Biomedical subjects

L Kun

Publications and source records attributed to L Kun.

At least 19 recordsLinked to original sources

PubMed2001

Patterns of intellectual development among survivors of pediatric medulloblastoma: a longitudinal analysis.

PURPOSE: To examine two competing hypotheses relating to intellectual loss among children treated for medulloblastoma (MB): Children with MB either: (1) lose previously learned skills and information; or (2) acquire new skills and information but at a rate slower than expected compared with healthy same-age peers. PATIENTS AND METHODS: Forty-four pediatric MB patients were evaluated who were treated with postoperative radiation therapy (XRT) with or without chemotherapy. After completion of XRT, a total of 150 examinations were conducted by use of the child version of the Wechsler Intelligence SCALES: These evaluations provided a measure of intellectual functioning called the estimated full-scale intelligence quotient (FSIQ). Changes in patient performance corrected for age (scaled scores) as well as the uncorrected performance (raw scores) were analyzed. RESULTS: At the time of the most recent examination, the obtained mean estimated FSIQ of 83.57 was more than one SD below expected population norms. A significant decline in cognitive performance during the time since XRT was demonstrated, with a mean loss of 2.55 estimated FSIQ points per year (P =.0001). An analysis for the basis of the intelligence quotient (IQ) loss revealed that subtest raw score values increased significantly over time since XRT, but the rate of increase was less than normally expected, which resulted in decreased IQ scores. CONCLUSION: These results support the hypothesis that MB patients demonstrate a decline in IQ values because of an inability to acquire new skills and information at a rate comparable to their healthy same-age peers, as opposed to a loss of previously acquired information and skills.

Adolescent↗

PubMed2001

Growth hormone replacement therapy in children with medulloblastoma: use and effect on tumor control.

PURPOSE: Progress has been made in the treatment of medulloblastoma, the most common childhood malignant brain tumor: However, many long-term survivors will have posttherapy growth hormone insufficiency with resultant linear growth retardation. Growth hormone replacement therapy (GHRT) may significantly improve growth, but there is often reluctance to initiate GHRT because of concerns of an increased likelihood of tumor relapse. PATIENTS AND METHODS: This study retrospectively reviewed the use of GHRT for survivors of medulloblastoma in 11 neuro-oncology centers in North America who received initial treatment for disease between 1980 and 1993 to determine its impact on disease control. A Landmark analysis was used to evaluate the relative risk of relapse in surviving patients. RESULTS: Five hundred forty-five consecutive patients less than 15 years of age at diagnosis were identified. Six-year progression-free survival (mean +/- SD) was 40% +/- 5% in children less than 3 years of age at diagnosis compared with 59% +/- 3% for older patients. Older patients with total or near-total resections (P = .003) and localized disease at diagnosis (P < .0001) had the highest likelihood of survival. One hundred seventy patients (33% +/- 3% of the cohort) received GHRT. GHRT use varied widely among institutions, ranging from 5% to 73%. GHRT was begun a mean of 3.9 years after diagnosis, later in children younger than 3 years at diagnosis (5.4 years). By Landmark analyses, for those surviving 2, 3, and 5 years after diagnosis, there was no evidence that GHRT increased the rate of disease relapse. CONCLUSION: This large retrospective review demonstrates that GHRT is underutilized in survivors of medulloblastoma and is used relatively late in the course of the illness. GHRT is not associated with an increased likelihood of disease relapse.

Adolescent↗

PubMed2001

Emergency re-operation for postoperative hemorrhage following partial esophagectomy for carcinoma of the esophagus and cardia of the stomach.

The clinical records of 12 cases of emergency re-operation for management of postoperative hemorrhage (POH) following partial esophagectomy and esophago-gastrostomy or colonic interposition for a group of 3690 cases of carcinoma of the esophagus (CE) and cardia of the stomach in this institute between August 1954 and April 2001 were studied. There were 10 survivors and two deaths, giving a mortality rate of 16.6% (2/12). It was concluded that an emergency re-operation was a cardinal surgical procedure to save the patient's life if a serious POH had developed. The POH could be prevented by a careful, conscientious and strict hemostasis during the primary operation. The criteria for the diagnosis are presented.

