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Biomedical subjects

Fredric A Hoffer

Publications and source records attributed to Fredric A Hoffer.

At least 19 recordsLinked to original sources
PubMed2008

Hematometrocolpos in an adolescent female treated for pelvic Ewing sarcoma.

Radiation therapy is often used to achieve local control of pelvic Ewing sarcoma in children. The effects of radiation on the female reproductive tract have been well documented in adults with gynecological malignancies, but the long-term consequences of pelvic radiation in pre-pubertal or adolescent girls are not as well described. We report a case of hematometrocolpos developing in an adolescent previously treated with chemotherapy and radiation therapy for pelvic Ewing sarcoma. We describe the clinical presentation, radiographic features, gross pathology, treatment strategies, outcome, as well as putative predisposing factors and preventative interventions.

Bone Neoplasms↗
PubMed2007

Core body temperature regulation of pediatric patients during radiofrequency ablation.

Core body temperature elevation (hyperthermia) can occur during radiofrequency ablation of large centrally located tumors in small children. Hyperthermia can be predicted on the basis of long burn times, high wattage delivered by the RF system and low body weight. If hyperthermia is anticipated, cooling blankets using refrigerated air or water are recommended. The advantage of these systems is that the cooling can help maintain normal core body temperature.

Air↗
PubMed2007

Pleurodesis for effusions in pediatric oncology patients at end of life.

BACKGROUND: Pleurodesis for end-of-life care has been used in adults for decades, but little is known about the usefulness of this technique in improving the quality of care for pediatric patients. OBJECTIVE: To assess whether intractable pleural effusions in pediatric oncology patients at end of life could be sufficiently relieved by pleurodesis. MATERIAL AND METHODS: Eleven pleurodeses were performed with doxycycline in seven pediatric cancer patients (age 3-21 years) with intractable pleural effusions at the end of life. Five patients had unilateral pleurodeses and two had a unilateral followed by bilateral pleurodeses. RESULTS: Respiratory rates decreased in all seven patients (P = 0.016) and aeration improved significantly after chest tube placement (P = 0.033). The chest tubes were placed a median of 1 day before pleurodesis. Eight of nine chest tubes (89%) were removed before discharge at a median of 3 days after pleurodesis. Pain secondary to the pleurodesis lasted 1 day or less. Improvement in the respiratory rate remained after pleurodesis and chest tube removal (P = 0.031). Five of seven patients (70%) were able to leave the hospital to return home. The five patients discharged lived 10 to 49 days (median 19 days) after discharge. CONCLUSION: Pediatric oncology patients with intractable effusions at end of life can have respiratory benefit from pleurodeses and, as a result, are more likely to return home for terminal care.

Adolescent↗
PubMed2007

Evaluation of pediatric oncology patients with previous multiple central catheters for vascular access: is Doppler ultrasound needed?

BACKGROUND/PURPOSE: Pediatric oncology patients who have undergone placement of multiple central venous catheters may have thrombosis or stenosis in the upper venous system. The purpose of this study was to identify factors that predict venous thrombosis or stenosis and to evaluate the role of Doppler ultrasonography in assessing the upper venous system of pediatric patients requiring multiple central vascular catheters. METHODS: The medical records of eligible patients were reviewed with regard to demographics, primary disease, type of catheter, duration of previous central venous access, association with infection, operative notes, and Doppler ultrasonographic findings. RESULTS: Our evaluation criteria were met in 50 cases (47 patients). In 10 cases, Doppler ultrasonography revealed abnormality in the upper venous system. Patient demographics, primary disease, type of catheter, duration of previous central venous access, or association with infection were not found to significantly predict the abnormality in the upper venous system. Placement of central venous access device was performed without difficulty when the site of placement was chosen on the basis of ultrasonographic findings. CONCLUSION: Doppler ultrasonography is useful in diagnosing thrombosis or stenosis in asymptomatic pediatric patients requiring placement of multiple central venous catheters.

Adolescent↗
PubMed2006

A model for quantitative changes in the magnetic resonance parameters of muscle in children after therapeutic irradiation.

