Radiosurgery reirradiation for high-grade glioma recurrence: a retrospective analysis.

Despite various treatment strategies being available, recurrent high-grade gliomas (r-HGG) are difficult to manage. To obtain local control, radiosurgery (SRS) reirradiation has been considered as potential treatment. In the present study, a retrospective analysis was performed on r-HGG patients treated with salvage single- (s-SRS) or multi-fraction SRS (m-SRS). The aim of this study was to evaluate the effectiveness of salvage SRS in terms of overall survival (OS); toxicity was analyzed as well. Between 2004 May and 2011 December, 128 r-HGG patients (161 lesions) treated with CyberKnife(®) SRS reirradiation were retrospectively analyzed. Toxicity was graded according to Radiation Therapy Oncology Group and by Common Terminology Criteria for Adverse Events v.3 criteria. OS from the diagnosis date and OS from reirradiation were estimated using the Kaplan-Meier method. Median follow-up was 9 months (range 15 days-82 months). All patients completed SRS without high-grade toxicity. Radiation necrosis was observed in seven patients (6 %) with large volume lesions. The median survival from initial diagnosis was 32 months. The 1-, 2-, and 3-years survival rates from diagnosis were 95, 62, and 45 % respectively. Median survival following SRS was 11.5 months. The 1-, 2-, and 3-years survival rate following SRS was 48, 20, and 17 % respectively. On multivariate analysis, age <40 years, salvage surgery before SRS, and other post-SRS therapies (second-line chemotherapy and/or surgery) were found to significantly improve survival (p = 0.03). SRS represents a safe and feasible option to treat r-HGG patients with low complication rates and potential survival benefit.

Prospective study on the dose distribution to the acoustic structures during postoperative 3D conformal radiotherapy for parotid tumors: dosimetric and audiometric aspects.

BACKGROUND AND PURPOSE: To analyze dose distribution in the hearing organ and to evaluate the dose effect on the hearing thresholds in patients treated with post-parotidectomy 3-dimensional conformal radiotherapy (3D-CRT). METHODS AND MATERIALS: A total of 17 patients received post-parotidectomy 3D-CRT (median dose: 63 Gy). The audiometric evaluation comprised pure tone audiometry and tympanometry performed before radiotherapy (RT) and 3, 6, and 24 months after RT. The ear structures were delineated on planning computer tomography scans. Mean and maximum doses were calculated and dose-volume histograms were plotted. RESULTS: Before RT, the median baseline audiometric thresholds were normal. At 3 months post-RT, 3 patients were diagnosed as having middle ear underpressure and/or effusion that resolved completely by 6 months. During 2-year follow-up, none of the ears showed perceptive hearing loss at speech frequencies. The mean doses at ipsilateral external auditory canal, mastoids cells, tympanic case, Eustachian tube, semicircular canals, and cochlea were 44.8 Gy, 39.0 Gy, 30.9 Gy, 33.0 Gy, 19.6 Gy, and 19.2 Gy, respectively. The doses to the contralateral ear were negligible, except for the Eustachian tube (up to 28.2 Gy). CONCLUSION: Post-parotidectomy 3D-CRT is associated with relatively low doses to the ear and the surrounding structures. Post-RT audiometry did not show any permanent (neither conductive nor perceptive) hearing impairment. Only in 3 patients were there signs of transient unilateral dysfunction of the Eustachian tube observed during the first few months after RT. Longer follow-up and larger patient series are warranted to confirm these preliminary findings.

Image-guided robotic radiosurgery as salvage therapy for locally recurrent prostate cancer after external beam irradiation: retrospective feasibility study on six cases.

AIMS AND BACKGROUND: Technological advances in treatment planning and execution are providing new potential opportunities in the treatment of recurrent prostate cancer. This study was conducted to evaluate the feasibility and safety of reirradiation with image-guided radiosurgery using CyberKnife, a robotic arm-driven compact linear accelerator, for intraprostatic recurrence after external beam radiotherapy (EBRT). METHODS: Between September 2007 and May 2008, 6 patients diagnosed with locally recurrent prostate cancer after EBRT were treated using the CyberKnife system. The total reirradiation dose was 30 Gy in five fractions. Prior to radiosurgery four patients were treated with androgen-deprivation therapy. Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria and the Houston-Phoenix definition (PSA nadir + 2 ng/mL) were used for toxicity and biochemical failure evaluation, respectively. RESULTS: After a median follow-up of 11.2 months (range, 9.6-18.6 months), all patients are alive with no evidence of severe urinary or rectal acute morbidity. Local control cannot be exactly determined due to the short follow-up and the bias of the use of androgen ablation. Four patients had biochemical failure, three of them with clinical failure evidence (lymph node, bone and lung metastasis, respectively): none of these patients had clinical evidence of tumor persistence in the prostate. CONCLUSIONS: Salvage radiosurgery with CyberKnife after irradiation is feasible with low urinary and rectal morbidity. A longer follow-up and a larger number of patients are necessary to evaluate its effectiveness and optimal patient selection criteria.

