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

[Normal tissue: radiosensitivity, toxicity, consequences for planning]

Along with chemotherapy, surgery and immunotherapy, radiotherapy is a mainstay of cancer treatment. Considering the improving survival rates for various malignancies during the past decades, the importance of radiation-induced late normal tissue response is increasing. Quality of life is becoming an important issue in modern cancer treatment and is correlated with acute and late normal tissue response after radiotherapy. A profound understanding of radiation-induced normal tissue response is necessary to sufficiently diagnose and treat radiation-induced side effects and thereby increase the patients' quality of life. Here, the various normal tissue responses in consideration of the radiation biology are specified and prospective options to attenuate radiation-induced side effects are discussed.

[White matter alterations after chemotherapy and radiation]

Nowadays chemotherapy and radiotherapy are fundamental therapy concepts in the guidelines of malignant tumors of the central nervous system. Both therapy concepts can cause neurological symptoms or white matter alterations can occur, which can be classified into acute, subacute and chronic. Both symptoms and white matter alterations during acute and subacute phases are in most cases completely reversible, whereas chronic white matter alterations can lead to severe neurological limitations and further impair the quality of life of cancer patients.

Cognitive Functioning After Hematopoietic Cell Transplantation for Hematologic Malignancy: Results From a Prospective Longitudinal Study

Purpose

Cognitive impairment is well-recognized after myeloablative allogeneic hematopoietic cell transplantation (HCT). However, cognitive functioning after reduced-intensity allogeneic or autologous HCT remains unclear.

Methods

A total of 477 HCT recipients (236 autologous, 128 reduced-intensity allogeneic, 113 myeloablative allogeneic) underwent standardized neuropsychologic testing before HCT and at 6 months and 1, 2, and 3 years after HCT. Ninety-nine frequency-matched healthy controls underwent testing at commensurate time points. Primary outcomes of the study were practice effect–adjusted domain-specific T scores and global deficit scores. Piecewise generalized estimating equation models were used to compare groups and to identify associated variables and post-HCT trends of cognitive impairment.

Results

Median age was 52 years (range, 18 to 74 years) for HCT recipients and 55 years (range, 19 to 73 years) for controls. Post-HCT scores were comparable between controls and autologous and reduced-intensity HCT recipients. Myeloablative HCT recipients had significantly lower ( P < .001) post-HCT scores than controls for executive function, verbal speed, processing speed, auditory memory, and fine motor dexterity. Pre-HCT to 6 months post-HCT scores did not change after reduced-intensity HCT but declined significantly for fine motor dexterity ( P < .001) after myeloablative HCT. However, pre-HCT to 3 years post-HCT scores declined significantly ( P < .003) in reduced-intensity HCT recipients for executive function, verbal fluency, and working memory. Older age, male sex, and lower education, income, and cognitive reserve were associated with post-HCT cognitive impairment. At 3 years post-HCT, global cognitive impairment was present in 18.7% of autologous and 35.7% of allogeneic HCT recipients.

Conclusion

Myeloablative allogeneic HCT recipients showed significant cognitive decline compared with healthy controls. Reduced-intensity allogeneic HCT recipients showed evidence of delayed decline. Cognitive functioning in autologous HCT recipients generally was spared. The study identified vulnerable subpopulations that could benefit from targeted interventions.

Prospective assessment of white matter integrity in adult stem cell transplant recipients

Hematopoietic stem cell transplantation (HSCT) is often used in the treatment of hematologic disorders. Although it can be curative, the pre-transplant conditioning regimen can be associated with neurotoxicity. In this prospective study, we examined white matter (WM) integrity with diffusion tensor imaging (DTI) and neuropsychological functioning before and one year after HSCT in twenty-two patients with hematologic disorders and ten healthy controls evaluated at similar intervals. Eighteen patients received conditioning treatment with high-dose (HD) chemotherapy, and four had full dose total body irradiation (fTBI) and HD chemotherapy prior to undergoing an allogeneic or autologous HSCT. The results showed a significant decrease in mean diffusivity (MD) and axial diffusivity (AD) in diffuse WM regions one year after HSCT (p-corrected <0.05) in the patient group compared to healthy controls. At baseline, patients treated with allogeneic HSCT had higher MD and AD in the left hemisphere WM than autologous HSCT patients (p-corrected <0.05). One year post-transplant, patients treated with allogeneic HSCT had lower fractional anisotropy (FA) and higher radial diffusivity (RD) in the right hemisphere and left frontal WM compared to patients treated with autologous HSCT (p-corrected <0.05).There were modest but significant correlations between MD values and cognitive test scores, and these were greatest for timed tests and in projection tracts. Patients showed a trend toward a decline in working memory, and had lower cognitive test scores than healthy controls at the one-year assessment. The findings suggest a relatively diffuse pattern of alterations in WM integrity in adult survivors of HSCT.

