases developed in almost 50% of patients, but additional GKS was extremely effective in controlling disease. Using our algorithm, fewer than 20% of patients required WBRT, and only 12% died of progressive intracranial disease.

Hippocampal neuron number is unchanged 1 year after fractionated whole-brain irradiation at middle age

PURPOSE

To determine whether hippocampal neurons are lost 12 months after middle-aged rats received a fractionated course of whole-brain irradiation (WBI) that is expected to be biologically equivalent to the regimens used clinically in the treatment of brain tumors.

METHODS AND MATERIALS

Twelve-month-old Fischer 344 X Brown Norway male rats were divided into WBI and control (CON) groups (n = 6 per group). Anesthetized WBI rats received 45 Gy of (137)Cs gamma rays delivered as 9 5-Gy fractions twice per week for 4.5 weeks. Control rats were anesthetized but not irradiated. Twelve months after WBI completion, all rats were anesthetized and perfused with paraformaldehyde, and hippocampal sections were immunostained with the neuron-specific antibody NeuN. Using unbiased stereology, total neuron number and the volume of the neuronal and neuropil layers were determined in the dentate gyrus, CA3, and CA1 subregions of hippocampus.

RESULTS

No differences in tissue integrity or neuron distribution were observed between the WBI and CON groups. Moreover, quantitative analysis demonstrated that neither total neuron number nor the volume of neuronal or neuropil layers differed between the two groups for any subregion.

CONCLUSIONS

Impairment on a hippocampal-dependent learning and memory test occurs 1 year after fractionated WBI at middle age. The same WBI regimen, however, does not lead to a loss of neurons or a reduction in the volume of hippocampus.

Improvement in dose homogeneity with electronic tissue compensation over IMRT and conventional RT in whole brain radiotherapy

BACKGROUND AND PURPOSE

To perform a dosimetric analysis of whole brain radiotherapy using electronic tissue compensation (ECOMP) with dynamic multileaf collimation (dMLC) and its comparisons with inverse-planned intensity modulated radiation therapy (IMRT) with optimization constraints and conventional whole brain radiotherapy (WBRT).

MATERIALS AND METHODS

Ten patients (6 adult, 4 pediatric) who were treated at our institution were selected for this study. WBRT fields were defined using opposed lateral fields directed at the intracranial contents and MLC leaves were used to block the critical normal structures. A two-field inverse-planned IMRT plan was then developed using sliding window technique and two optimization constraints. Finally, a dMLC plan with electronic tissue compensation (ECOMP) was developed using identical beam and collimator angles and blocking strategy; the fluence map was generated based on tissue compensation and no additional constraints were given for optimization purposes. This tissue compensation based fluence map was applied to deliver a homogenous dose to the intracranial contents. Radiation dose was identically prescribed to the isocenter (30.0 Gy in 10 fractions) for all the cases. A dosimetric comparison was then performed for each method in our patient population.

RESULTS

ECOMP significantly reduced the mean maximum dose (D(max)) to the intracranial contents as compared to both WBRT (103.9% vs. 112.4%, p<0.0001) and IMRT (106.1%, p=0.02). ECOMP also reduced the intracranial volume receiving greater than 103% of the prescribed dose (2.6% vs. 54.9%, p<0.0001) and the intracranial volume receiving greater than 105% of the prescribed dose (0% vs. 26%, p<0.0001) as compared to WBRT; there was no statistical difference in these two parameters between ECOMP and IMRT. The mean number of monitor units was increased, however, using both ECOMP and IMRT as compared to WBRT (870 and 860 vs. 318, p<0.0001).

CONCLUSIONS

Dynamic multileaf collimation with electronic tissue compensation (ECOMP) leads to improved dose homogeneity with less 'hot spots' as compared to conventional and inverse-planned intensity modulated whole brain radiotherapy. At our institution, ECOMP is being used in all pediatric patients or select adult patients with a long life expectancy requiring cranial radiotherapy.

