Phase II trial of primary chemotherapy followed by reduced-dose radiation for CNS germ cell tumors.
PURPOSE: A prospective phase II study was initiated to assess the response rate, survival, and late effects of treatment in patients with newly diagnosed CNS germ cell tumors (GCT), using etoposide plus cisplatin followed by radiation therapy prescribed by extent of disease, histology, and response to chemotherapy. PATIENTS AND METHODS: Seventeen patients aged 8 to 24 years with histologically proven CNS GCT received etoposide (100 mg/m2/d) plus cisplatin (20 mg/m2/d) daily for 5 days every 3 weeks for four cycles, followed by radiation therapy. Nine patients had germinomas; eight had mixed GCT. Four patients (three with germinomas and one with mixed GCT) presented with leptomeningeal dissemination. RESULTS: Radiographically, 14 of 17 patients were assessable for response; 11 patients experienced complete regression, and three had major partial regression before radiation. Six of seven assessable patients with elevated CSF levels of alpha-fetoprotein or betahuman chorionic gonadotropin had normalization with chemotherapy alone; all normalized with combined chemotherapy and radiation therapy. All 17 patients are alive without evidence of disease (median follow-up, 51 months). One patient developed a relapse in the spinal leptomeninges and was rendered free of disease with spinal radiation more than 5 years ago. One patient developed carotid stenosis requiring surgery. Thus far, only minimal long-term deterioration in neurocognitive function has been detected as a consequence of protocol treatment. CONCLUSION: Conventional-dose intravenous chemotherapy with etoposide and cisplatin can effect tumor regression in a high proportion of patients with CNS GCT, including those with leptomeningeal metastases. Acute and long-term toxicities are acceptable. Progression-free survival and overall survival are excellent. (+info)
Dose-related effects of single focal irradiation in the medial temporal lobe structures in rats--magnetic resonance imaging and histological study.
The dose-related effects of single focal irradiation on the medial temporal lobe in rats were investigated by sequential magnetic resonance imaging and histological examination. Irradiation of 200 Gy as a maximum dose using 4 mm collimators with a gamma unit created an area of necrosis consistently at the target site within 2 weeks after irradiation. Irradiation of 100 Gy caused necrosis within 10 weeks, and 75 Gy caused necrosis within one year. Irradiation of less than 50 Gy did not induce necrosis consistently, although a restricted area of necrosis was created in the medial temporal structures including the intraparenchymal portion of the optic tract. 75 Gy may be the optimum dose for creating necrosis consistently in the medial temporal lobe structures. However, careful dose planning considering both dose-time and dose-volume relationships in necrosis development is necessary to avoid injury to vulnerable neural structures such as the optic tract when applying radiosurgical techniques to treat functional brain disorders in medial temporal lobe structures such as temporal lobe epilepsy. (+info)
Dosimetry of 131I-labeled 81C6 monoclonal antibody administered into surgically created resection cavities in patients with malignant brain tumors.
The objective of this study was to perform the dosimetry of 131I-labeled 81C6 monoclonal antibody (MAb) in patients with recurrent malignant brain tumors, treated by direct injections of MAb into surgically created resection cavities (SCRCs). METHODS: Absorbed dose estimates were performed for nine patients. Dosimetry was performed retrospectively using probe counts (during patient isolation) and whole-body and SPECT images thereafter. Absorbed doses were calculated for the SCRC interface and for regions of interest (ROIs) 1 and 2 cm thick, measured from the margins of cavity interface. Also, mean absorbed doses were calculated for normal brain, liver, spleen, thyroid gland, stomach, bone marrow and whole body. The average residence time for the SCRC was 111 h (65-200h). RESULTS: The average absorbed dose per unit injected activity (range) to the SCRC interface and ROIs 1 and 2 cm thick from the cavity interface were 31.9 (7.8-84.2), 1.9 (0.7-3.6) and 1.0 (0.4-1.8) cGy/MBq, respectively. Average absorbed doses per unit administered activity to brain, liver, spleen, thyroid, stomach, bone marrow and whole body were 0.18, 0.03, 0.08, 0.05, 0.02, 0.02 and 0.01 cGy/MBq, respectively. The high absorbed dose delivered to the SCRC interface may have produced an increase in cavity volume independent of tumor progression. CONCLUSION: At the maximum tolerated dose of 3700 MBq 131I-labeled 81C6 MAb, the absorbed doses to the SCRC interface and ROIs of 1 and 2 cm thickness were estimated to be 1180, 71 and 39 Gy, respectively. The estimated average absorbed dose to the brain was 6.5 Gy. There was no neurological toxicity and minimal hematologic toxicity at this maximum tolerated administration level. (+info)
Phase I study of 90Y-labeled B72.3 intraperitoneal administration in patients with ovarian cancer: effect of dose and EDTA coadministration on pharmacokinetics and toxicity.