Potential toxicities of prophylactic cranial irradiation

Prophylactic cranial irradiation (PCI) with total doses of 20-30 Gy reduces the incidence of brain metastasis (BM) and increases survival of patients with limited and extensive-disease small-cell lung cancer (SCLC) that showed any response to chemotherapy. PCI is currently not applied in non-small-cell lung cancer (NSCLC) since it has not proven to significantly improve OS rates in stage IIIA/B, although novel data suggest that subgroups that could benefit may exist. Here we briefly review potential toxicities of PCI which have to be considered before prescribing PCI. They are mostly difficult to delineate from pre-existing risk factors which include preceding chemotherapy, patient age, paraneoplasia, as well as smoking or atherosclerosis. On the long run, this will force radiation oncologists to evaluate each patient separately and to estimate the individual risk. Where PCI is then considered to be of benefit, novel concepts, such as intensity-modulated radiotherapy and/or neuroprotective drugs with potential to lower the rates of side effects will eventually be superior to conventional therapy. This in turn will lead to a re-evaluation whether benefits might then outweigh the (lowered) risks.

A prospective evaluation of changes in brain structure and cognitive functions in adult stem cell transplant recipients

Hematopoietic stem cell transplantation (HSCT) is an efficacious treatment for many hematologic malignancies. However, the conditioning regimen of high-dose (HD) chemotherapy with or without total body irradiation (TBI) can be associated with neurotoxicity. In this prospective study, we used quantitative neuroimaging techniques to examine regional gray matter and ventricular volumes, and standardized neuropsychological tests to assess cognitive function before and 1 year after HSCT in 28 patients with hematologic malignancies and in ten healthy controls evaluated at similar intervals. Nineteen patients received conditioning treatment with HD chemotherapy alone and nine had both TBI and HD chemotherapy. There was a significant reduction in gray matter volume in the middle frontal gyrus bilaterally and in the left caudate nucleus in the patient group (all patients combined) but not among healthy controls over the 1-year follow-up period. There was a significant increase in left lateral ventricle volume and in total ventricle volume in the patient group, relative to healthy controls. Similar brain structural changes were seen for patients treated with HD chemotherapy alone. The neuropsychological results showed that 21% of patients could be classified as impaired at baseline. The Reliable Change Index suggested no significantly different rates of cognitive decline between patients and healthy controls. The findings suggest that HSCT patients may be at an increased risk for developing regional brain volume loss, and that subgroups may experience cognitive dysfunction prior to and 1 year following the transplant.

A systematic review and meta-analysis of changes in cognitive functioning in adults undergoing hematopoietic cell transplantation

Evidence is mixed regarding the effects of hematopoietic cell transplantation (HCT) on changes in cognitive functioning among adults. Meta-analysis, which is designed to help reconcile conflicting findings, has not yet been conducted on studies of adults receiving HCT. To fill this gap, the current study provides a systematic review and meta-analysis of cognitive functioning in adults receiving HCT. A search of PubMed, PsycInfo, CINAHL, and Cochrane Library yielded 732 abstracts, which were independently evaluated by pairs of raters. Seventeen studies were systematically reviewed; eleven were retained for meta-analysis. There was agreement that cognitive impairments are evident for a subset of patients prior to HCT. Meta-analytic findings of 404 patients revealed no significant changes in cognitive functioning pre- to post-HCT (P values > .05). Age, time since transplant, and total body irradiation were not associated with changes in cognitive functioning. Patients who received autologous transplants were more likely to demonstrate improvements in attention (P = .004). The systematic review identified several limitations of existing literature, including small, clinically heterogeneous samples. Large, cooperative group studies are needed to address these design limitations. Nevertheless, results from the current meta-analysis suggest that cognitive functioning does not significantly change following HCT.