A dosimetric evaluation of conventional helmet field irradiation versus two-field intensity-modulated radiotherapy technique

PURPOSE

To compare dosimetric differences between conventional two-beam helmet field irradiation (external beam radiotherapy, EBRT) of the brain and a two-field intensity-modulated radiotherapy (IMRT) technique.

METHODS AND MATERIALS

Ten patients who received helmet field irradiation at our institution were selected for study. External beam radiotherapy portals were planned per usual practice. Intensity-modulated radiotherapy fields were created using the identical field angles as the EBRT portals. Each brain was fully contoured along with the spinal cord to the bottom of the C2 vertebral body. This volume was then expanded symmetrically by 0.5 cm to construct the planning target volume. An IMRT plan was constructed using uniform optimization constraints. For both techniques, the nominal prescribed dose was 3,000 cGy in 10 fractions of 300 cGy using 6-MV photons. Comparative dose-volume histograms were generated for each patient and analyzed.

RESULTS

Intensity-modulated radiotherapy improved dose uniformity over EBRT for whole brain radiotherapy. The mean percentage of brain receiving >105% of dose was reduced from 29.3% with EBRT to 0.03% with IMRT. The mean maximum dose was reduced from 3,378 cGy (113%) for EBRT to 3,162 cGy (105%) with IMRT. The mean percent volume receiving at least 98% of the prescribed dose was 99.5% for the conventional technique and 100% for IMRT.

CONCLUSIONS

Intensity-modulated radiotherapy reduces dose inhomogeneity, particularly for the midline frontal lobe structures where hot spots occur with conventional two-field EBRT. More study needs to be done addressing the clinical implications of optimizing dose uniformity and its effect on long-term cognitive function in selected long-lived patients.

Managing the cognitive effects of brain tumor radiation therapy

Postoperative radiation therapy (RT), either alone or in combination with chemotherapy, is the mainstay of treatment for primary and/or metastatic brain tumors. The majority of patients with brain tumors will have significant symptoms of their disease and of RT that will have a negative impact on their quality of life and neurocognitive function. The symptoms of brain tumors depend on tumor location. Radiation-induced brain injury is a complex and dynamic process involving all cells in the brain, including endothelial and oligodendroglial cells, astrocytes, microglia, neurons, and neuronal stem cells. The symptoms of radiation-induced brain injury may be acute, subacute, or chronic, occurring hours, days, weeks, months, and even years after exposure to radiation, the pathogenesis of which is oxidative stress and inflammation. At present, there are no effective preventive approaches for radiation-induced brain injury. Rather, the management of radiation-induced fatigue, changes in mood, and cognitive dysfunction involves a multidisciplinary approach using pharmacologic, behavioral, and rehabilitative therapies. Given the prevalence of brain neoplasms and the high incidence of the radiation-induced symptom cluster and brain injury, clinical research to address these important clinical problems is critical.

Decision Analysis for Prophylactic Cranial Irradiation for Patients With Small-Cell Lung Cancer

Purpose

Prophylactic cranial irradiation (PCI) has been shown to provide survival benefit in patients with limited disease small-cell lung cancer (LD-SCLC) who have achieved complete response. However, PCI may also produce long-term neurotoxicity (NT). The benefits and risks of PCI in LD-SCLC are evaluated.

Methods

We developed a decision-analytic model to compare quality-adjusted life expectancy (QALE) in a cohort of SCLC patients who do or do not receive PCI by varying survival rates and the frequency and severity of PCI-related NT. Sensitivity analyses were applied to examine the robustness of the optimal decision.

