CyberKnife Stereotactic Body Radiation Therapy Research Articles

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.

Repeated CyberKnife stereotactic body radiation therapy in hepatocellular carcinoma

BackgroundTo explore the survival and side effects of repeated CyberKnife stereotactic body radiation therapy (CK-SBRT) on hepatocellular carcinoma patients.Methods24 HCC patients were collected at The Fifth Medical Center of PLA General Hospital from November 2011 to July 2016. They received second-course CK-SBRT with a prescribed dose of 50(48–55) Gy/5-8fx, and a single dose of 10 (7–11) Gy/fx. Cumulative overall survival rates (OS), progression-free survival rates (PFS) and local control rates (LC) were calculated by Kaplan-Meier method.ResultsAll patients finished their radiotherapy plans. The 1-,2- and 3-year cumulative OS rate were 95.8,81.1 and 60.8%. The 1-,2- and 3-year LC rate were 95.5,90.7 and 90.7%, respectively. The 1-, 2- and 3-year PFS were 74.8, 49.2 and 39.4%, respectively. 16 patients complained of fatigue during second-course therapy, 2 patients showed Grade 2 gastrointestinal reaction, 1 patient was diagnosed radiation-induced liver disease and none died. PFS was significantly higher in the interval time < 12 months group than in the interval time ≥ 12 months group (p = 0.030).ConclusionsIt is preliminarily believed that re-CK-SBRT is an effective and safe treatment for HCC patients, but the treatment criteria should be strictly controlled.

Preliminary analyses of efficacy and safety of Cyberknife stereotactic body radiotherapy for 26 patients with recurrent cholangiocellular carcinoma after surgery

Objective To evaluate the efficacy and safety of stereotactic body radiation therapy (SBRT) using Cyberknife in the treatment of patients with recurrent cholangiocellular carcinoma (RCC) after surgery. Methods Clinical data of 26 patients with recurrent RCC after surgery undergoing Cyberknife SBRT from 2010 to 2015 were retrospectively analyzed. The median recurrence time was 10 months (range 2.0-63.0 months) and the median tumor diameter was 2.8 cm (range 1.2-4.8 cm). The median prescription dose/fraction was 45 Gy/5f (range 40-50 Gy/3-8 f). The tumor progression was evaluated based on enhanced CT or MRI. Overall survival (OS), progression-free survival (PFS) and local control rate (LC) were analyzed by Kaplan-Meier method. Toxicity was assessed using the common terminology criteria for adverse events version 4.0. Results For the entire cohort, the median OS and PFS were 13.5 months and 6.5 months at a median follow-up of 29.3 months (range 2.1-62.0 months). The 1-and 2-year OS and PFS rates were 52% and 21% as well as 28% and 15%, respectively. Among them, 4 patients (4/26, 15%) were recurrent in situ after SBRT. Three patients experienced grade Ⅲ adverse reactions including 1 case of gastrointestinal reaction, 1 case of liver dysfunction and 1 case of biliary tract infection. Only 1 patient suffered from ≥grade IV gastrointestinal bleeding during the advanced stage. Conclusions SBRT using Cyberknife is a safe and effective treatment for patients with recurrent RCC after surgery. The adverse reactions can be tolerated by patients. Key words: Cholangiocellular neoplasm/stereotactic body radiotherapy; Cyberknife; Treatment outcome

A review and analysis of stereotactic body radiotherapy and radiosurgery of patients with cardiac implantable electronic devices.

The implementation of stereotactic body radiation therapy (SBRT) and stereotactic radiosurgery (SRS) has greatly increased due to its convenience and advantages from perspectives ranging from radiobiology to radio physics. Because SBRT/SRS delivers high doses in few fractions, precise dose delivery to target volumes and sufficient sparing of adjacent organs at risk (OARs) are required. Achieving these conflicting objectives is challenging for all patients receiving SBRT/SRS and may be particularly challenging when SBRT/SRS is adopted for treating patients with cardiac implantable electronic devices (CIEDs) because cumulative doses in CIEDs must be limited. Published research considering the different aspects of stereotactic treatment in patients with CIEDs was reviewed to summarise their findings in the following sections: (I) conventional linear accelerator (linac)-based SBRT and SRS; (II) CyberKnife, Gamma-Knife, VERO and helical tomotherapy SBRT and SRS; and (III) proton therapy. A total of 65 patients who had CIEDs and underwent SRS, SBRT, or SABR treatments were identified in the reviewed studies. The functionality of the CIEDs was assessed for 58 patients. Of those, CIED malfunctions (such as data loss, mode change, and inappropriate shock) were reported in four patients (6.89%). This review highlights the available sparse information in the literature by posing questions for future research.

