Robotic Stereotactic Radiosurgery Research Articles

Robotic stereotactic radiosurgery for intracranial meningiomas in elderly patients: assessment of treatment efficacy and safety.

Stereotactic radiosurgery (SRS) has been increasingly used to treat intracranial pathologies in elderly patients. The treatment efficiency of SRS has been demonstrated in meningiomas, with excellent local control. We aimed to analyze the safety of robotic SRS in elderly patients with meningiomas. We searched for patients with suspected WHO °I meningioma ≥ 60 years old, who underwent CyberKnife (CK) SRS from January 2011 to December 2021. Tumor localization was categorized using the "CLASS" algorithmic scale. Tumor response was evaluated using the Response Assessment in Neuro-Oncology (RANO) criteria for meningiomas. Adverse effects were graded using the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 and a cox regression was performed to investigate possible predictors. We identified 82 patients with 102 CK-treated lesions that matched the criteria for the first SRS. The median age was 70 [IQR 64-75] years, and 24.3% of the patients were aged > 75 years. Multiple lesions (up to six) were treated in 14.1% of the SRS-sessions. A previous surgery was performed in 57.3% of lesions, with a median time interval of 41 [IQR 10 - 58] months between the initial surgical procedure and the SRS treatment. In 47.9% of cases, CLASS 3 meningiomas at high-risk locations were irradiated. Single fraction radiosurgery was applied to 62.5% of the lesions, while in the remaining cases multi-session SRS with three to five fractions was used. During the median follow-up period of 15.9 months, lesion size progression was observed in 3 cases. Karnofsky Performance Status (KPS) declined by ≥ 20 points in four patients. Adverse effects occurred in 13 patients, while only four patients had CTCAE ≥2 toxicities. Hereby only one of these toxicities was persistent. The occurrence of complications was independent of age, planned target volume (PTV), high-risk localization, and surgery before SRS. The data indicates that SRS is a safe, efficient, and convenient treatment modality for elderly patients with meningioma, even at high-risk locations.

Robotic stereotactic radiosurgery with CyberKnife - brain metastases and fibrinolysis.

Deviations in haemostasis are found in about 50% of patients with cancer and up to 90% of those with metastatic disease. Many studies investigate the dynamics of the processes of coagulation and fibrinolysis and their role as apredictor of therapeutic response, early relapse, or metastasis risk. To investigate the serum levels of urokinase plasminogen activator (uPA) in patients with brain metastases treated with robotic stereotactic radiosurgery (SRS) with CyberKnife. Serum levels of urokinase plasminogen activator (uPA) were measured in 66patients with solid tumours, divided into two groups, with oligometastatic disease and brain metastases. In this prospective longitudinal study, the serum levels of uPA were measured before starting the therapy and at the first, third, and sixth months after patients were irradiated with the CyberKnife system. Analysis of serum uPA levels in the post-treatment period showed astatistically significant decrease between the baseline and the 6 months post-treatment time point in both patient groups. The baseline value of serum uPA in the group with lung cancer decreased by 62.7%, and in the group with other types of cancer - by 60%. Despite the significant reduction of serum uPA levels 6 months after the treatment, the levels remained significantly higher in both groups than in healthy controls. Ongoing research on uPA and cancer will enrich our knowledge and expand the possibilities for clinical utilization of the marker in the oncology setting (Tab. 2, Ref. 18).

Proton Teletherapy and Cyberknife Stereotactic Robotic Radiosurgery in Uveal Melanoma

As uveal malignant melanoma is sensitive to radiation, radiotherapies other than plaque brachytherapy are applicable with successful outcomes. Therefore, in this review, we evaluated the alternatives to plaque brachytherapy, such as proton teletherapy and Cyberknife robotic-controlled stereotactic radiotherapy in the light of previously published case series and our experience in Cyberknife regarding the outcomes of treatment, clinical follow-up parameters, and prognostic parameters.