Results

At current published survival rates (26% 5-year survival rate with PCI and 22% without PCI) and a low NT rate, PCI offered a benefit over no PCI (QALE = 4.31 and 3.70 for mild NT severity; QALE = 4.09 and 3.70 for substantial NT severity, respectively). With a moderate NT rate, PCI was still preferred. If the PCI survival rate increased to 40%, PCI outperformed no PCI with a mild NT severity. However, no PCI was preferred over PCI (QALE = 5.72 v 5.47) with substantial NT severity. Two-way sensitivity analyses showed that PCI was preferred for low NT rates, mild NT severity, and low long-term survival rates. Otherwise, no PCI was preferred.

Conclusion

The current data suggest PCI offers better QALE than no PCI in LD-SCLC patients who have achieved complete response. As the survival rate for SCLC patients continues to improve, NT rate and NT severity must be controlled to maintain a favorable benefit-risk ratio for recommending PCI.

Phase II study of donepezil in irradiated brain tumor patients: effect on cognitive function, mood, and quality of life

PURPOSE

A prospective, open-label phase II study was conducted to determine whether donepezil, a US Food and Drug Administration-approved reversible acetylcholinesterase inhibitor used to treat mild to moderate Alzheimer's type dementia, improved cognitive functioning, mood, and quality of life (QOL) in irradiated brain tumor patients.

PATIENTS AND METHODS

Thirty-four patients received donepezil 5 mg/d for 6 weeks, then 10 mg/d for 18 weeks, followed by a washout period of 6 weeks off drug. Outcomes were assessed at baseline, 12, 24 (end of treatment), and 30 weeks (end of wash-out). All tests were administered by a trained research nurse.

RESULTS

Of 35 patients who initiated the study, 24 patients (mean age, 45 years) remained on study for 24 weeks and completed all outcome assessments. All 24 patients had a primary brain tumor, mostly low-grade glioma. Scores significantly improved between baseline (pretreatment) and week 24 on measures of attention/concentration, verbal memory, and figural memory and a trend for verbal fluency (all P < .05). Confused mood also improved from baseline to 24 weeks (P = .004), with a trend for fatigue and anger (all P < .05). Health-related QOL improved significantly from baseline to 24 weeks, particularly, for brain specific concerns with a trend for improvement in emotional and social functioning (all P < .05).

CONCLUSION

Cognitive functioning, mood, and health-related QOL were significantly improved following a 24-week course of the acetylcholinesterase inhibitor donepezil. Toxicities were minimal. We are planning a double blinded, placebo-controlled, phase III trial of donepezil to confirm these favorable results.

Prophylactic cranial irradiation with combined modality therapy for patients with locally advanced non-small cell lung cancer

Central nervous system (CNS) metastasis is a significant problem for many patients with non-small cell lung cancer (NSCLC). The earlier data reported a high incidence of CNS metastasis in patients with locally advanced NSCLC who were treated with radiotherapy alone. However, poor control of both thoracic and extracranial systemic disease dominated the results of the early trials. The risk for CNS metastasis as the first site of failure remains a significant concern for patients who have completed modern combined modality therapy. With improvements in the treatment of thoracic and systemic disease, there is renewed interest in prophylactic cranial irradiation (PCI). The results from the Radiation Therapy Oncology Group (RTOG) trial of PCI to prevent CNS relapse in patients with locally advanced NSCLC are anticipated.

Radiation as a Nervous System Toxin

Neurotoxicity from radiation can range widely and produce effects that may include (1) small absolute increases in cancer risks, (2) subtle effects on higher level functioning in some individuals, (3) severe cognitive impairment in some individuals, (4) severe focal injury tat may include necrosis or irreversible loss of function, and (5) overwhelming and rapidly fatal diffuse injury associated with high-dose, whole-body exposures. An understanding of the implications of nervous system exposure to radiation can guide efforts in radiation protection and aid in the optimization of the medical uses of radiation.