Adult↗

PubMed2001

Pleomorphic xanthoastrocytoma: favorable outcome after complete surgical resection.

To describe the clinical features, histologic characteristics, and management of patients with pleomorphic xanthoastrocytoma (PXA), we reviewed data on 13 children who had histologically confirmed PXA and were referred to the neuro-oncology service between 1985 and 1999. Neuro-imaging with CT and/or MRI documented the anatomic location, tumor extent, and degree of resection. There were 3 males and 10 females; median age was 12.9 years (range, 8.2-17.2 years). The most frequent presentations included seizures (n = 8) and headache (n = 5). Tumor sites included temporal (n = 5), parietal (n = 3), frontal (n = 1), frontoparietal (n = 1), parietooccipital (n = 1), and temporoparietal (n = 1) lobes and the spinal cord (n = 1). CT/MRI revealed a cystic component in 6 patients, with cyst wall enhancement in 3 patients. The solid component was uniformly enhancing in 11 patients. Vasogenic edema was present in 9 patients, and calcification was noted in 4 patients. Histopathologic findings included meningeal invasion in 12 patients, calcifications in 4, and necrosis in 2. Mitotic figures (1-12 per high-power field) were seen in 8 patients. Gross total resection was achieved in 8 patients, near total resection in 1, and subtotal resection in 4. Ten patients were alive with a median follow-up of 41 months at this writing. Two patients died of progressive disease, and 1 died of an unrelated cause. In conclusion, pleomorphic xanthoastrocytoma is a rare neoplasm in childhood, commonly presenting with seizures. Gross total resection without adjuvant therapy provides prolonged disease control, as seen in 6 of 7 patients (85%) in our series.

Adolescent↗

PubMed2000

Late effects in survivors of infant leukemia.

Little is known about the incidence of and risk factor for late effects of infant leukemia. We evaluated 19 children with acute lymphoblastic leukemia and 15 with acute myeloid leukemia who were diagnosed at age 12 months or younger and have survived for more than 5 years after the diagnosis (median length of follow-up, 13 years; range, 5.7-29 years). Ten patients received chemotherapy alone (group A), 17 received chemotherapy and CNS-directed radiation therapy (CRT) (group B), and seven received chemotherapy, CRT and bone marrow transplantation (group C). The most frequently observed late sequelae included problems in growth (66% of survivors), learning (50%), hypothyroidism (15%), and pubertal development (12%). Cataract, cardiac and hearing abnormalities occurred in 6% of patients. Only eight patients (24%) survive without late effects. In comparison to patients in group A, patients in groups B and C had a higher incidence of having at least one late complication (P = 0.009), a greater decrease in height Z score at 5 years after diagnosis (P = 0.023), and a higher incidence of academic difficulties (P = 0.004). The estimated odds of academic difficulties increased by 18% (P = 0.032) for each month younger in age at the time of CRT. These results indicate that late sequelae are common in longterm survivors of infant leukemia and are often related to CRT and the patient's age at the time of CRT.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2000

Silent lacunar lesions detected by magnetic resonance imaging of children with brain tumors: a late sequela of therapy.

