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Biomedical subjects

L E Kun

Publications and source records attributed to L E Kun.

At least 73 records · Page 4Linked to original sources
PubMed1997

Patterns of failure in children with medulloblastoma: effects of preirradiation chemotherapy.

PURPOSE: To evaluate the effects of preirradiation chemotherapy on patterns of failure in children with medulloblastoma. METHODS AND MATERIALS: Fifty-three patients (pts) with medulloblastoma were given preirradiation chemotherapy as initial postoperative treatment at St. Jude Children's Research Hospital from November 1984 to September 1993. Patients < or = 3 years of age (n = 23) received chemotherapy (CH) with delayed craniospinal irradiation (CSI). Children > or = 3 years with more advanced disease (T3b-T4, M+ or measurable residual after resection) were given CH followed by CSI (30 patients). Chemotherapy regimen depended on protocol, but usually included cis- or carboplatin and etoposide, +/- cyclophosphamide and vincristine. RESULTS: Actuarial overall survival and event-free survival rates are 60% (95% confidence interval [41,79]) and 37% [19,55] at 5 years. Children < or = 3 at diagnosis: six of 23 pts completed CH without progression and received consolidative CSI; all six are alive with no evidence of disease (NED) at 2.4-9.1 years. Seventeen patients progressed during CH and were then given CSI. Sites of progression during CH were posterior fossa (PF) in 11 patients, neuraxis (NEUR) in 4, and PF+NEUR in 2. Following CSI, 7 patients are alive NED at 2.0-8.6 years; 10 patients died of progressive disease. Eleven patients had M0 disease at diagnosis; 8 (73%) progressed during CH, 3 in the neuraxis. Children > or = 3 at diagnosis: 20 of 30 patients completed pre-CSI CH without progression; 15 are alive NED at 1.3-9.2 years, and 5 showed post-CSI progression in the PF (n = 3), in the NEUR (n = 1) and in bone marrow (n = 1). Ten of the 30 (33%) patients progressed on CH (6 in NEUR, 4 in PF); 5 are alive and NED or with stable disease. Seventeen patients had M0 disease at diagnosis; 3 out of 17 (18%) progressed during CH, 2 in NEUR and 1 in an extraneural site. In the total group of 30 patients, 11 have had disease recurrence after completion of XRT. The actuarial rate of failure was 23 +/- 9% for the patients < or = 3 years of age and 21 +/- 8% for the older children when evaluated at 4 months after diagnosis (at the completion of chemotherapy in the older children but during the ongoing chemotherapy in the younger children). CONCLUSIONS: In patients presenting with M0 disease and receiving pre-CSI chemotherapy, the risk of neuraxis progression seems to increase with duration of chemotherapy. The sites of progression during preirradiation chemotherapy are nearly equally divided between posterior fossa and other neuraxis sites. CSI salvage of patients progressing on chemotherapy is possible in approximately 50% of patients. Following CSI, neuraxis progression is more frequent than posterior fossa relapse.

Adolescent↗
PubMed1997

Brain metastases in children with melanoma.

BACKGROUND: Brain metastases complicate the course of malignant melanoma in at least 20% of adult cases. These events are commonly preceded by metastases to other sites. Due to the rarity of malignant melanoma in children, little is known about the incidence, clinical features, and outcome of children with melanoma who develop brain metastases. METHODS: The authors reviewed the records of 44 children with malignant melanoma treated at St. Jude Children's Research Hospital over a 33-year period. Eight (18%) developed brain metastases during the course of their disease. The authors reviewed the clinical and radiologic features of six of these cases, for whom complete clinical information and imaging studies were available. RESULTS: The median age at diagnosis of malignant melanoma was 15 years (range, 11-21 years). Brain metastases developed a median of 20 months (range, 0-50 months) after diagnosis and were preceded by metastases to other organs in 5 patients. In most cases, lesions were supratentorial and multiple. Most showed radiologic signs of intralesional hemorrhage. All patients received whole brain radiotherapy, and one had surgical resection. Three patients received chemotherapy. Five patients died a median of 5 months (range, 2-10 months) after diagnosis of brain involvement. One patient, who had a single brain metastasis at diagnosis, is alive more than 34 months later. CONCLUSIONS: Brain metastases develop in a significant proportion of children with malignant melanoma and are associated with a poor outcome. The incidence, features, and outcome in children do not appear to differ from those in adults.

