Prognostic value of complete response after the initial treatment for malignant astrocytoma

Correlation between hypoxic area in primary brain tumors and WHO grade: differentiation from malignancy using 18F-fluoromisonidazole positron emission tomography

Background 18F-fluoromisonidazole positron emission tomography (FMISO-PET) has been used for identification of hypoxic areas in tumors, and since hypoxia causes hypoxia-inducible factor-1 and enhancement of tumor growth, identifying the hypoxic area in the tumor tissue is important. Purpose To evaluate the usefulness of FMISO-PET in the grading of primary brain tumors. Material and Methods FMISO-PET was performed preoperatively on 41 consecutive patients with pathologically confirmed brain tumor. A neuroradiologist retrospectively measured both maximum standardized uptake value (SUVmax) and mean SUV (SUVmean) in the tumor and normal cerebellar parenchyma. Maximum tumor/normal control ratio (T/Nmax) and mean tumor/normal control ratio (T/Nmean) were calculated and analyzed. Results There was a positive correlation between World Health Organization (WHO) grade and both T/Nmax and T/Nmean (r = 0.731 and 0.713, respectively). When all cases were divided into benign (WHO grade II) and malignant groups (III and IV), there were significant differences between the two groups in both T/Nmax and T/Nmean ( P < 0.001). If the cutoff value was defined as T/Nmax = 1.25 and T/Nmean = 1.23, T/Nmax had a sensitivity of 90.0% and a specificity of 90.9% while T/Nmean had a sensitivity of 93.3% and a specificity of 90.9% in differentiating the benign group from the malignant group. Conclusion Both T/Nmax and T/Nmean in FMISO-PET have a positive correlation with primary brain tumor grading, making FMISO-PET useful in diagnosing the malignancy of primary brain tumors.

Diffusion Tensor Imaging for Glioma Grading: Analysis of Fiber Density Index

Introduction:

The most common primary tumors of brain are gliomas and tumor grading is essential for designing proper treatment strategies. The gold standard choice to determine grade of glial tumor is biopsy which is an invasive method. The purpose of this study was to investigate the role of fiber density index (FDi) by means of diffusion tensor imaging (DTI) (as a noninvasive method) in glial tumor grading.

Methods:

A group of 20 patients with histologically confirmed diagnosis of gliomas were evaluated in this study. We used a 1.5 Tesla MR system (AVANTO; Siemens, Germany) with a standard head coil for scanning. Multidirectional diffusion weighted imaging (measured in 12 noncollinear directions), and T1 weighted nonenhanced were performed for all patients. We defined two regions of interest (ROIs); 1) White matter fibers near the tumor and 2) Similar fibers in the contralateral hemisphere.

Results:

FDi of the low-grade gliomas was higher than those of high-grade gliomas, which was significant (P=0.017). FDi ratio (ratio of fiber density in vicinity of the tumor to homologous fiber tracts in the contralateral hemisphere) is higher in low-grade than high-grade tumors, (P=0.05). In addition, we performed ROC (receiver operating characteristic) curve and the area under curve (AUC) was 0.813(P=0.013).

Conclusion:

Our findings prove significant difference in FDi near by low-grade and high-grade gliomas. Therefore, FDi values and ratios are helpful in glial tumor grading.

Practical surgical indicators to identify candidates for radical resection of insulo-opercular gliomas

Object

Maximum resection of gliomas with minimum surgical complications usually leads to optimum outcomes for patients. Radical resection of insulo-opercular gliomas is still challenging, and selection of ideal patients can reduce risk and obtain better outcomes.

Methods

This retrospective study included 83 consecutively treated patients with newly diagnosed gliomas located at the insulo-opercular region and extending to the sylvian fissure around the primary motor and somatosensory cortices. The authors selected 4 characteristics as surgical indicators: clear tumor boundaries, negative enhancement, intact lenticulostriate arteries, and intact superior extremity of the central insular sulcus.

