CyberKnife Stereotactic Body Radiation Therapy Research Articles

Simultaneous Focal Boost With Stereotactic Radiation Therapy for Localized Intermediate- to High-Risk Prostate Cancer: Primary Outcomes of the SPARC Phase 2 Trial

Purpose: Dose escalated radiotherapy is associated with better biochemical control at the expense of toxicity. Stereotactic body radiotherapy (SBRT) with dose escalation to the dominant intraprostatic lesion (DIL) provides a logical approach to improve outcomes in high-risk disease whilst limiting toxicity. This study evaluated the toxicity and quality of life (QOL) with CyberKnife-based SBRT and simultaneous integrated boost in localised prostate cancer. Methods and Materials: Eligible participants included newly diagnosed, biopsy-proven unfavourable intermediate to high risk localised prostate cancer (at least one of the following: Gleason ≥ 4+3, MRI defined T3a N0, PSA ≥ 20) with up to two MRI-identified DILs. Participants received 36.25Gy in 5 fractions on alternative days with a simultaneous boost to DIL up to 47.5Gy as allowed by organs at risk constraints delivered by CyberKnife. All participants received androgen deprivation therapy. The primary outcome measure was acute grade 2 + genitourinary toxicity. Acute and late genitourinary and gastrointestinal toxicity using RTOG scoring, biochemical parameters, IPSS, IIEF5, EQ5D QOL outcomes were assessed. Results: Between 2013 and 2023, 20 participants were enrolled with a median follow-up of 30 months. The median D95 dose to DIL was 47.43Gy. Cumulative acute grade 2 + genitourinary and gastrointestinal toxicity was 25% and 30%, respectively. One patient developed acute grade 3 genitourinary toxicity (5%). There is no late grade 3 genitourinary or gastrointestinal toxicity to date. IPSS score and urinary QOL scores recovered to baseline by 6months. Patient-reported outcomes showed no significant change in EQ-5D QOL scores at 12 weeks and 1 year. There are no cases of biochemical relapse reported to date. Conclusions: CyberKnife SBRT delivered dose of 36.25Gy to the prostate with a simultaneous integrated boost up to 47.5Gy is well tolerated. Acute and late GU and GI toxicity rates are comparable to other contemporary SBRT trials and series with focal boost.

Abscopal effect in metastatic breast cancer treated with stereotactic body radiotherapy in the absence of immunotherapy.

In this study, we aimed to assess the abscopal effect (AE) after CyberKnife stereotactic body radiotherapy (SBRT) in metastatic breast cancer patients without immunotherapy. We reviewed breast cancer patients who received SBRT with a fraction size of ≥ 6 Gy for metastatic lesions between July 2008 and December 2021. We selected patients who had at least one measurable extracranial lesion in addition to SBRT target lesions and were not treated with immunotherapy. A total of 40 SBRT cases from 34 patients were included in the analysis. The AE was defined as occurring before the overall progression of the disease, regardless of the use of systemic treatment. The median follow-up duration was 16.4 months. Among 40 SBRT cases, the AE was observed in 10 (25.0%) with a median interval of 2.1 months. Of these lesions, 70.0% did not progress for one year. In multivariate logistic regression analysis, no change in systemic treatment after SBRT was significantly associated with an increase in the AE (odds ratio [OR] = 1.428, 95% confidence interval [CI] = 1.108 - 1.841, p = 0.009). A post-SBRT neutrophil-to-lymphocyte ratio (NLR) of < 2 marginally increased the AE (OR = 1.275, 95% CI = 0.998 - 1.629, p = 0.060). However, a high SBRT dose and large planning target volume did not (p = 0.858 and 0.152, respectively) in univariate analysis. One out of four patients experienced the AE after SBRT in the absence of immunotherapy. The AE could occur more frequently when systemic treatment remains unchanged, and patients have a low NLR after SBRT.

