[Extra-axial brain tumors]

Neuroradiology plays a key role in the diagnosis of patients with brain tumors. Computed tomography (CT) and especially magnetic resonance imaging (MRI) allow accurate anatomic depiction of intracerebral lesions. The implementation of native and contrast studies allows the characterization of the various lesions. This review discusses the imaging aspects with CT and MRI of the most common primary extra-axial brain tumors.

[Meningiomas: multiparametric approach for risk stratification and grading]

The prognosis of the generally benign meningiomas is mainly an issue of the likelihood of recurrence, which increases with WHO grade (7-20% in WHO grade I, 29-40% in WHO grade II, and 50-78% in WHO grade III meningiomas). Among clinical parameters the most important prognostic factor is the completeness of neurosurgical tumor resection. Among histopathological prognostic parameters the mitotic activity is the most important one. As the cutoffs of the mitotic index (MI) are defined for each grade by the WHO classification of brain tumors and because the MI can be applied as the sole grading criterion, the reliable and reproducible assessment of the MI is crucial for an appropriate risk stratification. This is provided by immunohistochemical mitosis markers, i.e., phospho-histone H3 (PHH3). The PHH3 method is superior to the conventional mitosis counting method and therefore allows a more reliable risk stratification. The Ki-67 labeling index provides additional prognostic information, especially in prognostically ambiguous meningiomas. Cytogenetically, the deletion of the short arm of one chromosome 1 (1p-) is an unfavorable prognostic parameter and is correlated with a high risk of recurrence. The enzyme reaction for alkaline phosphatase (ALPL) is a fast and efficient screening method, which strongly indicates an intact chromosome 1 in cases with a positive enzyme reaction.

[Remifentanil-propofol versus fentanyl-midazolam combinations for intracranial surgery: influence of anaesthesia technique and intensive sedation on ventilation times and duration of stay in the ICU]

INTRODUCTION

After neurosurgery patients often need to be sedated and ventilated in the intensive care unit (ICU). However, rapid postoperative recovery and neurological examination are particularly important for the early recognition of complications. In this retrospective study two different strategies of anaesthesia technique and ICU sedation (fentanyl-midazolam versus remifentanil-propofol) were compared.

METHODS

Intraoperatively, patients received continuous infusions of either fentanyl (0.2-1.0 mg/h) and midazolam (2-10 mg/h) or remifentanil (0.2-0.5 microg/kg body weight/min) and propofol (3-6 mg/kg body weight/h). After arrival in the ICU fentanyl (0.03-0.2 mg/h) and midazolam (2-12 mg/h) or remifentanil (0.1-0.2 microg/kg body weight/min) and propofol (0.5-3 mg/kg body weight/h) were infused to reach a Ramsay score of 4. The times between termination of infusion and extubation and the length of stay in the ICU were examined.

RESULTS

A total of 60 patients (n=30 each group) undergoing supratentorial brain tumour surgery were enrolled. The groups were comparable for age, weight, ASA status (American Society of Anesthesiologists) and duration of drug administration (remifentanil-propofol 528+/-382 min versus fentanyl-midazolam 548+/-360 min). Extubation times were significantly shorter after remifentanil-propofol (47 min) than after fentanyl-midazolam (481 min), and the length of stay in the ICU was also significantly reduced (1.8 days versus 3.7 days). As a result of prolonged unconsciousness and impaired neurological assessability, a brain CT scan was necessary in 3 patients after fentanyl-midazolam to exclude neurosurgical complications.

CONCLUSION

This retrospective study demonstrates that remifentanil-propofol anaesthesia and ICU sedation are superior to the combination of fentanyl and midazolam in terms of ventilation time and length of ICU stay. Moreover, the use of fentanyl-midazolam may lead to unnecessary CT scans.

Predictive value of progression-associated chromosomal aberrations for the prognosis of meningiomas: a retrospective study of 198 cases

OBJECT

The goal of this study was to determine whether in meningiomas cytogenetic findings are suitable as a predictive parameter relevant to prognosis.

