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Dive into the research topics where Zbigniew Petrovich is active.

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Featured researches published by Zbigniew Petrovich.


Cancer | 1990

Treatment of uterine sarcomas.

Gregory Echt; Joanne Jepson; John Steel; Bryan Langholz; Gary Luxton; Wilfredo Hernandez; Melvin A. Astrahan; Zbigniew Petrovich

During a 21‐year period, 66 patients with uterine sarcomas were treated at California Medical Center. Histological diagnoses were mixed mesodermal sarcoma in 32 patients (48%), leiomyosarcoma in 24 (36%), and endometrial stromal sarcoma in 10 (15%) patients. The majority of patients (73%) had Stage I tumors. The treatment consisted of surgery alone in 27 (41%), surgery in combination with radiation therapy in 36 (55%), and radiation therapy alone in three (4%) patients. The overall 1‐, 2‐, and 5‐year actuarial survival was 74%, 57%, and 38%, respectively. The 1‐, 2‐, and 5‐year actuarial survival for the 27 surgery alone patients was 73%, 50%, and 25%, which compared with 75%, 61%, and 44% for the 36 surgery plus radiation therapy patients (P = 0.12). The disease‐free survival was better for the surgery plus radiation therapy patients, as compared with the surgery alone group (38% vs. 18% at 5 years, P = 0.081). The 5‐year survival by histology was 70% for the 10 endometrial stromal sarcoma patients, 40% for the 24 leiomyosarcoma patients, and 23% for the 32 mesodermal sarcoma patients (P = 0.064). As expected, survival depended on the stage of disease (P < 0.0001). Treatment failure was observed in 35 (53%) patients, which included 9 (14%) with failure in the pelvis. There was no difference in the incidence of failure among patients in the three treatment groups and also in the three histologic groups. There was, however, a significant difference in the incidence of pelvic failure between surgery alone and surgery plus radiation therapy patients. in the 27 surgery alone patients, nine (33%) relapsed in the pelvis, whereas none of the 36 surgery plus radiation therapy patients had locoregional failure, P < 0.0001. Adjuvant radiation therapy is an important treatment in the management of patients with sarcoma of the uterus.


Neurosurgery | 1999

Gamma Knife Radiosurgery for Metastatic Melanoma: An Analysis of Survival, Outcome, and Complications

Sean D. Lavine; Zbigniew Petrovich; Aaron A. Cohen-Gadol; Lena S. Masri; Donald L. Morton; Steven O'day; Richard Essner; Vladimir Zelman; Cheng Yu; Gary Luxton; Michael L.J. Apuzzo

OBJECTIVE Although the mainstays for treatment of metastatic brain disease have been surgery and/or external beam radiation therapy, an increasing number of patients are being referred for stereotactic radiosurgery as the primary intervention for their intracranial pathological abnormalities. The lack of efficacy and cognitive and behavioral consequences of whole brain irradiation have prompted clinicians to select patients for alternative therapies. This study analyzes the effectiveness of Leksell gamma unit therapy for metastatic melanoma to the brain. METHODS We present our experience with 59 Leksell gamma unit treatment sessions in 45 consecutive patients who presented with metastatic melanoma to the brain. Five of these procedures were performed as salvage therapy for patients who needed second radiosurgical treatment for new lesions that were remote from the previous targets and were not included in the overall analyses. RESULTS The population included 78% male patients. The mean patient age was 53 years (age range, 24-80 yr). The mean time from diagnosis of primary melanoma to discovery of brain metastasis was 43 months (median, 27.5 mo; range, 1-180 mo). At the time of diagnosis of brain disease, 35.5% of the patients (16 of 45 patients) had neurological symptoms, 77.7% (35 of 45 patients) had known visceral metastases, and 11.1% (5 of 45 patients) had seizure disorders. Eighty-six percent of the lesions (80 of 93 lesions) were cortical, 12% (11 of 93 lesions) were cerebellar, 1% (1 of 93 lesions) were pontine, and 1% (1 of 93 lesions) were thalamic. Fifty-seven percent of the sessions (31 of 54 sessions) were performed for a single lesion, 24.1% (13 of 54 sessions) for two lesions, 9.2% (5 of 54 sessions) for three lesions, 7.4% (4 of 54 sessions) for four lesions, and 1.8% (1 of 54 sessions) for five lesions. The mean treatment volume was 5.6 cc, with a mean prescription of 21.6 Gy to the 56.0% mean isodose line. The median survival time of the patients in our population, using Kaplan-Meier curves, was 43 months from the time of diagnosis of primary melanoma (range, 3-180 mo) and 8 months (range, 1-20 mo) from the time of gamma knife treatment. Complications included seizures within 24 hours of the procedure in four patients, with transient nausea and vomiting in three patients, transient worsening of preprocedure paresis responsive to steroids in three patients, and increased confusion in one patient. All 45 patients were located for follow-up (mean follow-up duration, 1 yr). After gamma knife treatment, 78% of the patients (35 of 45 patients) experienced either improved or stable neurological symptomatology before death or at the time of the latest follow-up examination. There were 26 deaths (58%). The cause of death was determined to be neurological in only 2 of 45 patients (7.7%). Follow-up magnetic resonance images revealed a 97% local tumor control rate of gamma knife-treated lesions, with 28% radiographic disappearance (9 of 32 cases). Six patients developed new lesions remote from radiosurgical targets and underwent second procedures. CONCLUSION Although metastatic melanoma to the brain continues to have a foreboding prognosis for long-term survival, gamma knife radiosurgery seems to be a relatively safe, noninvasive, palliative therapy, halting or reversing neurological progression in 77.8% of treated patients (35 of 45 patients). The survival rate matches or exceeds those previously reported for surgery and other forms of radiotherapy. Only 7.7% of the patients in our study population who died as a result of metastatic melanoma (2 of 26 patients) died as a result of neurological disease. The routine use of therapeutic level antiseizure medication is emphasized, considering the findings of our review.