Intrafraction motion during CyberKnife® prostate SBRT: impact of imaging frequency and patient factors

To determine the relationship between imaging frequencies and prostate motion during CyberKnife stereotactic body radiotherapy (SBRT) for prostate cancer. Intrafraction displacement data for 331 patients who received treatment with CyberKnife for prostate cancer were retrospectively analysed. Prostate positions were tracked with a large variation in imaging frequencies. The percent of treatment time that patients remained inside various motion thresholds for both real and simulated imaging frequencies was calculated.Results: 84,920 image acquisitions over 1635 fractions were analysed. Fiducial distance travelled between consecutive images were less than 2, 3, 5, and 10mm for 92.4%, 94.4%, 96.2%, and 97.7% of all consecutive imaging pairs respectively. The percent of treatment time that patients received adequate geometric coverage increased with more frequent imaging intervals. No significant correlations between age, weight, height, BMI, rectal, bladder or prostate volumes and intrafraction prostate motion were observed. There are several combinations of imaging intervals and movement thresholds that may be suitable for consideration during treatment planning with respect to imaging and calculation of the marginbetween the clinical target volume and planning target volume (CTV-to-PTV), resulting in adequate geometric coverage for approximately 95% of treatment time. Rectal toxicities and treatment duration need to be considered when implementing combinations clinically.

CyberKnife Stereotactic Body Radiotherapy as a treatment option for renal cell carcinoma: The complex case of a patient with unilateral renal agenesis

Surgery is the standard treatment for local renal cell carcinoma (RCC), but many patients are medically inoperable and local approaches such as radiofrequency ablation and cryoablation may be limited to smaller tumours. Conventional radiotherapy has not been effective in RCC, but higher dose-per-fraction radiotherapy has shown high local control rates accompanied by low toxicity. This is particularly important in the case of patients with a solitary kidney, either congenital or due to previous surgical history. Here, we present the case of a 68-year-old female patient with congenital right renal agenesis diagnosed with clear cell renal cell carcinoma in her left (solitary) kidney. Originally, the patient started treatment with sunitinib but 9 months later, due to important side effects, it was decided to treat her with CyberKnife Stereotactic Body Radiotherapy (SBRT) using a prescription dose of 45 Gy in five sessions. Ten months after her treatment, PET/CT images showed no signs of local hypermetabolism and more than a year after treatment, kidney function remains stable. Curiously, PET/CT also revealed the presence of percutaneous tumour seeding probably after renal biopsy. This case supports the growing body of evidence showing the value of Stereotactic Body Radiotherapy for renal cancer, especially for medically inoperable renal tumours in a solitary kidney.

Real-time Prostate Gland Motion and Deformation During CyberKnife Stereotactic Body Radiation Therapy

Real-time Prostate Gland Motion and Deformation During CyberKnife Stereotactic Body Radiation Therapy

A 54 Gy in three fractions of stereotactic body radiotherapy using CyberKnife for T1b-2aN0M0 pathologically confirmed non-small cell lung cancer

Abstract Objective Optimal dose-fractionation regimen of stereotactic body radiotherapy for peripheral early-stage non-small cell lung cancer remains unclear. We retrospectively investigated outcomes of stereotactic body radiotherapy using CyberKnife at 54 Gy in three fractions in 26 patients (median age: 76 years) with pathologically confirmed T1b–T2aN0M0 non-small cell lung cancer. Methods A 54 Gy in three fractions was prescribed to cover the 99% of gross tumor volume. We estimated cumulative local control, progression-free survival and overall survival rates (Kaplan–Meier method), and toxicity (Common Toxicity Criteria for Adverse Events, version 5.0). Results All the tumors were located at peripheral area of lung. Mean distance from chest wall to tumor was 6.5 mm (range: 0–32 mm). The patients’ pathological diagnoses were: adenocarcinoma: n = 18, squamous cell carcinoma: n = 7 and non-small cell carcinoma: n = 1. Their stages were T1b: n = 9, T1c: n = 14 and T2a: n = 3. Median follow-up was 24 months (range: 6–54). Cumulative 2-year effect rates were local control: 100%, progression-free survival 70% and overall survival: 92%. Twenty patients developed grade one radiation pneumonitis, but grade 2 or greater radiation pneumonitis was not observed. Conclusions We found CyberKnife-stereotactic body radiotherapy for pathologically confirmed T1b–T2aN0M0 non-small cell lung cancer to be effective and safe. However, these results should be validated with a larger patient cohort and prospective follow-up monitoring.

