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John C Flickinger

Publications and source records attributed to John C Flickinger.

51 records · Page 3Linked to original sources
PubMed2002

External beam irradiation of craniopharyngiomas: long-term analysis of tumor control and morbidity.

PURPOSE: To delineate the long-term control and morbidity with external beam radiotherapy (EBRT) of craniopharyngiomas. METHODS AND MATERIALS: Between 1971 and 1992, 24 craniopharyngioma patients underwent EBRT at the University of Pittsburgh. Most (19 of 24) were treated within 1-3 months after subtotal resection. The other prior surgical procedures were biopsy (n = 2) and gross total resection (n = 1); 2 patients did not undergo any surgical procedure. The median follow-up was 12.1 years. The median patient age was 29 years (range 5-69). The total radiation doses varied from 36 to 70 Gy (median 59.75). The normalized total dose (NTD, biologically equivalent dose given in 2 Gy/fraction [alpha/beta ratio = 2]) varied from 28 to 83 Gy (median 55.35). RESULTS: The actuarial survival rate at 10 and 20 years was 100% and 92.3%, respectively. The actuarial local control rate at 10 and 20 years was 89.1% and 54.0%, respectively. No local failures occurred with doses >or=60 Gy (n = 12) or NTDs >or=55 Gy. The complication-free survival rate at 10 and 20 years was 80.1% and 72.1%, respectively. No complications were noted with an NTD of <or=55 Gy. The actuarial survival free from any adverse outcome (recurrence or complication) was 70.1% and 31.8% at 10 and 20 years, respectively. The adverse outcome-free survival appeared optimized (at 73%) with an NTD of 55-63 Gy. Multivariate analysis found that tumor control correlated significantly with the total dose (p = 0.02), treatment complications with NTD (p = 0.008), and adverse outcome with hypopituitarism on presentation (p = 0.03). CONCLUSION: We recommend treating craniopharyngioma with 1.6-1.7-Gy dose fractions to 60 Gy to optimize outcome from EBRT.

Adolescent↗
PubMed2002

Analysis of repeat stereotactic radiosurgery for progressive primary and metastatic CNS tumors.

PURPOSE: To identify and evaluate the pretreatment and patient factors that would predict for complications after repeat radiosurgery. METHODS AND MATERIALS: The data from 26 patients who underwent re-irradiation with Gamma Knife surgery after a previous procedure in the same or subjacent location were available for evaluation. The range of follow-up was 1-45 months (mean 10). The mean minimal and maximal initial dose and volume for all 26 patients was 16.2 Gy (range 12-22), 31.0 Gy (range 22.2-40.0), and 12.4 cm(3) (range 1.20-70.84), respectively. The mean marginal and maximal repeated radiosurgery dose and volume for all 26 patients was 14.9 Gy (range 12-22.5), 29.7 Gy (range 18.0-45.0) and 12.8 cm(3) (range 1.10-39.20), respectively. RESULTS: Tumor control was significantly better statistically (p = 0.0129) for benign tumors (6 of 6, 100% actuarial rate at 4 years) compared with malignant tumors (7 of 20, 35% actuarial rate at 3 years, 3 of 4 metastatic tumors and 2 of 10 primary malignant gliomas). The retreatment volume for radiosurgery correlated significantly with the probability of neurologic decline (any cause) (p = 0.0181). CONCLUSION: Repeat radiosurgery can be performed for recurrent tumors with minimal central nervous system toxicity, especially for benign tumors, with reasonable tumor control.

Adolescent↗
PubMed2002

An analysis of the dose-response for arteriovenous malformation radiosurgery and other factors affecting obliteration.

