Cell phones and brain tumors: a review including the long-term epidemiologic data

Vini G. Khurana, PhD, FRACS, Charles Teo, MBBS, FRACS, Michael Kundi, PhD, Lennart Hardell, MD, PhD, Michael Carlberg, MSc.

Surgical Neurology Volume 72, Issue 3, Pages 205-214 (September 2009) doi:10.1016/j.surneu.2009.01.019


The debate regarding the health effects of low-intensity electromagnetic radiation from sources such as power lines, base stations, and cell phones has recently been reignited. In the present review, the authors attempt to address the following question: is there epidemiologic evidence for an association between long-term cell phone usage and the risk of developing a brain tumor? Included with this meta-analysis of the long-term epidemiologic data are a brief overview of cell phone technology and discussion of laboratory data, biological mechanisms, and brain tumor incidence.

In order to be included in the present meta-analysis, studies were required to have met all of the following criteria: (i) publication in a peer-reviewed journal; (ii) inclusion of participants using cell phones for ≥10 years (ie, minimum 10-year “latency”); and (iii) incorporation of a “laterality” analysis of long-term users (ie, analysis of the side of the brain tumor relative to the side of the head preferred for cell phone usage). This is a meta-analysis incorporating all 11 long-term epidemiologic studies in this field.

The results indicate that using a cell phone for ≥10 years approximately doubles the risk of being diagnosed with a brain tumor on the same (“ipsilateral”) side of the head as that preferred for cell phone use. The data achieve statistical significance for glioma and acoustic neuroma but not for meningioma.

Conclusion

The authors conclude that there is adequate epidemiologic evidence to suggest a link between prolonged cell phone usage and the development of an ipsilateral brain tumor.

Fronto-basal interhemispheric approach for tuberculum sellae meningiomas; long-term visual outcome

Ganna, Ahmed, Dehdashti, Amir R., Karabatsou, Konstantina and Gentili, Fred. British Journal of Neurosurgery,23:4,422-430, (2009).

URL: http://dx.doi.org/10.1080/02688690902968836

We report our experience with the treatment of tuberculum sellae meningiomas using the fronto-basal interhemispheric approach. A retrospective analysis was performed on a series of 24 patients with tuberculum sellae meningiomas who were operated between March 2000 and January 2007. Patients’ presenting symptoms, radiological images, operative reports, and clinical follow-up data were reviewed with special consideration for visual outcome. Visual deterioration was the presenting symptom in all patients, followed by headache in 9 patients (37.5%). The average duration of visual symptoms was 17.6 months. The average tumor diameter was 2.63 cm; encasement of the carotid artery was identified in 7 patients (29%). Complete tumor removal was achieved in 21 patients (87.5%). Mean follow-up period was 52 months. Vision improved in 19 patients (79%), remained stable in 4 (17%) and deteriorated in 1 patient (4%). The degree of tumor removal or visual outcome were both unrelated to the tumor size (p=0.2 and p=0.6 respectively). While the degree of preoperative visual deficit did not affect the visual improvement rate in the whole group (p=0.9), those patients with improvement to good functional vision (>20/40) after the surgery, had a less severe preoperative deficit (p<0.001). The most common complication was anosmia (29.1%) and there was no mortality. The frontobasal interhemispheric approach is safe and provides a direct anatomical approach to tuberculum sellae meningiomas with relatively low incidence of complications. Patients with improved vision to good functional level had a better preoperative visual status.

A comparison between surgical resection in combination with WBRT or hypofractionated stereotactic irradiation in the treatment of solitary brain metastases

Peter Lindvall & Per Bergström & Per-Olov Löfroth &A. Tommy Bergenheim

Acta Neurochir (2009) 151:1053-1059

The standard treatment of solitary brain metastases previously has been tumour resection in combination with whole-brain radiation therapy (WBRT). Stereotactic radiotherapy has emerged as a non-invasive treatment option especially for small brain metastases. We now report our results on resection + WBRT or hypofractionated stereotactic irradiation (HCSRT) in the treatment of solitary brain metastases.

Between 1993 and 2004 patients with metastatic cancer and solitary brain metastases were selected for surgical resection + WBRT or HCSRT alone at the Umeå University Hospital. Fifty-nine patients were treated with surgical resection + WBRT (34 male, 25 female, mean age 63.3 years). Forty-seven patients were treated with HCSRT alone (15 male, 32 female, mean age 64.9 years). Findings In patients followed radiologically, 28% treated with resection + WBRT showed a local recurrence after a median time of 8.0 months, whereas there was a lack of local control in 16% in the HCSRT group after a median time of 3.0 months. There was a significantly longer survival time for patients treated with resection + WBRT (median 7.9, mean 12.9 months) compared to HCSRT (median 5.0, mean 7.6 months). Even in patients with a tumour volume <10 cc, there was a significantly longer survival in favour of resection + WBRT (median 8.4, mean 17.4 months) compared to HCSRT (median 5.0, mean 7.9 months).