Adolescent↗
PubMed1997

Efficacy of targeted supradose cisplatin and concomitant radiation therapy for advanced head and neck cancer: the Memphis experience.

PURPOSE/OBJECTIVE: To evaluate the feasibility, response rates, and toxicity of a Phase II study using targeted supradose cisplatin and concurrent radiation therapy in unresectable Stage III-IV head and neck squamous cell carcinoma. METHODS AND MATERIALS: Sixty patients presenting between 6/93-9/94 were enrolled, 44 (73%) of whom had T4 and/or N2-N3 nodal disease. All patients were treated with rapid targeted superselective intraarterial infusions of cisplatin (150 mg/m2 weekly x 4) and simultaneous sodium thiosulfate intravenously (9 g/m2) for systemic neutralization of cisplatin. Concurrent (day 1) daily radiation therapy was delivered to the primary tumor and overt nodal disease to 66-74 Gy while the uninvolved lower neck received 50 Gy, at 2.0 Gy/fraction. RESULTS: Fifty-one (85%) patients completed the full RADPLAT protocol as planned. Fifty-seven of 60 patients were evaluable for response. Histological (n = 50) or clinical (n = 7) assessment of primary site revealed a complete response (CR) in 52 patients, partial response (PR) in 4, and stable disease (SD) in 1. Of the 40 patients presenting with nodal metastases, pathological (n = 31) or clinical (n = 6) assessment revealed a CR in 25, PR in 11, and SD in 1, while 3 were unevaluable. Overall, for both primary site and nodal disease, CR was attained in 44 (75%), PR in 12 (23%), and SD in 1 (2%) of the 57 evaluable patients. Only 2 (4%) of 57 evaluable patients have recurred above the clavicle, 1 in the primary site and 1 in the regional lymph nodes. Twelve patients (23%) have failed in distant sites. Grade III/VI toxicity has included gastrointestinal in 6, hematologic in 6, mucosal in 12, vascular in 4, and neurological in 4 patients. CONCLUSION: Concurrent radiation therapy and targeted supradose cisplatin (i.e., RADPLAT) can be safely delivered with high response rates and excellent loco-regional control in advanced Stage III/IV head and neck squamous cell carcinoma.

Adult↗
PubMed1997

Brain tumors. Challenges and directions.

Brain tumors account for 20% of childhood cancers and provide a "frontier" in which improved disease control and functional outcome require coordinated, directed studies in neurosurgery, radiation therapy, and chemotherapy. Among the several brain tumor types common in children, the recent experiences in medulloblastoma, ependymoma, and tumors occurring in infants and very young children are reviewed in the context of recent clinical trials and ongoing investigations.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Brain stem involvement in children with neurofibromatosis type 1: role of magnetic resonance imaging and spectroscopy in the distinction from diffuse pontine glioma.

OBJECTIVE: To evaluate the ability of magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) to distinguish neurofibromatosis Type 1 (NF-1) with brain stem enlargement from diffuse pontine glioma (PG) in pediatric patients. METHODS: A chart review was used to identify all patients with NF-1 and diffuse brain stem enlargement who were seen at our institution and who had undergone MRI. Comparison groups were as follows: 1) eight patients who did not have NF-1 but who did have diffuse PG, and 2) seven healthy children. Midsagittal diameters of the pons, midbrain, and medulla were measured in all patients, and the results were statistically analyzed. Two MRS variables were also statistically compared: N-acetyl aspartate and the vector sum of the metabolites choline and creatine/phosphocreatine. RESULTS: In MRI-based measurements, only the pontine midsagittal diameter differed significantly between the NF-1 and PG groups (P = 0.002). Altogether, 21 children underwent MRS, including 6 in the NF-1 group. Measures of both MRS variables were significantly lower in patients with PG than in the others (P < or = 0.007). The two MRS variables classified the 21 children into the three respective groups with 100% accuracy. Of the seven patients with NF-1, four presented with symptoms attributable to brain stem involvement. The brain stems of all seven patients with NF-1 were hyperintense on T2-weighted magnetic resonance images, and five were isointense on T1-weighted images; only one exophytic tumor was identified. Four of the patients with NF-1 were followed up clinically without treatment; all remained alive and neurologically stable for a median of 40 months. All eight patients in the PG group were symptomatic at presentation, and all except one died despite therapy. CONCLUSION: Both MRI measurements and MRS seem to be useful for distinguishing patients with NF-1 and diffuse brain stem enlargement from patients without NF-1 but with diffuse PG. They should be most helpful in differentiating symptomatic patients with NF-1 from patients with PG, thereby minimizing aggressive treatment and its side effects in patients destined to have better outcomes.

