Prognostic factors in pediatric high-grade astrocytoma: the importance of accurate pathologic diagnosis.

To characterize a population of pediatric high-grade astrocytoma (HGA) patients by confirming the proportion with a correct diagnosis, and determine prognostic factors for survival in a subset diagnosed with uniform pathologic criteria. Sixty-three children diagnosed with HGA were treated at the Johns Hopkins Hospital between 1977 and 2004. A single neuropathologist (P.C.B.) reviewed all available histologic samples (n = 48). Log-rank analysis was used to compare survival by patient, tumor, and treatment factors. Median follow-up was 16 months for all patients and 155 months (minimum 54 months) for surviving patients. Median survival for all patients (n = 63) was 14 months with 10 long-term survivors (survival >48 months). At initial diagnosis, 27 patients were grade III (43%) and 36 grade IV (57%). Forty-eight patients had pathology slides available for review, including seven of ten long-term surviving patients. Four patients had non-HGA pathology, all of whom were long term survivors. The remaining 44 patients with confirmed HGG had a median survival of 14 months and prognostic analysis was confined to these patients. On multivariate analysis, five factors were associated with inferior survival: performance status (Lansky) <80% (13 vs. 15 months), bilaterality (13 vs. 19 months), parietal lobe location (13 vs. 16 months), resection less than gross total (13 vs. 22 months), and radiotherapy dose <50 Gy (9 vs. 16 months). Among patients with more than one of the five adverse factors (n = 27), median survival and proportion of long-term survivors were 12.9 months and 0%, compared with 41.4 months and 18% for patients with 0-1 adverse factors (n = 17). In an historical cohort of children with HGA, the potential for long term survival was confined to the subset with less than two of the following adverse prognostic factors: low performance status, bilaterality, parietal lobe site, less than gross total resection, and radiotherapy dose <50 Gy. Pathologic misdiagnosis should be suspected in patients who are long term survivors of a pediatric high grade astrocytoma.

Pediatric soft tissue sarcomas.

Soft tissue sarcomas in children are rare. Approximately 850 to 900 children and adolescents are diagnosed each year with rhabdomyosarcoma (RMS) or a non-RMS soft tissue sarcoma (NRSTS). RMS is more common in children 14 years old and younger and NRSTS in adolescents and young adults. Infants get NRSTS, but their tumors constitute a distinctive set of histologies. Surgery is a major therapeutic modality and radiation plays a role. RMS is treated with adjuvant chemotherapy, whereas chemotherapy is reserved for the NRSTS that are high grade or unresectable. This review discusses the etiology, biology, and treatment of pediatric soft tissue sarcomas.

Long-term outcomes of vestibular schwannomas treated with fractionated stereotactic radiotherapy: an institutional experience.

PURPOSE: We assessed clinical outcome and long-term tumor control after fractionated stereotactic radiotherapy (FSRT) for unilateral schwannoma. METHODS AND MATERIALS: Between 1995 and 2007, 496 patients were treated with fractionated stereotactic radiotherapy at Johns Hopkins Hospital (Baltimore, MD); 385 patients had radiologic follow-up that met the inclusion criteria. The primary endpoint was treatment failure. Secondary endpoints were radiologic progression and clinical outcome. Logistic regression analysis assessed the association of age, race, tumor side, sex, and pretreatment symptoms. RESULTS: In 11 patients (3%) treatment failed, and they required salvage (microsurgical) treatment. Radiologic progression was observed in 116 patients (30.0%), including 35 patients (9%) in whom the treatment volume more than doubled during the follow-up period, although none required surgical resection. Tumors with baseline volumes of less than 1 cm(3) were 18.02 times more likely to progress than those with tumor volumes of 1 cm(3) or greater (odds ratio, 18.02; 95% confidence interval, 4.25-76.32). Treatment-induced neurologic morbidity included 8 patients (1.6%) with new facial weakness, 12 patients (2.8%) with new trigeminal paresthesias, 4 patients (0.9%) with hydrocephalus (1 communicating and 3 obstructive), and 2 patients (0.5%) with possibly radiation-induced neoplasia. CONCLUSIONS: Although the rate of treatment failure is low (3%), careful follow-up shows that radiologic progression occurs frequently. When reporting outcome, the "no salvage surgery needed" and "no additional treatment needed" criteria for treatment success need to be complemented by the radiologic data.

A treatment planning method for sequentially combining radiopharmaceutical therapy and external radiation therapy.

