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Biomedical subjects

R J Packer

Publications and source records attributed to R J Packer.

At least 109 records · Page 6Linked to original sources
PubMed1992

Chemotherapy of malignant brain tumors in children.

Chemotherapy has become an important modality in the management of children with brain tumors. Factors that impede improved effectiveness of anti-neoplastic drugs are being identified and addressed. Specific agents have emerged that show anti-brain tumor activity alone or in combination therapy. Use of these agents requires facility regarding their dosing, routes of delivery, mechanisms of action, metabolism and toxicities. Multi-institution cooperative group trials provide the optimum means by which to evaluate the effectiveness of chemotherapy in children with brain tumors.

Adolescent↗
PubMed1992

Brainstem gliomas.

Brainstem gliomas, a relatively common form of childhood brain tumor, are highly resistant to therapy. With computed tomography and magnetic resonance imaging, these lesions can be diagnosed with a high degree of reliability. The indications for surgery are unclear. Focal lesions may be amenable to partial resections. Stereotactic approaches can be used for diffuse lesions, but it has not been shown that the information obtained changes the approach to treatment or outcome. Higher dose radiotherapy has been recently used but has not improved survival for most patients. Patients with brainstem gliomas must be stratified into risk groups, and new means of treatment are needed.

Brain Neoplasms↗
PubMed1991

Is craniospinal irradiation required to cure children with malignant (anaplastic) intracranial ependymomas?

Between 1970 and 1989, 17 children with histologically malignant intracranial ependymomas received treatment at the University of Pennsylvania (Philadelphia, PA). Eleven were treated with prophylactic cranial or craniospinal irradiation plus a local boost (CS-XRT), five with local (L-XRT) irradiation only, and one was treated without (NRT) irradiation. With a median survival of 2 years and a median follow-up time for long-term survivors of 6.0 years, five of 11 patients who received CS-XRT are alive compared with none treated with L-XRT and none treated with NRT. Two-year actuarial survival rates are 40% (L-XRT) and 52% (CS-XRT). When examined for other factors, age and local radiation dose remain the most significant prognostic indicators of survival. The 2-year actuarial survival for children younger than 4 years at diagnosis is 20% compared with 83% for their older counterparts. Likewise, the 2-year survival for patients treated with local radiation doses over 4500 cGy was 55% compared with 0% for patients treated with lesser doses. To date there are a total of 28 recurrences. All have occurred with local components except for six (unknown) who died before the exact site(s) could be determined. There is no significant difference in the failure rates outside the original tumor bed in the three groups. These data suggest that local relapse remains the most significant component of failure. Because intrinsic and extrinsic factors such as age and radiation dose seem to be interrelated and at least as important as the use of craniospinal irradiation, the need for prophylactic treatment for children with anaplastic ependymoma could neither be substantiated nor refuted. The use of local radiation alone, however, should be restricted to carefully designed clinical trials in which meticulous pretreatment evaluation is performed, and vigilant posttreatment evaluation of the spine and brain is mandatory.

Brain Neoplasms↗
PubMed1991

Cognitive deficits in long-term survivors of childhood brain tumors.

Improvements in survival for patients who had childhood brain tumors has led to an increasing emphasis on the quality of life for these long-term survivors. Initial survival studies relied on global descriptions of functional abilities to assess cognitive deficits and reported that from 20% to 40% of long-term survivors had obvious partial disability and less than 10% were severely disabled. Formal neuropsychological testing has revealed that from 40% to 100% of long-term survivors have some form of cognitive deficit in various intelligence quotients, visual/perceptual skills, learning abilities, and adaptive behavior. Prospective, controlled studies have found a younger age at diagnosis, radiotherapy, methotrexate chemotherapy, tumor location and time interval to testing to be important (alone or in combination) and related to a high risk of subsequent cognitive deficits. Some variables play an as yet unresolved role. However, despite the progress of the last decade, future prospective studies are needed to define the role of certain variables in the development of cognitive deficits that maximize survival while minimizing cognitive deficits.

Brain Neoplasms↗
PubMed1991

Comparison of myelography with CT follow-up versus gadolinium MRI for subarachnoid metastatic disease in children.

