Biomedical subjects

John Flickinger

Publications and source records attributed to John Flickinger.

12 recordsLinked to original sources

PubMed2006

Gamma knife radiosurgery for refractory epilepsy caused by hypothalamic hamartomas.

BACKGROUND: Hypothalamic hamartomas are associated with precocious puberty and chronic epilepsy characterized by gelastic seizures. The seizure disorder is usually refractory to most antiepileptic drugs. Gamma knife surgery has emerged as an alternative to microsurgical removal or radiofrequency ablation to improve seizure control. We present our experience with radiosurgery in 4 patients afflicted by this disorder. METHODS: Using gamma knife radiosurgery, 4 patients with intractable gelastic seizures and complex epilepsy were managed. Patient age varied from 5 to 29 years. The duration of symptoms was 4-28 years. A conformal radiosurgery plan was designed with a mean of 4.25 isocenters to cover the hamartoma at the 50% isodose line. A mean margin dose of 17.5 Gy was used. The clinical outcome was evaluated with the Engel scale. RESULTS: No complication occurred. After a median follow-up of 22 months, 3 patients had shown some improvement, with 2 attaining Engel class II status. CONCLUSION: Gamma knife surgery is a promising alternative to microsurgical removal for patients with refractory epilepsy caused by hypothalamic hamartomas.

Adolescent↗

PubMed2005

Stereotactic radiosurgery for pituitary adenomas: an intermediate review of its safety, efficacy, and role in the neurosurgical treatment armamentarium.

OBJECT: Pituitary adenomas are very common neoplasms, constituting between 10 and 20% of all primary brain tumors. Historically, the treatment armamentarium for pituitary adenomas has included medical management, microsurgery, and fractionated radiotherapy. More recently, radiosurgery has emerged as a viable treatment option. The goal of this research was to define more fully the efficacy, safety, and role of radiosurgery in the treatment of pituitary adenomas. METHODS: Medical literature databases were searched for articles pertaining to pituitary adenomas and stereotactic radiosurgery. Each study was examined to determine the number of patients, radiosurgical parameters (for example, maximal dose and tumor margin dose), duration of follow-up review, tumor growth control rate, complications, and rate of hormone normalization in the case of functioning adenomas. A total of 35 peer-reviewed studies involving 1621 patients were examined. Radiosurgery resulted in the control of tumor size in approximately 90% of treated patients. The reported rates of hormone normalization for functioning adenomas varied substantially. This was due in part to widespread differences in endocrinological criteria used for the postradiosurgical assessment. The risks of hypopituitarism, radiation-induced neoplasia, and cerebral vasculopathy associated with radiosurgery appeared lower than those for fractionated radiation therapy. Nevertheless, further observation will be required to understand the true probabilities. The incidence of other serious complications following radiosurgery was quite low. CONCLUSIONS: Although microsurgery remains the primary treatment modality in most cases, stereotactic radiosurgery offers both safe and effective treatment for recurrent or residual pituitary adenomas. In rare instances, radiosurgery may be the best initial treatment for patients with pituitary adenomas. Further refinements in the radiosurgical technique will likely lead to improved outcomes.

Adenoma↗

PubMed2005

Gamma knife surgery for glomus jugulare tumors: an intermediate report on efficacy and safety.

OBJECT: Glomus jugulare tumors are rare tumors that commonly involve the middle ear, temporal bone, and lower cranial nerves. Resection, embolization, and radiation therapy have been the mainstays of treatment. Despite these therapies, tumor control can be difficult to achieve particularly without undo risk of patient morbidity or mortality. The authors examine the safety and efficacy of gamma knife surgery (GKS) for glomus jugulare tumors. METHODS: A retrospective review was undertaken of the results obtained in eight patients who underwent GKS for recurrent, residual, or unresectable glomus jugulare tumors. The median radiosurgical dose to the tumor margin was 15 Gy (range 12-18 Gy). The median clinical follow-up period was 28 months, and the median period for radiological follow up was 32 months. All eight patients demonstrated neurological stability or improvement. No cranial nerve palsies arose or deteriorated after GKS. In the seven patients in whom radiographic follow up was obtained, the tumor size decreased in four and remained stable in three. CONCLUSIONS: Gamma knife surgery would seem to afford effective local tumor control and preserves neurological function in patients with glomus jugulare tumors. If long-term results with GKS are equally efficacious, the role of stereotactic radiosurgery will expand.