Cognitive sequelae of brain radiation in adults

Radiotherapy (RT) is a proven curative and palliative therapeutic tool in the treatment of a wide variety of primary and metastatic brain tumors in adults. Recent advances in multimodality therapy have led to improvement in survival for many cancer patients. As survival has improved, more attention has been directed toward long-term treatment-related morbidity. Specifically, the effect of RT on the long-term cognitive performance of these patients is a major concern. This article reviews the neurocognitive effects of cranial RT on adult patients with brain tumors. Analyses of neurocognitive function are confounded by factors such as surgery, chemotherapy, tumor characteristics, tumor progression, concurrent medical illnesses, neurologic comorbidity, and medications that can contribute to neurocognitive deficits. Risk of deficits after cranial RT is associated with high RT dose, large fraction size, larger field size, and extremes of age at time of treatment. Using modern techniques with moderate total doses (50 to 54 Gy), conformal RT, conventional fractionation, and advanced planning imaging and software, the risks of neurocognitive deficits are quite small and greatly overshadowed by deficits caused by the tumor itself. Further studies need to be undertaken to elucidate the degree and cause of cognitive decline in adult patients undergoing multimodality therapy for cranial tumors.

Progress in the therapy of small cell lung cancer

Small cell lung cancer (SCLC) accounts for approximately 14% of all cases of lung cancer. Combination chemotherapy is the most effective treatment modality for SCLC and recently, several new active drugs have emerged. Combinations of platinum agents with CPT-11 or gemcitabine have been successfully compared in phase III trials against the cisplatin/etoposide standard. Modest improvements in the outcome of patients with SCLC have been noted over the last two decades. Thoracic irradiation given concurrently with chemotherapy improves survival compared with sequential chemotherapy and radiation, but this approach is associated with more toxicity. Moreover, the optimal doses and fractionation of thoracic irradiation remain to be determined. Three-dimensional treatment planning is under investigation. Prophylactic cranial irradiation (PCI) has established a role in the management of patients who have achieved a complete response to the initial therapy. Novel molecular targeted therapies are among the strategies currently being investigated in SCLC.

A critical review of the clinical effects of therapeutic irradiation damage to the brain: the roots of controversy

We critically examined the damaging affects of therapeutic irradiation by comparing results from cross-disciplinary studies of early- and late-delayed radiotherapy effects. Focus is attained by concentrating on clinical treatment issues (volume of brain, dose, timing of effects, age, modality types, and stereotactic treatment techniques), rather than on methodological means or problems, which is necessary to understand the mechanisms and characteristics of radiotherapy-induced behavioral dysfunction including cognition. We make observations and hypotheses about the actual risks from radiotherapy that could be informative in the treatment decision process, and which may lessen the concerns of some patients and their families about the risks they take when receiving radiation. Conditions that predispose to radiation injury are reviewed: (1) higher doses even to part of the brain versus lower doses to the whole brain, (2) combined treatment modalities, (3) malignancy itself, (4) radiation early during postnatal brain development, and (5) late-delayed effects (more than 3 years posttreatment). Current neurocognitive frameworks for understanding cognitive change over time in children and adults are summarized, along with the literature on effects of brain tumors and treatment on depression. No studies have as yet identified candidate brain regions that are more sensitive to radiotherapy. Two studies have provided early, preliminary evidence for a specific vulnerability of visual attention/memory to the early stage of late radiation damage. Furthermore, radiation effects appear severe only in a minority of patients. Risk is related to direct and indirect effects of cancer type, concurrent clinical factors, and premorbid risk factors.

Cognitive deficits in adult patients with brain tumours

Cognitive function, with survival and response on brain imaging, is increasingly regarded as an important outcome measure in patients with brain tumours. This measure provides us with information on a patient's clinical situation and adverse treatment effects. Radiotherapy has been regarded as the main cause of cognitive decline in these patients, because children with brain tumours can develop intellectual deterioration caused by radiotherapy. In long-term surviving patients, radiotherapy may indeed lead to cognitive deficits, or even dementia. Recent studies, however, have made clear that focal radiotherapy in patients with glioma is not the main reason for cognitive deficits. The tumour itself and other medical treatments contribute largely to the cognitive deficits. Cognitive function is now also recognised as an independent prognostic factor in the survival of glioma patients. Additionally, cognitive deterioration can be the first indicator of progressive disease after treatment.