PURPOSE/OBJECTIVE: This study aimed to develop objective models of radiation effects on musculature in children with soft tissue sarcoma using treatment dosimetry and clinical and quantitative magnetic resonance imaging (MRI) parameters that may be used to guide treatment planning or predict side effects. METHODS: In the initial 13 patients undergoing external beam radiation therapy (RT) on a Phase II study of conformal or intensity-modulated RT for the treatment of soft tissue sarcoma approved by an Institutional Review Board, we evaluated quantitative MRI changes in the musculature to assess radiation-related treatment effects. Patients with soft tissue sarcoma, including Ewing's sarcoma, had quantitative T1, T2 and dynamic enhanced MRI (DEMRI) performed before, during (Week 4) and after RT (Week 12). Regions of interest were selected in consistent locations within and outside the high-dose regions (on ipsilateral and contralateral sides when available). Mean RT dose, T1, T2 and DEMRI parameters were calculated and modeled using a mixed random coefficient dose model. RESULTS: The mean doses to the high- and low-dose regions were 56.4 Gy (41.8-75.3 Gy) and 13.0 Gy (0.1-37.5 Gy), respectively. Compared with tissues distant from the tumor bed, maximal enhancement was significantly increased in tissues adjacent to the tumor/tumor bed prior to RT (60.6 vs. 44.2, P=.045) and remained elevated after 12 weeks. T1 was significantly elevated in tissues adjacent to the tumor bed prior to RT (942.4 vs. 759.0, P=.0078). The slope of longitudinal change in T1 was greater for tissues that received low-dose irradiation than those that received high-dose irradiation (P=.0488). The effect of dose on the slope of T2 was different (P=.0333) when younger and older patients are compared. CONCLUSIONS: Acute affects of irradiation in muscle are quantifiable via MRI. These models provide evidence that quantifiable MRI parameters may be correlated with patient parameters of radiation dose and clinical factors including patient age. Long-term follow-up will be required to determine if acute changes correlate with clinically significant late effects.

Child↗
PubMed2005

Percutaneous biopsy of pediatric solid tumors.

BACKGROUND: The objective of the current study was to determine the diagnostic accuracy of percutaneous biopsy of pediatric solid tumors, a procedure that is less invasive than open biopsy. METHODS: The authors conducted a retrospective analysis of clinical data related to 202 percutaneous core-needle biopsies of solid tumors at St. Jude Children's Research Hospital over 5.5 years (from 1997 to 2003). In 103 patients, the procedure was performed to establish an initial diagnosis of a suspected malignancy; and, in 99 patients, disease recurrence was suspected. Biopsies were guided by ultrasound, computed tomography, or fluoroscopic imaging. From each tumor, 1-17 core biopsy samples (median, 6 samples) were obtained; the median needle size was 15 gauge (range, 13-20 gauge). The specimens were submitted for histopathologic analysis and other ancillary procedures (molecular pathology and/or cytogenetic analyses). The accuracy of the diagnoses from the biopsies was determined by subsequent surgery with or without pathologic assessment or by outcome. RESULTS: When the biopsy samples were assessed for the presence of malignancy, there were 121 true-positive results (90% sensitivity), 67 true-negative results (100% specificity), and 14 false-negative results (93% accuracy). In 103 tumors, when the procedure was performed for initial diagnosis, percutaneous needle biopsy showed a sensitivity of 97%, a specificity of 100%, and an accuracy of 98%. The 99 procedures for suspected recurrence were less reliable (sensitivity, 83%; specificity, 100%; accuracy, 88%). CONCLUSIONS: Image-guided percutaneous biopsy was highly accurate and safe in the diagnosis of pediatric malignant solid tumors. This technique may be able to supplant diagnostic open biopsy.

Adolescent↗
PubMed2005

Which MRI sequence of the spine best reveals bone-marrow metastases of neuroblastoma?