Prospective neurocognitive function over 5 years after allogeneic hematopoietic cell transplantation for cancer survivors compared with matched controls at 5 years

PURPOSE

Research has documented cognitive deficits both before and after high-dose treatment followed by allogeneic hematopoietic cell transplantation (HCT), with partial recovery by 1 year. This study prospectively examined the trajectory and extent of long-term cognitive dysfunction, with a focus on 1 to 5 years after treatment.

PATIENTS AND METHODS

Allogeneic HCT recipients completed standardized neuropsychological tests including information processing speed (Trail Making A and Digit Symbol Substitution Test), verbal memory (Hopkins Verbal Learning Test-Revised), executive function (Controlled Oral Word Association Test and Trail Making B), and motor dexterity and speed (Grooved Pegboard). Survivors (n = 92) were retested after 80 days and 1 and 5 years after transplantation. Case-matched controls (n = 66) received testing at the 5-year time point. A Global Deficit Score (GDS) summarized overall impairment. Response profiles were analyzed using linear mixed effects models.

RESULTS

Survivors recovered significant cognitive function from post-transplantation (80 days) to 5 years in all tests (P < .0001) except verbal recall (P > .06). Between 1 and 5 years, verbal fluency improved (P = .0002), as did executive function (P < .01), but motor dexterity did not (P > .15), remaining below controls (P < .0001) and more than 0.5 standard deviation below population norms. In GDS, 41.5% of survivors and 19.7% of controls had mild or greater deficits (NcNemar test = 7.04, P = .007).

CONCLUSION

Although neurocognitive function improved from 1 to 5 years after HCT, deficits remained for more than 40% of survivors. Risk factors, mechanisms and rehabilitation strategies need to be identified for these residual deficits.

Acute neurocognitive impairment during cranial radiation therapy in patients with intracranial tumors

BACKGROUND AND PURPOSE

The objective of the current study was to evaluate the acute effects of cranial radiation therapy (CNS-RT) using different radiation doses (0, 1.8, 2, 3, >or=20 Gy) on cognitive function with special emphasis on memory. We assessed patients with and without intracranial tumors to distinguish between direct and indirect radiation effects on brain tissue.

MATERIALS AND METHODS

Eighty-two patients were evaluated with neuropsychological testing before and acutely after radiotherapy (RT). Sixty-four patients received RT to the brain (55 with, 9 without intracranial tumor). Eighteen patients treated with RT to the breast served as controls.

RESULTS

Patients with intracranial tumor demonstrated attention (19-38th percentile) and verbal memory scores (34-46th percentile) below the population average at baseline. The average Verbal Memory score was significantly different between patients with intracranial tumor and controls both at baseline (38th vs. 58th percentile) and after irradiation (27th vs. 52th percentile). Patients with preexisting peritumoral edema performed worse than patients without edema and controls. Radiation dose-related deficits were seen for working memory performance in patients with intracranial tumor.

CONCLUSION

Our data indicate no measurable impairment of cognitive functioning acutely after prophylactic cranial irradiation. Patients with intracranial tumor show a deterioration of almost all memory functions with a dose-dependent impairment in working memory. Patients with preexisting peritumoral brain edema show the strongest deterioration.

Memory function before and after whole brain radiotherapy in patients with and without brain metastases

PURPOSE

To prospectively compare the effect of prophylactic and therapeutic whole brain radiotherapy (WBRT) on memory function in patients with and without brain metastases.

METHODS AND MATERIALS

Adult patients with and without brain metastases (n = 44) were prospectively evaluated with serial cognitive testing, before RT (T0), after starting RT (T1), at the end of RT (T2), and 6-8 weeks (T3) after RT completion. Data were obtained from small-cell lung cancer patients treated with prophylactic cranial irradiation, patients with brain metastases treated with therapeutic cranial irradiation (TCI), and breast cancer patients treated with RT to the breast.

RESULTS

Before therapy, prophylactic cranial irradiation patients performed worse than TCI patients or than controls on most test scores. During and after WBRT, verbal memory function was influenced by pretreatment cognitive status (p < 0.001) and to a lesser extent by WBRT. Acute (T1) radiation effects on verbal memory function were only observed in TCI patients (p = 0.031). Subacute (T3) radiation effects on verbal memory function were observed in both TCI and prophylactic cranial irradiation patients (p = 0.006). These effects were more pronounced in patients with above-average performance at baseline. Visual memory and attention were not influenced by WBRT.

