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M Prados

Publications and source records attributed to M Prados.

At least 37 records · Page 2Linked to original sources
PubMed1994

Laparoscopic splenectomy: technical aspects and preliminary results.

UNLABELLED: The success of laparoscopic cholecystectomy has prompted the application of laparoscopic techniques to other abdominal procedures. Laparoscopic splenectomy poses certain specific difficulties for the control of the vascular pedicle, handling and mobilisation of a parenchymatous organ and the retrieval of the specimen. The aim of this paper is to present a technique for laparoscopic splenectomy. MATERIAL AND METHODS: Between February and October, 1993 we attempted laparoscopic splenectomy (LS) in 7 patients. Splenectomy was indicated in 5 patients for treatment of an idiopathic thrombocytopenic purpura and in two patients for treatment of hereditary microspherocytosis. One patient had concomitant cholelithiasis. RESULTS: LS was completed in 6 and converted in one patient to an open procedure due to blood from the splenic bed obscuring vision. Laparoscopic cholecystectomy and splenectomy were performed simultaneously in the patient with cholelithiasis. Three patients required transfusion of two packed cell units. In one patient, the bag broke during extraction of the spleen, and a minilaparotomy was required to remove the spleen. In one patient an accessory spleen was removed. Oral intake was started the next morning. Two patients developed pulmonary atelectasis. Analgesia requirements ranged between 2 and 10 doses, and postoperative stay ranged between 4-8 days. CONCLUSION: LS is technically feasible, and offers the functional and aesthetic advantages of laparoscopic surgery.

Adolescent↗
PubMed1993

Carboplatin and vincristine for recurrent and newly diagnosed low-grade gliomas of childhood.

PURPOSE: This study investigates the response rate to and toxicity of carboplatin and vincristine in children with recurrent low-grade gliomas (LGGs) or patients younger than 60 months with newly diagnosed LGGs. PATIENTS AND METHODS: Twenty-three children with recurrent and 37 children with newly diagnosed LGGs were treated with a 10-week induction cycle of carboplatin and vincristine, followed by maintenance treatment with the same drugs. Patients were evaluated for response to treatment and toxicity. RESULTS: Twelve of 23 (52% +/- 10%; 95% confidence interval [CI], 0.32 to 0.72) assessable children with recurrent disease had an objective response to treatment, which included a greater than 50% reduction in tumor size in seven of 23 (30% +/- 10%; 95% CI, 0.10 to 0.50). Twenty-three of 37 (62% +/- .08; 95% CI, 0.46 to 0.78) of newly diagnosed patients had an objective response, 16 of 37 (43% +/- 0.08%; 95% CI, 0.27 to 0.59) with greater than 50% reduction in tumor size. The majority of those with an objective response had diencephalic tumors (n = 29), but children with thalamic (n = 2), cortical (n = 1), and brain stem (n = 2) LGGs also responded to treatment. Of the 35 patients with objective response to treatment, the maximum response was seen in 25 after completion of induction and in the remaining 10 after two to six cycles of maintenance treatment. Forty-nine of 53 (92% +/- .04%) patients who were stable or improved after induction remain without progressive disease (PD). Hematologic toxicity was common, but resulted in cessation of therapy in only one patient. Six children have been removed from the study because of allergic reactions, which were considered to be carboplatin-associated. CONCLUSION: Carboplatin and vincristine have activity in children with recurrent and newly diagnosed progressive LGGs. Objective responses to treatment after chemotherapy can be seen. This drug regimen is relatively well tolerated, and further studies are indicated to define the role of this combination of drugs in children with newly diagnosed LGGs.

Adolescent↗
PubMed1991

The therapy of primary brain lymphoma.