Gastrointestinal Kanserlerden Gelişen Beyin Metastazı Olan Hastalarda Stereotaktik Radyocerrahiye Yanıtın ve Sağkalım Sonuçlarının Değerlendirilmesi

Aim: Gastrointestinal cancers rarely metastasize to the brain and constitute 4-8% of all brain metastases (BM). Survival is generally poor for BM from gastrointestinal cancers and stereotactic radiosurgery (SRS) is frequently used in its management. Since the data are still insufficient due to their rare presentation, we aim to analyze the clinical results of patients who underwent SRS for BM due to gastrointestinal cancers.
 Material and Method: We retrospectively reviewed patients with BM from gastrointestinal cancers who received robotic SRS with CyberKnife at our institute from October 2013 to December 2022. Clinical characteristics and treatment outcomes were recorded. Study endpoints were local control rates, distant brain control rates, and overall survival (OS).
 Results: A total of 61 BM were detected in 42 patients. The median clinical follow-up time was 7 (0.5-36) months. Nine lesions progressed in the irradiated area, 14 new lesions were observed outside the irradiated area. The local control rate was 85.1% and the distant brain control rate was 77%. The median OS was 8 months; 12-month and 24-month OS were 31.6% and 10.5%, respectively. Patients with high performance status had better OS (p=0.016). The prognostic scoring scales RPA and GI-GPA were both associated with OS (p=0.049, p=0.002). Multivariate analysis found a significant association between GI-GPA classes and OS (p=0.011). 
 Conclusion: We obtained comparable results in terms of local control, distant brain control and OS in this challenging patient population. The use of GI-GPA prognostic scoring scales in routine practice will guide the selection of the most appropriate patient for SRS.

PO-1643 Towards automated treatment planning for robotic stereotactic radiosurgery

PO-1643 Towards automated treatment planning for robotic stereotactic radiosurgery

Long-term follow-up results of spine tumor treatment using high-dose radiotherapy after 3-dimensional-printed vertebral bodies implantation.

To investigate the long-term safety and efficacy of high-dose radiotherapy after 3D-printed vertebral body implantation in the treatment of spinal tumors. Thirty-three participants were recruited between July 2017 and August 2019. 3D-printed vertebral bodies were implanted in each participant, followed by postoperative robotic stereotactic radiosurgery at a dose of 35-40 Gy/5f. The tolerance of the 3D-printed vertebral body and the participant to the high-dose radiotherapy were evaluated. In addition, the local control of tumor and the local progression-free survival of the study participants following 3D-printed vertebral body implantation and high-dose radiotherapy were measured as indexes of effectiveness. Of the 33 participants included in the study, 30, including three participants (10%) with esophagitis of grade 3 or above and two participants (6.7%) with advanced radiation nerve injury, successfully underwent postoperative high-dose radiotherapy. The median follow-up was 26.7 months, and IQR was 15.9 months. Most participants had primary bone tumors with 27 cases (81.8%), and the rest had bone metastases in six cases (18.2%). After high-dose radiotherapy, the 3D-printed vertebrae maintained good vertebral stability and exhibited histocompatibility, without implant fractures. The local control rates were 100%, 88%, and 85% 6 months, 1 year, and 2 years after high-dose radiotherapy, respectively. Tumors recurred in four participants (12.1%) during the follow-up period. The median local progression-free survival after treatment was 25.7 months, with a range of 9.6-33.0 months. High-dose radiotherapy for spinal tumors after 3D-printed vertebral body implantation is feasible, elicits low toxicity, and yields satisfactory tumor control.