Stereotactic body radiotherapy using a hydrogel spacer for localized prostate cancer: A dosimetric comparison between tomotherapy with the newly‐developed tumor‐tracking system and cyberknife

PurposeWith a new tumor‐tracking system (Synchrony®) for tomotherapy (Radixact®), the internal and set‐up margins can be tightened, like cyberknife (CyberKnife®), in the planning of stereotactic body radiotherapy (SBRT) for prostate cancer. Recently, the usefulness of placing a hydrogel spacer between the prostate and rectum has been established in prostate radiotherapy. We evaluated the characteristics of tomotherapy plans with the tumor‐tracking system and compared them with cyberknife SBRT plans for localized prostate cancer using a hydrogel spacer.MethodsIn 20 patients, two plans were created and compared using tomotherapy and cyberknife. All patients underwent hydrogel spacer injection behind the prostate before simulation CT and MRI for fusion. For all plans, 36.25 Gy in 7.25‐Gy fractions for a minimum coverage dose of 95% of planning target volume (PTV) (D95%) was prescribed. The D99% of PTV and D0.1 ml of the PTV, urethra, bladder, and rectum were intended to be > 90%, 110–130%, 100–110%, <110%, and <100%, respectively, of the prescribed doses.ResultsAll plans using tomotherapy and cyberknife achieved the intended dose constraints. The cyberknife plans yielded better median PTV‐V110% (volume of PTV covered by 110% isodose line, 54.8%), maintaining lower median D0.1 ml of the urethra (37.5 Gy) and V80% of the bladder (11.0 ml) compared to the tomotherapy plans (39.0%; p < 0.0001, 38.2 Gy; p < 0.0001, and 18.3 ml; p < 0.0001, respectively). The tomotherapy plans were superior to the cyberknife plans for the rectum (V80% = 0.4 vs. 1.0 ml, p < 0.001; D1ml = 26.4 vs. 29.0 Gy, p = 0.013).ConclusionsOur results suggested that tomotherapy with the tumor‐tracking system has reasonable potential for SBRT for localized prostate cancer using a hydrogel spacer.

Efficacy and Prognostic Factors of Trans-Arterial Chemoembolization Combined With Stereotactic Body Radiation Therapy for BCLC Stage B Hepatocellular Carcinoma.

PurposeThis study aimed to evaluate the efficacy and safety of trans-arterial chemoembolization (TACE) followed by stereotactic body radiation therapy (SBRT) in treating Barcelona Clinic Liver Cancer (BCLC) stage B hepatocellular carcinoma (HCC) not amenable to resection and radiofrequency ablation (RFA).MethodsFrom February 2012 to January 2017, a total of 57 BCLC stage B HCC patients who were unsuitable candidates for resection and RFA treated with TACE combined with CyberKnife SBRT were included in this retrospective study. Patients underwent TACE for a median of two times (1–5 times) before SBRT. SBRT prescription doses ranged from 30 Gy to 50 Gy in 3–5 fractions.ResultsThe median follow-up time was 42 months. The objective response rate (CR + PR) was 85.9%, and the disease control rate (CR + PR + SD) was 96.5%. The local control (LC) rates were 91.1% and 84.3% at 1 and 2 years, respectively. The 1-, 2-, 3-year overall survival (OS) and the median survival time were 73.2%, 51.4%, 32.4% and 26.6 months, respectively. The 1-, 2-, and 3-year progression-free survival (PFS) were 34.2%, 21.6%, and 9%, respectively, with a median PFS time of 9.7 months. A subgroup analysis was conducted in 32 patients with AFP ≥ 200 ng/ml before TACE. OS was significantly prolonged in those with AFP that decreased by more than 75% than those with AFP that decreased by less than 75% (P = 0.018) after SBRT. The treatment was well tolerated with only one patient (1.8%) developed grade 3 gastrointestinal toxicity, and another patient developed non-classical RILD. In multivariate analysis, tumor length ≥ 10 cm and AFP ≥ 200 ng/ml were independent poor prognostic factors for OS.ConclusionThe combination of TACE and Cyberknife SBRT showed optimal efficacy with acceptable toxicity for BCLC stage B HCC.

Secondary cancer risk from modern external-beam radiotherapy of prostate cancer patients: Impact of fractionation and dose distribution.