Conclusion This retrospective and non-randomised study indicates that surgical resection in combination with WBRT may be an option even for small brain metastases suitable for treatment with HCSRT. Since survival and local control following resection + WBRT was at least as favourable as compared to HCSRT alone, tumour location and expected neurological outcome may be the strongest aspect when selecting treatment modality.

Functional outcome after language mapping for insular WHO Grade II gliomas in the dominant hemisphere: experience with 24 patients

Neurosurg Focus 27 (2):E7, 2009
Despite the report of recent experiences of insular surgery in the past decade, there has been no series specifically dedicated to studying functional outcome following resection of insular WHO Grade II gliomas involving the dominant hemisphere, in patients with no or only mild preoperative language deficit. In this article, the authors analyze the contribution of awake mapping for preservation of brain function, especially language, in a homogeneous series of 24 patients who underwent surgery for insular Grade II gliomas within the dominant insular lobe.

Methods
Twenty-four patients underwent surgery for an insular Grade II glioma involving the dominant hemisphere (22 left, 2 right), revealed by seizures in all but 1 case. The preoperative neurological examination result was normal in 17 patients (71%), whereas 7 patients presented with language disorders detected using an accurate language assessment performed by a speech therapist. All surgeries were performed on awake patients utilizing intra-operative language mapping involving cortical and subcortical stimulation.

Results
There were no intrasurgical complications or postsurgical sensorimotor deficits. Despite an immediate postoperative language worsening in 12 cases (50%), all patients recovered to a normal status within 3 months, and 6 cases even improved in comparison with their preoperative examination results. The 24 patients returned to normal social and professional lives. Moreover, the surgery had a favorable impact on epilepsy in all but 4 cases (83%). On control MR imaging, 62.5% of resections were total or subtotal. Three patients underwent a second or third awake surgery, with no additional deficit. All but 2 patients (92%) are alive after a mean follow-up of 3 years (range 3–133 months).

Conclusions
Although insular surgery was long believed to be too risky, the present results show that the rate of permanent deficit, especially dysphasia, following resection of Grade II gliomas involving the dominant insula has been dramatically reduced (none in this patient series), thanks to the systematic use of intraoperative awake mapping, even in cases of repeated operations. Furthermore, patient quality of life may be improved due to a decrease of epilepsy after surgery. Thus, the authors suggest systematically considering resection when an insular Grade II glioma is diagnosed after seizures in a patient with no or mild deficit, even a glioma invading the dominant hemisphere.

Neurosurgical management of intracranial epidermoid tumors in children

J Neurosurg Pediatrics 4:91-96, 2009

Epidermoid tumors are benign lesions representing 1% of all intracranial tumors. There have been few pediatric series of intracranial epidermoid tumors reported previously. The authors present their experience in the management of these lesions.

The neurosurgical database at the Hospital for Sick Children was searched for children with surgically managed intracranial epidermoid tumors. The patients’ charts were reviewed for demographic data, details of clinical presentation, surgical therapy, and follow-up. Ethics board approval was obtained for this study.

Seven children, all girls, were identified who met the inclusion criteria between 1980 and 2007. The average age at surgery was 11.2 years (range 8–15 years), and the mean maximal tumor diameter was 2.1 cm. Headache was the most common presenting symptom, and 1 tumor was found incidentally. Most patients had normal neurological examinations, but meningism was found in 2 cases. There were 3 cerebellopontine angle lesions, 1 pontomedullary lesion, and 3 supratentorial tumors. Hydrocephalus developed in 1 patient after aseptic meningitis, and she underwent shunt placement. There were no operative deaths. Complete resection could be performed in 2 patients. One patient experienced a small recurrence that did not require a repeated operation, while 1 subtotally resected lesion recurred and the patient underwent a second operation.

Conclusions: Intracranial epidermoid tumors are rare in the pediatric population. Total resection is desirable to minimize the risk of postoperative aseptic meningitis, hydrocephalus, and tumor recurrence. Aggressive neurosurgical resection may be associated with cranial nerve or ischemic deficits, however. In these cases, neurosurgical judgment at the time of surgery is warranted to ensure maximum resection while minimizing postoperative neurological deficits.