PURPOSE: The aim of this study was to better understand arteriovenous malformation (AVM) obliteration rates after radiosurgery. METHODS AND MATERIALS: We studied obliteration after Gamma knife radiosurgery in 351 AVM patients with 3-11 years of follow-up imaging. The median marginal dose was 20 Gy (range: 12-30) and median treatment volume was 5.7 cm(3) (range: 0.26-24). Stereotactic targeting was with angiography alone in 250 AVMs, and additional magnetic resonance (MR) imaging in 101 AVMs. RESULTS: We documented obliteration by angiography in 193/264 (73%) AVM, and by MR alone in 75/87 (86%) AVM for a 75% corrected obliteration rate. We identified persistent out-of-field nidus in 18% of embolized vs. 5% of non-embolized patients, (P = 0.006). Multivariate analysis correlated in-field obliteration with marginal dose (P < 0.0001) and sex (P < or = 0.026, but not for overall obliteration P = 0.19). A mathematical dose-response model for overall obliteration was constructed to generate a dose-response curve for AVM obliteration with a maximum overall obliteration rate of 88% and minimal improvement above 25 Gy. We could not define the value of alpha/beta for AVM obliteration to a level of statistical significance. CONCLUSION: The rate of AVM obliteration from radiosurgery depends on the marginal dose administered with a dose-response curve that reaches a maximum of approximately 88%. The dose-response plateau reflects problems with target definition which is made more difficult by prior embolization.

Adolescent↗
PubMed2002

Repeat radiosurgery for refractory trigeminal neuralgia.

OBJECTIVE: Stereotactic radiosurgery has become an important and minimally invasive alternative for patients with refractory trigeminal neuralgia. When a second procedure is necessary, the outcomes are unknown. The degree of pain relief and morbidity after repeat radiosurgery were studied. METHODS: Thirty-one patients underwent a second gamma knife radiosurgery procedure because of unsatisfactory or unsustained relief of pain after the first procedure. Twenty-seven patients were assessable at median follow-up periods of 42.7 and 20.4 months after the first and second procedures, respectively. Most patients had undergone multiple previous operations of other types (microvascular decompression, radiofrequency rhizotomy, glycerol rhizotomy, balloon compression). The median target doses of the first and second radiosurgeries were 75 and 64 Gy, respectively. All patients were evaluated by a physician who did not participate in patient treatment. RESULTS: After the first radiosurgical procedure, 13 patients had an excellent response initially (complete relief without any medication), 3 had a good response (complete relief with some medication), 7 had a fair response (>50% relief), and 4 had a poor response (<50% pain relief or treatment failure). Repeat radiosurgery was performed in patients with recurrent or residual pain. After the second radiosurgical procedure, 5 patients had an excellent response, 8 had a good response, 10 had a fair response, and 4 had a poor response. Thirteen patients (48%) achieved complete pain relief (with or without medication). Two patients (7.4%) experienced new sensory symptoms after the first radiosurgical procedure, and three (12.7%, actuarial) experienced new sensory symptoms after the second procedure. CONCLUSION: Repeat radiosurgery provided a similar rate of pain relief as the first procedure, despite a modest dose reduction. The risk of new sensory symptoms was increased, but no other morbidity was identified. For patients who experience recurrent pain and choose to undergo a second procedure, our current procedure is to deliver a maximum dose of 50 to 60 Gy to a trigeminal target anterior to the root entry zone near the entrance of the nerve beneath the petrous dura.

Adult↗
PubMed2002

Long-term results after stereotactic radiosurgery for patients with cavernous malformations.