Modern radiotherapy (RT) uses altered fractionation, long beam-on time and image-guided procedure. This study aimed to compare secondary cancer risk (SCR) associated with primary field, scatter/leakage radiations and image-guided procedure in prostate treatment using intensity-modulated RT (IMRT), CyberKnife stereotactic body RT (CK-SBRT) in relative to 3-dimensional conformal RT (3D-CRT). Prostate plans were generated for 3D-CRT, IMRT (39 fractions of 2 Gy), and CK-SBRT (five fractions of 7.25 Gy). Excess absolute risk (EAR) was calculated for organs in the primary field using Schneider’s mechanistic model and concept of organ equivalent dose (OED) to account for dose inhomogeneity. Doses from image-guided procedure and scatter/leakage radiations were determined by phantom measurements. The results showed that hypofractionation relative to conventional fractionation yielded lower SCR for organs in primary field (p ≤ 0.0001). SCR was further modulated by dose-volume distribution. For organs near the field edge, like the rectum and pelvic bone, CK-SBRT plan rendered better risk profiles than IMRT and 3D-CRT because of the absence of volume peak in high dose region (relative risk [RR]: 0.65, 0.22, respectively, p ≤ 0.0004). CK-SBRT and IMRT generated more scatter/leakage and imaging doses than 3D-CRT (p ≤ 0.0002). But primary field was the major contributor to SCR. EAR estimates (risk contributions, primary field: scatter/leakage radiations: imaging procedure) were 7.1 excess cases per 104 person–year (PY; 3.64:2.25:1) for CK-SBRT, 9.93 (7.32:2.33:1) for IMRT and 8.24 (15.99:2.35:1) for 3D-CRT (p ≤ 0.0002). We conclude that modern RT added more but small SCR from scatter/leakage and imaging doses. The primary field is a major contributor of risk which can be mitigated by the use of hypofractionation.

A treatment planning study comparison between supine and prone position for different lung tumour locations using CyberKnife TPS

AbstractAim:CyberKnife is the most advanced form of stereotactic body radiotherapy (SBRT) system that uses a robotic arm to deliver highly focused beams of radiation; however, a limitation is that it only irradiates from ceiling to floor direction. In patients with posterior lungs tumour who are positioned supine, normal lung tissue may suffer undesirable radiation injuries. This study compares the treatment planning between the prone set-up and the supine set-up for lung cancer in CyberKnife SBRT to decrease normal lung dose to avoid radiation side effects.Materials and methods:A human phantom was used to generate 108 plans (54 for prone and 54 for supine) using the CyberKnife planning platform. The supine and prone plans were compared in terms of the dosimetric characteristics, delivery efficiency and plan efficiency.Results:For posterior targets, the area of low-dose exposure to normal lungs was smaller in the prone set-up than in the supine set-up. V10 of the lungs was 7·53% and 10·47% (p &lt; 0·001) in the anterior region, and 10·78% and 8·03% (p &lt; 0·001) in the posterior region in the supine and prone set-up plans, respectively.Conclusions:The comparison between the prone set-up and the supine set-up was investigated with regard to target coverage and dose to organs at risk. Our results may be deployed in CyberKnife treatment planning to monitor normal tissue dose by considering patient positioning. This may assist in the design of better treatment plans and prevention of symptomatic radiation pneumonitis in lung cancer patients.

Hepatic Resection Versus Stereotactic Body Radiation Therapy Plus Transhepatic Arterial Chemoembolization for Large Hepatocellular Carcinoma: A Propensity Score Analysis