Results

Univariate analysis showed that tumors with clear boundaries were associated with higher rates of gross-total resection than were tumors with ambiguous boundaries (75.7% vs 19.6%). Tumors with negative enhancement compared with enhanced tumors were associated with lower frequency of tumor progression (32.0% vs 81.8%, respectively) and lower rates of surgical complications (14.0% vs 45.5%, respectively). Tumors with intact lenticulostriate arteries were associated with higher rates of gross-total resection than were tumors with involved lenticulostriate arteries (67.3% vs 11.8%, respectively). Tumors with intact superior extremity of the central insular sulcus were associated with higher rates of gross-total resection (57.4% vs 20.7%, respectively) and lower rates of surgical complications (18.5% vs 41.4%, respectively) than were tumors with involved anatomical structures. Multivariate analysis showed that clear tumor boundaries were independently associated with gross-total resection (p < 0.001). Negative enhancement was found to be independently associated with surgical complications (p = 0.005), overall survival times (p < 0.001), and progression-free survival times (p = 0.004). Independent associations were also found between intact lenticulostriate arteries and gross-total resection (p < 0.001), between intact lenticulostriate arteries and progression-free survival times (p = 0.026), and between intact superior extremity of the central insular sulcus and gross-total resection (p = 0.043). Among patients in whom all 4 indicators were present, prognosis was good (5-year survival rate 93.3%), resection rate was maximal (gross-total resection 100%), and surgical complication rate was minimal (6.7%). Also among these patients, overall rates of survival (p = 0.003) and progression-free survival (p = 0.005) were significantly higher than among patients in whom fewer indicators were present.

Conclusions

The authors propose 4 simple indicators that can be used to identify ideal candidates for radical resection of insulo-opercular gliomas, improve the outcomes, and promote maximum resection without introducing neurological complications. The indicators are clear tumor boundaries, negative enhancement, intact lenticulostriate arteries, and intact superior extremity of the central insular sulcus.

Long-term expression of rAAV2-hIL15 enhances immunoglobulin production and lymphokine-activated killer cell-mediated human glioblastoma cell death

Glioblastoma is the most aggressive primary brain tumor and its prognosis remains poor despite different treatment modalities including surgery, radiotherapy and chemotherapy. Therefore, more useful treatments for glioblastoma patients are required. Human interleukin 15 (hIL15) is an immunomodulator that has antitumor activities. hIL15 combined with gene therapy method is also currently under cosideration as a treatment option. Since recombinant adeno-associated virus serotype 2 (rAAV2) with low immunogenicity and long-term gene expression in human clinical trials has been demonstrated, rAAV2 encoding hIL15 (rAAV2-hIL15) were used to inhibit human glioblastoma growth in the present study. rAAV2-hIL15, which is able to express IL15 protein with bioactivity, was successfully produced and purified. Data of this study demonstrated that the long-term expression of rAAV2-hIL15 enhances immunoglobulin (Ig) production and the cytotoxic activity of lymphokine-activated killer (LAK) cells. In addition, results of the present study showed that rAAV2-hIL15 delays tumor growth on a xenografted human glioblastoma mice model. Taken together, these results indicated that rAAV2-hIL15 constitutes a powerful and potent gene immunotherapy method for human glioblastoma treatment.

Conditional survival of high-grade glioma in Los Angeles County during the year 1990-2000

Survival probabilities for high-grade glioma are estimated at the time of diagnosis and provide limited information following treatment. This study determined dynamic indices to predict post-diagnosis survival for high-grade glioma patients. Survival information for 2,743 patients with high-grade glioma, diagnosed in Los Angeles County during the years 1990-2000, were used to estimate conditional survival probabilities with 95 % confidence intervals, for patients still alive at 1, 2, 3, 4, or 5 years after diagnosis. The conditional probabilities of surviving one additional year increase as the post-diagnosis survival time increases (from 43 ± 2 % conditional on surviving 1 year after diagnosis to 91 ± 2 % conditional on surviving 5 years after diagnosis). Patients diagnosed with WHO grade III gliomas have higher conditional survival probabilities than those diagnosed WHO grade IV gliomas. However, as the years after diagnosis increase, the differences in the conditional probabilities between the two groups are attenuated. At the time of diagnosis, age and tumor histology (WHO grade), tumor site, primary treatment, time of treatment start after diagnosis, as well as whether the patient was treated at a teaching hospital were significantly associated with overall survival. By 4 years post-diagnosis however, with the exception of age, variables associated with survival at baseline were no longer significantly associated with survival. Conditional survival probabilities provide clinically relevant information for understanding the prognosis for patients with high-grade gliomas.