Lung Locations Most Affected by Dose-Calculation Algorithms in CyberKnife Stereotactic Body Radiotherapy

CyberKnife is a robotic stereotactic body radiotherapy (SBRT) system that precisely delivers large radiation doses to a target. Tissue heterogeneity and shape can be problems. The treatment -planning system allows for use of the Monte Carlo (MC) or fundamental Ray Tracing (RyTc) algorithms for ultimate dose calculation. The MC is more accurate but consumes more computer resources and time. We compared radiation dose calculations for lung targets between the MC and RyTc algorithms. We placed a prosthetic marker at different thorax sites in a Rando phantom to compare the calculation results. The peripheral sites followed by the diaphragm showed the greatest significant differences in parameters for evaluating the treatment quality. For gross tumor volume dose, peripheral lung targets were the most critical for the calculation algorithm. The MC mean doses were lower than the RyTc mean doses and generally demonstrated better conformity. However, the deviation between conformal index (CI) and new CI at the peripheral location was large. The coverage differences between the RyTc and MC were most obvious at the peripheral lung site. The MC algorithm for radiation dose calculation in the lungs was indispensable in SBRT using CyberKnife for accurate dose evaluation, especially at the peripheral and diaphragm locations.

Pattern of recurrence after CyberKnife stereotactic body radiotherapy for peripheral early non-small cell lung cancer.

The treatment efficacy after CyberKnife stereotactic body radiotherapy (SBRT) have not been adequately addressed. The purpose of this study was to investigate pattern of recurrence according to irradiation field after CyberKnife SBRT for early-stage non-small cell lung cancer (NSCLC). This retrospective study included patients with peripheral cT1/2N0M0 NSCLC that was treated with SBRT using a CyberKnife between May 2013 and March 2016 at single institute and followed up by more than two imaging examinations. Both operable and inoperable patients were included. Overall survival (OS) and progression-free survival (PFS) curves were estimated using the Kaplan-Meier method with 95% confidence intervals (CI). Cumulative incidence curves of recurrence were calculated and compared using the Gray's test. Total 71 patients were included and analyzed in this study. The median follow-up period for surviving patients was 34 months (range, 7-64 months). The 2-year OS and PFS rate were 93% (95% CI: 83-97%) and 77% (95% CI: 65-86%), respectively. The 2-year cumulative incidence rate of infield recurrence and out-of-field recurrence were 6% (95% CI: 2-14%) and 17% (95% CI: 9-27%), respectively. Gross tumor volume (GTV) ≥9 mL and diagnosis-to-treatment interval (DTI) ≥90 days were significantly associated with infield recurrence (P<0.001 and P=0.007), and epidermal growth factor receptor (EGFR) mutation was significantly associated with out-of-field recurrence (P=0.014). Treatment efficacy after CyberKnife SBRT for peripheral early-stage NSCLC was identical to previous conventional linac-based SBRT reports. With short follow-up period, it was found that GTV and DTI were the significant predictive factor of infield recurrence, and EGFR mutation was the significant predictive factor of out-of-field recurrence.

P015 Motion Management Without Fiducial Tracking Using Cyberknife SBRT for Multiple Lung Metastasis from Breast Cancers

Cyber Knife robotic stereotactic radiosurgery is minimally invasive tumor treatment modality that can deliver high precision radiotherapy to any part of the body with minimal exposure to adjacent and surrounding vital organs and is used to treat oligometastasis of the lung from primary breast cancer patients. In the modern high precision treatment delivery, utmost care should be taken for motion management of tumor targets. The Objective of this study was to investigate the accuracy and efficacy of Cyber knife in the treatment of lung metastasis from breast cancer using fuducial free respiratory tracking system using cyberknife stereotactic radiosurgery. We examined toxicity and local control rate with fiducial-free CyberKnife stereotactic body radiation therapy (SBRT) for lung metastases from 20 breast cancer patients. All patients had favorable performance status (ECOG 0–2), oligometastatic disease. Total of 56 Lungs lesions were treated with a prescribed dose of 30–35 Gy delivered in five fractions to the planning target volume (PTV) using the CyberKnife with X-sight lung tracking. A median 30 Gy (IQR, 30–35 Gy) dose was delivered to a median prescription isodose line of 70% (IQR, 65–77%) to 20 patients with a total median follow up of 34 months. The toxicity and local control rates were favourable and 1- and 2-year local control estimates were 87% and 73%, respectively. Two of the five local failures were infield in patients who had received irradiation to the gross tumor volume and remaining 3 were in patients who had received irradiation to clinical target volume. No local failures were identified beyond 21 months of therapy. There was no lung, oesophageal or spinal cord toxicity noted in the above patients. Initial evaluation with fiducial free based respiratory tracking system using five-fraction CyberKnife SBRT is a promising treatment option for lung metastasis from breast cancer patients, demonstrating encouraging local control rates with no toxicity. a dose escalation study for the pheripheral lung metastasis from breast cancers is being planned.

Dose fall-off during the treatment of thoracic spine metastasis with CyberKnife stereotactic body radiation therapy (SBRT).