OBJECTIVE: Stereotactic radiosurgery has been used for patients with high-risk cavernous malformations of the brain. We performed radiosurgery for patients with symptomatic, imaging-confirmed hemorrhages for which resection was believed to be associated with high risk. This study examines the long-term hemorrhage rate after radiosurgery. METHODS: We reviewed data obtained before and after gamma knife radiosurgery on 82 patients treated between 1987 and 2000. Most patients had multiple hemorrhages from brainstem or diencephalic cavernous malformations. Follow-up data were examined to identify hemorrhages, and an overall hemorrhage rate was calculated. RESULTS: Observation before treatment averaged 4.33 years (range, 0.17-18 yr) for a total of 354 patient-years. During this period, 202 hemorrhages were observed, for an annual hemorrhage rate of 33.9%, excluding the first hemorrhage. Temporal clustering of hemorrhages was not significant. After radiosurgery, patient follow-up averaged 5 years (range, 0.42-12.08 yr), for a total of 401 patient-years. During this period, 19 hemorrhages were identified, 17 in the first 2 years posttreatment and 2 after 2 years. The annual hemorrhage rate was 12.3% per year for the first 2 years after radiosurgery, followed by 0.76% per year from Years 2 to 12. Eleven patients had new neurological symptoms without hemorrhage after radiosurgery (13.4%). The symptoms were minor in six of these patients and temporary in five. CONCLUSION: Radiosurgery confers a reduction in the risk of hemorrhage for high-risk cavernous malformations. Risk reduction, although in evidence during initial follow-up, is most pronounced after 2 years. Given the difficulty of identifying high-risk patients, treatment after one major hemorrhage should be considered in selected younger patients. Such a strategy warrants further investigation.

Cerebral Hemorrhage↗
PubMed2002

The role of radiosurgery for the treatment of pineal parenchymal tumors.

OBJECTIVE: Radiosurgery is an appealing alternative management strategy for selected patients with biopsy-proved pineal parenchymal tumors. The purpose of this report was to clarify its role in conjunction with other surgical, radiation, and medical approaches. METHODS: We retrospectively evaluated 16 patients who had undergone radiosurgery as the primary or adjuvant treatment for pineal parenchymal tumors. Ten patients (62.5%) had pineocytomas, two (12.5%) had mixed pineocytoma and pineoblastoma, and four (25%) had pineoblastomas. The mean marginal dose was 15 Gy, and the mean tumor volume was 5.0 cm(3). The mean follow-up periods from the time of diagnosis or the time of radiosurgery were 61 and 52 months, respectively. RESULTS: The overall actuarial 2- and 5-year survival rates after diagnosis were 75.0 and 66.7%, respectively. In 14 patients who were evaluated with imaging, 4 (29%) demonstrated complete remission, 8 (57%) had partial remission, 2 (14%) had no change, and no patient had local progression. The local tumor control rate (complete remission, partial remission, or no change) was 100%. Five patients died during follow-up. One patient with a pineocytoma and three patients with pineoblastomas died secondary to leptomeningeal or extracranial spread tumor. No cause of death was established for one patient. Two patients developed adverse radiation effects after radiosurgery. CONCLUSION: Our initial experience suggests that stereotactic radiosurgery is a valuable primary management modality for patients with pineocytomas. As adjuvant therapy, radiosurgery may be used to boost local tumor dose during multimodality management of malignant pineal parenchymal tumors.

Adolescent↗
PubMed2002

Stereotactic radiosurgery for well-circumscribed fibrillary grade II astrocytomas: an initial experience.

OBJECTIVE: To examine the role of stereotactic radiosurgery in the management of patients with progressive, well-circumscribed grade II fibrillary astrocytomas. METHODS: During a 13-year interval, 12 patients (median age: 25 years) required multimodality management for recurrent or unresectable World Health Organization (WHO) grade II fibrillary astrocytomas. Tumors involved the brainstem (n = 4), thalamus (n = 1), cerebellum (n = 1), frontal lobe (n = 4), temporal lobe (n = 1), and parietal lobe (n = 1). Diagnosis was confirmed by stereotactic biopsy (n = 5), partial resection (n = 5), and near total resection (n = 2). Multimodality management of patients prior to radiosurgery included fractionated radiation therapy (n = 4), stereotactic cyst drainage (n = 1), and ventriculoperitoneal shunt placement (n = 2). Tumor volumes varied from 1.2 to 45.1 cm(3). The median radiosurgical dose to the tumor margin was 16 Gy. RESULTS: After radiosurgery, serial imaging showed complete tumor resolution in 1 patient, reduced tumor volume in 4, stable tumor volume in 3, and delayed tumor progression in 4 (3 patients with increase in cyst size only). Therapy after radiosurgery included additional cytoreductive surgery (n = 1) for recurrence of a higher grade tumor, stereotactic cyst aspiration (n = 1), and stereotactic intracavitary irradiation (n = 1). All patients were alive at a median follow-up of 52 months after radiosurgery and 103 months after diagnosis. In 8 patients, follow-up lasted more than 60 months. CONCLUSION: Stereotactic radiosurgery is a potential alternative or adjunctive strategy in the management of selected patients with WHO grade II fibrillary astrocytomas.