Background and AimsThere are no comparative studies on the efficacy of hepatic resection (HR) and CyberKnife stereotactic body radiation therapy (CK-SBRT) plus transhepatic arterial chemotherapy embolization (TACE) in the treatment of large hepatocellular carcinoma (HCC). Therefore, this study aimed to compare the efficacy of HR and CK-SBRT+TACE in large HCC.MethodsA total of one hundred and sixteen patients were selected from November 2011 to December 2016. Among them, 50 were allocated to the CK-SBRT+TACE group and 66 were allocated to the HR group. The Kaplan-Meier method was applied to calculate overall survival (OS) and progression-free survival (PFS) rates. Propensity score matching was performed to control for baseline differences between the groups.ResultsThirty-six paired patients were selected from the CK-SBRT+TACE and HR groups. After propensity score matching, the 1-, 2- and 3-year OS rates were 83.3%, 77.8% and 66.7% in the HR group and 80.6%, 72.2% and 52.8% in the CK-SBRT+TACE group, respectively. The 1-, 2- and 3-year PFS rates were 71.6%, 57.3% and 42.3% in the HR group and 66.1%, 45.8% and 39.3% in the CK-SBRT+TACE group, respectively (OS: p=0.143; PFS: p=0.445). Both a high platelet count and low alpha-fetoprotein value were revealed as influencing factors in improving OS and PFS.ConclusionsCK-SBRT+TACE brought local effects that were similar to those of HR in HCC patients with a large and single lesion. Moreover, the liver injury occurrence rate was acceptable in both groups.

Long-term outcome of Stereotactic Body Radiation Therapy for patient with unresectable liver metastases from colorectal cancer

PurposeTo investigate clinical outcome and predicting factors of local failures in patients with colorectal cancer treated for unresectable liver metastases with stereotactic body radiation therapy (SBRT). Methods and materialsWe restrospectively reviewed the medical records of 67 patients treated with the Cyberknife SBRT system for 99 hepatic metastases between January 2007 and December 2015 in our center. In total, 37.5 to 54.0Gy in 3 to 5 fractions were prescribed to the 80% isodose line. Local control (LC), intrahepatic progression incidence, Progression-Free Survival (PFS), Overall Survival (OS) and toxicity were evaluated. ResultsThe median follow-up was 47 months (IQR, 28–59 months). The median OS was 53 months, the 2-year OS and PFS rates were 81.4% and 54.0%. The 1- and 2-year LC rates were 86.6% and 72.4%. In the multivariate analysis, the degree of differentiation was the only prognostic factor for LC (HR 0.31, 95% CI, 0.10–0.98, P=0.046). Margin expansion>5mm was not associated with a better LC (HR 0.72, 95% CI, 0.38–1.37, P=0.317). Performans Status≥2 (HR 3.27, 95% CI, 1.07–9.98, P=0.038), chemotherapy for metastases before SBRT (HR 0.36, 95% CI, 0.18–0.75, P=0.006) and regional lymph node at diagnosis (HR 2.19, 95% CI, 1.09–4.43, P=0.029) were independent prognostic factors for OS. We report 2 cases of grade≥3 toxicity (3.0%) – one grade 3 acute nausea and one grade 3 late gastric ulcer. ConclusionStereotactic body radiation therapy is an effective and well-tolerated treatment that allow high LC for liver metastases from colorectal cancer during the first two years. A prescription dose of 45Gy in 3 fractions to the 80% isodose line with a risk adapted schedule to respect Organ At Risk constraints allows a low rate of toxicity.

Prospective evaluation of fiducial marker placement quality and toxicity in liver CyberKnife stereotactic body radiotherapy.

BackgroundEvaluate morbidities and “quality” of fiducial marker placement in primary liver tumours (hepatocellular carcinoma [HCC]) for CyberKnife.Materials and MethodsThirty-six HCC with portal vein thrombosis (PVT) were evaluated for “quality” of fiducial placement, placement time, pain score, complications, recovery time and factors influencing placement.ResultsOne hundred eight fiducials were placed in 36 patients. Fiducial placement radiation oncologist score was “good” in 24 (67%), “fair” in 4 (11%), and “poor” in 3(8%) patients. Concordance with radiologist score in “poor”, “fair”, and “good” score was 2/2 (100%), 4/5 (80%), and 24/27 (89%), respectively (p=0.001). Child-Pugh score (p=0.080), performance status (PS) (p=0.014) and accrued during “learning curve” (p=0.013) affected placement score. Mean placement time (p=0.055), recovery time (p=0.025) was longer and higher major complications (p=0.009) with poor PS. Liver segment involved (p=0.484) and the Barcelona Clinic Liver Cancer (BCLC) stage did not influence placement score. “Good” placement score was 30% in first cohort whereas 93% in last cohort (p=0.023). Time for placement was 42.2 and 14.3 minutes, respectively (p=0.069). Post-fiducial pain score 0–1 in 26 patients (72%) and pain score 3–4 was in 2 (6%). Five patients (14%) admitted in “day-care” (2 mild pneumothorax, 3 pain). Mortality in 1 patient (3%) admitted for hemothorax.ConclusionFiducial placement is safe and in experienced hands, “quality” of placement is “good” in majority. Major complications and admission after fiducial placement are rare. Complications, fiducial placement time, recovery time is more during the “learning curve”. Poor Child-Pugh score, extensive liver involvement, poor PS have higher probability of complications.