Cyberknife Radiosurgery for Trigeminal Neuralgia.

Introduction Image-guided robotic radiosurgery is an emerging minimally-invasive treatment option for trigeminal neuralgia (TN). Our group has treated 560 cases up to date, and report here the clinical outcomes of 387 treatments with three years follow-up. This study represents the largest single-center experience on CyberKnife radiosurgery for the treatment of TN so far reported. Methods CyberKnife radiosurgery treatment was offered to patients with drug-resistant TN, after the failure of other treatments or refusal of invasive procedures. A second treatment was offered to patients with a poor response after the first treatment or with recurrent pain. Treatment protocol required the non-isocentric delivery of 60 Gy prescribed to the 80% isodose to a 6 mm retrogasserian segment of the affected trigeminal nerve. Retreatments typically received 45 Gy, again prescribed to the 80% isodose. The final plan was developed accordingly to individual anatomy and dose distribution over the trigeminal nerve, gasserian ganglion, and brainstem. Clinical outcomes such as pain control and hypoesthesia/numbness have been evaluated after 6, 12, 24, and 36 months.  Results Our group has treated 527 patients with Cyberknife radiosurgery at Centro Diagnostico Italiano (CDI), Milan, Italy, during the last decade. A minimum follow-up of six months was available on 496 patients. These patients received 560 treatments: 435 patients (87.7%) had a single treatment, 60 patients (12.1%) had two treatments, and one patient (0.2%) had five treatments (two on the right side, three on the left side). Twenty four patients had multiple sclerosis (4.8%). Four hundred and forty-three patients (84%) received the treatment without previous procedures, while 84 patients (16%) underwent radiosurgery after the failure of other treatments. A neurovascular conflict was identified in 59% of the patients. Three hundred and forty-three patients (receiving a total of 387 treatments) had a minimum of 36 months follow up. Pain relief rate at 6, 12, 18, 24, 30 and 36 months was respectively 92, 87, 87, 82, 78 and 76%. Forty-four patients out of 343 (12.8%) required a second treatment during the observed period. At 36 months post-treatment, 21 patients (6,1%) reported the presence of bothering facial hypoesthesia. Eighteen patients out of 21 (85.7%) developed this complication after a repeated treatment.  Conclusions Frameless image-guided robotic radiosurgery in experienced hands is a safe and effective procedure for the treatment of TN, providing excellent pain control rates in the absence of major neurological complications. Repeated treatments due to recurrent pain are associated with restored pain control but at the price of a higher rate of sensory complications.

Localization accuracy of robotic radiosurgery in 1-view tracking.

PURPOSE: When a lung lesion is detected by only one couple of X-ray tube and image detector integrated with CyberKnife®, the fiducial-less tracking is limited to 1-view (34% of lung treatments at Centro Diagnostico Italiano). The aim of the study was mainly to determine the margin needed to take into account the localization uncertainty along the blind view (out-of-plane direction). METHODS: 36 patients treated in 2-view tracking modality (127 fractions in total) were included in the study. The actual tumor positions were determined retrospectively through logfile analysis and were projected onto 2D image planes. In the same plots the planned target positions based on biphasic breath-hold CT scans were represented preserving the metric with respect to the imaging center. The internal margin necessary to cover in out-of-plane direction the 95% of the target position distribution in the 95% of cases was calculated by home-made software in Matlab®. A validation test was preliminarily performed using XLT Phantom (CIRS) both in 2-view and 1-view scenarios. RESULTS: The validation test proved the reliability of the method, in spite of some intrinsic limitations. Margins were estimated equal to 5 and 6 mm for targets in upper and lower lobe respectively. Biphasic breath-hold CT led to underestimate the target movement in the hypothetical out-of-plane direction. The inter-fractional variability of spine-target distance was an important source of uncertainty for 1-view treatments. CONCLUSION: This graphic comparison method preserving metric could be employed in the clinical workflow of 1-view treatments to get patient-related information for customized margin definition.