Adolescent↗
PubMed2002

A proposed radiosurgery-based grading system for arteriovenous malformations.

OBJECT: Radiosurgery is an effective treatment strategy for properly selected patients harboring arteriovenous malformations (AVMs). Grading scales that are currently used to predict patient outcomes after AVM resection are unreliable tools for the prediction of the results of AVM radiosurgery. METHODS: A grading system was developed to predict outcomes following AVM radiosurgery, based on the multivariate analysis of data obtained in 220 patients treated between 1987 and 1991 (Group 1). The dependent variable in all analyses was excellent patient outcome (complete AVM obliteration without any new neurological deficit). The grading scale was tested on a separate set of 136 patients with AVMs treated between 1990 and 1996 at a different center (Group 2). One hundred twenty-one (55%) of 220 Group 1 patients had excellent outcomes. Multivariate analysis identified five variables related to excellent patient outcomes: AVM volume (p = 0.001), patient age (p < 0.001), AVM location (p < 0.001), previous embolization (p = 0.02), and number of draining veins (p < 0.001). Regression analysis modeling permitted removal of two significant variables (previous embolization and number of draining veins) and resulted in the following equation to predict patient outcomes after AVM radiosurgery: AVM score = (0.1)(AVM volume in cm3) + (0.02)(patient age in years) + (0.3)(location of lesion: frontal or temporal) = 0; parietal, occipital, intraventricular, corpus callosum, cerebellar = 1; or basal ganglia, thalamic, or brainstem = 2). Seventy-nine (58%) of 136 Group 2 patients had excellent outcomes. All variables in the model remained significant for the Group 2 patients: AVM volume (p = 0.01), patient age (p = 0.01), and AVM location (p < 0.001). Testing of the entire model on the Group 2 patients demonstrated that the AVM score could be used to predict patient outcomes after radiosurgery (p < 0.0001). All patients with an AVM score of 1 or lower had an excellent outcome compared with only 39% of patients with an AVM score higher than 2. The Spetzler-Martin grade (p = 0.13), the K index (p = 0.26), and the obliteration prediction index (p = 0.21) did not correlate with excellent patient outcomes. CONCLUSIONS: Despite significant differences in preoperative patient characteristics and dose prescription guidelines at the two centers, the proposed AVM grading system strongly correlated with patient outcomes after single-session radiosurgery for both patient groups. Although further testing of this model by independent centers using prospective methodology is still required, this system allows a more accurate prediction of outcomes from radiosurgery to guide choices between surgical and radiosurgical management for individual patients with AVMs.

Adolescent↗
PubMed2002

Stereotactic radiosurgery for pilocytic astrocytomas when multimodal therapy is necessary.