Neurosurgery | 1993

Stereotactic radiosurgery: Principles and comparison of treatment methods

Gary Luxton; Zbigniew Petrovich; Gabor Jozsef; Lucien A. Nedzi; Michael L.J. Apuzzo

Methods of stereotactic radiosurgery are reviewed and compared with respect to technical factors and published clinical results. Heavy-ion beams, the Leksell cobalt-60 gamma knife, and the conventional linear accelerator (linac) are compared with respect to dosimetry, radiobiology, treatment planning, cost, staffing requirements, and ease of use. Clinical results on the efficacy of treatment of arteriovenous malformations are tabulated, and other applications of radiosurgery are described. It is concluded that although there are dosimetric and radiobiological advantages to charged-particle beams that may ultimately prove critical in the application of radiosurgery to large (> 30 mm) lesions, these advantages have not yet demonstrated clinical effect. On the other hand, equally excellent clinical results are obtained for small lesions with photon beams--the gamma knife and the linac. There are only minor differences between gamma and x-ray beam dose distributions for small, spherical-shaped targets. Mechanical precision is superior for the gamma knife as compared with the linac. The superior mechanical precision is of limited importance for most clinical targets, because inaccuracy of cranial target localization based on radiological imaging is greater than the typical linac imprecision of +/- 1 mm. Treatment planning for the linac is not standardized, but existing systems are based on well-known algorithms. The linac allows flexible, ready access to individualized beam control, without intrinsic field size limitations. Thus, it is more readily possible to achieve homogeneous dose distributions for nonspherical targets with one or more dimensions greater than 25 mm, as compared with that achieved with the gamma unit.(ABSTRACT TRUNCATED AT 250 WORDS)


Neurosurgery | 2003

The CyberKnife Stereotactic Radiosurgery System: Description, Installation, and an Initial Evaluation of Use and Functionality

John Kuo; Cheng Yu; Zbigniew Petrovich; Michael L.J. Apuzzo

The CyberKnife Stereotactic Radiosurgery System is manufactured by Accuray, Inc. (570 Del Rey Avenue, Sunnyvale, CA 94085; telephone 1-888/522-3740 or 1-408/522-3740; http://www.accuray.com). It is currently available for purchase (capital cost of US


Neurosurgery | 2003

Gamma knife radiosurgery for pituitary adenoma: early results.

Zbigniew Petrovich; Cheng Yu; Steven L. Giannotta; Chi-Shing Zee; Michael L.J. Apuzzo

3.2 million plus US


Cancer | 1989

Primary central nervous system lymphoma in AIDS. Results of radiation therapy.

Silvia C. Formenti; Parkash S. Gill; Eva Lean; Mark U. Rarick; Paul R. Meyer; William D. Boswell; Zbigniew Petrovich; Linda Chak; Alexandra M. Levine

0.5 to 0.75 million for site setup), or in a revenue-sharing plan (US


International Journal of Radiation Oncology Biology Physics | 2002

Metastatic melanoma to the brain: prognostic factors after gamma knife radiosurgery.

Cheng Yu; Joseph C.T. Chen; Michael L.J. Apuzzo; Steven J. O’Day; Steven L. Giannotta; Jeffrey S. Weber; Zbigniew Petrovich

0.5 to 0.75 million setup cost). [Figure: see text].


Neurosurgery | 2005

Gamma knife radiosurgery for trigeminal neuralgia.

Sean A. McNatt; Cheng Yu; Steven L. Giannotta; Chi-Shing Zee; Vladimir Zelman; Michael L.J. Apuzzo; Zbigniew Petrovich