Use of dose-area product to assess plan quality in robotic radiosurgery

PurposeIn robotic stereotactic radiosurgery (SRS), optimal selection of collimators from a set of fixed cones must be determined manually by trial and error. A unique and uniformly scaled metric to characterize plan quality could help identify Pareto-efficient treatment plans. MethodsThe concept of dose-area product (DAP) was used to define a measure (DAPratio) of the targeting efficiency of a set of beams by relating the integral DAP of the beams to the mean dose achieved in the target volume. In a retrospective study of five clinical cases of brain metastases with representative target volumes (range: 0.5–5.68 ml) and 121 treatment plans with all possible collimator choices, the DAPratio was determined along with other plan metrics (conformity index CI, gradient index R50%, treatment time, total number of monitor units TotalMU, radiotoxicity index f12, and energy efficiency index η50%), and the respective Spearman's rank correlation coefficients were calculated. The ability of DAPratio to determine Pareto efficiency for collimator selection at DAPratio < 1 and DAPratio < 0.9 was tested using scatter plots. ResultsThe DAPratio for all plans was on average 0.95 ± 0.13 (range: 0.61–1.31). Only the variance of the DAPratio was strongly dependent on the number of collimators. For each target, there was a strong or very strong correlation of DAPratio with all other metrics of plan quality. Only for R50% and η50% was there a moderate correlation with DAPratio for the plans of all targets combined, as R50% and η50% strongly depended on target size. Optimal treatment plans with CI, R50%, f12, and η50% close to 1 were clearly associated with DAPratio < 1, and plans with DAPratio < 0.9 were even superior, but at the cost of longer treatment times and higher total monitor units. ConclusionsThe newly defined DAPratio has been demonstrated to be a metric that characterizes the target efficiency of a set of beams in robotic SRS in one single and uniformly scaled number. A DAPratio < 1 indicates Pareto efficiency. The trade-off between plan quality on the one hand and short treatment time or low total monitor units on the other hand is also represented by DAPratio.

Factors Associated with Hemorrhage of Melanoma Brain Metastases after Stereotactic Radiosurgery in the Era of Targeted/Immune Checkpoint Inhibitor Therapies.

Simple SummaryMelanoma brain metastases (MBM) have a high propensity for hemorrhage (HA) after treatment. Our retrospective analysis evaluated factors associated with HA of MBM after robotic stereotactic radiosurgery (SRS) in the era of modern systemic therapy, and to the best of our knowledge, this is the first study focusing on this side effect. A total of 55 patients with 279 MBM were treated. The use of anticoagulants was the only predictive factor, both for radiologically evident HA and HA causing grade 3 toxicity. The interval between the administration of systemic therapy and SRS was also significant with regard to HA causing grade 1 toxicity, but it appears that the combination was safe, at least concerning grade 3 toxicity. We believe that our study is a useful contribution to the current literature, as it provides insights regarding the factors that correlate with HA.We aimed to evaluate the factors associated with hemorrhage (HA) of melanoma brain metastases (MBM) after Cyberknife stereotactic radiosurgery (SRS) in the modern era of systemic therapy. A total of 55 patients with 279 MBM were treated in 93 fractions. The median age, SRS dose, radiological follow-up, and time to HA were 60.4 years, 20 Gy, 17.7 months, and 10.7 months, respectively. Radiologically evident HA was documented in 47 (16.8%) metastases. Of the 55 patients, 25 (45.4%) suffered an HA. Among those, HA caused grade 3 toxicity in 10 patients (40%) and grade 1 symptoms in 5 patients (20%). Ten patients (40%) with HA experienced no toxicity. Logistic regression revealed the use of anticoagulants and the administration of systemic therapy within 7/15 days from SRS to be predictive for HA. When considering the HA causing grade 3 symptomatology, only the use of anticoagulants was significant, with the delivery of whole brain radiation therapy (WBRT) before the HA narrowly missing statistical significance. Our retrospective analysis showed that the administration of modern systemic therapy within 7/15 days from SRS may contribute to HA of MBM, though it appears safe, at least concerning grade 3 toxicity. The use of anticoagulants by the time of SRS significantly increased the risk of HA.

Propensity Score-Matched Analysis of Single Fraction Robotic Radiosurgery Versus Open Partial Nephrectomy in Renal Cell Carcinoma: Oncological Outcomes.