Phase I/II Study of Extreme Hypofractionated Stereotactic Body Radiation Therapy Boost to Prostate for Locally Advanced, Node-Positive and Oligometastatic Cancer.

Introduction: Stereotactic body radiation therapy (SBRT) is increasingly being utilized to deliver escalated radiation doses for improving outcomes in various malignancies. We analyzed our cohort of locally advanced, node-positive, and bone oligometastatic prostate cancer patients, that were treated with a combination of pelvic RT using conventional fractionation (CF) and SBRT boost to prostate using extreme hypofractionation (EH), along with hormone therapy (HT).Materials and Methods: Outcomes of 44 prospectively treated patients were analyzed. Volumetric modulated arc therapy (VMAT) was utilized to deliver a dose of 45 Gy to pelvic nodal region, 50 Gy to prostate, and 54-56 Gy to gross nodes in 25 fractions. EH boost 18 Gy in three fractions was delivered to the prostate using CyberKnife (Accuray, Sunnyvale, CA, USA) SBRT. Bone oligometastasis, if any, were treated to a dose of 16 Gy in two fractions, delivered on weekends. Serum prostate-specific antigen (PSA), multi-parametric magnetic resonance imaging (MRI) of pelvis, and prostate-specific membrane antigen-positron emission tomography (PSMA-PET) were used for response assessment during follow-up. HT was given as per standard guidelines.Results: There were 33 (75%) locally advanced, nine (20.5%) node-positive, and two (4.5%) oligometastatic cases. At a median follow-up of 63.5 months, the five-year progression-free survival (PFS) was 88.2%, biochemical PFS (bPFS) was 91.4% and overall survival (OS) was 96.9%. Grade III or greater acute genitourinary and gastrointestinal toxicity was 2.3% each, and late toxicity was 4.5% and 0%, respectively.Conclusion: Excellent five-year outcomes can be attained even for locally advanced, node-positive and bone oligometastatic prostate cancer, by means of dose-escalation using EH-SBRT boost to the prostate.

Simultaneous integrated boost with stereotactic radiotherapy for dominant intraprostatic lesion of localized prostate cancer: a dosimetric planning study

Dominant intraprostatic lesion (DIL) has been known as the most common local recurrence site of prostate cancer. We evaluated the feasibility of simultaneous integrated boost (SIB) to DIL with CyberKnife stereotactic body radiotherapy (CK-SBRT). We selected 15 patients with prostate cancer and visible DIL and compared 3 plans for each patient: 1) No boost plan of 35 Gy to prostate, 2) DIL_40 plan of SIB 40 Gy to DIL and 35 Gy to prostate, and 3) DIL_45 plan with 45 Gy to DIL and 35 Gy to the prostate in 5 fractions. All targets satisfied with the prescription coverage per protocol. However, some patients failed to meet the Dmax of the rectum in DIL_40 plans (n = 4), and DIL_45 plans (n = 6). Violations of bladder constraints occurred in four DIL_45 plans. Consequently, the DIL boost with SBRT was possible in 73% of patients with DIL_40 plans, and 60% of patients with DIL_45 plans without any violation of normal organ constraints. All patients who experienced constraint violations had DILs in posterior segments. DIL boost using CK-SBRT could be an option for localized prostate cancer patients. For patients who had DIL in posterior segments, a moderate dose escalation of 40 Gy seemed appropriate.

Stereotactic body radiotherapy versus hepatic resection for hepatocellular carcinoma (≤ 5cm): a propensity score analysis.

