|
|
|
 |
Search published articles |
 |
|
Showing 8 results for Stereotactic Body Radiotherapy
Dr. H.j. Kim, J.h. Phak, W.ch. Kim,
Volume 14, Issue 4 (10-2016)
Abstract
Background: stereotactic body radiotherapy (SBRT) has emerged as an effective treatment for localized prostate cancer. However, prostate-specific antigen (PSA) kinetics after SBRT has not been well characterized. The objective of the current study is to analyze the rate of PSA decline and PSA nadir following hypofractonated SBRT in localized prostate cancer. Materials and Methods: From 2008 to 2014, thirty-nine patients newly diagnosed, localized prostate (25.6% low risk, 66.7% intermediate risk and 7.7% high risk) cancer were treated with SBRT using Cyberknife. Total dose of 36.25 Gy in 5 fractions of 7.25 Gy were administered. No one received androgen deprivation therapy (ADT). PSA nadir and rate of change in PSA (slope) were calculated and compared. Results: With a median follow-up of 52 months (range, 13-71), the median rates of decline of PSA were -0.372, -0.211 and -0.128 ng/mL/month, respectively, for durations of 1, 2 and 3 years after radiotherapy, respectively. The decline of PSA was maximal in the first year and continuously decreased for durations of 2 and 3 year. The median PSA nadir was 0.28 ng/mL after a median 33 months. There was one biochemical failure, occurring in a high risk patient. 5-year actuarial biochemical failure (BCF) free survival was 94.2%. Conclusion: In this report of localized prostate cancer, continuous decrease of PSA level for duration 1, 2 and 3 year following SBRT using Cyberknife resulted in lower PSA nadir. Also, SBRT leaded to long-term favorable BCF-free survival.
Phd., H.j. Kim, J.s. Lee, W.c. Kim,
Volume 18, Issue 3 (7-2020)
Abstract
Background: Stereotactic body radiotherapy (SBRT) is an emerging treatment option which allows for extreme hypofractionation using modern technologies, because the low α/β-ratio favors the use of high dose per fraction in prostate cancer. There is a need for more data about SBRT. We provide a long-term update of SBRT clinical outcome using CyberKnife for the treatment of localized prostate cancer. Materials and Methods: This study was based on a retrospective analysis of 43 patients treated with SBRT using CyberKnife for localized prostate cancer (23.3% in low risk, 67.4% in intermediate risk and 9.3% in high risk). The target volume included the prostate with or without the seminal vesicles depending on the risk stratification and uncertainty margins that are kept at 3-5 mm. Total dose of 36.25 Gy in 5 fractions of 7.25 Gy were administered. Results: 43 patients with a median 73.6 months (range, 14 to 119 months) follow-up were analyzed. There was three biochemical failure (BCF). Eight-year BCF free survival and overall survival were 92.0% and 73.1%, respectively. Median PSA decline rates were -0.301, -0.191 and -0.115 ng/mL/month, respectively, for durations of 1, 2 and 3 years after radiotherapy and has remained plateau. Median PSA nadir was 0.27 ng/mL at median 38 months and PSA bounce (median 0.33 ng/mL) occurred in 32.6% (n = 14) of patients at median 19 months after SBRT. There was no grade 3 acute and late toxicity. Conclusion: Our long-term experience with SBRT using CyberKnife for localized prostate cancer demonstrates favorable efficacy and toxicity.
Ph.d., M. Okutan, A. Franko, C. Köksal, E.o. Göksel, Ş. Karaman, Y. Emre Akpınar, N. Dağoğlu, B. Demir,
Volume 18, Issue 4 (10-2020)
Abstract
Background: Radiation Pneumonia (RP) is one of the most extensive side effects in Stereotactic Body Radiotherapy (SBRT) of lung cancer. SBRT are performed by means of Intensity Modulated Radiotherapy (IMRT), Intensity Modulated Arc Therapy (IMAT), CyberKnife (CK) or Helical Tomotherapy (HT) treatment methods. In this study, we performed a plan study to determine the plan parameter such as the Mean Lung Dose (MLD), V20Gy Lung Volume and V5Gy Lung Volume in the evaluation of RP risk in the treatment of lung with SBRT. Materials and Methods: Fifteen patients with Lung Cancer who had a tumor diameter of less than 5 cm and peripheral located were included to this study. Intensity Modulated Radiotherapy, Intensity Modulated Arc Therapy, CyberKnife and Helical Tomotherapy plans were separately created for each patients. For each plan, a total of 54 Gy dose were given to Planning Target Volume (PTV) in 3 fractions using a dose of 18 Gy per fraction. Results: In each technique for all parameters of PTV and critical organ doses (OAR) meet the required criteria. Total Lung MLD were found as 3.21 Gy and Total Lung V20Gy Volume were found as 4.05 cc, Total Lung V5Gy Volume were found as 14.06 cc as the lowest value in IMRT-SBRT plan. Conclusion: When treatment plans are evaluated in terms of RP risk, Total Lung MLD, Total Lung V20Gy Volume and Contralateral Lung V5Gy Volume are found the lower in IMRT- SBRT plan than other SBRT techniques. We suggest that IMRT-SBRT irradiation should be preferred in lung radiotherapy in case of high RP risk.