Wireless modification of the intraoperative examination monitor for awake surgery

The dedicated intraoperative examination monitor for awake surgery (IEMAS) was originally developed by us to facilitate the process of brain mapping during awake craniotomy and successfully used in 186 neurosurgical procedures. This information-sharing device provides the opportunity for all members of the surgical team to visualize a wide spectrum of the integrated intraoperative information related to the condition of the patient, nuances of the surgical procedure, and details of the cortical mapping, practically without interruption of the surgical manipulations. The wide set of both anatomical and functional parameters, such as view of the patient's mimic and face movements while answering the specific questions, type of the examination test, position of the surgical instruments, parameters of the bispectral index monitor, and general view of the surgical field through the operating microscope, is presented compactly in one screen with several displays. However, the initially designed IEMAS system was occasionally affected by interruption or detachment of the connecting cables, which sometimes interfered with its effective clinical use. Therefore, a new modification of the device was developed. The specific feature is installation of wireless information transmitting technology using audio-visual transmitters and receivers for transfer of images and verbal information. The modified IEMAS system is very convenient to use in the narrow space of the operating room.

Can diffusion tensor metrics help in preoperative grading of diffusely infiltrating astrocytomas? A retrospective study of 36 cases

INTRODUCTION

Diffusion weighted imaging and diffusion tensor imaging (DTI) give information about the amount and directionality of water diffusion occurring in a given tissue. Here we study the role of diffusion tensor metrics including fractional anisotropy (FA) and spherical anisotropy (CS) in preoperative grading of diffusely infiltrating astrocytomas.

METHODS

We performed DTI in 38 patients with pathologically proven diffusely infiltrating astrocytomas, who were classified into two groups, i.e., 15 patients with high-grade astrocytoma (HGAs, WHO grade III and IV) and 23 patients with low-grade astrocytoma (LGAs, WHO grade II). We measured maximum FA and minimum CS values in all cases from tumor. Histopathological diagnosis was established in all cases.

RESULTS

The mean maximum FA values were higher in HGA (0.583 ± 0.104) than LGA (0.295 ± 0.058), while mean minimum CS values were lower in HGA (0.42 ± 0.121) than LGA (0.722 ± 0.061). The difference in the diffusion tensor indices between HGA and LGA was found to be statistically significant with P value of <0.001. Keeping cutoff FA value of 0.4, all HGAs showed higher maximum FA values, and all LGAs showed lower maximum FA values. Also, all HGAs showed minimum CS values less than a cutoff value of 0.6, and all LGAs showed minimum CS values higher than 0.6.

CONCLUSION

Diffusion tensor metrics such as maximum FA and minimum CS can help to differentiate HGA from LGA.

Three-dimensional conformal radiotherapy for hepatocellular carcinoma with inferior vena cava invasion

BACKGROUND

Hepatocellular carcinoma with inferior vena cava invasion is a rare but fatal condition of disease progression. The aim of this study was to analyze the results of treatment for hepatocellular carcinoma with inferior vena cava invasion by three-dimensional conformal radiation therapy.

METHODS

From 1990 to 2006, 18 histopathologically confirmed hepatocellular carcinoma patients with inferior vena cava invasion who were unsuitable for surgery were treated by three-dimensional conformal radiation therapy at our hospital with two to four static or dynamic conformal arc fields.

RESULTS

A median total tumor dose of 50 Gy (range 30-60 Gy) was delivered. The progression-free rate was 91.6% among the patients in whom follow-up computed tomography was obtained. Actuarial survival at 1 year was 33.3%, and the median survival period was 5.6 months.

CONCLUSIONS

Three-dimensional conformal radiation therapy might offer a chance of long survival for a part of the hepatocellular carcinoma patients with inferior vena cava invasion, since a third of such patients survived more than a year. Additional treatments should be considered to prevent distant metastases and hepatic functional deterioration after three-dimensional conformal radiation therapy.