[The influence of age on radiation-induced cognitive deficit:experimental studies on brain irradiation of 30 gy in 10 sessions and 12 hours in the Wistar rat at 1 1/2, 4 and 18 months age]

The objective of this study was to determine the influence of age on the learning and memory dysfunction induced by cranial radiation in the male Wistar rat. Ninety-six 45-day-old, 70 4-month-old, and 78 18-month-old male rats were divided in two equal groups: (i) irradiated and (ii) control. A course of whole-brain radiation therapy (30 Gy in 10 fractions over 12 days) was administered to the irradiated group, while the control group received sham irradiation. Sequential behavioral studies including one and two-way avoidance tests were undertaken before and after the 7 months following radiation. The results suggest that radiation induced progressive and irreversible memory dysfunction in elderly (18-month-old) rats, but this effect was partial or almost reversible in the 4-month-old and 45-day-old rats, respectively. In return, the learning dysfunction was age non-dependent despite the fact that is occurs more rapidly in the young (45 days, 4 months) rats.

Patterns of failure after prophylactic cranial irradiation in small-cell lung cancer: analysis of 505 randomized patients

BACKGROUND

Prophylactic cranial irradiation (PCI) has a beneficial effect on overall survival in patients with small-cell lung cancer (SCLC) in complete remission as shown in a worldwide meta-analysis. The current analysis aimed to evaluate PCI effects on patterns of failure in this patient category.

PATIENTS AND METHODS

The Institut Gustave-Roussy coordinated two parallel randomized studies including a total of 511 patients with SCLC. Patients were randomly assigned to either PCI (24 Gy in eight fractions and 12 days) or no PCI. Patterns of failure were analyzed according to (i) total event rates and (ii) isolated first site of relapse using a competing risk approach.

RESULTS

Five hundred and five patients were analyzed. The 5-year cumulative rate of brain metastasis as an isolated first site of relapse was 37% in the control group and 20% in the PCI group (P < 0.001). The overall 5-year rates of brain metastasis were 59% and 43%, respectively [relative risk (RR) 0.50; P < 0.001]. The 5-year overall survival rates were 15% in the control group and 18% in the PCI group (RR 0.84; P = 0.06).

CONCLUSIONS

PCI decreased significantly the risk of brain metastasis. Other events were not influenced. The relative death risk reduction was of borderline significance. Results reported as isolated first cause of failure and subsequent competing events may explain why a major treatment effect on brain metastases rate has a rather moderate effect on survival.

Management of small cell lung cancer

Small cell lung carcinoma typically presents as a central endobronchial lesion in chronic cigarette smokers with hilar enlargement and disseminated disease. The diagnostic pathology should be reviewed by a pathologist accomplished in reading pulmonary pathology, and, if any doubt exists in the diagnosis, additional special stains or diagnostic material should be obtained. Patients with extensive stage disease should be managed by combination chemotherapy, whereas patients with limited stage disease should be treated with etoposide/cisplatin plus concurrent chest irradiation. The chemotherapy should be administered for 4 to 6 months and then should be discontinued. Prophylactic cranial irradiation should be given to patients who achieve a complete remission. Patients should be retreated with chemotherapy if they develop a relapse of their small cell lung cancer. The patients who are followed in complete remission should be observed carefully for second cancers, and appropriate therapy should be administered if the cancer reappears.