IntroductionHigh-dose local stereotactic robotic radiosurgery (RRS) is a non-invasive alternative to surgery in renal masses and selected patients. We have, so far, limited its use to the elderly and patients at high risk from surgery. In this study, we matched patients with renal tumors who were treated with single fraction RRS to patients who underwent open partial nephrectomy (OPN).MethodsBetween January 2009 and December 2017, we included 571 consecutive patients undergoing OPN and 99 patients who underwent RRS in this retrospective analysis. Patients had to have a follow-up of at least six months and we were able to match 35 with a propensity score. Matching criteria were Eastern Cooperative Oncology Group (ECOG) status, age, clinical tumor, nodes, and metastases (TNM), and tumor diameter. Tumor response, renal function, survival, and adverse events were evaluated every three months until progression or death.ResultsMedian age was 65 years for RRS (range 58-75) and 71 (range 56-76) for OPN (p=0.131). Median diameter of renal tumors was 2.8 cm (range 2.4-3.9) for RRS and 3.5 cm (2.8-4.5) for OPN, p=0.104. Median follow-up was 28.1 months (range 6.0-78.3 months). Local tumor control nine months after RRS and OPN was 98% (95% CI: 89-99%). Renal function remained stable with a median creatinine clearance (Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI)) at baseline of 76.8mlmin/1.73m2 (range 25.3-126.3) and 70.3ml/min/1.73m2 (range 18.6-127.3) at follow-up (p=0.89). Median overall survival was not reached. No difference in overall survival (OS) was seen in RRS compared to OPN (p=0.459).ConclusionsSingle fraction RRS is an alternative to OPN in patients unfit for surgery. Oncological and functional results are comparable to those of OPN. Further studies are needed to determine long-term results and limits of RRS in this setting and in younger patients.

Is fractionated robotic stereotactic body radiosurgery optional salvage treatment for the re-irradiation of locally recurrent nasopharyngeal carcinoma?

Recurrent nasopharyngeal carcinoma (NPC) after previous radiation therapy is a significant problem. This study was to determine the potential benefits from re-irradiation by fractionated stereotactic body radiotherapy (FSRT) on survival benefits and effects of severe late toxicities. Between 2009 and 2018, treatment outcomes were evaluated retrospectively in 26 patients with locally recurrent NPC treated using FSRT with CyberKnife. Five patients who had metastatic disease and one who had second recurrence were excluded from the study, and the remaining 20 patients were analyzed. The median age was 52 years (range, 28-80 years); re-treatment T stage was as follows: 6 (30%) - T2, 5 (25%) - T3, and 9 (45%) - T4. The median time from initial RT to recurrence was 22 months (range, 8-159 months). The median re-irradiation FSRT dose was 30 Gy in 5 fractions. The median follow-up was 44 months; the overall survival (OS), local failure-free survival, and disease progression-free survival rates at 3 years were 89%, 73%, and 53%, respectively. All patients were evaluated for response after treatment: 9 (45%) had complete, 3 (15%) had partial, and 6 (30%) had no response. Univariate analysis demonstrated that higher cumulative total radiotherapy dose, gross tumor volume, and recurrent time interval were prognostic factors for local failure-free survival. The recurrent time interval was also an independent factor for progression-free survival and OS. The incidence of temporal lobe necrosis and trismus was 10% and 20%, respectively. One patient had Grade 5 toxicity to treatment-related bleeding. Tumor dose coverage is important for treating recurrent NPC, and treatment-related mortality was vascular in nature. FSRT is a promising treatment modality for recurrent NPC.

Cyberknife Radiosurgery for the Treatment of Head and Neck Cancer: A Systematic Review.

Cyberknife radiosurgery is a frameless stereotactic robotic radiosurgery which has shown to deliver better treatment outcomes in the treatment of advanced head and neck (H&N) carcinomas, especially in previously irradiated and recurrent cases. The aim of the study was to perform a systematic review of the available data on the outcomes of Cyberknife radiosurgery for treatment of head and neck cancer and to evaluate its collective outcomes. This systematic review was registered with the university with the registration no. FRP/2019/63 and was approved by the Institutional Review Board (RC/IRB/2019/132). Literature search was performed in the following: PubMed, Science direct, SciELO, MyScienceWork, Microsoft Academ EMBASE, Directory of Open Access Journals, and Cochrane databases with the keywords “Cyberknife,” “oral cancer,” “oropharyngeal cancer,” and “head and neck cancer” and data was extracted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The records identified were 147 manuscripts. Excluded articles included 5 duplicate articles, 33 abstracts, 101 full text articles due to being off-topic, case reports, review, non-English, 1 survey, and 2 other articles containing data extracted from a main study which was already included. A total of 5 articles were evaluated for qualitative synthesis. The mean dose of Cyberknife radiosurgery delivered for previously irradiated recurrent H&N carcinoma patients was 34.57 Gy, with a mean sample size of 5 studied during the period of 2000 to 2016. The available evidence from the systematic review indicates that Cyberknife can be an efficacious treatment option for recurrent previously irradiated H&N carcinoma, especially for nonresectable tumors. There is paucity of homogenous data and studies in this arena; hence, meta-analysis could not be performed. Further standardized studies are essential, especially where the treatment of H&N carcinoma is considered.