BACKGROUND: Cerebral lacunes, which generally appear on magnetic resonance imaging as foci of white matter loss, usually occur in adults after ischemic infarcts. We report the development of lacunes in children after therapy for brain tumors. PATIENTS AND METHODS: We reviewed the clinical characteristics and radiologic studies of 524 consecutive children with brain tumors treated over a 10-year period. We documented the neuropsychologic findings associated with lacunes and the factors predictive of lacunar development. RESULTS: Lacunes developed in none of the 103 patients observed or treated with surgery alone. Twenty-five of the 421 patients treated with chemotherapy or radiation therapy or both had lacunes. Patients were a median of 4.5 years old at the time of both diagnosis (range, 0.3 to 19.8 years) and radiotherapy (range, 1.5 to 20 years). Fourteen patients were treated with craniospinal irradiation, and 11 were treated with local radiotherapy. The median time from radiotherapy to the appearance of lacunes was 2.01 years (range, 0.26 to 5.7 years). For all patients, lacunes were an incidental finding with no corresponding clinical deficits. The factor most predictive of lacunar development was age less than 5 years at the time of radiotherapy (P =.010). There was no significant difference in estimated decline in intelligence quotient scores between patients with lacunes and age and diagnosis-matched controls. CONCLUSION: Lacunes may be caused by therapy-induced vasculopathy in children with brain tumors, with the most significant predictor being age less than 5 years at the time of radiotherapy.

Adolescent↗

PubMed1997

Isolation of novel HLA-DR restricted potential tumor-associated antigens from the melanoma cell line FM3.

Endogenous peptides bound to the constitutively expressed MHC class II molecules HLA-DR and HLA-DQ of the melanoma cell line FM3 were examined. By a combination of analytical methods (narrow bore and capillary reversed-phase high-performance liquid chromatography with subsequent spotting on polyvinylidene difluoride membranes, matrix-assisted laser desorption ionization mass spectrometry, and Edman microsequencing), we were able to isolate and identify a panel of HLA-DR4/2 (HLA-DRB1*0401/0201/DRB5*0101)-associated self-peptides from the melanoma cell line FM3. Among ubiquitously HLA-DR-associated peptides such as peptides from the class II-associated invariant chain peptide region of the invariant chain, HLA-class I, the transferrin receptor, and the IFN-gamma receptor, we identified several potential tumor-associated antigens stemming from the MHC class I-restricted tumor antigen gp100, the Ca2(+)-binding protein annexin II, and proteins from the hsp70 family. Chinese hamster ovary cells cotransfected with HLA-DRA, DRB1*0401, and CD80 genes were shown specifically to prime T lymphocytes from HLA-DRB1*0401 donors to the annexin II and gp100 peptides. These results demonstrate that MHC class II molecules expressed by melanoma cells potentially present a variety of novel antigens to the immune system, some of which could be exploited for immunotherapy.

Animals↗

PubMed1996

DNA index of glial tumors in children. Correlation with tumor grade and prognosis.

BACKGROUND: Although DNA index (DI) has prognostic significance in a variety of pediatric malignancies, there are few data regarding its utility in central nervous system (CNS) tumors. We have previously shown that patients with hyperdiploid medulloblastoma have a significantly better survival than those whose tumors are diploid. Here, we examine the effect of DI and tumor grade on the progression free survival (PFS) of 57 patients with a variety of glial neoplasms. METHODS: DI was determined by flow cytometry on freshly obtained tumor tissue from the initial diagnostic specimens; a DI = 1.0 was defined as diploid (DIP), 1.0 < DI < 1.1 as near diploid (NDIP), and DI > 1.1 as hyperdiploid (HYP). Tumors were histologically graded according to the World Health Organization classification. RESULTS: There were 21 Grade I tumors, 20 Grade II, 8 Grade III, and 8 Grade IV. Among the 41 low grade tumors (Grade I-II), 39 were DIP or NDIP, and 2 were HYP. Among the 16 high grade tumors (Grade III-IV), 9 were DIP, 2 NDIP, and 5 HYP. The 4-year PFS of low grade tumors was 70% (standard deviation [SD] 12%) versus 8% (SD 7%) for high grade tumors. There was a significant correlation between low grade tumor histology and a DIP/NDIP DI (P = 0.015), and univariate analysis suggested improved PFS was associated with DIP/NDIP tumors (P = 0.05). However, DI did not remain a significant prognostic factor after being stratified by tumor grade (P = 0.87). CONCLUSIONS: Unlike medulloblastoma, DI is not an independent prognostic factor in pediatric glial tumors.