The treatment of limited small cell lung cancer: a report of the progress made and future prospects

The improvements in the treatment of small cell lung cancer over the last 30 years have been realised by understanding that it is a systemic disease, but that areas of bulk and sanctuary require a complementary therapy. Despite successful strategies using combinations and thoracic radiotherapy, there remains uncertainty about what the best regimens are, their timing and their intensity. However, earlier concurrent therapy and rather brief intense chemotherapy and radiotherapy seem to produce the best results in moderately fit patients of all ages. How to select the fit patients and what to do about the less fit ones remains controversial and have economic consequences for governments and payers. Despite a meta-analysis demonstrating the success of prophylactic cranial irradiation (PCI), doubts linger about its safety, despite nothing more than anecdotal evidence from a previous era. The role of surgery continues to be explored, more in Europe than North America or Asia. Strategies for treatment of minimum residual disease seem a focus. New drugs, molecular targeted therapy, immunotherapy and other molecular therapies offer promise and theory, but there is little evidence about their place in the treatment protocols of today.

Rehabilitation of patients with advanced cancer

Despite growing interest in advanced cancer patients' quality of life, little attention has been directed toward preservation or recovery of their function. Although there is a dearth of supportive literature, extensive experience with other advanced disease populations suggests that standard, widely available rehabilitation strategies can enhance function in cancer. Logistic challenges to the provision of adequate rehabilitation to advanced cancer patients is discussed in this article, based on the author's experience and discussions in the literature. Common sources of functional impairment are reviewed with elucidation of rehabilitation approaches likely to benefit affected patients. Appropriate physical and occupational therapy techniques, as well as appropriate orthotics, assistive devices, and environmental modifications, are outlined for each of these impairments. In the author's view, rehabilitation should be considered for all advanced cancer patients experiencing functional decline. Pathways and referral patterns need to be established so that timely and appropriate functional restoration may occur.

Prophylactic cranial irradiation in small cell lung cancer: a systematic review of the literature with meta-analysis

PURPOSE

A systematic review of the literature was carried out to determine the role of prophylactic cranial irradiation (PCI) in small cell lung cancer (SCLC).

METHODS

To be eligible, full published trials needed to deal with SCLC and to have randomly assigned patients to receive PCI or not. Trials quality was assessed by two scores (Chalmers and ELCWP).

RESULTS

Twelve randomised trials (1547 patients) were found to be eligible. Five evaluated the role of PCI in SCLC patients who had complete response (CR) after chemotherapy. Brain CT scan was done in the work-up in five studies and brain scintigraphy in six. Chalmers and ELCWP scores are well correlated (p < 0.001), with respective median scores of 32.6 and 38.8 %. This meta-analysis based on the available published data reveals a decrease of brain metastases incidence (hazard ratio (HR): 0.48; 95 % confidence interval (CI): 0.39 - 0.60) for all the studies and an improvement of survival (HR: 0.82; 95 % CI: 0.71 - 0.96) in patients in CR in favour of the PCI arm. Unfortunately, long-term neurotoxicity was not adequately described.

CONCLUSIONS

PCI decreases brain metastases incidence and improves survival in CR SCLC patients but these effects were obtained in patients who had no systematic neuropsychological and brain imagery assessments. The long-term toxicity has not been prospectively evaluated. If PCI can be recommended in patients with SCLC and CR documented by a work-up including brain CT scan, data are lacking to generalise its use to any CR situations.

Central nervous system involvement in adult acute lymphocytic leukemia

With effective CNS prophylaxis, most adults with ALL may remain free of CNS leukemia. Several combinations of IT chemotherapy, high-dose systemic chemotherapy, and cranial irradiation have been used with varying results. Excellent prophylaxis can be achieved without cranial irradiation, and in view of the potential acute and long-term toxicity of radiation, these methods may be preferable. A prophylactic approach tailored to the risk of CNS leukemia was shown to be valuable in childhood ALL and in at least one adult study. Further studies should focus on defining risk groups for CNS leukemia and designing effective prophylaxis for each group. More research is needed to define the intensity and duration of treatment and the role of cranial irradiation in the treatment of isolated CNS relapses.