CyberKnife stereotactic body radiation therapy (CK-SBRT) has been applied to hepatocellular carcinoma (HCC) patients for several years. The study aim was to compare the efficacy of hepatic resection (HR) and CK-SBRT in naive small hepatocellular carcinoma (sHCC) patients with hepatitis virus-related cirrhosis using a 5-year follow-up study. This retrospective cohort study included 317 naive sHCC patients (246 men and 71 women) with hepatitis B or C virus cirrhosis who were treated with HR (n = 195) or CK-SBRT (n = 122) from November 2011 to December 2015. Cumulative overall survival (OS) rates and progression-free survival (PFS) rates were calculated using Kaplan-Meier method. After the propensity score-matched analysis, 104 patients were selected from each group for further analysis. The 1-, 2-, 3-, and 5-year OS rates were 96.2%, 89.4%, 85.5% and 70.7% in the HR group and 93.3%, 89.4%, 83.7% and 71.0% in the CK-SBRT group, respectively. The 1-, 2-, 3-, and 5-year PFS rates were 78.8%, 64.3%, 56.4% and 47.3% in the HR group and 84.5%, 67.8%, 58.9% and 49.0% in the CK-SBRT group, respectively. No significant difference was found between the two groups in the OS and PFS rates (OS, p = 0.673; PFS, p = 0.350). No death occurred due to the toxicity or complications of HR or CK-SBRT. CK-SBRT could be an effective alternative to HR for sHCC naive patients with hepatitis-related cirrhosis, especially if patients have higher CP scores and lower PLT counts. PLT counts should be factored into survival evaluation of HCC treatment.

Real-world dosimetric comparison between CyberKnife SBRT and HDR brachytherapy for the treatment of prostate cancer

PurposeHigh-dose-rate (HDR) brachytherapy (BRT) and stereotactic body radiotherapy (SBRT) are currently the two treatment options for definitive radiotherapy of prostate cancer, employing extreme hypofractionation. There are only very few studies comparing their dosimetry, all using computed tomography for treatment planning. We present here a real-word dosimetric comparison between SBRT and ultrasound-based virtual HDR-BRT, with both imaging modalities coming from the same patient. Methods and MaterialsPatients with prostate cancer on a prospective trial evaluating the toxicity of robotic-based SBRT were treated to a total dose of 35 Gy in 5 fractions. Fifteen patients were included in this analysis. During ultrasound-based fiducial implantation, a three-dimensional data set as in real HDR-BRT procedure was acquired. Virtual HDR-BRT plans were generated and various organs at risk and prostate dosimetric parameters were evaluated. ResultsConcerning prostate, SBRT achieved significant higher D98, V35 Gy, and V37.5 Gy coverage, whereas virtual HDR-BRT achieved significant higher intratumoral doses reflected in the V42 Gy and V52.5 Gy. Rectal Dmax, V36 Gy, and V29 Gy were significantly lower for HDR-BRT with no difference as for V18 Gy. SBRT was significantly inferior regarding bladder dosimetry (Dmax, V36 Gy, V18 Gy), whereas urethra Dmax and V44 Gy where significantly higher at the expense of HDR-BRT. ConclusionsHDR-BRT is superior regarding rectum and bladder dosimetry, with SBRT being superior relative to urethra dosimetry. A randomized study is warranted to define the best extreme hypofractionated modality.

Clinical efficacy of Stereotactic Body Radiation Therapy (SBRT) for adrenal gland metastases: A multi-center retrospective study from China