The tumor-associated glycoprotein 72 (TAG-72) antigen is present on a high percentage of tumor types including ovarian carcinomas. Antibody B72.3 is a murine monoclonal recognizing the surface domain of the TAG-72 antigen and has been widely used in human clinical trials. After our initial encouraging studies (M. G. Rosenblum et al., J. Natl. Cancer Inst., 83: 1629-1636, 1991) of tissue disposition, metabolism, and pharmacokinetics in 9 patients with ovarian cancer, we designed an escalating dose, multi-arm Phase I study of 90Y-labeled B72.3 i.p. administration. In the first arm of the study, patients (3 pts/dose level) received an i.p. infusion of either 2 or 10 mg of B72.3 labeled with either 1, 10, 15, or 25 mCi of 90Y. Pharmacokinetic studies demonstrated that concentrations of 90Y-labeled B72.3 persist in peritoneal fluid with half-lives >24 h after i.p. administration. In addition, 90Y-labeled B72.3 was absorbed rapidly into the plasma with peak levels achieved within 48 h, and levels declined slowly thereafter. Cumulative urinary excretion of the 90Y label was 10-20% of the administered dose which suggests significant whole-body retention of the radiolabel. Biopsy specimens of bone and marrow obtained at 72 h after administration demonstrated significant content of the label in bone (0.015% of the dose/g) with relatively little in marrow (0.005% of the dose/g). The maximal tolerated dose was determined to be 10 mCi because of hematological toxicity and platelet suppression. This typically occurred on the 29th day after administration and was thought to be a consequence of the irradiation of the marrow from the bony deposition of the radiolabel. In an effort to suppress the bone uptake of 90Y, patients were treated with a continuous i.v. infusion of EDTA (25 mg/kg/12 h x 6) infused immediately before i.p. administration of the radiolabeled antibody. Patients (3 pts/dose level) were treated with doses of 10, 15, 20, 25, 30, 35, 40, or 45 mCi of 90Y-labeled B72.3 for a total of 38 patients. EDTA administration resulted in significant myeloprotection, which allowed escalation to the maximal tolerated dose of 40 mCi. Dose-limiting toxicity was thrombocytopenia and neutropenia. Studies of plasma and peritoneal fluid pharmacokinetics demonstrate no changes compared with patients without EDTA pretreatment. Cumulative urinary excretion of the radiolabel was not increased in patients pretreated with EDTA compared with the untreated group. However, analysis of biopsy specimens of bone and marrow demonstrated that bone and marrow content of the 90Y label was 15-fold lower (<0.001% injected dose/g) than a companion group without EDTA. Four responses were noted in patients who received 15-30 mCi of 90Y-labeled B72.3 with response durations of 1-12 months. These results demonstrate the myeloprotective ability of EDTA, which allows safe i.p. administration of higher doses of 90Y-labeled B72.3 and, therefore, clearly warrant an expanded Phase II trial in patients with minimal residual disease after standard chemotherapy or for the palliation of refractory ascites. (+info)
Locoregional regulatory peptide receptor targeting with the diffusible somatostatin analogue 90Y-labeled DOTA0-D-Phe1-Tyr3-octreotide (DOTATOC): a pilot study in human gliomas.
Human gliomas, especially of low-grade type, have been shown to express high-affinity somatostatin receptor type 2 (J-C. Reubi et al., Am. J. Pathol, 134: 337-344, 1989). We enrolled seven low-grade and four anaplastic glioma patients in a pilot study using the diffusible peptidic vector 90Y-labeled DOTA0-D-Phe1-Tyr3-octreotide (DOTATOC) for receptor targeting. The radiopharmakon was locoregionally injected into a stereotactically inserted Port-a-cath. DOTATOC competes specifically with somatostatin binding to somatostatin receptor type 2 in the low nanomolar range as shown by a displacement curve of 125I-[Tyr3]-octreotide in tumor tissue sections. Diagnostic (111)In-labeled DOTATOC-scintigraphy following local injection displayed homogeneous to nodular intratumoral vector distribution. The cumulative activity of regionally injected peptide-bound 90Y amounted to 370-3300 MBq, which is equivalent to an effective dose range between 60 +/- 15 and 550 +/- 110 Gy. Activity was injected in one to four fractions according to tumor volumes; 1110 MBq of 90Y-labeled DOTATOC was the maximum activity per single injection. We obtained six disease stabilizations and shrinking of a cystic low-grade astrocytoma component. The only toxicity observed was secondary perifocal edema. The activity:dose ratio (MBq:Gy) represents a measure for the stability of peptide retention in receptor-positive tissue and might predict the clinical course. We conclude that SR-positive human gliomas, especially of low-grade type, can be successfully targeted by intratumoral injection of the metabolically stable small regulatory peptide DOTATOC. (+info)
A radionuclide therapy treatment planning and dose estimation system.