Psychophysiological evaluation of short-term neurotoxicity after prophylactic brain irradiation in patients with small cell lung cancer: a study of event related potentials

BACKGROUND

The aim of this study was to show, whether a certain prophylacting applicable radiation affects the cognition, particularly, the specific cognitive components P50, N100, P300 and N400 of auditory event related potentials (ERPs) during a short memory test.

METHODS AND MATERIALS

Eleven patients with small cell lung cancer (SCLC), who had presented complete response of disease after chemotherapy and radical radiotherapy in the lung, were prescribed to receive a prophylacting cranial irradiation (PCI) with a 6 MeV linear accelerator. The dose schedule was consisting of a total dose up to 30 Gy in 10 fractions, within 12 days (5 days a week). The psychophysiological approach before and after PCI was assessed by measurements of the auditory ERPs during a short memory performance using the digit-span Wechsler test. Components of ERP were recorded from 15 scalp electrodes. Additionally, symptomatology of depression and anxiety were assessed using Zung Self-Rating Depression Scale and Spielberger Anxiety Inventory, respectively, for pre- and post-PCI.

RESULTS

No significant difference was noticed pre- and post-radiotherapy of all particular level of psychophysiological analysis concerning both the latencies and the amplitudes of ERPs auditory components P50, N100, P300 and N400 (P > 0.05, Wilcoxon signed test). Additionally, no changes were found with regard to behavioral performance (memory recall), depression symptomatology and state anxiety, according to pre- and post-radiation measurements. However, the self-reported depression symptomatology showed that the patients presented moderate depression.

CONCLUSION

No short-term psychophysiological neurotoxicity was detected with this PCI schedule using these instruments, lending additional support to evidence suggesting the benefit of this certain PCI schedule for patients with SCLC.

Prospective evaluation of delayed central nervous system (CNS) toxicity of hyperfractionated total body irradiation (TBI)

PURPOSE

Prospective evaluation of chronic radiation effects on the healthy adult brain using neuropsychological testing of intelligence, attention, and memory.

METHODS AND MATERIALS

58 patients (43 +/- 10 yr) undergoing hyperfractionated total body irradiation (TBI) (TBI, 14.4 Gy, 12 x 1.2 Gy in 4 days) before bone marrow or peripheral blood stem cell transplantation were prospectively included. Twenty-one recurrence-free long-term survivors were re-examined 6-36 months (median 27 months) after completion of TBI. Neuropsychological testing included assessment of general intelligence, attention, and memory using normative, standardized psychometric tests. Mood status was controlled, as well. Test results are given as IQ scores (population mean 100) or percentiles for attention and memory (population mean 50).

RESULTS

The 21 patients showed normal baseline test results of IQ (101 +/- 13) and attention (53 +/- 28), with memory test scores below average (35 +/- 21). Test results of IQ (98 +/- 17), attention (58 +/- 27), and memory (43 +/- 28) showed no signs of clinically measurable radiation damage to higher CNS (central nervous system) functions during the follow-up. The mood status was improved.

CONCLUSION

The investigation of CNS toxicity after hyperfractionated TBI showed no deterioration of test results in adult recurrence-free patients with tumor-free CNS. The median follow-up of 27 months will be extended.

Neurobehavioral toxicity of total body irradiation: a follow-up in long-term survivors

PURPOSE

Total body irradiation (TBI) in preparation for bone marrow transplantation (BMT) is a routine treatment of hematological malignancy. A retrospective and a prospective group study of long-term cerebral side effects was performed, with a special emphasis on neurobehavioral toxicity effects.