BACKGROUND: MRI is an effective tool in evaluating bone marrow metastases. However, no study has defined which MRI sequences or image characteristics best correlate with bone-marrow metastases in neuroblastoma. OBJECTIVE: To identify and refine MRI criteria and sequence selection for the diagnosis of bone-marrow metastases in children with neuroblastoma. MATERIALS AND METHODS: Ninety-one children (mean age: 3.2 years; standard deviation: 2.8 years) enrolled in the RDOG IV study participated in our study. Forty-five children had bone metastases determined by bone-marrow aspiration or biopsy (n=4), radionuclide imaging (n=2), or both (n=39). Spine lesions were characterized using coronal T1-weighted (T1W) sagittal short tau inversion recovery (STIR) and coronal gadolinium-enhanced T1-weighted (GAD) MR sequences. Contingency table analysis was performed to determine which MRI sequences and characteristics were associated with metastases. The MRI criteria for metastatic disease were then developed for each imaging sequence. The sensitivity, specificity, predictive values, and accuracy of these criteria were determined for the whole group, children younger than 12 months old, and children 12 months and older. RESULTS: The MR characteristics that had significant (P<or=0.05) associations with metastases were homogeneous low T1-signal intensity, homogeneous high STIR-signal intensity, and heterogeneous pattern on T1, STIR, or GAD. Homogeneous low T1-signal had the highest sensitivity (88%), but a specificity of 62% for detecting metastases. A heterogeneous pattern on GAD was highly specific (97%), but relatively insensitive (65%) for detecting metastases. These MR characteristics were most accurate in children 12 months and older. CONCLUSION: The combination of non-contrast-enhanced T1W and GAD sequences can be used to determine the presence of spinal metastases in children with neuroblastoma, particularly those children who are 1 year and older.

Bone Marrow Neoplasms↗
PubMed2005

Radiographic assessment of resectability of locoregional disease in children with high-risk neuroblastoma during neoadjuvant chemotherapy.

BACKGROUND: The optimal timing for attempting removal of the primary tumor and regional disease in patients with high-risk neuroblastoma is uncertain. The purpose of this study was to evaluate resectability of the primary tumor and regional disease, as determined radiographically, in children with high-risk neuroblastoma during neoadjuvant chemotherapy. PROCEDURE: Patients enrolled in our institutional high-risk neuroblastoma protocol were evaluated prospectively by CT scan and/or MRI to determine the resectability of their primary tumor and regional disease at diagnosis, after two cycles of experimental therapy and after standard induction therapy. Tumors were considered to be unresectable if there was significant involvement with major vascular structures or contiguous organs, or would likely require nephrectomy to remove the entire tumor. RESULTS: Twenty-four patients were referred prior to surgery for treatment of high-risk neuroblastoma. Seven of 24 (29%) patients were felt to be resectable at diagnosis, with an additional 9 patients becoming resectable after the initial experimental therapy. Thus, overall, 16 of 24 (67%) patients were felt to be resectable by the completion of the initial therapy. Only four additional patients of the remaining eight were considered resectable after the completion of standard induction therapy. CONCLUSIONS: Based on these data, we conclude that complete resection of the primary tumor and regional disease in children with high-risk neuroblastoma can be performed after an initial phase therapy in the majority of patients. Since earlier tumor removal may decrease the chance for the subsequent development of chemotherapy-resistant disease, we are recommending surgical resection as soon as the locoregional disease appears to be resectable.

Adolescent↗
PubMed2005

Interventional radiology in pediatric oncology.

There are many radiological interventions necessary for pediatric oncology patients, some of which may be covered in other articles in this publication. I will discuss a number of interventions including percutaneous biopsy for solid tumor and hematological malignancy diagnosis or recurrence, for the diagnosis of graft versus host disease after stem cell or bone marrow transplantation, and for the diagnosis of complications of immunosuppression such as invasive pulmonary aspergillosis. In the past, tumor localization techniques have been necessary to biopsy or resect small lesions. However improved guidance techniques have allowed for more precise biopsy and the use of thermal ablation instead of excision for local tumor control. A percutaneously placed radio frequency, microwave, laser or cryogen probe can ablate the primary and metastatic tumors of the liver, lung, bone, kidney and other structures in children. This is an alternative treatment for the local control of tumors that may not be amenable to surgery, chemotherapy or radiotherapy. I will also describe how chemoembolization can be used to treat primary or metastatic tumors of the liver that have failed other therapies. This treatment delivers chemotherapy in the hepatic artery infused with emboli to increase the dwell time and concentration of the agents.