Minute glioma identified by 3.0 Tesla magnetic resonance spectroscopy--case report

A 33-year-old man presented with a minute tumor incidentally detected by magnetic resonance (MR) imaging screening. 1.5 Tesla MR spectroscopy indicated normal brain tissue whereas 3.0 Tesla MR spectroscopy indicated neoplasm. The tumor was completely resected. The histological diagnosis was fibrillary astrocytoma. Minute glioma, measuring less than 15 mm in diameter on MR imaging, can be completely resected, resulting in a good prognosis. 3.0 Tesla MR spectroscopy can establish the diagnosis in the early stage of glioma.

Diffusion tensor imaging for preoperative evaluation of tumor grade in gliomas

The relationship between water diffusion parameters measured using diffusion tensor imaging (DTI) and histological malignancy of gliomas was investigated. DTI was performed using a 3.0T MR scanner in 41 consecutive patients with histologically proven gliomas. Fractional anisotropy (FA) and mean diffusivity (MD) were calculated and compared with the WHO classification of the gliomas. The FA values of grade 1 gliomas (0.150 +/- 0.017) were significantly lower than those of grade 3 (0.23 +/- 0.033) or grade 4 gliomas (0.229 +/- 0.033) (P < 0.0001, respectively). The FA values of grade 2 gliomas (0.159 +/- 0.018) were significantly lower than those of grade 3 or grade 4 gliomas (P = 0.0002, P < 0.0001, respectively). The FA threshold between low grade and high grade gliomas was 0.188. The MD values of grade 1 gliomas (1619.1 +/- 157.4 x 10(-6) mm2/s) were significantly higher than those of grade 3 (1084.5 +/- 218.9 x 10(-6) mm2/s) (P = 0.0036) or grade 4 gliomas (1098.0 +/- 291.6 x 10(-6) mm2/s) (P = 0.0002). The MD values were not correlated with the other grades of glioma. FA values can distinguish between high grade and low grade gliomas. This is useful in deciding the surgical strategy or selecting the site of stereotactic biopsy.

Analysis of the extent of astrocytic tumour resection evaluated by magnetic resonance images

One of the most important prognostic factors in brain tumours is the extent of tumour resection. Its evaluation has been difficult on computed tomography (CT); however, magnetic resonance imaging (MRI) can clearly determine the extent of tumour resection. Using MRI, we analyzed 77 patients with astrocytic tumours that were surgically treated at our department from 1994 to 2001. The tumours were classified into the following types: (a) well-circumscribed: single lesions that can be distinguished from normal brain; (b) localised: single lesions that are localised in one gyrus; and (c) diffuse: other tumours. Our treatment of glioma resection is to use sulcus opening and gyrectomy, a technique based on identification and dissection of the sulcus adjacent to the tumour followed by en bloc tumour resection. Almost total tumour resection (> or =95% resection) was achieved in 76.8% in the well-circumscribed type, 100% in the localised type, and only 10.5% in the diffuse type. Nearly total resection was achieved in 61%, which is considerably more than in the literature of the CT era (10.4-23.5%). The sulcus opening and gyrectomy technique based on MRI achieved radical glioma removal in cases which could be identified by MRI, resulting in a better tumour removal rate than that based on CT.

AV.TK-mediated killing of subcutaneous tumors in situ results in effective immunization against established secondary intracranial tumor deposits

Gene transfer vectors expressing herpes simplex thymidine kinase (HSVtk), in addition to direct killing of tumor cells, often have an associated local "bystander effect" mediated by metabolic coupling of tumor cells. A systemic antitumor effect mediated by the immune system, termed the distant bystander effect, has also been reported. We have observed the development of cytotoxic T-lymphocyte (CTL) populations and long-lasting antitumor immunity following treatment of subcutaneous tumors with an adenoviral vector expressing HSVtk (AV.TK) and ganciclovir (GCV) in rat glioma model. This vaccination effect seen with AV.TK/GCV treatment of subcutaneous tumor could even abrogate or retard growth of previously established secondary intracranial tumors.