Search results for "Medulloblastoma"
showing 6 items of 36 documents
Medulloblastoma in Adulthood
2021
Abstract Defined as a tumour with increased malignancy potential in childhood, medulloblastoma was first reported in the literature by Percival Bailey and Harvey Cushing in 1925. Scientific studies over the years have shown that this type of tumour represents about 20% of all intracranial tumours encountered in childhood, their percentage decreasing with advancing age. The genetic factor plays an important part in the appearance of medulloblastoma; there are certain diseases, in the patient’s history, that can be associated with this type of tumour. Here, we can specify Turcot syndrome (an autosomal recessive disease, rarely encountered) or basal cell carcinoma syndrome. This article presen…
Evaluation of Prognostic Factors and Role of Participation in a Randomized Trial or a Prospective Registry in Pediatric and Adolescent Nonmetastatic …
2020
Purpose: We aimed to compare treatment results in and outside of a randomized trial and to confirm factors influencing outcome in a large retrospective cohort of nonmetastatic medulloblastoma treated in Austria, Switzerland and Germany. Methods and Materials: Patients with nonmetastatic medulloblastoma (n = 382) aged 4 to 21 years and primary neurosurgical resection between 2001 and 2011 were assessed. Between 2001 and 2006, 176 of these patients (46.1%) were included in the randomized HIT SIOP PNET 4 trial. From 2001 to 2011 an additional 206 patients were registered to the HIT 2000 study center and underwent the identical central review program. Three different radiation therapy protocols…
Time-point and dosage of gene inactivation determine the tumor spectrum in conditional Ptch knockouts
2009
Mutations in Patched (PTCH) have been associated with tumors characteristic both for children [medulloblastoma (MB) and rhabdomyosarcoma (RMS)] and for elderly [basal cell carcinoma (BCC)]. The determinants of the variability in tumor onset and histology are unknown. We investigated the effects of the time-point and dosage of Ptch inactivation on tumor spectrum using conditional Ptch-knockout mice. Ptch heterozygosity induced prenatally resulted in the formation of RMS, which was accompanied by the silencing of the remaining wild-type Ptch allele. In contrast, RMS was observed neither after mono- nor biallelic postnatal deletion of Ptch. Postnatal biallelic deletion of Ptch led to BCC preca…
A Log-Rank Test for Equivalence of Two Survivor Functions
1993
We consider a hypothesis testing problem in which the alternative states that the vertical distance between the underlying survivor functions nowhere exceeds some prespecified bound delta0. Under the assumption of proportional hazards, this hypothesis is shown to be (logically) equivalent to the statement [beta[log(1 + epsilon), where beta denotes the regression coefficient associated with the treatment group indicator, and epsilon is a simple strictly increasing function of delta. The testing procedure proposed consists of carrying out in terms of beta (i.e., the standard Cox likelihood estimator of beta) the uniformly most powerful level alpha test for a suitable interval hypothesis about…
Measurements of the volume and density of intracerebral tumors by CT following therapy.
1982
For the interpretation of curative measures in patients with cerebral tumors CT is of increasing importance. The therapeutic effects can be demonstrated by close follow-up studies without any of the disadvantage of invasive neuroradiological methods. Our investigations of 125 patients with cerebral tumors are based on volume and density determinations. The CT studies of removed or inoperable tumors followed by radiation and/or cytostatic therapy prove that the best results follow a combination of both. In the present cases however, if CT proves postoperatively, at the end of radiation or at the beginning of the application of cytostatics that there is a residual mass, a complete remission c…
Treatment of early childhood medulloblastoma by postoperative chemotherapy alone.
2005
The prognosis for young children with medulloblastoma is poor, and survivors are at high risk for cognitive deficits. We conducted a trial of the treatment of this brain tumor by intensive postoperative chemotherapy alone.After surgery, children received three cycles of intravenous chemotherapy (cyclophosphamide, vincristine, methotrexate, carboplatin, and etoposide) and intraventricular methotrexate. Treatment was terminated if a complete remission was achieved. Leukoencephalopathy and cognitive deficits were evaluated.Forty-three children were treated according to protocol. In children who had complete resection (17 patients), residual tumor (14), and macroscopic metastases (12), the five…