CONCLUSIONS

The results of our study have shown that WBRT causes cognitive dysfunction immediately after the beginning of RT in patients with brain metastases only. At 6-8 weeks after the end of WBRT, cognitive dysfunction was seen in patients with and without brain metastases. Because cognitive dysfunction after WBRT is restricted to verbal memory, patients should not avoid WBRT because of a fear of neurocognitive side effects.

Neurocognitive Functions and Quality of Life in Haematological Patients Receiving Haematopoietic Stem Cell Grafts: A One-Year Follow-Up Pilot Study

Longitudinal data of neurocognitive functions and quality of life (QOL) were obtained for a cohort of 25 patients followed before transplant and through the first year after haematopoietic stem cell transplantation (SCT). A battery of neuropsychological tests and two self-report questionnaires were used to assess neurocognitive functions, QOL and psychological functioning. In comparison to normative data, up to one-fourth of the patients experienced impaired functioning on several cognitive domains before SCT. Random regression modelling revealed a slight improvement in the mean group scores of memory tasks over time, especially for younger patients. Impairment in neurocognitive functions was positively related to depression and anger at baseline, and to the emotional functioning scale at follow-up. These preliminary results emphasize the significance of a pre-treatment assessment and the need of a large baseline sample in future longitudinal studies to overcome the expected dropout rate of more than 50%.

Neuropsychological and psychiatric functioning pre- and posthematopoietic stem cell transplantation in adult cancer patients: a preliminary study

The current study characterizes cognitive and psychiatric status in hematopoietic stem cell transplantation (HSCT) patients shortly before and after transplant. Thirty adult patients were assessed prospectively 1-2 weeks before transplantation and 100 days posttransplantation on neuropsychological and psychiatric measures. Before transplant, participants showed mild impairments on several neuropsychological measures, with the poorest performances occurring on learning and attention. Psychiatric functioning was significantly elevated compared with normative data. Significant improvements, however, were observed on neuropsychological measures by 100 days after transplant. Depression and anxiety scores also improved. Candidates for HSCT experienced mild diffuse cognitive dysfunction and psychiatric morbidity before the procedure, but these symptoms significantly improved by 3 months following their transplant in this small sample. Education about these possible pretransplant sequelae and the potential for rebound may be helpful to patients and families as they prepare for this treatment and the recovery period.

Assessment of pre-treatment cognitive performance in adult bone marrow or haematopoietic stem cell transplantation patients: A comparative study

The aim of this study was to examine cognitive performance in patients prior to bone marrow or haematopoietic stem cell transplantation (SCT) and in haematological patients who received non-myeloablative cancer therapies. A consecutive sample of 101 SCT patients and 82 haematological patients completed a neuropsychological test battery and five questionnaires assessing subjective cognitive complaints, psychological functioning, health-related quality of life and fatigue. Results were compared with normative data. Percentages of cognitively impaired patients were equally divided between groups. Most deficits were observed in visual memory, visuospatial and constructional ability and psychomotor functions. The SCT group showed a higher rate of anxiety cases and reported lower cognitive, emotional and social functioning. Results of neuropsychological testing were not associated with outcome of the questionnaires. This study showed impaired cognitive performance prior to SCT. Haematological patients treated with non-myeloablative cancer therapies proved to be a reliable reference group for longitudinal studies.

Neuropsychologic changes from before transplantation to 1 year in patients receiving myeloablative allogeneic hematopoietic cell transplant

Research indicates that myeloablative hematopoietic cell transplantation (HCT) impairs neurocognitive function. However, prospective studies on long-term effects are lacking. This longitudinal study examined neurocognitive changes over the first year in 142 adult recipients of allogeneic HC transplants who received neuropsychologic testing before transplantation and again after 80 days and 1 year. Age-, sex-, and education-adjusted population-based standardized scores were used for normative comparisons. Performance on all tests declined from before transplantation to 80 days (P &lt; .05) and improved by 1 year (P &lt; .05), returning to pretransplantation levels on all tests except for grip strength and motor dexterity. Although verbal fluency and memory recovered by 1 year, both were below norms at all 3 testing times (P &lt; .01). Logistic regressions indicated that patients without chemotherapy, other than hydroxyurea, previous to HCT and patients not receiving chronic graft-versus-host disease (GVHD) medication at 1 year had lower risk of impaired function (P &lt; .05). In conclusion, HCT was associated with significant generalized decline in neurocognitive performance at 80 days, with subsequent recovery to pretransplantation levels by 1 year for most survivors, except on motor tasks. Results indicate that long-term cognitive decrements, as distinct from motor disabilities, infrequently derive directly from HCT. (Blood. 2004;104:3386-3392)