Radiosurgery for Paragangliomas of the Head and Neck: Another Step for the Validation of a Treatment Paradigm.

BACKGROUND: Paragangliomas are highly vascular and predominantly benign neoplasms that traditionally have been treated by surgery, embolization, and/or external beam radiotherapy. The aim of this study was to evaluate long-term local tumor control and the safety of radiosurgery for head and neck paragangliomas. METHODS: Data were obtained from prospectively maintained databases of patients affected by brain tumors treated with radiosurgery at our institution. The inclusion criteria were histologically proven or radiologic-suspected diagnosis of paragangliomas; a follow-up period of at least 12 months, an magnetic resonance imaging-based tumor growth control analysis and a signed written consent. Twenty patients (21 paragangliomas) met the eligibility criteria and were included in the present study. All patients were clinically and radiologically evaluated before and after treatment. RESULTS: The mean follow-up at the time of the present analysis was 46 months. Seven patients had a follow-up longer than 60 months. Seven lesions underwent a single-session radiosurgery with a mean dose of 12.2 Gy (range 11-13 Gy). Fourteen lesions underwent multisession radiosurgery with a mean dose of 25.7 Gy (range 20-30 Gy) delivered in 3-5 fractions. The mean tumor volume for single-session radiosurgery was 4 cc (range 1.4-9.2). The mean volume for multisession radiosurgery was 18.9 cc (range 1.3-50.9). None of the lesions showed progression on radiology during the follow-up period. Neurologic conditions generally are maintained or improved. CONCLUSIONS: Both single and multisession radiosurgery were confirmed as a safe and effective treatment modality for paragangliomas. Multisession radiosurgery appears effective to treat large lesions.

Robotic image-guided stereotactic radiotherapy, for isolated recurrent primary, lymph node or metastatic prostate cancer.

PURPOSE: To evaluate the outcome of robotic CyberKnife (Accuray, Sunnyvale, CA)-based stereotactic radiotherapy (CBK-SRT) for isolated recurrent primary, lymph node, or metastatic prostate cancer. METHODS AND MATERIALS: Between May 2007 and December 2009, 34 consecutive patients/38 lesions were treated (15 patients reirradiated for local recurrence [P], 4 patients reirradiated for anastomosis recurrence [A], 16 patients treated for single lymph node recurrence [LN], and 3 patients treated for single metastasis [M]). In all but 4 patients, [(11)C]choline positron emission tomography/computed tomography was performed. CBK-SRT consisted of reirradiation and first radiotherapy in 27 and 11 lesions, respectively. The median CBK-SRT dose was 30 Gy in 4.5 fractions (P, 30 Gy in 5 fractions; A, 30 Gy in 5 fractions; LN, 33 Gy in 3 fractions; and M, 36 Gy in 3 fractions). In 18 patients (21 lesions) androgen deprivation was added to CBK-SRT (median duration, 16.6 months). RESULTS: The median follow-up was 16.9 months. Acute toxicity included urinary events (3 Grade 1, 2 Grade 2, and 2 Grade 3 events) and rectal events (1 Grade 1 event). Late toxicity included urinary events (3 Grade 1, 2 Grade 2, and 2 Grade 3 events) and rectal events (1 Grade 1 event and 1 Grade 2 event). Biochemical response was observed in 32 of 38 evaluable lesions. Prostate-specific antigen stabilization was seen for 4 lesions, and in 2 cases prostate-specific antigen progression was reported. The 30-month progression-free survival rate was 42.6%. Disease progression was observed for 14 lesions (5, 2, 5, and 2 in Groups P, A, LN, and M respectively). In only 3 cases, in-field progression was seen. At the time of analysis (May 2010), 19 patients are alive with no evidence of disease and 15 are alive with disease. CONCLUSIONS: CyberKnife-based stereotactic radiotherapy is a feasible approach for isolated recurrent primary, lymph node, or metastatic prostate cancer, offering excellent in-field tumor control and a low toxicity profile. Further investigation is warranted to identify the patients who benefit most from this treatment modality. The optimal combination with androgen deprivation should also be defined.