Adolescent↗
PubMed1997

Cerebellar pontine angle ependymoma in infants.

We discuss the surgical approach used for and outcome in 11 infants (< or =3 years) who were treated at our institution for ependymomas arising in the cerebellar-pontine (C-P) angle. The median age of the group was 19 months (range: 6-26 months). Of these 11 patients, the initial surgery for 8 was performed at our center and achieved a gross total resection (GTR) in 4 patients and a subtotal resection (STR) in the remaining 4. The 3 patients who had tumor debulking performed elsewhere were subsequently referred to our institution and had definitive surgery after receiving 3-4 courses of chemotherapy; one of these children had a GTR, whereas the remaining 2 had an STR. During the immediate postoperative period, 9 patients had cranial nerve deficits that necessitated placement of a tracheostomy and a gastrostomy feeding tube; these were discontinued in 6 of the 9 patients as the deficits resolved. The majority of the permanent cranial nerve deficits involved the sixth and seventh cranial nerves. Of the 11 patients, 4 have died (progressive disease, n = 1; accidental death, n = 2; withdrawal of life support, n = 1); the remaining 7 patients are alive, with a median follow-up of 37 months (range: 20-73 months). Aggressive surgical resection for tumors arising in the C-P region is associated with postoperative deficits, which resolve over time with appropriate supportive care. This approach may increase the number of children in whom GTR is achieved, thereby potentially increasing the cure rate for these patients.

Antineoplastic Agents↗
PubMed1997

Low-grade astrocytoma: a decade of experience at St. Jude Children's Research Hospital.

PURPOSE: To evaluate the impact of primary tumor site, age at diagnosis, extent of resection, and histology on progression-free survival (PFS) in pediatric low-grade astrocytoma. PATIENTS AND METHODS: Medical, pathologic, and imaging information were reviewed for 142 children (ages 2 months to 19 years) with low-grade astrocytoma treated between January 1984 and July 1994. Gross total resection (GTR) was attempted for cerebellar and cerebral hemisphere tumors, with biopsy or less aggressive resection used predominantly for tumors in other sites. Surgery was followed by observation in 107 cases, radiation therapy in 31, and chemotherapy in four. RESULTS: The overall survival rate was 90% +/- 3% (SE) at 4 years. PFS was significantly better for patients with cerebellar and cerebral hemisphere tumors (n = 75) than those with tumors in all other sites (P = .0006). Within the former group, there was no significant difference in PFS for patients in whom GTR was achieved versus those with incomplete resections (4-year estimates, 89% and 77%, respectively). Histology (juvenile pilocytic v astrocytoma not otherwise specified [NOS]) was not related to PFS in an analysis that controlled for tumor site and patient age. Patients younger than 5 years at diagnosis had a significantly poorer PFS than older children, regardless of histology (P < .03) or tumor site (P < .002). Treatment for progressive/recurrent disease was effective in a majority of patients, but appeared more successful in patients with hemispheric than thalamic or hypothalamic tumors. CONCLUSION: The overall survival in this series of pediatric low-grade astrocytomas is excellent. Age at diagnosis and tumor location, but not histology, had a significant impact on PFS. Efforts to improve treatment outcome should focus on young patients (< 5 years) and on those with central midline tumors. The majority of patients with completely resected hemispheric tumors were monitored without further therapy, which supports attempted GTR of cerebral and cerebellar hemisphere low-grade astrocytoma.

Adolescent↗
PubMed1997

O6-Methylguanine-DNA methyltransferase protein levels in pediatric brain tumors.