Adult↗

PubMed2005

Radiosurgery for patients with recurrent small cell lung carcinoma metastatic to the brain: outcomes and prognostic factors.

OBJECT: Lung carcinoma is the leading cause of death from cancer. More than 50% of those with small cell lung cancer develop a brain metastasis. Corticosteroid agents, radiotherapy, and resection have been the mainstays of treatment. Nonetheless, median survival for patients with small cell lung carcinoma metastasis is approximately 4 to 5 months after cranial irradiation. In this study the authors examine the efficacy of gamma knife surgery for treating recurrent small cell lung carcinoma metastases to the brain following tumor growth in patients who have previously undergone radiation therapy, and they evaluate factors affecting survival. METHODS: A retrospective review of 27 patients (47 recurrent small cell lung cancer brain metastases) undergoing radiosurgery was performed. Clinical and radiographic data obtained during a 14-year treatment period were collected. Multivariate analysis was utilized to determine significant prognostic factors influencing survival. The overall median survival was 18 months after the diagnosis of brain metastases. In multivariate analysis, factors significantly affecting survival included: 1) tumor volume (p = 0.0042); 2) preoperative Karnofsky Performance Scale score (p = 0.0035); and 3) time between initial lung cancer diagnosis and development of brain metastasis (p = 0.0127). Postradiosurgical imaging of the brain metastases revealed that 62% decreased, 19% remained stable, and 19% eventually increased in size. One patient later underwent a craniotomy and tumor resection for a tumor refractory to radiosurgery and radiation therapy. In three patients new brain metastases were demonstrating on follow-up imaging. CONCLUSIONS: Stereotactic radiosurgery for recurrent small cell lung carcinoma metastases provided effective local tumor control in the majority of patients. Early detection of brain metastases, aggressive treatment of systemic disease, and a therapeutic strategy including radiosurgery can extend survival.

Adult↗

PubMed2004

Hybrid PET-CT simulation for radiation treatment planning in head-and-neck cancers: a brief technical report.

PURPOSE: To prospectively study the impact on tumor and normal tissue delineation for RT planning by use of hybrid PET-CT simulation for patients with head-and-neck cancer. METHODS AND MATERIALS: Twenty-one patients were simulated in treatment position on a hybrid PET-CT scanner. Images were transferred to the Varian Eclipse planning system. Abnormal areas of fluorodeoxyglucose (FDG) uptake were contoured on PET for the gross tumor volume of primaries (GTVp) and abnormal nodal region of primaries (ABNp) then compared with the same CT gross tumor volumes (GTVc) and abnormal nodal region (ABNc). A statistical analysis was performed to evaluate the correlation of PET and CT volumes. RESULTS: Positron emission tomography demonstrated the primary in all cases, whereas CT did not find the primary in 3 cases. In 8 patients, additional areas of disease were seen only in PET. The average ratio of GTVc/GTVp was 3.1 (range, 0.3-23.6), whereas for ABNc/ABNp was 0.7 (range, 0-4). Volumes for the primaries were significantly larger on CT than on PET (p = 0.002) but not for nodal regions (p = 0.5). CONCLUSIONS: Hybrid PET-CT simulation is feasible and provides valuable information that results in greater delineation of normal tissues from tumor bearing areas at high risk for recurrence. This finding may further improve therapeutic window for IMRT for head-and-neck cancers.

Adult↗

PubMed2004

Brachytherapy in the treatment of Stage IV carcinoma of the base of tongue.