We evaluated 17 children with primary intracranial neoplasms for subarachnoid metastatic disease (SAMD) using myelography with computed tomographic follow-up (Myelo + CT) and cerebrospinal fluid (CSF) histopathologic examination, as well as magnetic resonance imaging with gadolinium DTPA (MRI + Gd), between December 1988 and December 1989. There were 12 boys, and the median age was 5.7 years (range, 0.8 to 21.8 years). Tumor histology included 8 primitive neuroectodermal tumors (PNETs), 3 ependymomas, 2 low-grade astrocytomas, 1 anaplastic astrocytoma, 1 glioblastoma multiforme, 1 atypical rhabdoid tumor, and 1 malignant fibrous histiocytoma. Thirteen tumors originated in the posterior fossa, 2 were supratentorial, and 2 were in the spinal cord. The median interval between the 2 diagnostic tests was 2 days. MRI + Gd was positive in 11 (65%), Myelo + CT in 8 (47%), and CSF in 5 (29%) cases. MRI + Gd was superior in delineating spinal cord nodules and "sugar coating" whereas Myelo + CT more readily revealed nerve root sleeve filling defects. There was no case in which Myelo + CT was positive that MRI + Gd did not reveal SAMD. MRI + Gd is a safe, noninvasive test that should be used as the initial imaging modality for the presence of SAMD.

Adolescent↗
PubMed1991

Improved survival with the use of adjuvant chemotherapy in the treatment of medulloblastoma.

Between 1975 and 1989, 108 children with newly diagnosed medulloblastoma/primitive neuroectodermal tumor (MB/PNET) of the posterior fossa were treated at the authors' institution. The patients were managed uniformly, and treatment included aggressive surgical resections, postoperative staging evaluations for extent of disease, and craniospinal radiation therapy with a local boost. Beginning in 1983, children with MB/PNET were prospectively assigned to risk groups; those with "standard-risk" MB/PNET were treated with radiation therapy alone, while those in the "poor-risk" group received similar radiation therapy plus adjuvant chemotherapy with 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), vincristine, and cisplatin. The 5-year actuarial disease-free survival rate for all patients treated between 1975 and 1982 was 68%, and 73% when patients who died within 2 weeks after operation were excluded. This survival rate was statistically better for patients treated after 1982 (82%) compared to those treated between 1975 and 1982 (49%) (p less than 0.004). There was no difference in disease-free survival rates over time for children with standard-risk factors; however, there was a significant difference in the 5-year survival rate for poor-risk patients treated prior to 1982 (35%) compared to those treated later (87%) (p less than 0.001). For the group as a whole, a younger age at diagnosis correlated with a poorer survival rate; however, this relationship between age and outcome was significant only for children treated before 1983 (p less than 0.001). These results demonstrated an encouraging survival rate for children with MB/PNET, especially those treated with aggressive surgical resection followed by both radiation therapy and chemotherapy. The results strongly suggest that chemotherapy has a role for some, and possibly all, children with MB/PNET.

Adolescent↗
PubMed1991

Fusiform dilatations of the carotid artery following radical surgery of childhood craniopharyngiomas.

Between 1982 and 1990, a series of 31 children with craniopharyngiomas underwent initial surgery at the Children's Hospital of Philadelphia with an attempt at total tumor removal. Nine (29%) of them were found to have fusiform dilatation of the supraclinoid carotid artery either at the time of surgery for recurrence (one patient) or on routine surveillance with enhanced computerized tomography 6 to 18 months postoperatively (eight patients). The finding of carotid enlargement was confirmed in seven cases with magnetic resonance angiography and in one case with a formal arteriogram. Eight of the nine patients remain alive at a mean of 3.7 years after diagnosis. None have experienced hemorrhage or other symptoms referrable to fusiform dilatation of the carotid artery, which is believed to result from surgical manipulation of the carotid artery.

Adolescent↗
PubMed1991

Nerve growth factor receptor expression in peripheral and central neuroectodermal tumors, other pediatric brain tumors, and during development of the adrenal gland.