Recommendations regarding the current therapy of primary brain lymphoma (NHL-CNS) take into account the occurrence of this tumor in immunocompetent and immunosuppressed hosts. Immunohistochemical evaluation of biopsy material or spinal fluid provides the diagnosis in 90% of patients. For the immunocompetent, pre-irradiation intra-venous or intra-arterial chemotherapy with Methotrexate alone or in combination with other agents is provided to treat tumor within multiple brain sites. Subarachnoid deposits are treated with Methotrexate by intrathecal administration. Radiation is provided after chemotherapy and for the treatment of vitreal/retinal deposits or symptomatic lesions within the spinal axis. The therapy of recurrent NHL-CNS makes use of intravenous Methotrexate or high dose Cytosine Arabinoside. Immunosuppressed patients respond to reduction of immunosuppressive medication. The therapy of NHL-CNS in the AIDS patient makes use of corticosteroids followed by cranial irradiation. A discussion of emerging trends in the therapy of NHL-CNS in the AIDS and non-AIDS population is provided.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Hyperfractionated irradiation for adults with brainstem gliomas.

Hyperfractionated irradiation appears to have improved survival for pediatric patients with brainstem gliomas. However, the efficacy and safety of this technique are less well established for adults with brainstem tumors. In 1984 the UCSF Department of Radiation Oncology began treating adults with brainstem gliomas using 100 cGy fractions given twice daily to total doses ranging between 6600-7800 cGy (median dose 7200 cGy). By the end of 1989, a total of 14 patients had been irradiated with follow-up times for surviving patients ranging between 4-69 months (median follow-up 33 months). Tumor histologies included five moderately anaplastic astrocytomas, one highly anaplastic astrocytoma, and eight which were unbiopsied. At the time of this analysis, six patients had failed locally, with five dying as a result of recurrent tumor. There were no deaths caused by complications or intercurrent illness. The 3-year actuarial survival rate was 59%, with a corresponding 3-year actuarial local control rate of 48%. The projected median survival was in excess of 5 years, whereas the actuarial median time to progression was 31 months (134 weeks). The treatments were well tolerated: the mean pretreatment Karnofsky Performance Status was 74% (range 60-90%); at the end of treatment the mean KPS was 78% (range 60-100%). In terms of neurologic status, six patients improved by the end of treatment, seven were stable, and one experienced only minor deterioration without change in KPS. There were no significant long-term complications (specifically, no instances of either radiation brain necrosis or myelitis). Seven patients required prolonged steroid administration after completing radiotherapy; six of these eventually recurred locally. These results appear to be substantially better than those achieved using conventional radiotherapy regimens, and suggest that this technique merits further investigation.

Adult↗
PubMed1991

Intravenous recombinant interferon beta in patients with recurrent malignant gliomas: a phase I/II study.

A multicenter phase I/II trial of a human recombinant interferon beta (Betaseron; Triton Biosciences, Alameda, CA) was conducted in patients with recurrent glioblastoma and anaplastic astrocytoma in six centers between 1986 and 1988. Betaseron was given intravenously three times per week, starting at 90 x 10(6) IU per dose and escalating by 90 x 10(6) IU every 2 weeks up to a maximum dose of 540 x 10(6) per treatment. All patients had failed prior radiotherapy, and most had failed one or more courses of chemotherapy. Of the 72 patients entered into the protocol, 65 were considered assessable. Of 65 patients, 41 had glioblastoma, and 24 had anaplastic astrocytoma. Of the 65 assessable patients, 15 (23%) had an objective response (R), and 18 (28%) had stable disease (S), with a combined R and S rate of 51%. The Kaplan-Meier median time to progression was 24 weeks for the responders, 10 weeks for the nonresponders, and 23 weeks for the whole group. These results suggest that Betaseron has definite activity in recurrent gliomas, with an R + S rate of 51%. The maximum-tolerated dose (MTD) is between 180 and 360 x 10(6) IU, with neurotoxicity being the most troublesome toxicity at higher doses. Two patients died of treatment-related complication. Since most responders showed responses at the 180 x 10(6 IU dose range, further studies using a lower dose of Betaseron aimed at decreasing toxicity and allowing chronic maintenance therapy are merited.

Adult↗
PubMed1991

Recombinant interferon beta: a phase I-II trial in children with recurrent brain tumors.