PURPOSE: Effective cancer treatment generally requires combination therapy. The combination of external beam therapy (XRT) with radiopharmaceutical therapy (RPT) requires accurate three-dimensional dose calculations to avoid toxicity and evaluate efficacy. We have developed and tested a treatment planning method, using the patient-specific three-dimensional dosimetry package 3D-RD, for sequentially combined RPT/XRT therapy designed to limit toxicity to organs at risk. METHODS AND MATERIALS: The biologic effective dose (BED) was used to translate voxelized RPT absorbed dose (D(RPT)) values into a normalized total dose (or equivalent 2-Gy-fraction XRT absorbed dose), NTD(RPT) map. The BED was calculated numerically using an algorithmic approach, which enabled a more accurate calculation of BED and NTD(RPT). A treatment plan from the combined Samarium-153 and external beam was designed that would deliver a tumoricidal dose while delivering no more than 50 Gy of NTD(sum) to the spinal cord of a patient with a paraspinal tumor. RESULTS: The average voxel NTD(RPT) to tumor from RPT was 22.6 Gy (range, 1-85 Gy); the maximum spinal cord voxel NTD(RPT) from RPT was 6.8 Gy. The combined therapy NTD(sum) to tumor was 71.5 Gy (range, 40-135 Gy) for a maximum voxel spinal cord NTD(sum) equal to the maximum tolerated dose of 50 Gy. CONCLUSIONS: A method that enables real-time treatment planning of combined RPT-XRT has been developed. By implementing a more generalized conversion between the dose values from the two modalities and an activity-based treatment of partial volume effects, the reliability of combination therapy treatment planning has been expanded.

Stereotactic radiosurgery in the management of brain metastases: an institutional retrospective analysis of survival.

PURPOSE: The objective of this study was to report our experience with stereotactic radiosurgery performed with the Gamma Knife (GK) in the treatment of patients with brain metastases and to compare survival for those treated with radiosurgery alone with survival for those treated with radiosurgery and whole-brain radiotherapy. METHODS AND MATERIALS: Prospectively collected demographic and clinical characteristics and treatment and survival data on 237 patients with intracranial metastases who underwent radiosurgery with the GK between 2003 and 2007 were reviewed. Kaplan-Meier and Cox proportional hazards regression analyses were used to compare survival by demographic and clinical characteristics and treatment. RESULTS: The mean age of the patient population was 56 years. The most common tumor histologies were non-small-cell lung carcinoma (34.2%) and breast cancer (13.9%). The median overall survival time was 8.5 months from the time of treatment. The median survival times for patients with one, two/three, and four or more brain metastases were 8.5, 9.4, and 6.7 months, respectively. Patients aged 65 years or greater and those aged less than 65 years had median survival times of 7.8 and 9 months, respectively (p = 0.008). The Karnofsky Performance Score (KPS) at the time of treatment was a significant predictor of survival: those patients with a KPS of 70 or less had a median survival of 2.9 months compared with 10.3 months (p = 0.034) for those with a KPS of 80 or greater. There was no statistically significant difference in survival between patients treated with radiosurgery alone and those treated with radiosurgery plus whole-brain radiotherapy. CONCLUSIONS: Radiosurgery with the GK is an efficacious treatment modality for brain metastases. A KPS greater than 70, histology of breast cancer, smaller tumor volume, and age less than 65 years were associated with a longer median survival in our study.

Tandem dosing of samarium-153 ethylenediamine tetramethylene phosphoric acid with stem cell support for patients with high-risk osteosarcoma.

BACKGROUND: Samarium-153 ethylenediamine tetramethylene phosphoric acid (153Sm-EDTMP) is a radiopharmaceutical that has been used to treat osteosarcoma. The authors conducted a phase 2 study to test safety and response of high-risk osteosarcoma to tandem doses of 153Sm-EDTMP and to determine correlation between radiation delivered by low and high administered activities. METHODS: Patients with recurrent, refractory osteosarcoma detectable on standard 99mTc bone scan received a low dose of 153Sm-EDTMP (37.0-51.8 MBq/kg), followed upon count recovery by a second, higher dose (222 MBq/kg). Fourteen days later, patients were rescued with autologous hematopoietic stem cells. The authors assessed response to therapy, performed dosimetry to determine the relationship between administered activity and tumor absorbed dose, and investigated whether changes in 2-(fluorine-18) fluoro-2-deoxy-d-glucose (18F-FDG) tumor uptake upon hematologic recovery reflected disease response. RESULTS: Nine patients were given tandem doses of 153Sm-EDTMP; 2 received only the initial dose because of disease progression. Six patients experienced radiographic disease stabilization, but this was not considered a response, so the study was terminated early. There was a linear relationship between administered activity and tumor absorbed dose, but there was no correlation between change in 18F-FDG positron emission tomography tumor uptake and tumor absorbed dose or time to progression. The median time to progression for the entire group was 79 days. CONCLUSIONS: Tandem doses of 153Sm-EDTMP were safe for this cohort of heavily pretreated patients with very high-risk disease. The strong correlation between absorbed dose and administered activity within each evaluable patient provides a methodology to individually tailor tandem doses of this agent.