Adolescent↗

PubMed1996

[Relationship between intestinal permeability and antibodies against food antigens in IgA nephropathy].

Elevated antibody titers to food antigens and increased intestinal permeability in IgA nephropathy (IgA NP) suggest that these factors may be interdependent and play a role in the pathogenesis of the disease. In 1989 IgA and IgG antibodies against eight common food antigens were examined in the sera of 35 IgA NP patients and 12 controls using the ELISA method. Intestinal permeability was determined in 29 IgA NP patients and 20 controls using the 51Cr-EDTA test. Both examinations were carried out in 17 patients. Twenty-one patients allowed the intestinal permeability examinations to be repeated five years later. Compared with controls, significantly elevated IgA antibody titers against gliadin, soy, HAV (salt extracted antigens of oat flour) and ovalbumin were found. Intestinal permeability was significantly higher in IgA NP patients both in 1989 (3.86% +/- 0.29 vs. control, 2.72% +/- 0.23; p < 0.005) and in 1994 (4.57% +/- 0.63; p < 0.02) than in controls. A strong correlation was observed between the intestinal permeability and the IgA type of antibody titers against soy (p < 0.01; r = 0.72) and HAV (p < 0.02; r = 0.57). In patients without azotemia (serum creatinine > 150 mumol/l; n = 22) the decrease in creatinine clearance was significant only in the cases of increased intestinal permeability. On the basis of these data we assume that there is a connection between intestinal permeability and the production of IgA type antibody against food antigens in least a proportion of patients with IgA NP, and as a results of the lasting increase in intestinal permeability the production and the mesangial deposition of IgA immunocomplexes also increase.

Antibodies↗

PubMed1996

Results of a prospective randomized trial comparing standard dose neuraxis irradiation (3,600 cGy/20) with reduced neuraxis irradiation (2,340 cGy/13) in patients with low-stage medulloblastoma. A Combined Children's Cancer Group-Pediatric Oncology Group Study.

PURPOSE: To determine in a prospective randomized trial the effect on survival, progression-free survival, and patterns of relapse of a decrease in the neuraxis radiation dose from 3,600 cGy in 20 fractions to 2,340 cGy in 13 fractions in patients with newly diagnosed medulloblastoma between 3 and 21 years of age with low T stage (T1, T2 and T3A), minimal postoperative residual tumor, and no evidence of dissemination (M0). METHODS AND MATERIALS: Between June 1986 and November 1990, the Children's Cancer Group and the Pediatric Oncology Group randomized 126 patients in a two-arm study comparing the two different doses of neuraxis irradiation. In both arms, the posterior fossa received 5,400 cGy in 30 fractions. All patients were staged with myelography, postoperative lumbar cerebrospinal fluid cytology, and postoperative contrast-enhanced cranial computerized tomography to ensure no evidence of dissemination and no more than 1.5 cm3 residual tumor volume. Overall survival, progression-free survival, and patterns of recurrence were carefully monitored. Prospective endocrine and psychometric studies were performed to determine the benefit of decreasing the neuraxis radiation dose. RESULTS: Following an interim analysis at a median time on study of 16 months, the study was closed, since a statistically significant increase was observed in the number of all relapses as well as isolated neuraxis relapses in patients randomized to the lower dose of neuraxis radiation. CONCLUSIONS: In patients with newly diagnosed medulloblastoma considered to have a good prognosis on the basis of low T stage, minimal residual tumor after at least subtotal resection, and no evidence of dissemination after thorough evaluation, there is an increased risk of early relapse associated with lowering the dose of neuraxis radiation from 3,600 cGy in 20 fractions to 2,340 cGy in 13 fractions.

Adolescent↗

PubMed1996

Do intestinal hyperpermeability and the related food antigens play a role in the progression of IgA nephropathy? I. Study of intestinal permeability.