METHODS AND MATERIALS

Twenty disease-free patients treated with hyperfractionated TBI (14.4 Gy, 12 x 1.2 Gy, 4 days), 50 mg/kg cyclophosphamide, and autologous BMT (mean age 38 years, range 17-52 years; age at TBI 35 years, 16-50 years; follow-up time 32 months, 9-65 months) participated in a neuropsychological, neuroradiological, and neurological examination. Data were compared to 14 patients who were investigated prior to TBI. Eleven patients with renal insufficiencies matched for sex and age (38 years, 20-52 years) served as controls. In a longitudinal approach, neuropsychological follow-up data were assessed in 12 long-term survivors (45 years, 23-59 years; follow-up time 8.8 years, 7-10.8 years; time since diagnosis 10.1 years, 7.5-14.2 years).

RESULTS

No evidence of neurological deficits was found in post-TBI patients except one case of peripheral movement disorder of unknown origin. Some patients showed moderate brain atrophy. Neuropsychological assessment showed a subtle reduction of memory performance of about one standard deviation. Cognitive decline in individual patients appeared to be associated with pretreatment (brain irradiation, intrathecal methotrexate). Ten-years post disease onset, survivors without pretreatment showed behavioral improvement up to the premorbid level.

CONCLUSION

The incidence of long-term neurobehavioral toxicity was very low for the present TBI/BMT regimen.

Late radiation toxicity after whole brain radiotherapy: the influence of antiepileptic drugs

This retrospective study had the following aims: (a) calculation of actuarial rate of late radiation toxicity after whole-brain radiotherapy (WBRT), (b) correlation of clinical symptoms with changes of computed tomography (CT) scans, and (c) analysis of potentially predictive factors with special regard to concomitant treatment with antiepileptic drugs. We analyzed 49 adult patients, selected from a preexisting data base. Inclusion criteria were as follows: no previous brain irradiation; WBRT without boost; CT, clinical, and neurologic examination before and more than 3 months after completion of WBRT. Uni- and multivariate tests of various patient- and treatment-related parameters as possible predictive factors for clinical symptoms of late radiation toxicity (scored according to the RTOG/EORTC system) as well as cerebral atrophy and white matter abnormalities were performed. Median age was 54 years. Patients were treated for brain metastases (n = 37), primary cerebral lymphoma (n = 2), primary brain tumors (n = 7), or with prophylactic intention (n = 3). Carbamazepine was given to 15 patients, phenytoin to 12, and barbiturate to 7, respectively; 42 patients also received corticosteroids. The median dose of WBRT was 30 Gy (range 27-66 Gy). Median fraction size was 3 Gy (1-3 Gy). Nine patients received two fractions per day. The biologically effective dose (BED) according to the linear-quadratic model ranged between 90 and 141 Gy (median, 120 Gy; alpha/beta value, 1 Gy). Median follow-up was 10 months (range, 4-130 months). In 16 cases, symptoms of late radiation toxicity grade I-III appeared. Actuarial rates were 32% after 1 year, 49% after 2 years, and 83% after 5 years. Actuarial rates of cerebral atrophy were 50% after 1 year and 84% after 2 years (white matter abnormalities: 25% and 85%, respectively). There was a significant correlation between atrophy and white matter abnormalities, but not between CT changes and clinical symptoms. CT changes were dependent on BED, absence of barbiturate use, and preexisting cerebral atrophy. Clinical symptoms usually were dependent on BED too, but treatment with carbamazepine was more important in the multivariate model. Neither other drugs nor other factors influenced late radiation toxicity. A detailed analysis showed that most carbamazepine-treated symptomatic patients took the drug during WBRT as well as during follow-up. Actuarial rates of grade I-III symptoms were 18% versus 50% after 1 year with or without carbamazepine. Even after exclusion of carbamazepine-treated patients, CT changes and clinical symptoms did not correlate. In conclusion, a BED <120 Gy was associated with a lower rate of late radiation toxicity after WBRT. The anticonvulsant drug carbamazepine showed a surprisingly clear influence on clinical symptoms of late radiation toxicity; that might be explained by the fact that the side effects of long-term drug treatment are indistinguishable from mild or moderate true radiation sequelae, rather than that it has a role in the pathogenesis of radiation-induced changes.