OBJECT: The goal of this study was to examine the role of stereotactic radiosurgery in the treatment of patients with recurrent or unresectable pilocytic astrocytomas. METHODS: During a 13-year interval, 37 patients (median age 14 years) required multimodal treatment of recurrent or unresectable pilocytic astrocytomas. Tumors involved the brainstem in 18 patients, cerebellum in three, thalamus in five, temporal lobe in four, and parietal lobe in two, as well as the hypothalamus, optic tract, corpus callosum, insular cortex, and third ventricle in one patient each. Diagnosis was confirmed with the aid of stereotactic biopsy in 12 patients, open biopsy in five, partial resection in eight, and near-total resection in 12. Multimodal treatment included fractionated radiation therapy in 10 patients, stereotactic intracavitary irradiation of tumor in four, chemotherapy in two, cyst drainage in six, ventriculoperitoneal shunt placement in three, and additional cytoreductive surgery in four. Tumor volumes varied from 0.42 to 25 cm3. The median radiosurgical dose to the tumor margin was 15 Gy (range 9.6-22.5 Gy). After radiosurgery, serial imaging demonstrated complete tumor resolution in 10 patients, reduced tumor volume in eight, stable tumor volume in seven, and delayed tumor progression in 12. No procedure-related death was encountered. Thirty-three (89%) of 37 patients are alive at a median follow-up period of 28 months after radiosurgery and 59 months after diagnosis. Eight patients participated in follow-up review for more than 60 months. Three patients died of local tumor progression. CONCLUSIONS: Stereotactic radiosurgery is a valuable adjunctive strategy in the management of recurrent or unresectable pilocytic astrocytomas. Despite the favorable histological characteristics and prognosis usually associated with this neoplasm, an adverse location, recurrence, or progression of this disease requires alternative therapeutic approaches such as radiosurgery.

Adolescent↗
PubMed2002

Stereotactic radiosurgery providing long-term tumor control of cavernous sinus meningiomas.

OBJECT: To evaluate long-term outcomes of patients who have undergone stereotactic radiosurgery for cavernous sinus meningiomas, the authors retrospectively reviewed their 14-year experience with these cases. METHODS: One hundred seventy-six patients harbored meningiomas centered within the cavernous sinus. Seventeen patients were lost to follow-up review, leaving 159 analyzable patients, in whom 164 procedures were performed. Seventy-six patients (48%) underwent adjuvant radiosurgery after one or more attempts at surgical resection. Eighty-three patients (52%) underwent primary radiosurgery. Two patients (1%) had previously received fractionated external-beam radiation therapy. Four patients (2%) harbored histologically verified atypical or malignant meningiomas. Conformal multiple isocenter gamma knife surgery was performed. The median dose applied to the tumor margin was 13 Gy. Neurological status improved in 46 patients (29%), remained stable in 99 (62%), and eventually worsened in 14 (9%). Adverse effects of radiation occurred after 11 procedures (6.7%). Tumor volumes decreased in 54 patients (34%), remained stable in 96 (60%), and increased in nine (6%). The actuarial tumor control rate for patients with typical meningiomas was 93.1 +/- 3.3% at both 5 and 10 years. For the 83 patients who underwent radiosurgery as their sole treatment, the actuarial tumor control rate at 5 years was 96.9 +/- 3%. CONCLUSIONS: Stereotactic radiosurgery provided safe and effective management of cavernous sinus meningiomas. We believe it is the preferred management strategy for tumors of suitable volume (average tumor diameter < or = 3 cm or volume < or = 15 cm3).

Adolescent↗
PubMed2002

Update on results of multifield conformal radiation therapy of non-small-cell lung cancer using multileaf collimated beams.