Dose-finding study of 153Sm-EDTMP in patients with poor-prognosis osteosarcoma.

BACKGROUND: Samarium-153 ethylenediaminetetramethylene phosphonic acid ((153)Sm-EDTMP) has been used to treat patients with high-risk osteosarcoma. The purpose of the current study was to determine the maximally tolerated dose of (153)Sm-EDTMP that permits hematopoietic recovery within 6 weeks. METHODS: Patients with recurrent or refractory osteosarcoma with bone metastases were enrolled in this study. Subjects were treated with increasing doses of (153)Sm-EDTMP, beginning with 1.0 millicuries (mCi)/kg and followed initially with 40% increment dose level escalations, using a continual reassessment method for dose escalation and de-escalation with a target dose-limiting toxicity (DLT) rate of 30%. Complete blood counts were monitored weekly, and the primary DLT was defined as failure to achieve an absolute neutrophil count >750/mm(3) and a platelet count >75,000/mm(3) within 6 weeks of treatment. In addition to assessing toxicity, dosimetry measurements were made to estimate the radiation dose delivered to target lesions. RESULTS: The maximally tolerated dose of (153)Sm-EDTMP was 44.8 megabecquerel (MBq)/kg (1.21 mCi/kg). DLTs were confined to hematologic toxicities, particularly delayed platelet recovery in 2 patients treated at a dose of 51.8 MBq/kg (1.4 mCi/kg). Grade 2 and 3 pulmonary toxicity (graded according to the National Cancer Institute Common Toxicity Criteria [version 3.0]) as reported in 2 patients (at administered activities of 44.8 MBq/kg and 51.8 MBq/kg) was attributable to progressive pulmonary disease. No other significant nonhematologic toxicities were observed. CONCLUSIONS: Patients with osteosarcoma who have previously been heavily treated with chemotherapy can be safely administered (153)Sm-EDTMP with rapid hematologic recovery. The data from the current study support the development of a future trial to assess the efficacy of combining targeted radiotherapy with cytotoxic chemotherapy as a treatment option for patients with high-risk osteosarcoma.

A virtual frame system for stereotactic radiosurgery planning.

PURPOSE: We describe a computerized (or virtual) model of a stereotactic head frame to enable planning prior to the day of radiosurgery. The location of the virtual frame acts as a guide to frame placement on the day of the procedure. METHODS AND MATERIALS: The software consists of a triangular mesh representation of the essential frame hardware that can be overlaid with any MR scan of the patient and manipulated in three dimensions. The software calculates regions of the head that will actually be accessible for treatment, subject to the geometric constraints of the Leksell Gamma Knife hardware. DICOM-compliant MR images with virtual fiducial markers overlaid onto the image can then be generated for recognition by the treatment planning system. RESULTS: Retrospective evaluation of the software on 24 previously treated patients shows a mean deviation of the position of the virtual frame from the actual frame position of 1.6 +/- 1.3 mm. Initial clinical use on five patients indicates an average discrepancy of the virtual frame location and the actual frame location of <1 mm. MR images with virtual fiducial markers can be imported into radiosurgical treatment planning software and used to generate an initial treatment plan. CONCLUSIONS: The virtual frame provides a tool for prospective determination of lesion accessibility, optimization of the frame placement, and treatment planning before the day of the procedure. This promises to shorten overall treatment times, improve patient comfort, and reduce the need for repeat treatments due to suboptimally placed frames.

The role of radiation treatment in the contemporary management of bone tumors.

Radiotherapy is integral in the multidisciplinary approach to patients with musculoskeletal neoplasms. Multiple studies have established a role for radiotherapy as a definitive local treatment of unresectable lesions or when surgery might yield unacceptable functional outcomes, such as in Ewing's tumor or base of skull chondrosarcoma. Radiotherapy is also used as an adjuvant treatment after surgery with close or positive margins. In the metastatic setting, external beam radiotherapy and bone-seeking intravenous radioisotopes are used on a case-by-case basis for palliation. As radiotherapy and its delivery techniques have evolved, so has its role in treating tumors such as Ewing's sarcoma, chordoma and chondrosarcoma, osteosarcoma, primary lymphoma of bone, malignant fibrous histiocytoma of bone, and vascular tumors. Radiation can also be successfully used to treat unresectable or recurrent benign tumors, such as giant cell tumor and aneurysmal bone cyst. This article reviews the indications for radiotherapy for various bone tumors and summarizes some of the important data supporting its use.