Nerve growth factor (NGF) is important to the survival, development, and differentiation of neurons. Its action is mediated by a specific cell surface transmembrane glycoprotein, nerve growth factor receptor (NGFR). In this study, NGFR expression by human fetal and adult adrenal medullary tissue, peripheral nervous system (PNS) neuroectodermal tumors (neuroblastoma, ganglioneuroblastoma, ganglioneuroma), pediatric primitive neuroectodermal tumors (PNETs) of the central nervous system (CNS), and CNS gliomas was examined by an immunohistochemical technique. Sixty-nine tumors in total were probed in this manner. Nerve growth factor receptor immunoreactivity was confined to nerve fibers and clusters of primitive-appearing cells in the fetal adrenal, and to nerve fibers and ganglion cells of the adult adrenal medulla; adrenal chromaffin cells were negative. In PNS neuroectodermal tumors, there was NGFR expression in tumor cells of 6 of 11 neuroblastomas and 6 of 6 ganglioneuroblastomas or ganglioneuromas. Thirteen of thirty-five CNS PNETs showed NGFR positivity. In most CNS PNETs, NGFR was restricted to scattered single or small groups of cells, but two tumors with astroglial differentiation showed much more extensive immunoreactivity. Most astrocytomas (11 of 14) and all ependymomas (3 of 3) were intensely NGFR positive.

Adolescent↗
PubMed1991

Biologic and immune modulating agents in the treatment of childhood brain tumors.

The data on the utility of biologic response modifiers are quite sketchy. Although no true home-runs have been hit, there is evidence that some patients will benefit from these immunologic agents. The majority of studies for central nervous system tumors have been done in adults with highly aggressive anaplastic gliomas. Many of these patients had extensive disease at the time of treatment and determination of benefit is difficult. Few pediatric trials have been attempted. The evidence for efficacy for most agents is lacking, although there are encouraging responses in children with isolated leptomeningeal spread to radiolabeled monoclonal antibodies and for patients with progressive intracranial mass lesions to one form of beta-interferon. Given the limited alternatives for many of these patients, and the neurotoxicity of other means of therapy, future studies are clearly indicated in children with malignant brain tumors. The lack of evidence of efficacy in adult glioblastoma trials cannot be used as direct evidence for the nonutility of these agents for childhood brain tumors. By and large, children tend to tolerate higher doses of biologic response modifiers than adults, again raising the hope of greater utility of these drugs for pediatric patients. From the information available, it seems unlikely that these immunomodulating agents, in themselves, will be effective in the treatment of the majority of patients with brain tumors. But in combination with aggressive surgery, radiation, and possibly chemotherapy, these agents may in time add to the armamentarium available for the treatment of childhood brain tumors.

Adjuvants, Immunologic↗
PubMed1990

Recurrent intracranial ependymomas in children. Survival, patterns of failure, and prognostic factors.

Thirty-six pediatric patients (ages 0.8-16.8 years) with recurrent intracranial ependymoma were treated for a total of 52 separate cases of relapse from 1970 to 1989. Therapy consisted of surgery in 33 cases and chemotherapy in 38 cases. Twelve patients received radiation at the time of first relapse, and five of these 12 who had initially been treated with surgery and chemotherapy alone were irradiated to full dose. The 2-year actuarial survival and progression-free survival (PFS) rates are 29% and 23%, respectively. Two-year survival after treatment of first relapse is 39%. Of the 52 cases, there have been 44 subsequent relapses (and one septic death), three of which have occurred in the five patients treated with definitive radiation. Twenty-seven relapses have occurred exclusively with local disease. Eight patients failed with disease outside as well as in the primary site. Survival was better for patients who had histologically benign lesions at relapse (53% versus 9%, P less than 0.02), and for patients in first versus subsequent relapse (p less than 0.005). Cisplatin and etoposide (VP-16) appeared to be the most active chemotherapeutic agents. The authors conclude that some patients with histologically benign ependymoma at first relapse may benefit from aggressive therapy, with occasional long-term, progression-free survival possible. Patients with malignant lesions, or patients who relapse a second time, are less likely to benefit from conventional therapy for a significant period of time.

Actuarial Analysis↗
PubMed1990

Results of treatment of children with recurrent medulloblastoma/primitive neuroectodermal tumors with lomustine, cisplatin, and vincristine.

