ISSN:1040-8746    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Recent publications emphasized the correlation between molecular events in brain tumors and clinical outcome. Alterations in tumor-suppressor genes, growth factors, and enzyme systems have been previously described in gliomas; the relationships between these various changes and tumor grade, growth rate, and response to therapy are subjects of current investigations. Loss of genetic heterozygosity on chromosomes 10 and 17p, amplification and rearrangement of the epidermal growth factor receptor gene, express ion of its protein product, and changes in chromosomes 9, 19, and the enzyme system protein kinase C are the specific molecular events that were compared. Changes in chromosome 22 were correlated with histologic features of meningioma. Various methods of measuring tumor cell proliferation (proliferating cell nuclear antigen, bromodeoxyuridine, Ki-67, nucleolar organizer regions, and DNA flow cytometry) are being compared with each other and correlated with clinical outcome in an attempt to validate these methods and to discover the most relevant one. More recently described tumor types continue to be characterized using standard techniques and some of these newer methods. Neurocytoma has been morphologically and immunochemically defined as a neuronal neoplasm, but determination of the full compass of its clinical behavior and position in the continuum of cerebral neuronal tumors awaits additional studies.

ISSN:1040-8746    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Neurosurgery may be the ultimate treatment of benign tumors,eg, certain meningiomas and acoustic neurinomas; however, for invasive and malignant tumors, it is just another part in a multimodality approach coupled with radiotherapy, chemotherapy, and possibly immunotherapy. Still heading for more efficiency, new surgical techniques and aids have been developed. Their multiplicity and precision should encourage the neurosurgeon to even more carefully plan the type of surgery by a thorough preoperative evaluation. Preoperative management now not only assesses the size and the extent of the tumor but tries to find hints of its degree of malignancy to understand the perilesional edema and to guide the surgeon's hand. Although surgical approaches have been improved over the past years by the introduction of microsurgery, the ultrasonic aspirator, laser, and perioperative ultrasound, computer-assisted stereotactic neuronavigation seems to be the major novelty, and its future developments may prove to be of great medical value. Finally, the postoperative evaluation of the patient also benefits from new standards in neuroimaging and radionuclide investigations, allowing better estimation of residual tumor and early diagnosis of recurrence.

ISSN:1040-8746    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

This review concentrates on malignant gliomas, with brief mention of cerebral lymphomas, other primary intracranial tumors, and metastases. A recurring theme in the current literature on malignant glioma is the importance of prognostic factors other than treatment in determining outcome. Interesting results are emerging from newer strategies of stereotactic radiotherapy, brachytherapy, and photodynamic therapy, although authors who report these results acknowledge that they have often reviewed patients with intrinsically good prognoses. The year's literature has provided a consolidation of information on prognostic factors, relapse patterns, treatment volume, and dose, providing a basis for future progress.

ISSN:1040-8746    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

This review summarizes papers published during 1991 and 1992. The poor results obtained in the postneurosurgical treatment of gliomas led researchers to pursue attempts to try to overcome glioma cell resistance. The intra-arterial route was explored in several phase II studies with new drugs and even immunoconjugates; rates of response between 30% to 60% were obtained. New drugs (fotemustine, eflornithine, and estramustine) or combined protocols planned to circumvent chemoresistance were tested and showed some efficiency with moderate toxicity, enlarging the number of drugs available against malignant gliomas. On the contrary, two retrospective analyses warned about the risk of reduction of median time to survival due to adjuvant chemotherapy in anaplastic astrocytomas; this finding, if confirmed, would suggest to defer chemotherapy at the time of recurrence in this type of glial tumor. Immunobiologic therapies as immunomodifiers, immunoconjugates, or cytotoxic lymphocyte-activated killer cells and tumor-infiltrating lymphocytes were tested and allowed some responses to be obtained. In young children, chemotherapy regimens were found to be efficient in malignant plexus choroid carcinomas and low-grade gliomas, allowing radiation therapy to be deferred. Many studies were methodologically unsatisfactory because of uncertain pathology grouping, noncompliance to initial protocols, or too small populations of patients.