Intestinal permeability was investigated by using 51Cr-EDTA as a probe molecule in 29 patients with immunoglobulin A nephropathy (IgA NP) and 20 healthy controls in 1990. Intestinal permeability was significantly higher in the IgA NP patients than in the controls (IgA NP, 3.86 +/- 0.29%; controls, 2.72 +/- 0.23%, p < 0.005). There was a significant relation between the manifestations of the disease (proteinuria and/or microhematuria) and the increased intestinal permeability (p < 0.05). By 1994, after an interval of 4 years, average intestinal permeability in the 21 patients available for study had not changed (3.80 +/- 0.36 vs. 4.57 +/- 0.63%) and was significantly higher than in the controls (p < 0.02). In patients with elevated serum IgA levels (serum IgA > 3.2 g/l; n = 15) there was a significant correlation between serum IgA levels and the degree of intestinal permeability (p < 0.02). During the 4-year period, the patients' kidney function deteriorated (n = 25; creatinine clearance in 1990, 92.4 +/- 6.1 ml/min; in 1994, 73.9 +/- 7.6 ml/min; p < 0.0002), the deterioration being greater in patients with increased intestinal permeability. There was no relation between the histologic grade of the biopsy specimen, hypertension and intestinal permeability. These data collected over a 4-year period suggest that in IgA NP increased intestinal permeability may play a role in the pathogenesis of the disease and adversely influence its progression.

Adult↗

PubMed1996

Response of recurrent medulloblastoma to low-dose oral etoposide.

PURPOSE: The outcome for patients with recurrent medulloblastoma has historically been poor, with most patients dying of disseminated disease. Here, we report on seven patients with recurrent medulloblastoma, most heavily pretreated with a variety of chemotherapeutic agents, including parenteral etoposide (VP-16), who showed responses to the administration of repeated courses of low-dose oral VP-16. PATIENTS AND METHODS: Seven patients age 4 to 16 years were treated with VP-16 after neuroradiographic and clinical evidence of tumor progression. Six had received prior irradiation. All seven had been pretreated with a variety of chemotherapeutic agents and schedules, including parenteral VP-16. VP-16 was administered orally as repeated 21-day courses at 50 mg/m2/d with a 7-day interval between courses. Evaluation consisted of neuroradiographic and clinical examination after completion of every two courses of therapy. Complete blood cell counts were performed weekly. RESULTS: The major toxicity of oral VP-16 was hematologic, with two patients requiring platelet transfusions due to thrombocytopenia and two requiring RBC transfusions. All seven patients developed treatment-related neutropenia. Two patients were supported with granulocyte colony-stimulating factor (G-CSF) between courses. One patient developed infectious epididymitis after course 2 and required intravenous antibiotics; this illness was complicated by Clostridium difficile colitis. There was one episode of fever associated with neutropenia. There were no treatment-related deaths. Of seven patients assessed, six have demonstrated partial responses (PRs) and the remaining patient had stable disease (SD). CONCLUSION: This report demonstrates the activity of oral VP-16 in the treatment of a small cohort of pretreated patients with recurrent medulloblastoma. This form of administration of oral VP-16 was well tolerated and produced modest toxicity.

Administration, Oral↗

PubMed1995

Results of pediatric oncology group protocol 8104 for infants with stages D and DS neuroblastoma.

PURPOSE: We determined the complete response and survival rates for infants with disseminated (stage D) neuroblastoma that followed therapy identical to that for regional disease. In those infants whose disease excluded cortical bone metastases (stage DS), we determined complete response rates achieved either spontaneously or with stage D therapy. PATIENTS AND METHODS: Eighty-eight patients with metastatic disease received induction chemotherapy followed by a second operation, the results of which determined additional therapy. Twenty-five patients were observed after diagnosis, without chemotherapy, until a second operation. RESULTS: The complete response (CR) rates for patients with stage D disease after induction chemotherapy and postinduction surgery were 26% and 52%, respectively, and for immediately treated patients with stage DS disease 69% and 77%, respectively. Fifty-four percent of initially observed patients with stage DS disease achieved CR after a second operation; 44% were never treated beyond these two operations. Five-year actuarial survival rates for patients with stage D and for all those with stage DS disease were 60% (SE = 6%) and 90% (SE = 5%), respectively. CONCLUSIONS: Improved survival rates for patients with stage D disease were achieved on this protocol but remained considerably lower than those for infants with less extensive disease. Rates of survival for patients with stage DS disease were achieved with therapy less aggressive than in published series.