We evaluated the treatment outcome for 5-field 3-dimensional conformal radiation therapy (3D-CRT) in 46 consecutive patients with unresectable, nonmetastatic non-small-cell lung cancer treated from 1993-2001. Four percent of the patients had stage I tumors, 6% had stage II, 44% had stage IIIA, and 46% had stage IIIB tumors. The median radiation therapy (RT) dose to the gross tumor volume with a median of 467.5 cc (range, 75.0-3073.0 cc) was 6120 cGy (range, 3000-6840 cGy). Thirty-one of 46 patients (67.4%) received combined chemoradiotherapy. Mean follow-up was 13.2 months (range, 3-159 months). Survival for stage III patients was 48.7% +/-9.1% at 1 year and 25.0% +/-8.4% at 2 years, with a median survival of 12.0 months+/-4.4 months. The local control rate for stage III patients was 66.8%+/- 9.4% at 1 year and 28.5%+/- 10.4% at 2 years. Patients who received chemotherapy had better survival (P = 0.0533) and local control (P = 0.0984) compared with patients receiving RT alone. Esophageal toxicity >or= grade 3 was significantly greater in combined chemoradiotherapy patients (29% early, 13% late) compared to the patients receiving RT alone (0% early and late). Pulmonary toxicity (early and late) was limited to grades 1/2 in 24% of patients and early grade 3 in 2% of patients. Chemotherapy appears to improve survival and local control when added to 3D-CRT in this series. The addition of concurrent chemotherapy to RT significantly increased esophageal toxicity (within acceptable levels) and did not effect pulmonary toxicity in this series.

Journal Article↗
PubMed2002

Multi-modality therapy leads to longer survival in primary central nervous system lymphoma patients.

BACKGROUND: Primary central nervous system lymphoma (PCL) is more frequently encountered by neurosurgeons given the increasing incidence among both nonimmunocompromised and immunocompromised patients. The most frequent surgery is stereotactic biopsy. Historically, radiation therapy has been the standard treatment modality for this disease and median survival was in the 15-month range. More recently, multi-modality therapy combining radiation therapy with chemotherapy (systemic, intrathecal, and/or intra-arterial) have resulted in longer survivals. We reviewed survival data for our series of patients treated for PCL over the last decade. METHODS: Thirty-four patients with histologically confirmed PCL were treated at our center. Multivariate Cox regression analysis was performed to determine which factor(s) (age, gender, HIV status, Karnofsky Performance Scale, chemotherapy, single modality therapy, histology, location, number of lesions, surgical resection) had a significant impact on survival. RESULTS: The overall median survival was 19 months. Patients receiving multi-modality therapy (n=17) (chemotherapy and radiation) had a median survival of 34 months compared to four months for patients receiving single modality therapy (n=17 including seven HIV positive patients). Multi-modality therapy was the only significant factor affecting survival in this multivariate analysis (p<0.0001). CONCLUSIONS: Chemotherapy plus radiotherapy significantly enhances survival over patients treated with single modality therapy alone. Quality of life issues should be addressed on a case by case basis as additional treatment modalities are initiated.

Adult↗
PubMedDate not supplied

Stereotactic radiosurgery for the treatment of trigeminal neuralgia.

Stereotactic radiosurgery is an increasingly used and the least invasive surgical option for patients with medically refractory trigeminal neuralgia (TN). The authors began use of this technique at our center in 1992 and have evaluated outcomes serially. Independently acquired data from 220 patients with idiopathic TN that had Gamma Knife radiosurgery was reviewed. The median radiosurgery dose was 80 Gy with a range of 60 to 90 Gy. Most patients had features of typical TN, although 16 (7.3%) described additional atypical features. One hundred thirty-five patients (61.4%) had prior surgery. Patients were followed to a maximum of 6.5 years (median, 2 years). Complete or partial pain relief was achieved in 85.6% of patients at 1 year. Complete pain relief was achieved in 64.9 % of patients at 6 months, 70.3% at 1 year, and 75.4% patients at 33 months. Patients with an atypical pain component had a lower rate of achieving pain relief ( p = 0.025). Due to recurrences, 55.8% of patients had complete or partial pain relief at 5 years. The absence of preoperative sensory disturbance or prior surgery correlated with an increased proportion of patients in complete or partial pain relief over time. Ten percent of patients developed new or increased subjective facial paresthesia or facial numbness. Radiosurgery for idiopathic TN was safe and effective, and provided benefit to a patient population with a high frequency of prior surgical intervention. It is an important addition to the surgical armamentarium for TN.

Animals↗