PURPOSE: Survival in patients with Stage IV carcinoma of the base of tongue (BOT) treated by surgery and radiotherapy remains poor. External beam radiotherapy (EBRT) and brachytherapy (BT) have been used as an alternative treatment. METHODS AND MATERIALS: Eighteen patients with Stage IV carcinoma of the BOT were treated by EBRT and BT. RESULTS: Local control is 89%. The 5-year overall (OS) and disease specific survival (DSS) rates are 52% and 67%. No neck node positive patient implanted in the neck developed cervical metastases. Two patients (11%) developed complications. CONCLUSIONS: Local regional control, survival, and complications in patients with Stage IV carcinoma of the BOT treated by EBRT and BT have been satisfactory. The use of brachytherapy for nodal metastases has eliminated the need for neck dissection. We recommend this approach in the treatment of Stage IV carcinoma of the BOT.

Aged↗

PubMed2003

Radiosurgery for nonfunctioning pituitary adenoma.

OBJECT: Nonfunctioning pituitary adenomas comprise approximately 30% of all pituitary tumors. The purpose of this retrospective study was to evaluate the efficacy and role of gamma knife surgery (GKS) in the treatment of these lesions. METHODS: The authors conducted a review of cases in which GKS was performed at the University of Pittsburgh between 1987 and 2001. Forty-six patients with nonfunctioning pituitary adenomas and with at least 6 months of follow- up data were identified. In 41 of these patients some form of prior treatment such as transsphenoidal resection, craniotomy and resection, or conventional radiation therapy had been conducted. Five patients were deemed ineligible for microsurgery, and GKS served as the primary treatment modality. Endocrinological, ophthalmological, and radiological responses were evaluated. The mean radiation dose to the margin was 16 Gy. In all patients with microadenomas and 91% of those with macroadenomas tumor control was demonstrated after radiosurgery. Gamma knife surgery had essentially equal efficacy in terms of achieving tumor control in cases of adenomas with cavernous sinus invasion and suprasellar extension. No new endocrinopathies were noted following radiosurgery. In two patients, however, tumor growth and decline in visual function occurred. CONCLUSIONS: Gamma knife surgery is safe and effective in treating nonfunctioning pituitary adenomas. Radiosurgery may serve as a primary treatment modality in some or as a salvage treatment in others. Treatment must be tailored to meet the patient's symptoms, overall health, and tumor morphometry.

Adenoma↗

PubMed2003

Radiosurgery in patients with renal cell carcinoma metastasis to the brain: long-term outcomes and prognostic factors influencing survival and local tumor control.

OBJECT: Renal cell carcinoma is a leading cause of death from cancer and its incidence is increasing. In many patients with renal cell cancer, metastasis to the brain develops at some time during the course of the disease. Corticosteroid therapy, radiotherapy, and resection have been the mainstays of treatment. Nonetheless, the median survival in patients with renal cell carcinoma metastasis is approximately 3 to 6 months. In this study the authors examined the efficacy of gamma knife surgery in treating renal cell carcinoma metastases to the brain and evaluated factors affecting long-term survival. METHODS: The authors conducted a retrospective review of 69 patients undergoing stereotactic radiosurgery for a total of 146 renal cell cancer metastases. Clinical and radiographic data encompassing a 14-year treatment interval were collected. Multivariate analyses were used to determine significant prognostic factors influencing survival. The overall median length of survival was 15 months (range 1-65 months) from the diagnosis of brain metastasis. After radiosurgery, the median survival was 13 months in patients without and 5 months in those with active extracranial disease. In a multivariate analysis, factors significantly affecting the rate of survival included the following: 1) younger patient age (p = 0.0076); 2) preoperative Karnofsky Performance Scale score (p = 0.0012); 3) time from initial cancer diagnosis to brain metastasis diagnosis (p = 0.0017); 4) treatment dose to the tumor margin (p = 0.0252); 5) maximal treatment dose (p = 0.0127); and 6) treatment isodose (p = 0.0354). Prior tumor resection, chemotherapy, immunotherapy, or whole-brain radiation therapy did not correlate with extended survival. Postradiosurgical imaging of the brain demonstrated that 63% of the metastases had decreased, 33% remained stable, and 4% eventually increased in size. Two patients (2.9%) later underwent a craniotomy and resection for a tumor refractory to radiosurgery or a new symptomatic metastasis. Eighty-three percent of patients died of progression of extracranial disease. CONCLUSIONS: Stereotactic radiosurgery for treatment of renal cell carcinoma metastases to the brain provides effective local tumor control in approximately 96% of patients and a median length of survival of 15 months. Early detection of brain metastases, aggressive treatment of systemic disease, and a therapeutic strategy including radiosurgery can offer patients an extended survival.