A multicenter phase I-II trial of intravenous (IV) human recombinant interferon beta (rIFN-beta; Betaseron; Triton Bioscience Inc, Almeda, CA) was conducted in children with recurrent or progressive primary brain and spinal cord tumors. A total of 29 patients were enrolled: high-grade astrocytoma (12), brainstem glioma (nine), and primitive neuroectadermal tumor (three), ependymoma (two), germ cell (two), and spinal cord astrocytoma (one). Betaseron was given by IV infusion over 30 minutes 3 times per week (Monday-Wednesday-Friday [MWF]). Four dose levels were studied, and at least three patients were entered at each dose level. The treatment plan began with a three-step dose escalation for each patient over 6 weeks (initiation phase). The dose-escalation schema for the four dose levels was: 50-100-200, 100-200-400, 200-300-500, and 300-400-600 x 10(6) (M) IU/m2. Patients experiencing an objective response or stable disease after 6 weeks entered the maintenance phase at the final escalated dose, ie, 200, 400, 500, or 600 mlU/m2 (MWF). Common transient effects included chills, fever, and fatigue. Dose-limiting toxicities were hematologic, hepatic, and CNS. The maintenance maximum-tolerable dose (MTD) was 500 mlU/m2, ie, dose level 3. Response was assessed at completion of the initiation phase and at 2-month intervals during the maintenance phase. Objective partial responses were seen in patients with high-grade astrocytoma (two) and brain-stem glioma (two). Thus, four of 21 (19%) assessable patients had partial responses for a median of 4 months. Eight patients had stable disease for a median of 5+ (2 to 14+) months. Antineoplastic activity has been identified in children with high-grade astrocytomas and brainstem gliomas in a dose-intensive regimen.

Brain Neoplasms↗
PubMed1991

Gemistocytic astrocytomas: a reappraisal.

Although gemistocytic astrocytomas are considered slow-growing astrocytomas, they often behave aggressively. To clarify the biological and clinical behavior of these rare tumors, the authors retrospectively identified 59 patients with gemistocytic astrocytoma whose tumors were diagnosed and treated between June, 1976, and July, 1989. Three patients who were lost to follow-up review were excluded, as were two whose original slides could not be obtained and three whose tumors were diagnosed at recurrence or at autopsy. The pathological material of the remaining 51 patients was reviewed using two sets of histological criteria. Thirteen patients (Group A) had "pure" gemistocytic astrocytoma, defined as a glial tumor with more than 60% gemistocytes/high-power field and a background of fibrillary astrocytes. Fifteen patients (Group B) had "mixed" gemistocytic astrocytoma, defined as a glial tumor with 20% to 60% gemistocytes/high-power field and a background of anaplastic astrocytes. Twenty-three tumors did not meet these criteria and were excluded from analysis. The median age of the patients was 48.5 years in Group A and 38.3 years in Group B (p less than 0.05). In both groups, the median Karnofsky Performance Scale score was greater than 90%. All patients underwent surgical procedures (four total and 19 partial resections, and five biopsies) and postoperative radiation therapy. The majority also had interstitial brachytherapy, chemotherapy, or both. Ten patients had one reoperation for tumor recurrence and one had two reoperations; other treatments for recurrence included brachytherapy, chemotherapy, and repeat irradiation. All four patients who originally underwent gross total resection are still alive; all five who had a biopsy have died. There was no significant difference in median survival times between groups: 136.5 weeks in Group A (range 10 to 310+ weeks) and 135.6 weeks in Group B (range 31 to 460+ weeks). Analysis of all 28 patients showed a better prognosis for patients less than 50 years of age (185 vs. 36 weeks survival time; p less than 0.001), patients with preoperative symptoms lasting for more than 6 months (228.1 vs. 110.2 weeks survival time; p less than 0.05), and patients with seizures as the first symptom (185.7 vs. 80 weeks survival time; p less than 0.01). Survival time did not correlate with the presence of perivascular lymphocytic infiltration. The authors conclude that the presence of at least 20% gemistocytes in a glial neoplasm is a poor prognostic sign, irrespective of the pathological background. It is proposed that gemistocytic astrocytomas be classified with anaplastic astrocytomas and treated accordingly.