PO-1222 Robotic Stereotactic Radiosurgery for locally advanced pancreatic cancer-Local control and tolerance

PO-1222 Robotic Stereotactic Radiosurgery for locally advanced pancreatic cancer-Local control and tolerance

Long-term outcomes of 170 brain arteriovenous malformations treated by frameless image-guided robotic stereotactic radiosurgery: Ramathibodi hospital experience.

This study was conducted to report long-term outcomes of the frameless robotic stereotactic radiosurgery (SRS) for brain arteriovenous malformation (AVM) at Ramathibodi Hospital.Retrospective data of patients with brain AVM (bAVM), who underwent CyberKnife SRS (CKSRS) at Ramathibodi Hospital from 2009 to 2014, were examined. Exclusion criteria were insufficient follow-up time (<36 months) or incomplete information. Patients’ demographics, clinical presentation, treatment parameters, and results were analyzed. Excellent outcome was defined as AVM obliteration without a new neurological deficit. Risk factors for achieving excellent outcome were assessed.From a total of 277 CKSRS treatments for bAVM during the 6 years, 170 AVMs in 166 patients met the inclusion criteria. One hundred and thirty-nine cases (81.76%) presented with hemorrhages from ruptured bAVMs. Almost two-thirds underwent embolization before radiosurgery. With the median AVM volume of 4.17 mL, three-quarters of the cohort had single-fraction CKSRS, utilizing the median prescribed dose of 15 Gray (Gy). In the multisession group (25.29%), the median prescribed dose and the AVM volume were 27.5 Gy and 22.3 mL, respectively. An overall excellent outcome, at a median follow-up period of 72.45 months, was observed in 99 cases (58.24%). Seven AVMs (4.12%) ruptured after CKSRS but 1 patient suffered a new neurological deficit. Two patients (1.18%) were classified into the poor outcome category but there were no deaths. Negative factors for excellent outcome, by multivariate regression analysis, were the male sex and multisession SRS delivery, but not age, history of AVM rupture, previous embolization, or AVM volume.Despite relatively larger bAVM and utilizing a lower prescribed radiation dose, the excellent outcome was within the reported range from previous literature. This study offers one of the longest follow-ups and the largest cohorts from the frameless image-guided robotic SRS community.

Clinical and volumetric predictors of local control after robotic stereotactic radiosurgery for cerebral metastases: active systemic disease may affect local control in the brain.

BackgroundThe aim of the study was to assess the association between physical and biological dose normalized to volume of the metastatic tumor as well as clinical factors with local control in patients with brain metastases who underwent robotic stereotactic radiosurgery.Patients and methodsA cohort of 69 patients consecutively treated with robotic radiosurgery between 2011 and 2016 was analyzed. The patients were treated with either single fraction radiosurgery or hypofractionated regimens. Biologically effective dose (BED) was calculated assuming alpha/beta value = 10 and both physical dose and BED were normalized to the tumor volume to allow dose-volume effect evaluation. Moreover, clinical and treatment-related variables were evaluated to asses association with local control.ResultsA total of 133 tumors were irradiated and their volumes ranged between 0.001 and 46.99 cm3. Presence of extracranial progression was associated with worse local control whereas higher total dose, BED10 > 59 Gy and single metastasis predicted statistically significantly better local outcome. BED10/cm3 > 36 Gy, and BED2 > 60 Gy negatively affected local control in univariate analysis. In multivariate analysis performed on all these variables, presence of a single metastasis, BED10 > 59 Gy and extracranial progression retained their significance. Excluding a priori the BED2/ cm3 parameter resulted with a Cox model confirming significance of all remaining variables.ConclusionsHypofractionated treatment schemes have similar efficiency to single fraction treatment in terms of local control and the effect depends on BED irrespective of fractionation schedule. Effective control of extracranial sites of the disease is associated with higher probability of local control in the brain which in turn is consistently lower in patients with multiple lesions.