M.d., H.j. Kim, J.s. Lee, W.c. Kim,
Volume 20, Issue 1 (1-2022)
Abstract
Background: We report our long-term outcomes with Cyberknife to deliver hypofractionated SBRT boost combined with EBRT to patients with intermediate to high risk prostate cancer. Materials And Methods: From March 2008 to July 2014, 42 patients with newly diagnosed, intermediate (73.8%, 31) and high risk (26.2%, 11) localized prostate cancer were treated with EBRT and SBRT boost. The whole pelvis dose was 45 Gy (25 fractions of 1.8 Gy) and the SBRT boost dose was 21 Gy (3 fractions of 7 Gy). Results: With a median follow-up duration of 84.2 months (range, 20-139.6), the median PSA decline rates were -0.605, -0.229, -0.166 and -0.094 ng/mL/month, respectively, for durations of 1, 2, 3 and 4 years after radiotherapy and has remained near plateau. Four BCFs were observed only in high risk group. The actuarial 8 year BCF free survival and overall survival were 90.3 % and 83.7 %, respectively. BCF-free survival at 8 years were 100 % and 77.8 % for intermediate and high risk group, respectively (p=0.014). No grade 3 or 4 acute and late genitourinary (GU) and gastrointestinal (GI) toxicities were observed. Acute grade 2 GU toxicities were seen in 23.8 % (n = 10) and acute grade 2 GI toxicities in 21.4 % (n = 9). Late grade 2 GU toxicities were observed in 11.9 % (n = 5) and grade 2 GI toxicities in 14.2 % (n = 6). Conclusions: We demonstrated that SBRT boost after EBRT in intermediate- and high-risk prostate cancer had favorable outcomes with tolerable toxicities.
Ph.d., N. Isık, E. Algül, G. Yaprak, A. Özen,
Volume 20, Issue 3 (7-2022)
Abstract
Background: We compare plans involving two different stereotactic radiotherapy devices: Cyberknife (CK) and Helical Tomotherapy (HTT) and their results on the lumbarvertebra targets. Materials and Methods: Ten simulation tomographs of the first lumbar vertebra were selected from among the tomographies of patients who had previously undergone SBRT for any reason. In each planning tomography, two separate clinical target volumes (CTV) were drawn at the first lumbar vertebra, we used 2%, 95% and 98% doses of the target volume (D2, D95, D98) in the plan evaluation. The 2% dose of the planning target volume (PTV) was used for comparison with the hot spot; the 95% dose coverage of CTV was used for the target coverage comparison, and the 98% dose of the target volume was used for the dose volume histogram "shoulder" metric definitionTheHomogeneity Index (HI), new Conformity Index (nCI) and Gradient Index (GI) were evaluated for each planning system and target. Results: In both groups, CTV1 and CTV2, when compared with D95, the coverage for HTT was found statistically significantly higher. D98 was found to be statistically significantly higher with HTT. In both targets, the CKplans were found to have a higher hot area (D2), and inhomogeneous plans were obtained when compared to HTT. The NCI results were similar, and GI was higher with HTT. Conclusion: In lumbar vertebra stereotactic radiotherapy, more inhomogeneous plans were obtained with Cyberknife than with the Helical Tomotherapy device. A better gradient index was achieved with Cyberknife, while better coverage was achieved on the HTT plan.