To evaluate the efficacy and safety of CyberKnife Stereotactic Body Radiation Therapy (SBRT) in the treatment of adrenal gland metastases (AGM), we designed a large-scale multicenter retrospective study to report the safety and efficacy of SBRT for inoperable AGM. In this study, 75 (61 males, 14 females) patients with 84 AGM and Karnofsky performance score ≥70 were treated by SBRT from October 2006 to January 2017. Of these, the purpose of treatment were controlling all known metastatic sites for 21 patients while 54 for palliation of bulky adrenal metastases. The efficacy and safety of SBRT were evaluated during follow-up. Potential factors predictive of local control (LC) and overall survival (OS) were identified by univariate and multivariate analysis. Median follow-up time was 12.7 months (range 1.8–96.4). The complete response (CR), partial response (PR), stable disease (SD) and progressive disease (PD) rates were 23.8%, 23.8%, 31.0% and 21.4%, respectively. The 0.5, 1, and 2-year LC rates were 93.6%, 83.8%, and 62.1%, respectively; OS rates on the same follow-up intervals were 93.7%, 62.5%, and 49.6%, respectively, and the corresponding PFS rates were 48.5%, 33.9%, and 16.0%, respectively. The treatment was well tolerated with 2 patients reporting grade-3 diarrhea and fatigue, respectively. Multivariate analysis showed that simultaneous treatment of SBRT for other metastatic lesions, the number of AGM, initiation of systemic therapy, and the maximum diameter of AGM were predictive of LC rates. Moreover, patients with AGM < 5 cm had a superior OS compared with those with AGM ≥ 5 cm (28.0 months vs. 17.6 months, P = 0.032). SBRT is an effective therapeutic option for treatment of AGM with high LC rates with minimal toxicity.

Local Tumor Control for Metastatic Epidural Spinal Cord Compression Following Separation Surgery with Adjuvant CyberKnife Stereotactic Radiotherapy or Image-Guided Intensity-Modulated Radiotherapy

We sought to compare local tumor control after conventionally fractionated image-guided intensity-modulated radiotherapy (IMRT) versus adjuvant CyberKnife stereotactic body radiotherapy (SBRT) in patients who underwent separation surgery for metastatic epidural spinal cord compression (MESCC). We retrospectively reviewed patients with MESCC who were treated at our hospital. The Kaplan-Meier method was used to estimate local progression and overall survival. Fifty-six patients with MESCC underwent separation surgery between 2013 and 2018, among whom 6 were lost to follow-up, 24 received conventionally fractionated image-guided IMRT, and 26 were treated with CyberKnife SBRT. The median follow-up was 16.5 months (range, 2.1-47.5 months). Eleven patients experienced local failure including 9 and 2 from the IMRT and SBRT groups, respectively. The local progression-free survival rates were significantly higher in the SBRT group than IMRT group at 6 months (95.5% vs. 82.0%), 1 year (90.9% vs. 71.8%), and 2 years (90.9% vs. 57.6%) (P = 0.035). Multivariate Cox proportional hazards regression analysis identified radiotherapy method (P = 0.034) and receipt of preoperative radiotherapy (P = 0.047) as significant predictors of local control, while visceral metastasis (P = 0.048) and high-malignancy primary tumor type (P = 0.002) were negative predictors of overall survival. Moreover, postoperative SBRT was noninferior to IMRT in terms of pain control, adverse effects, and performance in treating irradiated spinal metastases. Hybrid surgery-radiosurgery therapy is a safe and effective treatment option for patients with MESCC. SBRT provided higher local control rates compared with IMRT. Thus postoperative SBRT should be considered for patients expected to have relatively long survival.

CyberKnife Stereotactic Body Radiation Therapy as an Effective Treatment for Hepatocellular Carcinoma Patients With Decompensated Cirrhosis.

Purpose: The aim of our study was to evaluate the curative effect and safety of CyberKnife stereotactic body radiation therapy in treating decompensated cirrhosis hepatocellular carcinoma (HCC) patients.Methods: From March 2011 to December 2015, 32 HCC patients who refused or were ineligible for other treatments were treated with CyberKnife stereotactic body radiation therapy. Among these patients, 17 were Child-Pugh score 7 (53.13%), 7 were Child-Pugh score 8 (21.87%), 4 were Child-Pugh score 9 (12.50%), and 4 were Child-Pugh score 10 (12.50%). A total dose of 45–54 Gy in 5–10 fractions was given according to the location of lesions.Results: The median follow-up period was 30 months (8–46 months). By July 2019, the tumors were recurrent or metastasized in 17 patients. The overall survival rates of 1, 2, and 3 years were 84.4, 61.8, and 46.0%, respectively. After 1, 2, and 3 years, the local control rates were 92.9%. The progression-free survival rates of the 1, 2, and 3-year treatments were 73.8, 44.6, and 33.4%, respectively.Conclusions: CyberKnife stereotactic body radiation therapy was an effective option for HCC patients with decompensated cirrhosis. The liver injury occurrence rate was acceptable in our study.