An object-oriented software system is described for estimating internal emitter absorbed doses using a set of computer modules operating within a personal computer environment. The system is called the Radionuclide Treatment Planning and Absorbed Dose Estimation System (RTDS). It is intended for radioimmunotherapy applications, although other forms of internal emitter therapy may also be considered. METHODS: Four software modules interact through a database backend. Clinical, demographic and image data are directly entered into the database. Modules include those devoted to clinical imaging (nuclear, CT and MR), activity determination, organ compartmental modeling and absorbed dose estimation. RESULTS: Both standard phantom (Medical Internal Radiation Dose [MIRD]) and patient-specific absorbed doses are estimated. All modules interact with the database backend so that changes in one process do not influence other operations. Results of the modular operations are written to the database as computations are completed. Dose-volume histograms are an intrinsic part of the output for patient-specific absorbed dose estimates. A sample dose estimate for a potential 90Y monoclonal antibody is described. CONCLUSION: A four-module software system has been implemented to estimate MIRD phantom and patient-specific absorbed doses. Computations of the doses and their statistical distribution for a pure beta emitter such as 90Y take approximately 1 min on a 300 MHz personal computer. (+info)
The increment of micronucleus frequency in cervical carcinoma during irradiation in vivo and its prognostic value for tumour radiocurability.
A potential usefulness of micronucleus assay for prediction of tumour radiosensitivity has been tested in 64 patients with advanced stage (II B-IV B) cervical carcinoma treated by radiotherapy. The study of cellular radiosensitivity in vitro was conducted in parallel with the study of cellular damage after tumour irradiation in vivo. Radiosensitivity of in vitro cultured primary cells isolated from tumour biopsies taken before radiotherapy was evaluated using cytokinesis-block micronucleus assay. Frequency of micronuclei per binucleated cell (MN/BNC) at 2 Gy was used as a measure of radiosensitivity. Radiation sensitivity in vivo was expressed as per cent increment of micronucleus frequency in cells isolated from biopsy taken after 20 Gy (external irradiation, 10 x 2 Gy) over the pre-treatment spontaneous micronucleus level and was called MN20. Very low correlation (r = 0.324) was observed between micronucleus frequency in vitro and in vivo. Although micronucleus frequency at 2 Gy differed widely between tumours evaluated (mean MN/BNC was 0.224; range 0.08-0.416), no significant correlation was observed between this parameter and clinical outcome. The average increment of micronucleus frequency after 20 Gy amounted to 193% of spontaneous level (range 60-610%) and was independent of spontaneous micronucleation before radiotherapy. In contrast to in vitro results, these from in vivo assay seem to have a predictive value for radiotherapy of cervix cancer. The micronucleus increment in vivo that reached at least 117.5% of pretreatment value (first quartile for MN20 data set) correlated significantly with better tumour local control (P < 0.008) and overall survival (P < 0.045). Our results suggest that evaluation of increment of micronucleus frequency during radiotherapy (after fixed tested dose of 20 Gy) offers a potentially valuable approach to predicting individual radioresponsiveness and may be helpful for individualization of treatment strategy in advanced stage cervical cancer. (+info)
Prognostic values of proliferating cell nuclear antigen (PCNA) and Ki-67 for radiotherapy of oesophageal squamous cell carcinomas.
The relationship of immunohistochemical indices of proliferating cell nuclear antigen (PCNA) and Ki-67 to local control and survival rates for patients with oesophageal squamous cell carcinomas treated by definitive radiotherapy (RT) was investigated. Biopsy materials before RT were obtained from 65 patients with oesophageal cancer. The median PCNA labelling index (LI) and the median Ki-67 LI were 52% and 45% respectively. The PCNA LI was independent of known prognostic factors on local control for oesophageal cancer, although Ki-67 LI correlated with several prognostic factors. In the univariate analysis, patients with the PCNA LI of < 52% or the Ki-67 LI of < 45% showed significantly higher local recurrence rates than those with higher LIs (both P < 0.05). This difference in local control rate according to LIs was prominent for the patients treated with conventional fractionation. In the multivariate analysis, T-stage (P = 0.0056) and PCNA LI (P = 0.0332) were significant factors for local control in the final model using a stepwise regression procedure. In conclusion, PCNA LI and Ki-67 LI were significantly correlated with local control probabilities in oesophageal squamous cell carcinomas treated by definitive RT. (+info)