Z. Dai, L. Zhu, A. Wang, X. Guo, Y. Liu, Y. Zhuang, P. Yang, Ph.d., N. Li, H. Zhang, Z. Xiang,
Volume 21, Issue 1 (1-2023)
Abstract
Background: The aim of this study was to make a comparison of plan quality between MLC-based EDGE and the cone-based CyberKnife systems in SBRT of localized prostate cancer. Materials and Methods: Ten patients with target volumes from 34.65 to 82.16 cc were included. Treatment plans were created for both systems using the same constraints. Dosimetric indices including target coverage, conformity index (CI), homogeneity index (HI), gradient index (GI) were applied for target, while the sparing of critical organs was evaluated with special dose-volume metrics and integral dose. Meanwhile, the delivery time and monitor units (MUs) were also estimated. The radiobiological indices such as equivalent uniform dose (EUD), tumor control probability (TCP) and normal tissue complication probability (NTCP) were also analyzed. Results: Both plans produced similar target coverage, HI and GI. For EDGE, more conformal dose distribution as well as reduced exposure of critical organs were obtained together with reduction of 91% delivery time and 72% MUs. EDGE plans also got lower EUD for bladder, rectum, urethra and penile bulk, which associated with reduction of NTCPs. However, higher values of EUD and TCP for tumor were obtained with CK plans. Conclusion: It indicated that both systems were capable of producing almost equivalent plan quality and can meet clinical requirements. CyberKnife has higher target dose while EDGE system has more advantages in normal tissue sparing and delivery efficiency.
M.d., H. Demir, S. Özdemir, N. Işık, G. Yaprak ,
Volume 21, Issue 4 (10-2023)
Abstract
Background: To evaluate treatment outcomes and toxicity of pulmonary SBRT for intrathoracic recurrence in patients with locally advanced NSCLC treated as a combination of surgery, radiotherapy or chemotherapy. Materials and Methods: A total of 46 patients with NSCLC who received thoracic SBRT for local or non local intrapulmonary recurrent lesions in our department from 2009 to 2019 were retrospectively enrolled in this study. The patients received median 43.4 Gy (25 Gy -60 Gy) radiotherapy using the CyberKnife radiosurgery system in median 3.6 fractions (range, 1-8).Univariate and multivariate Cox regression analyses were performed on the factors predicting outcomes. Results: The median follow up time after SBRT was 23.5 months. Treatment of the primary tumor consisted of surgical resection, radiochemotherapy, and systemic therapy in 25, 8 and 13 patients, respectively. İsolated local recurrence, intrathoracic recurrence and distant metastasis were detected in 5 (10.9%), 12 (26.1%) and 8 (17.4%) patients, respectively. Kaplan-Meier analysis of 2 year OS, PFS and LC for all tumors treated after SBRT were; 51%, 56% and 91%, respectively. In parameters related to patient and treatment; no statistical significance was found affecting local control and survival.(p>0.05). Grade 2 radiation pneumonitis and chest wall pain were observed in 2 (4.3%) and 1 (2.1 %) patients. Grade 3 toxicity was detected in 3 ( 6.5%) cases. Conclusion: Pulmonary SBRT for recurrent NSCLC is a good treatment option with favourable LC and promising survival. SBRT can be an effective treatment modality in the treatment of patients with local/limited pulmonary relapses with acceptable toxicity rates.
Y. Tanabe, T. Deguchi, M. Kiritani, N. Hira, S. Tomimoto, H. Nishikawa, S. Tsumoto, H. Tanaka,
Volume 22, Issue 1 (1-2024)
Abstract
Background: This study evaluates the tracking accuracy of the lung tumor volume and fiducial markers using four-dimensional computed tomography (4DCT) and fitted neural network models. Materials and Methods: This study utilized data from 31 patients (109 fiducial markers) who underwent stereotactic body radiotherapy (SBRT). The respiratory movements of fiducial markers, lung tumors, and lung volume were calculated using 4DCT. Cross-correlation coefficients were then calculated to analyze the phase movements of fiducial markers, lung tumors, lung volume, direction displacement, and lung area (upper, middle, and lower lobes). Statistical prediction models were used to evaluate the predictive accuracy of the left–right (LR), anterior–posterior (AP), cranial–caudal (CC), and three-dimensional (3D) cross-correlation coefficients between fiducial markers and lung tumors. The coefficient of determination (R2) was used to determine the accuracy of the statistical prediction models for the explanatory variables. Results: The correlation between fiducial marker and lung tumor, as well as lung tumor movement by time phase, yielded the following R2 values—LR: 0.920, AP: 0.319, CC: 0.675, and 3D: 0.449 for the upper lobe; LR: 0.567, AP: 0.627, CC: 0.955, and 3D: 0.939 for the middle/lower lobes. Statistically significant differences were observed in the CC and 3D directions within each lower lobe. Conclusions: The respiratory movements of fiducial markers and lung tumors in lung SBRT show stronger correlation with the movement of lung volume in the middle/lower lobes compared to that in the upper lobes. Combining a fiducial marker with lung volume improves the prediction accuracy of the respiratory movement of lung tumors.
|
|