OBJECTIVEIn recent years, gamma knife radiosurgery (GKRS) has emerged as an important treatment modality in the management of pituitary adenomas. Treatment results after performing GKRS and the complications of this procedure are reviewed. METHODSBetween 1994 and 2002, a total of 78 patients with pituitary adenomas underwent a total of 84 GKRS procedures in our medical center. This patient group comprised 46 men (59%) and 32 women (41%). All patients were treated for recurrent or residual disease after surgery or radiotherapy, with 83% presenting with extensive tumor involvement. The cavernous sinus was involved in 75 patients (96%), and 22 patients (28%) had hormone-secreting adenomas. This latter subset of patients included 12 prolactinomas (15%), 6 growth-hormone secreting tumors (8%), and 4 adrenocorticotropic hormone-secreting tumors (5%). The median tumor volume was 2.3 cm3, and the median radiation dose was 15 Gy defined to the 50% isodose line. The mean and median follow-up periods were 41 and 36 months, respectively. RESULTSGKRS was tolerated well in these patients; acute toxicity was uncommon and of no clinical significance. Late toxicity was noted in three patients (4%) and consisted of VIth cranial nerve palsy. In two patients, there was spontaneous resolution of this palsy, and in one patient, it persisted for the entire 3-year duration of follow-up. Of the 15 patients who presented with cranial nerve dysfunction, 8 (53%) experienced complete recovery and 3 (20%) showed major improvement within 12 months of therapy. Tumor volume reduction was slow, with 30% of patients showing decreased tumor volume more than 3 years after undergoing GKRS. None of the 56 patients with nonfunctioning tumors showed progression in the treated volume, and 4 (18%) of the 22 hormone-secreting tumors relapsed (P = 0.008). Of the four patients with adrenocorticotropic hormone-secreting adenomas, therapy failed in two of them. All six patients with growth hormone-producing tumors responded well to therapy. Of the 12 patients with prolactinomas 10 (83%) had normalization of hormone level and 2 patients experienced increasing prolactin level. Two patients with prolactinomas had three normal pregnancies after undergoing GKRS. CONCLUSIONGKRS is a safe and effective therapy in selected patients with pituitary adenomas. None of the patients in our study experienced injury to the optic apparatus. A radiation dose higher than 15 Gy is probably needed to improve control of hormone-secreting adenomas. Longer follow-up is required for a more complete assessment of late toxicity and treatment efficacy.


Cancer | 1979

Influence of cell type on failure pattern after irradiation for locally advanced carcinoma of the lung

James D. Cox; Raymond Yesner; William Mietlowski; Zbigniew Petrovich

Primary central nervous system (CNS) lymphoma is one of the clinical presentations of the acquired immune deficiency syndrome (AIDS). Ten patients had biopsy‐proven high‐grade lymphomas that were confirmed by further staging as limited to the CNS. All ten patients received cranial irradiation (total dose, 2200 to 5000 cGy). Six patients demonstrated complete response (CR) of the intracranial masses at the time of repeat computed tomography (CT) scan, whereas one attained a partial response (PR). Two of the CR patients died multiple opportunistic infections, two experienced relapse of lymphoma, and died at 7 and 16 months diagnosis, and two were alive without evidence of disease at 8 and 14 months from diagnosis. The moon survival of the whole group was 5.5 months (range, 2 to 16 months). Patients with AIDS‐related primary CNS lymphoma may respond to radiation treatment; however, response duration is usually short, and survival is influenced by refractory disease or systemic opportunistic infections.


Neurosurgery | 2001

Radiosurgical management of benign cavernous sinus tumors: dose profiles and acute complications.

Joseph C.T. Chen; Steven L. Giannotta; Cheng Yu; Zbigniew Petrovich; Michael L. Levy; Michael L.J. Apuzzo

PURPOSE To identify important prognostic factors predictive of survival and tumor control in patients with metastatic melanoma to the brain who underwent gamma knife radiosurgery. METHODS AND MATERIALS A total of 122 consecutive patients with 332 intracranial melanoma metastases underwent gamma knife radiosurgery over a 5-year period. Of these, 39 (32%) also received whole-brain irradiation (WBI). The median tumor volume was 0.8 cm(3) (range: 0.02-30.20 cm(3)), and the median prescribed dose was 20 Gy (range: 14-24 Gy). Median follow-up was 6.8 months. Univariate and multivariate analyses of survival and freedom from progression were performed using the following parameters: status of systemic disease, intracranial tumor volume, number of lesions, tumor location, Karnofsky performance status, gender, age, and WBI. RESULTS Overall median survival was 7.0 months from time of radiosurgery and 9.1 months from the onset of brain metastasis. In multivariate analysis, improved survival was noted in patients with total intracranial tumor volume <3 cm(3) (p = 0.003) and inactive systemic disease (p = 0.0065), whereas other parameters studied were of lesser importance (tumor location, p = 0.056, and Karnofsky performance status, p = 0.086), or of no significance (number of lesions, WBI, age, and gender). Freedom from subsequent brain metastasis depended on intracranial tumor volume (p = 0.0018) and status of systemic disease (p = 0.034). CONCLUSIONS Stereotactic radiosurgery is an effective treatment modality for patients with intracranial metastatic melanoma. Tumor volume and status of systemic disease are good independent predictors of survival and freedom from tumor progression.

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Melvin A. Astrahan

University of Southern California

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Michael L.J. Apuzzo

University of Southern California

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Bryan Langholz

University of Southern California

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Cheng Yu

University of Southern California

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Gary Lieskovsky

University of Southern California

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Donald G. Skinner

University of Southern California

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Gabor Jozsef

University of Southern California

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Luc Baert

Catholic University of Leuven

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Peter E. Liggett

University of Southern California

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