Chloroethylnitrosoureas (CENUs) are commonly used in the treatment of pediatric and adult central nervous system (CNS) tumors. The antitumor activity of CENUs has been hypothesized to be due to an alkylation occurring at the O6-position of guanine in DNA. The DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT) is responsible for the repair of these potentially cytotoxic lesions and may underlie tumor resistance to CENUs. The current study is the largest report of MGMT levels among newly diagnosed pediatric CNS tumors and the only study that has quantitated MGMT by both biochemical and Western immunoblot assays. Our results show a good correlation between the two methods (r = 0.66). Medulloblastoma/primitive neuroectodermal tumor and ependymoma had the highest level of MGMT, followed by high-grade glioma and low-grade glioma. These data may provide a guide to the use of CENUs in the treatment of pediatric CNS tumors.

Adolescent↗
PubMed1996

Clinical value of proton magnetic resonance spectroscopy for differentiating recurrent or residual brain tumor from delayed cerebral necrosis.

PURPOSE: Delayed cerebral necrosis (DN) is a significant risk for brain tumor patients treated with high-dose irradiation. Although differentiating DN from tumor progression is an important clinical question, the distinction cannot be made reliably by conventional imaging techniques. We undertook a pilot study to assess the ability of proton magnetic resonance spectroscopy (1H MRS) to differentiate prospectively between DN or recurrent/residual tumor in a series of children treated for primary brain tumors with high-dose irradiation. METHODS AND MATERIALS: Twelve children (ages 3-16 years), who had clinical and MR imaging (MRI) changes that suggested a diagnosis of either DN or progressive/recurrent brain tumor, underwent localized 1H MRS prior to planned biopsy, resection, or other confirmatory histological procedure. Prospective 1H MRS interpretations were based on comparison of spectral peak patterns and quantitative peak area values from normalized spectra: a marked depression of the intracellular metabolite peaks from choline, creatine, and N-acetyl compounds was hypothesized to indicate DN, and median-to-high choline with easily visible creatine metabolite peaks was labeled progressive/recurrent tumor. Subsequent histological studies identified the brain lesion as DN or recurrent/residual tumor. RESULTS: The patient series included five cases of DN and seven recurrent/residual tumor cases, based on histology. The MRS criteria prospectively identified five out of seven patients with active tumor, and four out of five patients with histologically proven DN correctly. Discriminant analysis suggested that the primary diagnostic information for differentiating DN from tumor lay in the normalized MRS peak areas for choline and creatine compounds. CONCLUSIONS: Magnetic resonance spectroscopy shows promising sensitivity and selectivity for differentiating DN from recurrent/progressive brain tumor. A novel diagnostic index based on peak areas for choline and creatine compounds may provide a simple discriminant for differentiating DN from recurrent or residual primary brain tumors.

Adolescent↗
PubMed1996

Local control in synchronous bilateral Wilms tumor.

PURPOSE: To evaluate the role of radiation therapy (RT), chemotherapy (CT), and surgery in the local control of synchronous bilateral Wilms Tumor (WT). METHODS AND MATERIALS: Between 1962 to 1993, 45 children were treated for bilateral WT; 38 patients with synchronous tumors were reviewed. Initial surgery depended on the era of treatment and included unilateral nephrectomy (N)/partial nephrectomy (PN) and contralateral PN in 6, unilateral N/PN alone in 7, and biopsy only in 25. Chemotherapy (CT) consisted of vincristine, actinomycin-D, and adriamycin in 32 and vincristine/ actinomycin-D in 6. Radiation therapy (RT) was given to 32 patients. Treatment included both kidneys in 20, unilateral kidney plus contralateral renal bed in 9, unilateral kidney in 2, and unilateral renal bed in 1. Follow-up was 16 months to 25 years (median: 6.3 years). RESULTS: Local control (LC) has been maintained in 66 out of 76 sites (87%). For Stage I-II disease with initial N/PN, LC was 10 out of 12 with RT and 11 out of 11 without RT; for Stage III with initial N/PN, LC was 8 out of 9 with RT and 1 out of 1 without RT. Initial CT and RT was followed by delayed N/PN for 20 sites; LC was 15 out of 17 in post induction Stage I-II and 1 out of 3 in postinduction Stage III. In 23 sites undergoing biopsy and chemotherapy, LC was 19 out of 20 with RT and 1 out of 3 without RT. Seven of 23 sites had a complete response (CR) after induction CT, and LC was maintained in four out of four with RT and one out of three without RT. Univariate Cox Regression analysis demonstrated that sites receiving two drugs had a statistically significant increase in loco-regional relapse when compared to sites receiving three drugs (p = 0.004). Major morbidities related to multimodality therapy have included renal failure in one patient and small bowel obstruction requiring lysis of adhesions in two patients. CONCLUSIONS: Local control does not seem to be compromised by renal conservation therapy. Local control is excellent in sites treated with radiation therapy in combination with three drug chemotherapy.