Adult↗
PubMed1991

Management of chiasmal and hypothalamic gliomas of infancy and childhood with chemotherapy.

Between March, 1983, and February, 1989, 19 infants or children with chiasmal/hypothalamic gliomas were treated with chemotherapy after either surgical or radiological diagnosis. The patients ranged in age from 15 weeks to 15.6 years (median 3.2 years) at the start of therapy. Twelve patients were treated immediately after diagnosis because of progressive symptoms, and seven received chemotherapy after either radiographic progression or clinical deterioration, including progressive visual loss or intracranial hypertension. Based on biopsy results, seven of these tumors were classified as juvenile pilocytic astrocytomas, two as astrocytomas, two as highly anaplastic astrocytomas, and one as a subependymal giant-cell astrocytoma. There was associated neurofibromatosis in four patients. The two initial patients were treated with either actinomycin D and vincristine or 5-fluorouracil, hydroxyurea, and 6-thioguanine. The remaining patients received nitrosourea-based therapy; 15 evaluable patients were treated with a five-drug regimen that included 6-thioguanine, procarbazine, dibromodulcitol, 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU), and vincristine and one received 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and 5-fluorouracil. Fifteen of the 18 evaluable patients initially managed with chemotherapy either responded to therapy or their condition stabilized. Median time to tumor progression has not been reached at a median follow-up period of 79 weeks (range 6.6 to 303 weeks), and no tumor-related death has occurred with a median follow-up period of 79 weeks (range 18 to 322 weeks) from the initiation of therapy. The four patients who failed therapy or whose disease progressed after chemotherapy were treated satisfactorily with radiation therapy. Initial improvement or stabilization of visual function was obtained in 16 patients. Endocrine function remained stable in all patients during treatment, although three patients required pharmacological treatment for endocrinopathy that was present at diagnosis. These preliminary results suggest that nitrosourea-based cytotoxic regimens are useful for the initial treatment of children with chiasmal/hypothalamic gliomas, and allow potentially harmful radiation therapy to be deferred until progression of disease.

Adolescent↗
PubMed1989

Reevaluation of procarbazine for the treatment of recurrent malignant central nervous system tumors.

Ninety-nine patients with primary recurrent malignant tumors of the central nervous system were treated with procarbazine as a single agent. Procarbazine was not given as a specified protocol, but for patients who were ineligible or refused other protocols. All patients had been treated previously with radiotherapy and 96 patients had also received previous chemotherapy. Twenty-five patients were treated at the first progression of their tumor, 47 were treated at the second progression, and 27 were treated at the third progression of their tumor. For the aggregate, the response plus stabilization rate was 27% for glioblastoma multiforme with median time to tumor progression of 30 weeks, and 28% for other anaplastic gliomas with a median time to tumor progression of 49 weeks. With respect to the percent of patients who responded or stabilized to treatment, these results are inferior to those reported previously for patients treated with procarbazine at recurrence. With respect to duration of response and stabilization, the data are comparable.

Adolescent↗
PubMed1989

Interstitial brachytherapy for metastatic brain tumors.

Since December 1979, 14 patients with progressive metastatic brain lesions have been treated with temporary implantation of high-activity iodine 125 sources using stereotaxic techniques. Four patients had prior surgical resections, and 13 had been treated with external whole-brain radiotherapy. Nine patients had brachytherapy performed at recurrence 4 to 16 months after conventional radiation therapy; the other four had implants as an adjuvant "boost" to the tumor area from 2 to 4 weeks after external radiation. Six patients have since died: two with stable brain lesions at 4 and 22 weeks, respectively; three with progressive systemic and CNS tumors at 23, 24, and 29 weeks, respectively; and one with progressive CNS disease 116 weeks postimplant. The remaining eight patients are alive with a median follow-up of 63 weeks (range, 52-239+ weeks). Median survival for the entire group is 80 weeks. Brain tumor brachytherapy may be useful for palliation and possible long-term survival in selected patients with solitary metastatic disease.