METHODS

Between 1992 and 1998 at the Department of Neurosurgery, Saarland University, 198 patients underwent surgery to resect meningiomas. The meningiomas were investigated cytogenetically and the patients were followed up for a mean period of 33 months. On the basis of the cytogenetic findings, the meningiomas were subdivided into four groups: Group 0 meningiomas displayed a normal diploid chromosome set; Group 1 tumors were found to have monosomy 22 as the sole cytogenetic aberration; Group 2 tumors were markedly hypodiploid meningiomas with loss of additional autosomes in addition to monosomy 22; and Group 3 meningiomas had deletions of the short arm of a chromosome 1, as well as additional chromosomal aberrations including loss of one chromosome 22. One hundred ninety-eight patients in whom tumor resections were determined to be Simpson Grade I or II could be followed up after complete tumor extirpation. In 20 patients, one or several recurrences were documented during the period of observation. The tumors were classified according to their different, but mostly uniform chromosomal aberrations. Recurrences were found in six (4.3%) of 139 tumors in Groups 0 and 1 and in two (10.5%) of 19 tumors in Group 2; the highest rate of recurrence was found in 12 (30%) of 40 tumors in Group 3. This supports the notion that the deletion of the short arm of one chromosome 1 is an important prognostic factor in meningiomas. The results of this study document a significant correlation between histological grade (p < 0.0001), location (p < 0.0001), and recurrences of meningiomas (p < 0.0001) (significance determined using chi-square tests).

CONCLUSIONS

The cytogenetic classification of meningiomas provides a significant contribution to the predictability of tumor recurrence and is, therefore, a valuable criterion for the neurosurgeon's postoperative management protocol.

Deletion of chromosome 1p and loss of expression of alkaline phosphatase indicate progression of meningiomas

Meningiomas are cytogenetically characterized by loss of one chromosome 22 as a typical primary aberration and progression-associated secondary chromosome changes, of which monosomy 1p is the most common. The aim of this study was to evaluate the significance of monosomy 1p and enzyme activity loss of tissue nonspecific alkaline phosphatase (ALPL), whose gene maps to chromosome 1p36.1-p34, as parameters for the diagnosis of progression-prone meningiomas. We analyzed smear preparations of 56 meningiomas and additional paraffin sections of 17 of the cases by two-color fluorescence in situ hybridization (FISH) using the D1Z1 and D1Z2 probes and by a metaphase cytogenetic analysis of 30 of these tumors. The results were compared to clinical and morphological parameters and the expression of ALPL. Smear preparations showed deletion of 1p36 in 27% of common-type, 70% of atypical (intermediate-type), and 100% of anaplastic meningiomas. Monosomy 1p, as detected by FISH or the karyotype, was strongly associated with complete loss of ALPL activity. Intermediate-type and anaplastic meningiomas of younger patients displayed an increasing rate of cells with trisomy 1q and relative loss of 1p. The highly significant correlation of FISH results and ALPL histochemistry with clinical parameters gives evidence of their strong prognostic relevance. The complete activity loss of ALPL and the immunologically detected loss of ALPL protein in areas of meningiomas with monosomy 1p indicate a cytogenetically undetectable inactivation of the homologous Alpl allele. The apparently homozygous loss of expression of ALPL supports the notion that Alpl is a candidate tumor suppressor gene in meningiomas.

Focal intratumoral heterogeneity for telomerase activity in human prostate cancer

PURPOSE

The value of telomerase activity as a marker in clinical decision-making is closely related to how representative the analysis of a small tumor sample is for the whole tumor. We therefore evaluated the intratumoral distribution pattern of telomerase activity in prostatic carcinomas.

MATERIALS AND METHODS

From 50 prostate cancer patients treated with radical prostatectomy, telomerase activity was determined using the telomeric repeat amplification protocol (TRAP assay). Comparative analysis of at least two separate cancer areas from a single tumor was performed in 42 cases.

RESULTS

Telomerase activation has been demonstrated in 90% of the prostatic carcinomas. Focal intratumoral heterogeneity was found in 38.1% of the tumors with at least two different areas examined. Telomerase positivity of all samples from one given tumor was detected in 50%, telomerase negativity of all samples in 11.9%. A heterogeneous telomerase activity pattern was more frequently detected in tumors with a Gleason score < or = 7 than in those with a Gleason score > 7. Furthermore, there was an increase in the proportion of homogeneously telomerase-positive tumors with increase in severity of the Gleason score. The differences reached statistical significance. Telomerase activity was also detected in non-cancerous prostatic tissue samples.

CONCLUSIONS

Telomerase activation is nearly ubiquitous in prostatic carcinomas, although a heterogeneous telomerase activity pattern within tumors might produce a false-negative result in the telomerase activity assay. This limits the value of telomerase activity assays for diagnostic means. There is evidence for a shift from telomerase-negative prostate cancer tissue toward telomerase positivity during the progression process of prostate cancer. The relatively high proportion of telomerase-positive nonmalignant prostatic tissue samples argues against cancer-specificity of telomerase activation.