Adolescent↗
PubMed1996

Long term survivors of childhood brain stem gliomas treated with hyperfractionated radiotherapy. Clinical characteristics and treatment related toxicities. The Pediatric Oncology Group.

BACKGROUND: Over the past decade, the principal focus of research in pediatric brain stem gliomas has been on the use of hyperfractionated radiotherapy (HRT). The purpose of this study was to evaluate the clinical characteristics and treatment related toxicities of long term survivors of HRT treatment. METHODS: Of the 130 children with brain stem tumors treated with escalating doses of HRT on Pediatric Oncology Group (POG) #8495, there are only 9 long term survivors. Prospectively collected data, including flow sheets and all pretreatment and follow-up radiologic studies, were reviewed for these patients. Additional information was requested from the treating institutions with regard to sequelae of treatment. RESULTS: Clinical characteristics (including age, sex, duration of symptoms, and presenting signs) for the nine surviving patients were not different from the total population of patients treated on POG #8495. Pretreatment imaging, however, revealed that only four of the nine patients had typical diffuse intrinsic pontine lesions and, conversely, that at least three of the nine patients had lesions that would now be considered relatively favorable. Complete information regarding treatment related toxicity was available for eight patients, only one of whom is without sequelae. Seven have schooling difficulties, two have a seizure disorder, five have hearing loss, and two have required growth hormone replacement. Follow-up imaging findings were striking in four of the eight patients because of white matter changes consistent with leukoencephalopathy (two patients), diffuse microhemorrhages (one patient), and dystrophic calcification (one patient) in the radiation field. CONCLUSIONS: The high frequency of treatment related sequelae in long term survivors of HRT suggests a need for caution in the use of HRT, particularly in patients who have brain stem tumors with a more favorable prognosis.

Adolescent↗
PubMed1996

Outcome in 43 children presenting with metastatic Ewing sarcoma: the St. Jude Children's Research Hospital experience, 1962 to 1992.

The purpose of this work was to review the St. Jude Children's Research Hospital experience of patients presenting with metastatic Ewing sarcoma over a 30-year period. Forty-three of 212 cases of Ewing sarcoma presented with metastases at diagnosis. These patients were analyzed to determine whether primary tumor site or size, metastatic site(s), or advances in therapy have had a positive impact on survival. The overall survival for our 43 patients was 35% (95% confidence intervals, 20% to 50%). Comparing patients treated prior to 1979 with those treated after 1979, the overall survival was significantly different (P = 0.0002). Comparing overall survival between pelvic and non-pelvic primaries (P = 0.24), among metastatic sites (P = 0.83), and between tumors measuring > 8 cm in diameter to tumors measuring < 8 cm in diameter (P = 0.12), no significant differences were observed. Approximately one-third of patients presenting with metastatic Ewing sarcoma may achieve long-term survival. Children with metastatic Ewing sarcoma may benefit from clinical trials which intensify the doses of doxorubicin, and the highly effective combination of ifosfamide/etoposide.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Role of irradiation in management of synovial sarcoma: St. Jude Children's Research Hospital experience.