Tolerance of normal human brain to boron neutron capture therapy

Data from the Harvard-MIT and the BNL Phase I and Phase I/II clinical trials, conducted between 1994 and 1999, have been analyzed and combined, providing the most complete data set yet available on the tolerance of the normal human brain to BPA-mediated boron neutron capture therapy. Both peak (1cm(3)) dose and average whole-brain dose show a steep dose-response relationship using somnolence syndrome as the clinical endpoint. Probit analysis indicates that the doses associated with a 50% incidence for somnolence (ED(50)+/-SE) were 6.2+/-1.0 Gy(w) for average whole-brain dose and 14.1+/-1.8 Gy(w) for peak brain dose.

Fractionated stereotactic radiotherapy in low-grade astrocytomas: Long-term outcome and prognostic factors

PURPOSE

To evaluate outcome after fractionated stereotactic radiotherapy (RT) of patients with World Health Organization Grade 2 astrocytoma in terms of progression-free survival, overall survival, toxicity, quality of life, and prognostic factors.

METHODS AND MATERIALS

Between 1984 and 2000, 143 patients with histologically proven Grade 2 astrocytoma were treated with fractionated stereotactic RT at our institution. The evaluation of the quality of life and toxicity was based on neurologic examinations and the Karnofsky performance score. Univariate analysis was performed on seven potential prognosticators and multivariate analysis on four prognosticators.

RESULTS

The median follow-up was 44 months. The actuarial overall survival and progression-free survival was 58% and 39% at 5 years, respectively. Out-of-field recurrences occurred in 1 patient (1.2%). We did not observe a dose-response relationship. Overall survival and progression-free survival were significantly correlated with the absence of contrast media enhancement before RT (p <0.01). Toxicity was mild and included severe side effects of European Organization for Research and Treatment of Cancer/Radiation Therapy Oncology Group Grade 3 in only 4 patients (2.8%). The Karnofsky performance score improved in most patients.

CONCLUSION

Fractionated stereotactic RT is effective and has low toxicity in the treatment of Grade 2 gliomas. The rate of field border recurrences was not increased compared with after conventional RT. Exceeding the tumor dose did not improve the tumor control rate but did enhance toxicity. Pretherapeutic contrast media enhancement should be interpreted as a sign of higher grade tumor elements.

Cognitive functioning and quality of life in long-term adult survivors of bone marrow transplantation

BACKGROUND

The late neurotoxic effects of bone marrow transplantation (BMT) on cognitive functioning and quality of life (QOL) were investigated in a consecutively treated cohort of long-term adult survivors.

METHODS

Progression-free patients treated with BMT or peripheral stem cell grafts for a hematologic malignancy at least 2 years before study participation were examined with a comprehensive battery of neuropsychological tests and questionnaires for QOL and mood states. The results of the neuropsychological tests were compared with healthy population norms.

RESULTS

Forty patients were included, 87.5% of whom had undergone an allogeneic transplantation. All received total body irradiation up to 12 Gy (in two fractions). Assessment took place 22-82 months after BMT. Mild to moderate cognitive impairment was found in 24 patients (60%). Compared with healthy population norms, selective attention and executive function, information processing speed, verbal learning, and verbal and visual memory were most likely to be affected. The mean score for the total patient group revealed that these patients scored significantly lower on the information processing speed task compared with expected scores obtained from the normal population. The main predictors for poor neuropsychological performance were fatigue, global health, and educational level. Other correlations with moderate to severe cognitive impairment were subjective cognitive complaints, physical functioning, social functioning, overall mood states, and employment status.

CONCLUSIONS

These data indicate that BMT may lead to cognitive complaints and late cognitive deficits in long-term adult survivors. Cognitive functioning should therefore be used as an outcome parameter in BMT studies.