Comprehensive Prognostic Index (CPI): A New Prognostic Index for Patients Treated with Stereotactic Robotic Radiotherapy for Brain Metastases

The goal of this study was to analyze potential prognostic factors in a population of patients treated with robotic radiosurgery for brain metastases irrespective of the location of the primary tumor, to create a simple prognostic score that can be used even in patients without full diagnostic workup. The indices currently used are either created based on population of patients with limited number of metastases or are diagnosis-specific and thus, cannot be used for certain populations of patients or require results of sophisticated test, not always available at the time of clinical decision making. A retrospective analysis of 142 patients with brain metastases treated with stereotactic robotic radiosurgery or hypofractionated radiotherapy was performed. The patients had 1 – 9 metastases (single metastasis – 56.4%, two – 22.1%, three or more – 21.5%) and were treated with single fraction or with hypofractionated (2-5 fractions) stereotactic radiosurgery with doses ranging between 5 Gy and 30 Gy. Volume of the lesions was calculated using linear dimensions of the tumors (CC, LR, AP) and 4/3*pi *(CC/2)*(LR/2)*(AP/2) formula for volume of a spheroid, to avoid the need for volumetric analysis of diagnostic images. Kaplan-Meier method and log-rank test were used to analyze survival. Variables significantly associated with overall survival in univariate analysis were included into Cox multivariate analysis. The validity of the model was tested with the bootstrap method and the variables from the final model were used to construct a new prognostic index by assigning points according to the impact of a certain variable on overall survival. Prognostic scores existing to date were also tested. In the multivariate analysis four factors: Karnofsky Performance Status (KPS), number of brain metastases, volume of the largest metastasis and presence of extracerebral metastases, were independent predictors of survival. Total scores ranged from 0 to 12 points, and patients were divided into four groups based on median survival of each subgroup. The median survival was: 18.8 months for 0-1 points, 16.9 months for 2-3 points, 5.6 months for 3-4 points, and 4.9 months for ≥6 points (p < 0.001). The prognostic value of all indices was confirmed. The most significant differences between classes were observed in the Score Index for Radiosurgery (SIR) and our new Comprehensive Prognostic Index (CPI) – p = 0.00021 and p = 0.00033 respectively. The new prognostic index is simple to calculate and has strong prognostic value in heterogeneous population of patients with various number of brain metastasis, but its value requires confirmation in another cohort.Abstract 3570; TablePrognostic factorHR95% CIp valueKPS0.960.93 – 0.980.000068Number of brain metastases1.191.03 – 1.370.019Volume of the largest lesion1.021.01. – 1.040.0037Extracerebral metastases0.510.34 – 0.780.0017 Open table in a new tab

Tumor-dose-rate variations during robotic radiosurgery of oligo and multiple brain metastases