Child↗

PubMed1995

An intensive re-treatment protocol for children with an isolated CNS relapse of acute lymphoblastic leukemia.

PURPOSE: To assess the salvage rate and long-term complications among children treated with an intensive regimen for isolated CNS relapse during first remission of acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: Twelve boys and eight girls, diagnosed at a median age of 4 years, had CNS relapse at a median age of 7 years. Five had CNS leukemia at presentation, while five completed treatment before relapse. First complete remission lasted a median of 22.5 months. Ten patients had received cranial irradiation plus intrathecal (IT) therapy, and the remainder had received high-dose intravenous and/or IT methotrexate (MTX) as CNS-directed treatment. Retrieval therapy consisted of a five-agent intensive reinduction regimen followed by continuation therapy with four rotating drug pairs. Triple-IT therapy was administered weekly for 4 to 5 weeks, then every 6 weeks until craniospinal radiation (cranium, 24 Gy; spine, 15 Gy; both sites, 1.5 Gy per fraction) was administered. RESULTS: All 20 children achieved a second complete remission. The 5-year estimate of disease-free survival (mean +/- SE) was 70% +/- 11%. Thirteen patients remain in remission at 71+ to 126+ months (median, 104+), and 10 of 13 patients tested have normal IQ scores. Four patients have had a second relapse (one CNS and three non-CNS), and three have developed other malignancies. Prior cranial irradiation was associated with subsequent failure; only three of 10 patients who previously received radiotherapy, compared with all of the other 10 patients, remained in second remission. CONCLUSION: This intensive retrieval therapy is effective and well tolerated by children with an isolated CNS relapse of ALL, especially those who have not received prior cranial irradiation. Most patients have no significant neuropsychologic impairment.

Adolescent↗

PubMed1995

Altered humoral immunity against cytomegalovirus and Epstein-Barr virus without detectable virus antigens and virus-DNA in the glomeruli of patients with IGA nephropathy in remission phase.

Herpes viruses, such as cytomegalovirus (CMV) and Epstein-Barr virus (EBV), very often occur in the nasopharynx. A pathogenetic role of these viruses in immunoglobulin A nephropathy (IgA NP) is a challenging hypothesis, since upper respiratory tract infections are frequently and closely related in time to the acute episodes of IgA NP. However, conflicting reports have been published in this field. We compared the IgA and IgG antibody (AB) titres against cytomegalovirus (CMV) in sera of 41 IgANP patients with 80 healthy controls. The prevalence rates of CMV-IgA and CMV-IgG AB were significantly higher in patients with IgA NP than in healthy controls (CMV-IgA, titre > = 8, p < 0.001; CMV-IgG, titre > = 16, p < 0.05). There was also a significant difference in the concentration of CMV-IgA AB between IgANP patients and controls (IgA NP: 0.34 +/- 0.66, healthy controls: 0.06 +/- 0.33, mean +/- SD, p = < 0.002), but not in the concentration of CMV-IgG AB between NP patients and controls. While examining 60 patients with IgA NP and 75 healthy controls a significantly elevated prevalence rate of IgA AB against EBV capsid antigen (EBV-VCA) was also detected in the sera of IgA NP patients vs controls (titre > = 16; p < 0.05). There was no significant difference in the prevalence of IgG AB to EBV-VCA between patients with IgA NP and healthy controls, except at titre = 1024 (p < 0.05). At a follow-up, CMV-IgA persisted in 4 of 5, and EBV-VCA-IgA in 8 of 12 seropositive patients with IgA NP. We could not detect virus antigens or virus deoxyribonucleic acid (DNA) in the glomeruli of NP patients either with immunohistology using a monoclonal antibody or with the DNA in situ hybridization technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

Ligation of the thoracic duct without thoracotomy for the treatment of postoperative chylothorax: a newly designed surgical procedure.