Adult↗

PubMed2002

Radiosurgery for treatment of recurrent intracranial hemangiopericytomas.

OBJECTIVE: Hemangiopericytomas are highly aggressive meningeal tumors with tendencies for recurrence and metastasis. The purpose of this retrospective, single-institution review was to evaluate the efficacy and role of stereotactic radiosurgery in the management of recurrent hemangiopericytomas. METHODS: We reviewed data for patients who underwent stereotactic radiosurgery at the University of Pittsburgh between 1987 and 2001. Fourteen patients underwent radiosurgery for 15 discrete tumors. Prior treatments included transsphenoidal resection (n = 1), craniotomy and resection (n = 27), embolization (n = 1), and conventional radiotherapy (n = 7). Clinical and radiological responses were evaluated. Follow-up periods varied from 5 to 76 months (mean, 31.3 mo; median, 21 mo). The mean radiation dose to the tumor margin was 15 Gy. RESULTS: Seventy-nine percent of patients (11 of 14 patients) with recurrent hemangiopericytomas demonstrated local tumor control after radiosurgery. Twelve of 15 tumors (i.e., 80%) dramatically decreased in size on follow-up imaging scans. Regional intracranial recurrences were retreated with radiosurgery for two patients (i.e., 15%); neither of those two patients experienced long-term tumor control. Local recurrences occurred 12 to 75 months (median, 21 mo) after radiosurgery. Local tumor control and survival rates at 5 years after radiosurgery were 76 and 100%, respectively (Kaplan-Meier method). We could not correlate prior irradiation or tumor size with tumor control. Twenty-nine percent of the patients (4 of 14 patients) developed remote metastases. Radiosurgery did not seem to offer protection against the development of intra- or extracranial metastases. CONCLUSION: Gamma knife radiosurgery provided local tumor control for 80% of recurrent hemangiopericytomas. When residual tumor is identified after resection or radiotherapy, early radiosurgery should be considered as a feasible treatment modality. Despite local tumor control, patients are still at risk for distant metastasis. Diligent clinical and radiological follow-up monitoring is necessary.

Adolescent↗

PubMed2002

Development of a posterior fossa cavernous malformation associated with bilateral venous anomalies: case report.

Venous angiomas (VAs) and cavernous malformations (CMs) are common cerebrovascular malformations. Frequently, these lesions are found in close proximity. The interrelationship between VAs and CMs has not yet been adequately defined. The authors report a case of a 48-year-old man with progressive dysarthria, dysmetria, and ataxia. Eight years previously, magnetic resonance imaging (MRI) revealed a solitary CM and bilateral posterior fossa VAs. Later imaging after neurological progression revealed the presence of 2 rather than 1 CM adjacent to the VAs. The sequential imaging suggests a causal relationship between VAs and some CMs. Furthermore, the detailed MRI permitted radiosurgical treatment of these CMs. The occurrence of de novo CMs adjacent to VAs on future imaging studies in other patients may help confirm the etiology of at least a subset of CMs.