PurposeFor step-and-shoot robotic stereotactic radiosurgery (SRS) the dose delivered over time, called local tumor-dose-rate (TDR), may strongly vary during treatment of multiple lesions. The authors sought to evaluate technical parameters influencing TDR and correlate TDR to clinical outcome.Material and methodsA total of 23 patients with 162 oligo (1–3) and multiple (>3) brain metastases (OBM/MBM) treated in 33 SRS sessions were retrospectively analyzed. Median PTV were 0.11 cc (0.01–6.36 cc) and 0.50 cc (0.12–3.68 cc) for OBM and MBM, respectively. Prescription dose ranged from 16 to 20 Gy prescribed to the median 70% isodose line. The maximum dose-rate for planning target volume (PTV) percentage p in time span s during treatment (TDRs,p) was calculated for various p and s based on treatment log files and in-house software.ResultsTDR60min,98% was 0.30 Gy/min (0.23–0.87 Gy/min) for OBM and 0.22 Gy/min (0.12–0.63 Gy/min) for MBM, respectively, and increased by 0.03 Gy/min per prescribed Gy. TDR60min,98% strongly correlated with treatment time (ρ = −0.717, p < 0.001), monitor units (MU) (ρ = −0.767, p < 0.001), number of beams (ρ = −0.755, p < 0.001) and beam directions (ρ = −0.685, p < 0.001) as well as lesions treated per collimator (ρ = −0.708, P < 0.001). Median overall survival (OS) was 20 months and 1‑ and 2‑year local control (LC) was 98.8% and 90.3%, respectively. LC did not correlate with any TDR, but tumor response (partial response [PR] or complete response [CR]) correlated with all TDR in univariate analysis (e.g., TDR60min,98%: hazard ration [HR] = 0.974, confidence interval [CI] = 0.952–0.996, p = 0.019). In multivariate analysis only concomitant targeted therapy or immunotherapy and breast cancer tumor histology remained a significant factor for tumor response. Local grade ≥2 radiation-induced tissue reactions were noted in 26.3% (OBM) and 5.2% (MBM), respectively, mainly influenced by tumor volume (p < 0.001).ConclusionsLarge TDR variations are noted during MBM-SRS which mainly arise from prolonged treatment times. Clinically, low TDR corresponded with decreased local tumor responses, although the main influencing factor was concomitant medication.

RADICAL PROSTATECTOMY AND ROBOTIC RADIOSURGERY AS TREATMENT OPTIONS FOR LOCALIZED PROSTATE CANCER

Purpose: to compare immediate, short-term and long-term treatment outcomes after radical prostatectomy and robotic radiosurgery in patients with localized prostate cancer. Material and methods. The study included 2 groups of patients. Group I patients (n=80) underwent radical surgery (nerve-sparing prostatectomy). Group II patients (n=102) underwent KiberKnife stereotactic robotic radiotherapy. Results. Immediate treatment outcomes after both radical prostatectomy and robotic radiosurgery did not demonstrate increased number of postoperative complications and severe radiation-induced injuries. The PSA level decreased and reached a nadir PSA level immediately after radical prostatectomy. After stereotactic radiation therapy, the PSA level decreased gradually every three months, reaching a nadir within a year. In the group of patients receiving CyberKnife treatment, changes in the prostate volume affected the quality of urination, which was confirmed by the assessment of the volume of residual urine. When comparing the quality of urination in treatment groups using the IPSS scale, the values were comparable. No differences in the 1-year disease-free survival rates between groups were found. However, 60 months later, disease free survival rate was higher by 8.2 % in patients treated with radiosurgery than in patients who underwent radical prostatectomy (p&lt;0.005). No differences in the 1-year cancer-specific survival rates between the groups were found. In patients, who underwent radiosurgery, the 5-year cancer-specific survival rate was 96.3 % (3.7 % higher than that observed in patients, who underwent radical surgery, p&lt;0.005). Conclusion. High 5-year survival rates in patients with localized prostate cancer indicate that both radical prostatectomy and KiberKnife stereotactic robotic radiosurgery are safe and effective treatment options.

Hypofractionated Robotic Stereotactic Radiosurgery for Vagal Paragangliomas: A Novel Treatment Strategy for Cranial Nerve Preservation.

To provide the first description of hypofractionated stereotactic radiosurgery (SRS) and evaluate tumor control and safety for vagal paragangliomas (VPs), which begin at the skull base but often have significant extracranial extension. Retrospective chart review. Tertiary-referral neurotology and neurosurgery practice. Five VPs in 4 patients (all male, ages 15-56 years) underwent SRS between 2010 and 2018. Outcome measures included tumor dimensions on serial imaging, cranial nerve function, and radiation side effects. CyberKnife hypofractionated SRS was performed. The prescription dose was 24 or 27 Gy (maximum dose 33.4 Gy; range, 29.3-35.5 Gy) delivered in 3 equal fractions. The mean isodose line was 79% (range, 76%-82%). Four VPs were treated primarily, and 1 tumor underwent SRS to treat regrowth 2 years after microsurgical subtotal resection via the modified infratemporal fossa approach. The treatment volume ranged from 8.81 to 86.3 cm3 (mean, 35.7 cm3). All demonstrated stable size (n = 3) or regression (n = 2) at last follow-up, 63 to 85 months after SRS (mean, 76 months). One patient had stable premorbid vocal fold paralysis from a prior ipsilateral glomus jugulare tumor resection. All others demonstrated normal vagal function following SRS. Treatment-related side effects, including dysgeusia (n = 1), mucositis (n = 1), and neck soft-tissue edema (n = 2), were self-limited. Hypofractionated SRS appears to be both safe and effective for treating VPs, including large-volume and predominantly extracranial tumors, while preserving vagal function. SRS should be considered as a cranial nerve preservation option, especially in settings of contralateral lower cranial nerve deficits or in those with multiple paragangliomas risking both vagal nerves.