Infratentorial ependymomas: prognostic factors and outcome analysis in a multi-center retrospective series of 106 adult patients

Acta Neurochirurgica (151)8: 947 960. 01/08/2009

This study was undertaken to analyze outcomes and to assess the prognostic impact of age, location, surgery, radiotherapy (RT), and histopathology in a series of adult infratentorial ependymomas. This was a retrospective study of a population of 106 adult patients with infratentorial ependymomas diagnosed between 1990 and 2004. A central pathological review of all cases was performed. Grading was according to the WHO and Marseille’s neograding classifications. The series consisted of 58 males (54.7%) and 48 females (45.3%) in the age range of 18-82 years. Using the WHO classification, 88 patients (83.0%) had grade II and 18 patients (17.0%) grade III ependymomas. Using the Marseille’s neograding system, 91 patients were low-grade and 15 high-grade. Gross total resection was achieved in 66 patients (62.3%). Thirty-seven patients (35.0%) received adjuvant RT. The 5- and 10-year overall survival rates for the entire cohort were 86.1% and 80.5%, respectively. On multivariate analysis, a preoperative Karnofski performance status score > 80, no recessus lateral extension and a low histological grade (Marseille’s grading) were associated with a longer overall survival. The 5- and 10-year progression-free survival rates for the entire cohort were 70.8% and 57.7%, respectively. On multivariate analysis, no recessus lateral extension, gross total resection and a low histological grade (Marseille’s grading) were associated with a longer progression-free survival. Adjuvant RT was significantly associated with a better overall and progression-free survival in incompletely resected WHO grade II ependymomas. This study highlights the key role of histology in the clinical outcome and the fact that gross total resection is a main prognostic factor and the treatment of choice for posterior fossa ependymomas. The use of adjuvant RT in patients with incompletely resected WHO grade II ependymomas appears beneficial, but its effect on high-grade tumors remains to be determined.

Risk factors for postoperative systemic complications in elderly patients with brain tumors

In elderly patients with brain tumors, the prevention of postoperative systemic complications is extremely important, and identification of the risk factors would be useful for planning therapy. The authors investigated ways to avoid postoperative complications by identifying risk factors.

Methods
The study population included 84 patients, 70 years of age or older, who underwent surgical brain tumor removal. The following independent factors were assessed by univariate and multivariate analyses: sex, age, preoperative underlying diseases and complications, histopathological findings, preoperative Karnofsky Performance Scale (KPS) score, preoperative whole blood hemoglobin (Hb) level, preoperative serum total protein (TP) level, operation time, intraoperative blood loss, change in Hb level (difference between pre- and postoperative values), and change in TP level (difference between pre- and postoperative values). The cutoff values for significant independent factors were also determined.

Results
Overall, 35 (41.7%) of the 84 patients had a total of 56 postoperative systemic complications. Univariate analysis identified the preoperative KPS score, intraoperative blood loss, change in Hb level, and change in TP level as risk factors for postoperative complications, and multivariate analysis extracted the following risk factors: the preoperative KPS score (p = 0.0450, OR 4.020), intraoperative blood loss (p = 0.0104, OR 6.571), and change in Hb levels (p = 0.0023, OR 9.301). The cutoff values were: KPS score < 80%, intraoperative blood loss ≥ 350 ml, and change in Hb level ≥ 2.0 g/dl.

Conclusions
In elderly patients with brain tumors, low preoperative KPS score, high intraoperative blood loss, and a large difference between pre- and postoperative Hb levels are significant risk factors for postoperative systemic complications.

Agraphia after awake surgery for brain tumor: new insights into the anatomo-functional network of writing

Surgical Neurology. Volume 72, Issue 3, Pages 223-241 (September 2009)

Background

Controversy still exists about neural basis underlying writing and its relation with the sites subserving oral language. Our objective is to study functional areas involved in writing network, based on the observations of different postoperative writing disorders in a population of patients without preoperative agraphia.

Methods

We analyzed the postoperative agraphia profiles in 15 patients who underwent surgery for cerebral LGGs in functional language areas, using electrical mapping under local anesthesia. These profiles were then correlated to the sites of the lesions, shown by preoperative cerebral imaging.

Results

Our findings showed that (1) spoken language and writing functions could be dissociated, and that (2) writing is subserved, at least partially, by a network of 5 areas located in the dominant hemisphere for language: the superior parietal region, the supramarginalis gyrus, the second and third frontal convolutions, the supplementary motor area, and the insula. Each of these areas seems to have a different role in writing, which will be detailed in this article. However, among the patients, only those with lesions of the supplementary motor area did not recover from agraphia in the postoperative period (in 50% of cases).

Conclusions

On the basis of these results, and in the light of the recent literature, we discuss the relevance of each area in this anatomo-functional network as well as the clinical implications of such better knowledge of the neural basis of writing, especially for brain surgery and functional rehabilitation.