Biopsy↗
PubMed2005

Magnetic resonance imaging of abdominal masses in the pediatric patient.

Magnetic resonance (MR) plays a unique role in the diagnosis and management of pediatric abdominal masses. The "as low as reasonably achievable" (ALARA) radiation dose of CT is zero when substituted by MR. Whole body MR may also compete with PET imaging to stage abdominal tumors. Specific advantages of MR include determination of resectability of hepatic tumors using MRI and MRA; staging of neuroblastoma in the bone marrow, lymph nodes, liver, and spinal canal; response of bilateral Wilms tumor and nephroblastomatosis; detection of pelvic tumors with sagittal sectioning, and peritoneal tumors with contrast enhancement.

Abdominal Neoplasms↗
PubMed2005

Pyogenic hepatic abscess after percutaneous liver biopsy in a patient with sickle cell disease.

Liver abscess is a rare complication of liver biopsy but has not been reported in a patient with sickle cell disease (SCD) undergoing this procedure. The authors report the case of a child with SCD, on treatment with chronic transfusions and desferrioxamine, who developed a delayed liver abscess after a liver biopsy in which Avitene, a topical hemostatic agent, was used. This is the first description of a liver abscess as a possible complication of liver biopsy in a child with SCD. The presence of a hepatic abscess should be considered in the differential diagnosis of atypical abdominal pain in patients with SCD.

Abdominal Pain↗
PubMed2004

Tumor recurrence at thoracostomy tube insertion sites: a report of two pediatric cases.

Recurrence of thoracic malignant tumors at port sites used for thoracoscopic procedures in adults have been described. However, there are no reports of tumor recurrence at thoracostomy tube or thoracoscopic trocar insertion sites after operation for thoracic malignancies in children. The authors report 2 cases of tumor recurrence at thoracostomy tube insertion sites after intraoperative gross spillage of pleuropulmonary blastoma and malignant epithelial thymoma and discuss approaches that may potentially prevent this devastating complication.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2004

The incidence and prognosis of osteosarcoma skip metastases.

The poor prognosis for patients with osteosarcoma skip metastases has been established in the literature; however, most of the data in the literature concerning osteosarcoma skip metastases were collected before routine use of magnetic resonance imaging and before the use of modern multiagent chemotherapy regimens. This retrospective multiinstitutional study was done to evaluate the efficacy of magnetic resonance imaging to detect skip metastases and to evaluate the prognosis for these patients when treated with modern multiagent chemotherapy protocols. In a group of 155 patients who were younger than 26 years when diagnosed and treated for high-grade osteosarcoma of the long bones, 10 (6.5%) patients with skip metastases were identified. Eight of the 10 lesions were detected on pretreatment magnetic resonance imaging scans and two were detected only from the surgical pathology specimens. Five patients had concomitant pulmonary metastases at presentation and five patients had no other known site of diseases. All 10 patients died, with an average survival of 32.5 months (range 11-71 months). The five patients with only skip metastases at presentation survived an average of 27.2 months (range 15-44 months). Despite advances in the treatment of patients with osteosarcomas, those with skip metastases continue to have a poor prognosis, and they should be counseled regarding the limitations of current therapies.

Adolescent↗
PubMed2003

Biopsy, needle localization, and radiofrequency ablation for pediatric patients.

Pediatric interventions for oncology patients include aspiration or percutaneous biopsy for malignancy diagnosis or recurrence, and percutaneous biopsy for the complications of tumor treatment. Tumor localization techniques have been used to resect small lesions with minimal invasion. However improved guidance techniques have allowed for more precise biopsy and the use of thermal ablation instead of excision for local tumor control. I will discuss these diagnostic and therapeutic techniques as they apply to children.

Aspergillosis↗