Geometric inaccuracy and co-registration errors for CT, DynaCT and MRI images used in robotic stereotactic radiosurgery treatment planning

PurposeTo measure the combined errors due to geometric inaccuracy and image co-registration on secondary images (dynamic CT angiography (dCTA), 3D DynaCT angiography (DynaCTA), and magnetic resonance images (MRI)) that are routinely used to aid in target delineation and planning for stereotactic radiosurgery (SRS). MethodsThree phantoms (one commercial and two in-house built) and two different analysis approaches (commercial and MATLAB based) were used to quantify the magnitude of geometric image distortion and co-registration errors for different imaging modalities within CyberKnife’s MultiPlan treatment planning software. For each phantom, the combined errors were reported as a mean target registration error (TRE). The mean TRE’s for different intramodality imaging parameters (e.g., mAs, kVp, and phantom set-ups) and for dCTA, DynaCTA, and MRI systems were measured. ResultsOnly X-ray based imaging can be performed with the commercial phantom, and the mean TRE ± standard deviation values were large compared to the in-house analysis using MATLAB. With the 3D printed phantom, even drastic changes in treatment planning CT imaging protocols did not greatly influence the mean TRE (<0.5 mm for a 1 mm slice thickness CT). For all imaging modalities, the largest mean TRE was found on DynaCT, followed by T2-weighted MR images (albeit all <1 mm). ConclusionsThe user may overestimate the mean TRE if the commercial phantom and MultiPlan were used solely. The 3D printed phantom design is a sensitive and suitable quality assurance tool for measuring 3D geometric inaccuracy and co-registration errors across all imaging modalities.

Stereotactic Radiosurgery for Large Benign Intracranial Tumors

Historically, it is stated that large intracranial tumors, herein defined as a maximum dimension of ≥3 cm or tumor volume ≥14.2 cm3, are not candidates for stereotactic radiosurgery (SRS). We report outcomes of patients with large benign intracranial tumors treated with SRS. With institutional review board approval, we retrospectively identified 74 patients with large benign intracranial tumors (59 meningiomas, 9 vestibular schwannomas, and 6 glomus jugulare tumors) treated with robotic SRS (2007-2018). Patients received definitive SRS in 47.3% of the cases, adjuvant to surgical resection in 44.6%, and salvage after past radiation treatment in 8.1%. A median tumor volume of 16.0 cm3 (range, 10.1-65.5 cm3) received a median dose of 24.0 Gy (range, 14.0-30.0 Gy) in a median of 3 fractions (range, 1-5), for a median single fraction equivalent dose (with alpha/beta of 3) of 14.8 Gy (range, 11.3-18.0 Gy). The Kaplan-Meier estimate of tumor local control (LC) was calculated from date of SRS. With a median clinical follow-up of 32.8 months (range, 0.6-125.9 months) and median radiologic follow-up of 28.5 months (range, 0.6-121.4 months), LC was 96.5% (95% confidence interval, 92.4%-100%) at 3 years and 91.7% (95% confidence interval, 87.6%-95.7%) at 5 years. Adverse radiation effect (ARE) was seen in 10 patients (13.5%) at a median of 13.5 months (range, 7.8-34.5 months). ARE occurred in 9% of those with prior treatment compared with 5% who were radiation-naïve (P= 0.23). With 236.4 person-years of follow-up, no secondary malignancies were seen. Despite the historical adage, we find that SRS provides high rates of LC for these large tumors, with rates of ARE similar to historical reports of SRS for smaller benign tumors.