Cranial Fossa, Posterior↗

PubMed2002

Radiosurgery for non-small cell lung carcinoma metastatic to the brain: long-term outcomes and prognostic factors influencing patient survival time and local tumor control.

OBJECT: Lung carcinoma is the leading cause of death from cancer. More than 25% of those patients with lung cancer develop a brain metastasis at some time during the course of their disease. Corticosteroid therapy, radiotherapy, and resection have been the mainstays of treatment. Nonetheless, the median survival for patients with lung carcinoma metastasis is approximately 3 to 6 months. The authors examine the efficacy of gamma knife radiosurgery (GKS) for treating non-small cell lung carcinoma (NSCLC) metastases to the brain and evaluate factors affecting long-term patient survival. METHODS: A retrospective review of 273 patients who had undergone GKS to treat a total of 627 NSCLC metastases was performed. Clinical and neuroimaging data encompassing a 14-year treatment interval were collected. Univariate and multivariate analyses were performed to determine significant prognostic factors influencing patient survival. The overall median patient survival time was 15 months (range 1-116 months) from the diagnosis of brain metastases. The median survival was 10 months from GKS treatment in those patients with adenocarcinoma and 7 months for those with other histological tumor types. In patients with no active extracranial disease at the time of GKS, the median survival time was 16 months. In multivariate analyses, factors significantly affecting survival included: 1) female sex (p = 0.014); 2) preoperative Karnofsky Performance Scale score (p < 0.0001); 3) adenocarcinoma histological subtype (p = 0.0028); 4) active systemic disease (p = 0.0001); and 5) time from lung cancer diagnosis to the development of brain metastasis (p = 0.0074). Prior tumor resection or whole-brain radiation therapy did not correlate with extended patient survival time. Postradiosurgical imaging of brain metastases revealed that 60% decreased, 24% remained stable, and 16% eventually increased in size. Factors affecting local tumor control included tumor volume (p = 0.042) and treatment isodose (p = 0.015). Fourteen patients (5.1%) later underwent craniotomy and tumor resection for tumor refractory to GKS or a new symptomatic metastasis. CONCLUSIONS: Gamma knife surgery for NSCLC metastases affords effective local tumor control in approximately 84% of patients. Early detection of brain metastases, aggressive treatment of systemic disease, and a therapeutic strategy including GKS can afford patients an extended survival time.

Adult↗

PubMed2002

Radiosurgery for residual or recurrent nonfunctioning pituitary adenoma.

OBJECT: Nonfunctioning pituitary adenomas comprise approximately 30% of all pituitary tumors. The purpose of this retrospective study is to evaluate the efficacy and role of gamma knife radiosurgery (GKS) in the management of residual or recurrent nonfunctioning pituitary adenomas. METHODS: A review was conducted of the data obtained in 42 patients who underwent adjuvant GKS at the University of Pittsburgh between 1987 and 2001. Prior treatments included transsphenoidal resection, craniotomy and resection, or conventional radiotherapy. Endocrinological, ophthalmological, and radiological responses were evaluated. The duration of follow-up review varied from 6 to 102 months (mean 31.2 months). Fifteen patients were observed for more than 40 months. The mean radiation dose to the tumor margin was 16 Gy. Conformal radiosurgery planning was used to restrict the dose to the optic nerve and chiasm. Tumor control after GKS was achieved in 100% of patients with microadenomas and 97% of patients with macroadenomas. Gamma knife radiosurgery was equally effective in controlling adenomas with cavernous sinus invasion and suprasellar extension. No patient developed a new endocrinological deficiency following GKS. One patient's tumor enlarged with an associated decline in visual function. Another patient experienced a deterioration of visual fields despite a decrease in tumor size. CONCLUSIONS: Gamma knife radiosurgery can achieve tumor control in virtually all residual or recurrent nonfunctioning pituitary adenomas. Dose sparing facilitates tumor management even when the adenoma is close to the optic apparatus or invades the cavernous sinus.

Adenoma↗