Primitive neuroectodermal tumors/medulloblastoma (PNET/MB) are the most common posterior fossa tumors in childhood. Despite surgery and radiation therapy, 40% to 50% of children with PNET/MB will have recurrent disease. Various chemotherapeutic agents are transiently effective in recurrent PNET/MB, but long-lasting responses are rarely attainable. To increase the rate and duration of response in children with recurrent PNET/MB, the authors treated seven patients (ages 2-18 years; median, 10 years) with lomustine (CCNU) (100 mg/m2), cisplatin (CPDD) (90 mg/m2) and vincristine (VCR) (1.5 mg/m2; maximum, 2 mg) in a 6-week cycle for a maximum of eight cycles. Six of six evaluable patients responded to chemotherapy. Four patients had a complete response; three with complete disappearance of tumor by imaging studies; and one with eradication of extraneural disease for a median of 24 months from relapse (13-29 months). Overall disease-free survival was 18.5 months. All six patients have subsequently died of recurrent tumor. Major toxicities consisted of reversible bone marrow suppression (six of six), high frequency hearing loss (six of six) and decreased renal function (three of six). All patients required dosage modification for toxicity. A regimen of CCNU, VCR, and CPDD is effective therapy in children with relapsed PNET/MB and can produce relatively long-term disease control with good quality of life. Further investigation into the efficacy of this combination as adjuvant chemotherapy in newly diagnosed high-risk PNET/MB is now being performed.

Adolescent↗
PubMed1990

Microphthalmia and chorioretinal lesions in a girl with an Xp22.2-pter deletion and partial 3p trisomy: clinical observations relevant to Aicardi syndrome gene localization.

We present a 4-year-old girl with a maternally derived, unbalanced X;3 translocation resulting in partial Xp monosomy and partial 3p trisomy. She had chorioretinal defects, developmental delay, infantile seizures, and microphthalmia. These findings initially suggested a diagnosis of Aicardi syndrome. However, she had a normal-appearing corpus callosum on CT and magnetic resonance imaging scans of the brain and her retinal findings were not typical for Aicardi syndrome. This represents the 6th reported example of microphthalmia associated with an Xp22 chromosome abnormality. Four of these individuals also had features suggestive of focal dermal hypoplasia (FDH), which was not evident in our patient. The available evidence supports the hypothesis that gene disruption at Xp22 may lead to findings similar to those seen in Aicardi syndrome and FDH, both of which are believed to be X-linked dominant male lethal conditions.

Child, Preschool↗
PubMed1990

Hyperfractionated radiotherapy for children with brainstem gliomas: a pilot study using 7,200 cGy.

Brainstem gliomas, constituting approximately 10% of all childhood central nervous system tumors, remain the most resistant of all brain tumors to therapy. A subgroup of high-risk patients with tumors that diffusely involve the brainstem or that microscopically demonstrate foci of anaplasia on biopsy specimens rarely survive after treatment. Conventional doses of radiotherapy result in temporary clinical improvement in the majority of these high-risk patients; however, few if any remain alive 18 months after treatment. Hyperfractionated radiotherapy, with delivery of larger numbers of smaller fractions of radiotherapy, is a possible way to increase tumor control without increasing neurological toxicity. In 1985, a multiinstitutional phase I/phase II trial, using 100 cGy of radiation therapy twice daily to a total dose of 7,200 cGy, was undertaken for patients with high-risk brainstem gliomas. At the time of writing, 24 (69%) had developed progressive disease and 11 remained in continuous progression-free remission. Actuarial progression-free survival at 20 months is approximately 30%. Twenty-three of 31 evaluable patients had an objective radiographic response to therapy. In comparison to both historical control patients and patients treated in a previous trial using 6,480 cGy of hyperfractionated radiation therapy, there was a statistically significant improvement in progression-free survival rate for patients treated with 7,200 cGy of hyperfractionated radiation therapy (p less than 0.01). To date no patient has died as a result of treatment. Six patients developed transient neurological deterioration or cystic intralesional changes, as demonstrated on magnetic resonance imaging, within 6 weeks of the completion of radiotherapy. Postmortem examination performed in 7 patients did not disclose significant radiation necrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Chemotherapy for medulloblastoma/primitive neuroectodermal tumors of the posterior fossa.