ISSN:1040-8746    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

The incidence of primary brain tumors has increased dramatically among elderly North Americans during the past two decades. Numerous chromosomal abnormalities have been associated with these tumors; various subsets of these abnormalities are specific to certain types of brain tumors. Astrocytic gliomas may exhibit losses of genetic information from chromosomes 9p, 10q, 11p, 13q, 17p, or 22. Mutations of thep53gene are found mostly in the malignant astrocytic forms and have been linked to malignant tumor transformation and progression. Functional and structural abnormalities of the neurofibromatosis 1 (NF1) gene and overexpression of the epidermal growth factor receptor have been associated with expression of the malignant glioma phenotype. Other less clearly defined abnormalities in astrocytomas include mutations of the retinoblastoma (RB) gene and overexpression of platelet-derived growth factor; transforming growth factor-α and -β; the c-erbB-1, c-myc, ras, c-fos, androsoncogenes; and insulin-like growth factor I and II. In other glioma tumors,p53mutations are either infrequent, as in oligodendrogliomas, or absent, as in ependymomas. Occasionally, rhedulloblastomas exhibitp53mutations and loss of genetic information from chromosomes 6q and 16q or expression of the c-erbB-2 oncogene. Loss of heterozygosity in chromosome 22 is the most frequent event in meningiomas, suggesting the presence of a tumor-suppressor gene in this chromosome.

ISSN:1040-8746    

出版商:OVID    

年代:1993

数据来源: OVID

ISSN:1040-8746    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

The integration of basic science perspectives into clinical head and neck oncology remains a priority. During this past year, we have witnessed initial results from many laboratories regardingp53expression. Point mutations in thep53gene have been identified and related to carcinogen exposure. Abnormalities inp53have been identified in not only intraepithelia neoplasia but also normal mucosa, suggesting an early genetic event. The ability to identify early genetic abnormalities will allow for earlier therapeutic strategies. The integration of basic science advances will likewise lead to improved prognostication and ultimately to improved staging. Prototypical of this process is DNA cytometric analysis. Reports in the past year have made use of integrated image analysis technology to measure both nuclear DNA content and nuclear volume. The incorporation of these measurements provided prognostic information beyond current staging techniques. Finally, the understanding of genetic alterations is beginning to carry with it potential therapeutic implications. Chromosome alterations at 11q13 may involve expression of several genes, including glutathione s-transferase (GST). Investigators have noted that the expression of this gene, as reflected in circulatingGSTblood levels, may predict chemotherapeutic responsiveness. Despite these basic science advances, population studies revealed that head and neck cancer mortality is increasing in certain segments of our society,eg, black American men. New strategies are required if improved survival from head and neck cancer is to be realized.

ISSN:1040-8746    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Recent publications dealing with the pathology of squamous carcinomas of the head and neck have been critically reviewed with particular reference to potential prognostic factors and improved methods for identifying nodal metastases. The topics covered include cytophotometry and proliferative patterns, molecular biology (EGFRandp53genes), cell adhesion molecules (E cadherin), and combined radiologic and pathologic approaches to detect small volume metastases in cervical lymph nodes.

ISSN:1040-8746    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

During the past year, several areas of head and neck surgery have had notable refinements and advancements. In the area of early laryngeal cancer, the complementary roles of radiation therapy and surgery have been discussed, as well as refinements in endoscopic laser techniques. Issues of the incidence of nodal metastasis and the role of in-continuity versus discontinuous neck dissection in oral and pharyngeal carcinoma have been considered. Rehabilitation techniques following treatment of oral cancer using free microvascular sensate flap reconstructions have been presented. The role of free jejunal interposition and gastric pull-up for reconstruction in hypopharyngeal cancer have been discussed, as well as their compatibility with postoperative radiotherapy. Finally, the concepts for treatment of neck nodal metastases have been discussed in relation to the roles of radiotherapy, radical neck dissection, and modified neck dissection.

ISSN:1040-8746    

出版商:OVID    

年代:1993

数据来源: OVID