A newly designed surgical procedure of ligation of the thoracic duct without thoracotomy for the treatment of postoperative chylothorax is presented. A case of chylothorax following resection of carcinoma of the oesophagus was treated successfully with ligation of the thoracic duct without thoracotomy. Its advantages were very prominent consisting of maintenance of the integrity of the thorax, less traumatization, no need of a drainage tube and shorter hospitalization, much easier to expose the thoracic duct than the conventional transthoracic approach. We can find no similar report in any published literature.

Chylothorax↗

PubMed1994

Systematic analysis of errors in target localization and treatment delivery in stereotactic radiosurgery (SRS).

PURPOSE: To systematically analyze the spatial uncertainties associated with each step of the stereotactic radiosurgery (SRS) procedure and the overall spatial accuracy in the treatment delivery. METHODS AND MATERIALS: A special test device has been designed and fabricated to permit accurate simulation, localization and treatment portal verification of a SRS target. This device with simulated targets dispersed in 3-D space can be rigidly attached to the BRW CT or angio frame for localization, to the BRW phantom base for target coordinate determination, and to the floor stand for portal verification. The setup allows evaluation of the accuracy of each procedure separately as well as the overall accuracy in the delivery of SRS treatment. RESULTS: Biplanar film localizations reveal a systematic error in the phantom base pointer of the order of 0.1 mm that is applied as a correction to the measured target coordinates. Targets localized by planar film angiography had a mean positional error of 0.38 +/- 0.1 mm compared to 1.0 +/- 0.7 mm for digital angiographic localization. The positional accuracy associated with CT localization was superior when a 2 mm vs. 4 mm slice thickness was used (0.9 +/- 0.3 mm vs. 1.6 +/- 0.5 mm error). Cumulative mean errors, including inaccuracies associated with treatment setup, were 1.0 +/- 0.4 mm for radiographic localization, 1.2 +/- 0.5 mm for CT with a 512 x 512 matrix and 2 mm slice thickness, and 2.0 +/- 0.6 mm for CT at a 4 mm slice thickness (256 x 256 matrix). Larger errors would be expected in the clinical setting. CONCLUSION: Spatial errors in stereotactic radiosurgery are best estimated using a systematic approach to isolate independent contributing factors. The accuracy in target localization determines the overall accuracy of SRS procedure, provided the mechanical accuracy of the treatment apparatus is assured. Biplanar treatment portal verification with a fiducial localization frame is an accurate method of verifying the target coordinates before delivering treatment.

Humans↗

PubMed1994

Neurofibromatosis type I and malignancy: review of 32 pediatric cases treated at a single institution.

Thirty-two cases of neurofibromatosis Type I (NF1) were identified among 6,678 pediatric cancer patients treated at St. Jude Children's Research Hospital over a 29-year period. A total of 35 malignant neoplasms have been diagnosed in these patients. Two of three patients with second malignant neoplasms had colon cancer at the primary or second tumor. Of particular interest are two cases in which both NF1 and malignant peripheral nerve sheath tumors were present in multiple successive generations: a patient with colon cancer and non-Hodgkin lymphoma who has a constitutional abnormality of the p53 gene, and a patient with acute lymphoblastic leukemia with the Philadelphia chromosome and other cytogenetic abnormalities, including the t(8;14). Outcome of patients in the largest subgroup, that of malignant peripheral nerve sheath tumors, was favorable only for those patients having resectable extremity lesions. In contrast, all patients with central nervous system tumors are surviving. These cases reflect the molecular and cytogenetic abnormalities that can be present in NF1 and the variety of tumors that may result in these patients.

Adolescent↗