Adult↗
PubMed1989

Phase I/II study of intraventricular and intrathecal ACNU for leptomeningeal neoplasia.

A total of 27 patients with leptomeningeal neoplasia were treated with the water-soluble nitrosourea ACNU given intraventricularly or intrathecally in a phase I/II study. Patients were entered in the study if they showed evidence of either a positive CSF cytology or neurodiagnostic evidence of leptomeningeal disease, or both. Patients were evaluated for toxicity and efficacy; additionally, in 13 patients ACNU pharmacokinetic studies were carried out. A variety of tumor types were represented in the study group, including primary and metastatic CNS tumors. Toxicity was mild and included pain at the injection site (four patients), transient radicular symptoms at a short distance from the injection site (three patients), and nausea and vomiting (one patient). No myelotoxicity was seen. Of 21 patients who presented with positive cytology, 8 (38%) had a conversion from positive to negative cytology, with a range of response durations from 1 to 20+ months. Of the remaining six patients with negative cytology but other neurodiagnostic evidence of leptomeningeal disease, one patient showed an improvement seen on the myelogram and one underwent a brief reduction in CSF protein. ACNU elimination from the ventricular system is rapid, with a beta slope of 0.028 min-1 and a computed elimination constant, Ko of 13 min. The mean clearance was 3.8 ml/min (range, 1.0-6.2 ml/min). Peak ACNU levels varied between 108 and 620 micrograms/ml, with the AUC being 1.4-14.7 mg.min/ml. The total dose of ACNU given was between 9 and 104 mg, and the single dose range was 4-16.5 mg. We conclude that ACNU can be given safely with minimal toxicity as intra-CSF therapy, that it demonstrates efficacy in some patients with leptomeningeal disease, and that further studies are warranted to evaluate more fully alternative dosing and drug delivery approaches.

Arachnoid↗
PubMed1989

Treatment of recurrent gliomas with 1,3-bis(2-chloroethyl)-1-nitrosourea and alpha-difluoromethylornithine.

Thirty-eight patients with primary recurrent anaplastic gliomas and glioblastomas, were treated with 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and the polyamine inhibitor alpha-difluoromethylornithine (DFMO). There were 5 brain stem, 1 cerebellar, and 32 supratentorial glioma tumors. All had been treated with surgery (except in the case of 4 brain stem tumors for which biopsies were not obtained) and radiotherapy. Eight patients had received prior chemotherapy. Of the 21 patients with evaluable supratentorial anaplastic gliomas, 2 (9.5%) had a partial response and 10 (47.6%) had stable disease. The median time to tumor progression for the anaplastic gliomas has not been attained yet. However, median survival for these 12 patients was 119 weeks measured from the initiation of chemotherapy. Median survival for the entire anaplastic glioma group of 21 was 56 weeks. Minimal activity was seen against glioblastoma multiforme. The median time to tumor progression was 8 weeks with median survival of 21 weeks. Of the 5 patients with brain stem tumors, 3 are alive with stable disease at 77, 93, and 220 weeks. The combination was well tolerated with dose-limiting toxicity being myelosuppression and hearing loss. Further trials are warranted to compare the combination of BCNU and DFMO against BCNU alone in a prospective randomized trial.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1989

Hyperfractionated radiation therapy for brain-stem glioma: a phase I-II trial.