Hyperfractionated and accelerated-hyperfractionated radiotherapy for glioblastoma multiforme

Because of promising radiobiological advantages allowing dose escalation and/or reduction of treatment time, hyperfractionated and accelerated-hyperfractionated radiotherapy (hf-rt, ahf-rt) were introduced as part of treatment of glioblastoma multiforme (gbm). In December 1988 we started a prospective study of hf-rt (total dose 78 Gy, two daily fractions of 1.3 Gy, interval between daily fractions 6 hr, treatment time 6 weeks, n = 34 patients). The results were compared with our previous regimen of conventionally fractionated radiotherapy (cf-rt: total dose 60 Gy, single dose 2 Gy, treatment time 6 weeks, n = 32 patients). In June 1990, the protocol was modified in order to reduce treatment time (ahf-rt: total dose 60 Gy, two daily fractions of 1.5 Gy, interval 6 hr, treatment time 4 weeks, n = 92 patients until December 1996). No chemotherapy was given. Entry criteria were: age > or = 17 years, pathological diagnosis of supratentorial gbm, and no previous treatment other than surgery. The ahf-rt group included significantly more patients with previous surgical resection instead of biopsy only. Compared with the cf-rt group, both the hf-rt and the ahf-rt group included significantly more patients with frontal tumor location. We found no significant survival difference between the groups (median survival 7-10 months, 1-year survival rate 19%-29%). Progression-free survival, clinical course, and toxicity were also not significantly different. Karnofsky performance status, age, and corticosteroid dose during radiotherapy were the most important prognostic factors. The results of this trial are in large agreement with most previous publications. It demonstrated no improved survival. However, it showed that treatment time can be reduced by ahf-rt without loss of survival benefit or intolerable toxicity. A short radiotherapy course might be appropriate for many patients with gbm who are not suitable for rather aggressive investigational therapies.

Selection toward diploid cells in prostatic carcinoma derived cell cultures

For elucidation of the growth-regulatory mechanisms in prostatic carcinoma, in vitro investigations on prostatic cell cultures are required. However, one major problem of cell culturing is the selection of particular cell types such that the cell lines representing only some of the features as compared with the tumor of origin. We studied the chromosomal composition of 20 prostatic tissue-derived cell cultures and 12 original (fresh) tissue specimens that were obtained from 13 patients with prostatic adenocarcinoma. Using fluorescence in situ DNA hybridization (FISH), evident clonal abnormalities were detected in 78% of the fresh cancer samples and in 47% of the cultured cancer samples. Of the seven cases revealing clonal abnormalities in the fresh cancer specimen, aneuploidy was detected in only two samples after cell culturing at the earliest passage studied. The aneuploid cell populations in the cultured samples were all lost during progressive subcultivation (after passage 4). Interestingly, by performing FISH on cytogenetic preparations aneuploidy was confined to the interphases, with the metaphases being found to be diploid. This finding indicates that the aneuploid cells have a proliferation disadvantage in cell culture resulting in an overgrowth of diploid cells.

Rearrangement of chromosome 1 is a frequent finding in endometrial carcinoma. An in situ hybridization study in nine endometrial carcinomas

Nine endometrial carcinomas were examined for numerical aberrations of the chromosomes 1,7, and X by fluorescence in situ hybridization using highly repetitive chromosome-specific probes. In addition, a combination of a centromeric and a telomeric chromosome 1 probe was applied to detect structural chromosome 1 aberrations. Chromosome aberrations were found in six tumors. In four of these, an imbalance between 1q12 and 1p36 was detected, indicating the presence of an extra 1p- chromosome. In regard to the chromosomes 7 and X, monosomies and trisomies were found. Intratumoral genetic heterogeneity in endometrial carcinomas was detectable by FISH and flow cytometry. In conclusion, our findings confirm that chromosome 1 is frequently involved in structural chromosome changes, indicating chromosome 1 to be of importance in the evolution of endometrial carcinoma.

DNA aneuploidy in prostatic adenocarcinoma: a frequent event as shown by fluorescence in situ DNA hybridization

Fluorescence in situ hybridization (FISH) using specific DNA probes for chromosomes 1, 7, 10, and Y was performed on 53 prostatic tissue samples obtained from 33 radical prostatectomy specimens and two benign control specimens. The 53 samples from carcinomatous prostates included 33 cancerous and 20 noncancerous samples. Additionally, four metastatic lymph node specimens were examined. Clonal chromosome abnormalities were observed in 78% of the tumors studied. They were detected in a higher proportion in stage pT2 and pT3 tumors (86% and 88%, respectively) compared with stage pT1 tumors (25%). No stage pT4 tumor was analyzed. There was evidence of remarkable focal intratumoral heterogeneity documented by the study of two samples from the same tumor in three of six cases. Comparing FISH determined ploidy patterns with DNA flow cytometry (FCM) in 22 samples, FISH showed aneuploidy whereas FCM showed none.