The role of irradiation in the management of synovial sarcoma (SS) in pediatric patients is evaluated. The review covers all children seen at St. Jude Children's Research Hospital between May 1969 and December 1992 with the diagnosis of soft tissue sarcoma, of the 37 patients with the subtype SS, 16 received irradiation for the management of primary site disease. There were four IRS Group I, six Group II, four Group III, and two Group IV patients receiving irradiation. Tumor grade included seven Grade II, and nine Grade III lesions. TMN staging identified eight T1 and eight T2 lesions. Follow-up has ranged from 14 to 117 months (med = 33 months). All IRS Group I patients had documented local control. Five of six IRS Group II and 4/4 Group III patients have had documented local control at last follow-up. IRS Group IV patients had either local control tumor stabilization (n=1) or evidence of tumor regression (n=1) at autopsy. Complications following irradiation include wound dehiscence (n=1), surgery to revise a painful scar (n=1) extremity length discrepancy (n=2), and femoral head avascular necrosis (n=1). At last follow-up, 10 of 14 patients receiving curative intent irradiation remain alive. This review indicates questionable benefit to the addition of irradiation for patients with adequate surgical resection and having "good" tumor characteristics (Grade I, II; IRS Group I, TMN T1A,T1B. For lesions that have had incomplete resection or partial response to chemotherapy, there is evidence that irradiation may provide durable local control. The role of irradiation in those patients with IRS Group IV disease is at present confined to palliative roles until the time when more effective chemotherapy will mandate the decision to treat primary disease for curative measures.

Adolescent↗
PubMed1996

Treatment outcome and dose-response relationship in infants younger than 1 year treated for retinoblastoma with primary irradiation.

Thirty-three infants ( < 1 year at diagnosis) were treated for retinoblastoma with primary irradiation at St. Jude Children's Research Hospital (SJCRH) between 1963 and June 1992. Staging of the 44 treated eyes was as follows: Reese-Ellsworth (R-E) Groups I (n = 20), Group II (n = 9), Group III (n = 6), Group IV (n = 2), Group V (n = 7). Irradiation was delivered using either a single anterior field (31 eyes) or lens-sparing techniques (13 eyes). Total doses ranged from 21-45 Gy (median = 36 Gy) in fractions of 150-180 cGy (n = 34) or > 180 cGy (n = 10). One child died of metastatic disease at 42 months. Three patients have developed second malignant neoplasms; two have succumbed at 88 and 125 months post-RB diagnosis; the remaining patients are alive at 6-259 months postdiagnosis (median follow-up = 127 months). Local control with irradiation alone and supplemented cryotherapy given within 2 months (n = 2) was maintained in 29 eyes, with no statistical difference seen for total doses < or = 36 Gy (21/8 eyes) vs. > 36 Gy (8/16). Of 15 eyes that required salvage therapy, tumor control has been maintained in 13. Enucleation was required for four patients, two with recurrent retinoblastoma and one with a phthisical eye. Cataract formation was documented in 23 eyes (87.5%) treated with lens-sparing techniques developed cataract. At last follow-up, 23 of 30 patients tested (77%) had visual acuity of 20/100 or better. This experience confirms early observations in that doses > or = 36 Gy do not appear to improve local control with irradiation alone in infants ( < 365 days) with retinoblastoma.

Cryotherapy↗
PubMed1996

Three-dimensional reconstruction of arteriovenous malformations from multiple stereotactic angiograms.

Stereotactic angiography is the preferred imaging modality in the radiosurgical treatment of arteriovenous malformations (AVM). A major limitation of this technique is the inability to determine the three-dimensional shape and the volume of the AVM. We developed a technique for reconstructing the AVM from multiple stereotactic angiograms. The fiducial marks and the identified target area are digitized for each view. The 2-D target area is then stereotactically backprojected into a 3-D volume. The spatial boundary of the target volume is defined by superimposing the backprojections from each of the views. In feasibility studies with a phantom, this technique accurately reconstructed complex 3-D structures, depicting fine details as small as 1 mm. Clinical studies in two patients indicated that this novel technique is very useful for the 3-D reconstruction of AVM for radiosurgical treatment. The number of views required depends on the complexity of the object. In general, six to eight views appear adequate. The accuracy of the reconstruction can be compromised if the view angles are limited as with the current radiographic frame. A new frame design with practically unlimited view angles is proposed to avoid this potential limitation. However, structures that are always obscured (such as concavity) could not be accurately reconstructed, leading to overestimates of the object size. This "limitation" has a positive side, in that the technique will not underestimate the actual target volume. The ability to delineate both the shape and volume of the lesion should facilitate optimal target coverage while sparing a significant amount of normal tissue.

Arteriovenous Malformations↗