Fifty-three patients (19 adults and 34 children) harboring brain-stem glioma were treated with hyperfractionated radiation therapy (100 cGy twice a day, 5 days/wk, to a total dose of 7200 cGy). For the entire group, the median time to tumor progression (TTP) was 59 weeks (adults 66 weeks, children 44 weeks) and the median survival time was 74 weeks (adults 92 weeks, children 64 weeks). Statistically significant prognostic factors associated with a decrease in TTP and median survival times (adults less than children) were: patient's age, a clinical history of less than 2 months, widespread brain-stem dysfunction, and a diffuse tumor as seen on magnetic resonance imaging. A finding of glioblastoma multiforme at histological analysis was associated with a statistical trend toward poorer survival, but in general tumor histology was not predictive of outcome. No evidence of an increase in acute or delayed radiation toxicity was seen with this fractionation schedule and total dose. This study suggests that hyperfractionation prolongs the TTP and survival time for many patients with brain-stem glioma. However, there remains a group of patients who are only moderately helped by this technique and for whom more aggressive treatment is warranted.

Adult↗
PubMed1989

Prognostic implications of the bromodeoxyuridine labeling index of human gliomas.

This study includes 182 patients with intracranial gliomas who received bromodeoxyuridine (BUdR), 200 mg/sq m intravenously, at the time of craniotomy but before tumor biopsy. The tumor specimens were stained for BUdR using the immunoperoxidase method; the BUdR labeling index (LI), or S-phase fraction, was calculated as the percentage of BUdR-positive cells. The median BUdR LI's for 127 primary moderately anaplastic astrocytomas, highly anaplastic astrocytomas, and glioblastomas (less than 1%, 2.7%, and 7.3%, respectively; range 0% to 38.1%) were not significantly different from those of 55 similar recurrent tumors (less than 1%, 4.3%, and 7.4%, respectively; range 0% to 30.5%). The mean LI was significantly higher in tumors from patients over 50 years of age than in tumors from younger patients (p less than 0.001). The age-related difference in LI's was found in both groups of patients with astrocytomas but not in those with glioblastomas. Kaplan-Meier survival curves showed a significantly greater probability of survival among patients whose tumors had LI's of less than 1% than among those with LI's greater than 5%; survival probability of patients with tumor LI's of 1% to 5% was intermediate between the two extremes. Thus, the BUdR LI appears to reflect the proliferative potential more accurately than the histopathological diagnosis and should therefore be considered an important factor in determining the prognosis of individual patients with intracranial gliomas and in selecting their treatment.

Astrocytoma↗
PubMed1988

Treatment of recurrent brain stem gliomas and other central nervous system tumors with 5-fluorouracil, CCNU, hydroxyurea, and 6-mercaptopurine.

Twenty-one patients with recurrent malignant central nervous system gliomas were treated with a combination of 5-fluorouracil, CCNU, hydroxyurea, and 6-mercaptopurine. Thirteen patients had brain stem gliomas, 3 patients had spinal cord gliomas, 3 patients had thalamic gliomas, and 2 patients had cerebellar astrocytomas. All patients had received radiation therapy, and 4 brain stem patients had also been treated with chemotherapy. Sixteen patients (76%) responded to treatment with either stabilization of disease or improvement. Nine of the 13 patients with brain stem gliomas (71%) had response or stabilization of disease. The median time to tumor progression (TTP) for the brain stem patients who responded or had stabilization of disease was 25 weeks. The median survival from recurrence for the brain stem glioma patients was 27 weeks. Patients with cerebellar, thalamic, and spinal cord tumors did very well, with an 87% response or stabilization of disease and a median TTP of 122 weeks.

Adolescent↗
PubMed1987

Malignant supratentorial gliomas in childhood.

In this review, we try to review concisely the incidence, genetic predilections, classification, and diagnosis of supratentorial gliomas (astrocytomas, oligodendrogliomas, and mixed gliomas) in children. While surgery and irradiation present the most commonly used and valuable modes of treatment, chemotherapy is a valuable adjunctive therapy. Used either with surgery and radiation in primary untreated patients or at recurrence (progression), chemotherapy can increase useful life. The late effects of treatment are primarily endocrine deficiencies and intellectual impairment; nevertheless, they are not of a degree to preclude aggressive therapy. In order to improve therapy, and because of the small number of patients with supratentorial tumors, collaborative multi-institutional trials should be encouraged.

Adolescent↗