Chemotherapy has only marginal efficacy in adult malignant brain tumors. In contrast, drug therapy is considerably more effective in medulloblastoma/primitive neuroectodermal tumors (MB/PNET) of the posterior fossa, the most common childhood primary central nervous system tumor. At the time of disease recurrence, a variety of different single agents and drug combinations result in tumor shrinkage and increased survival. The addition of chemotherapy to standard radiotherapy improves the rate and length of disease-free survival for those children with MB/PNET who have the most extensive tumors at diagnosis. It remains to be determined which drug or drug combinations are the most effective in MB/PNET, and which patients are most likely to benefit from chemotherapy. Chemotherapy may be useful to reduce or, in selected cases, obviate the need for radiotherapy and reduce treatment-related sequelae.

Antineoplastic Agents↗
PubMed1990

Pediatric brainstem glioma. Post-radiation clinical and MR follow-up.

Thirty-four pediatric patients, twenty with presumed and fourteen with biopsy or autopsy proven brainstem gliomas were imaged by CT and MR before radiation therapy. Twenty-eight patients received radiotherapy. Of these, eighteen fit the protocol for combined clinical and MR post-treatment evaluation. No cases of radionecrosis were seen at autopsy. This study shows that MR can demonstrate tumor response to radiation therapy, tumor progression prior to clinical deterioration, post-treatment cyst formation and hemorrhage. Although MR clinical correlation was not optimal on six week post-treatment evaluation, 4-10 month post-treatment MR scanning correlated well with clinical evaluation. MR appears useful in post-therapeutic monitoring of tumor response.

Adolescent↗
PubMed1990

Intracranial ependymomas in children.

Between 1970 and 1988, 51 children with intracranial ependymal tumors (33-infratentorial, 18-supratentorial received initial treatment at the University of Pennsylvania. Therapy consisted of total or near total tumor resection in 15 patients and partial resection or biopsy in 36. Postoperative irradiation alone was given to 18, chemotherapy to 4, and a combination of these two modalities to 26. Patients have been followed for a median period of 7.75 years. The 5-year actuarial survival and progression-free survival (PFS) rates are 46% and 30%, respectively. Of the 30 patients who have progressed, 29 did so locally and one died before the site of failure could be determined. Six patients also had disease outside the primary site at relapse; three of them had received craniospinal irradiation. Local control was significantly better for patients whose tumor dose exceeded 4500 cGy (32% vs. 0%, p = .01) and for Caucasian patients (34% vs. 15%, p =.05). Survival was better for patients who were over 4 years of age at diagnosis (55% vs. 30%, p = .04), for patients who received local radiation doses above 4500 cGy (51% vs. 18%, p = .01), and for Caucasian patients (43% vs. 14%, p = .01). Extent of resection, histology, location, the use of cranial or craniospinal irradiation, and the use of chemotherapy did not significantly impact on survival. We conclude that the inability to control local disease remains the single most important factor leading to treatment failure. Older age, higher local radiation dose, and Caucasian race appear to be the only favorable prognostic factors.

Adolescent↗
PubMed1990

Heterogeneity of clinical severity and molecular lesions in Aicardi syndrome.

All patients with Aicardi syndrome are female or have a 47,XXY karyotype. This finding, along with a report of an Aicardi syndrome patient with an Xp22/autosome translocation, led to the hypothesis that Aicardi syndrome might be caused by an X-linked dominant, male-lethal mutation on the short arm of the X chromosome. To study this hypothesis, we investigated X chromosome inactivation patterns in peripheral lymphocytes from seven patients. We used two methods: methylation-sensitive restriction enzyme analysis and segregation of the active X chromosome in somatic cell hybrids. We found that three of seven cytogenetically normal girls with Aicardi syndrome had profoundly skewed X-inactivation in their lymphocytes, supporting the concept that Aicardi syndrome is X linked. Three of the five girls with the greatest degree of psychomotor retardation and the poorest seizure control had skewed X-inactivation. In contrast, the two highest-functioning children had random X-inactivation. We screened DNA using eight polymorphic probes from the Xp22 region but were unable to identify a deletion in any of the seven patients. Nonrandom X-inactivation in lymphocytes and possibly other tissues in some, but not all, patients with Aicardi syndrome may reflect heterogeneity of their molecular lesions.

Agenesis of Corpus Callosum↗