CyberKnife stereotactic body radiation therapy (SBRT) is becoming increasingly used for cancer treatment and, to maximize its clinical application, it is important to define the dosimetric characteristics, optimal dose, and fractionation regimens. The aim of this study was to evaluate the dose fall-off in two fractionated regimens of CyberKnife SBRT during the treatment of thoracic spinal metastasis. Patients with spinal metastasis involving a vertebra and pedicle were treated with 40 Gy in 5 fractions (n = 4), and patients with spinal metastasis involving only a vertebra received 33 Gy in 3 fractions (n = 4). A new approach was used to measure absolute dose fall-off distance, relative dose fall-off distance, and the dose fall-off per unit distance along four reference directions in the axial plane. Patients treated with 33 Gy/3 fractions had a greater absolute dose fall-off distance in direction 1 (from the point with maximum dose [Dmax] towards the spinal cord) and direction 3 (the opposite of direction 1), a greater relative dose fall-off distance in direction 3, and a lower dose fall-off per unit distance in direction 1 and 3 compared to patients treated with 40 Gy/5 fractions (all p < 0.05). Overall, the dose fall-off towards the spinal cord is rapid during the treatment of thoracic spinal metastasis with CyberKnife SBRT, which allows a higher dose of radiation to be delivered to the tumor and, at the same time, better protection of the spinal cord.

Stereotactic body radiation therapy as an effective and safe treatment for small hepatocellular carcinoma

BackgroundTo evaluate the efficacy and safety of stereotactic body radiation therapy (SBRT) in patients with small hepatocellular carcinoma(sHCC) who were ineligible for surgery or ablation therapies.MethodsFrom March 2011 to December 2012, 28 cases with sHCC which were ineligible or refused surgical resection, transplantation or local ablation were treated with CyberKnife SBRT. Median size of tumors was 2.1 cm (range:1.1–3.0 cm), a dose of 10-15Gy per faction was given over 3–6 consecutive days, resulting in a total dose of 35-60Gy.ResultsThe median follow-up period was 36 months, with the response rate of complete response (CR) in 17 cases, partial response (PR) in 8 cases, stable disease (SD) in 2 cases and progressive disease (PD) in one case. Overall response rate was 89.28%. Overall survival rates in 1, 2 and 3 years were 92.86, 85.71 and 78.57%, respectively. Local control rates in 1, 2 and 3 years were 96.43, 92.86 and 89.28%, respectively. No grade ≥ 3 hepatic toxicity was observed.ConclusionCyberKnife treatment was a safe and effective option for sHCC, which had shown good local control, high overall survival rates and low toxicity. CyberKnife SBRT could be served as an alternative treatment for patients with sHCC which is unsuitable for surgical treatment or local ablation.

Utilization rate of gold fiducial markers and reasons for abandonment in CyberKnife stereotactic body radiation therapy

Objective To investigate the utilization rate of gold fiducial markers and reasons for abandonment of gold fiducial markers in the CyberKnife VSI System, and to provide reference data for implantation of gold fiducial markers and radiotherapy planning. Methods From March to August, 2017, a total of 47 patients had gold fiducial markers implanted or pasted. In those patients, 42 patients had gold fiducial markers implanted, including 32 receiving computed tomography (CT)-guided 3D-printing coplanar template assisted implantation, 1 receiving CT-guided 3D-printing non-coplanar template assisted implantation, 1 receiving CT-guided implantation, and 8 receiving ultrasound-guided implantation. A total of 44 patients received the CyberKnife treatment, including 2 patients who failed to use gold fiducial markers and were treated with spine tracking instead and 3 patients missing the treatment for other reasons. The numbers of utilized and abandoned gold fiducial markers were recorded for calculation of the utilization and abandonment rates. The reasons for abandonment of gold fiducial markers were analyzed and classified. Results A total of 134 gold fiducial markers were implanted into or pasted to the 44 patients. In all the gold fiducial markers, 111 were utilized and 23 abandoned, yielding a utilization rate of 82.8% and an abandonment rate of 17.2%.The reasons for abandonment of gold fiducial markers included large rigidity error (26.1%), unqualified implanted fold fiducial markers (17.4%), displacement of gold fiducial markers (26.1%), and others (30.4%). Conclusions Compared with the CT-guided or ultrasound-guided implantation of gold fiducial markers, the CT-guided 3D-printing coplanar or non-coplanar template assisted implantation of gold fiducial markers requires only two puncture needles for each implantation and implants two gold fiducial markers by a single needle, which reduces the number of puncture needles, risk of puncture-induced injury, and incidence of complications after implantation. Not all the gold fiducial markers implanted by a variety of ways will be utilized. Some gold fiducial markers will be abandoned for different reasons, which should be taken into account during implantation of gold fiducial markers. Key words: Neoplasms/stereotactic radiotherapy; CyberKnife; Fiducial markers; Qualified rate

Clinical efficacy of CyberKnife stereotactic body radiation therapy for hepatic hilar cancer

Objective To evaluate the efficacy and safety of CyberKnife stereotactic body radiation therapy (SBRT) in the treatment of hepatic hilar cancer. Methods A retrospective study was performed on the clinical data of 36 patients with hepatic hilar cancer who were admitted to our hospital and treated with CyberKnife SBRT from 2009 to 2015. In the 36 patients, 37 lesions were found with tumor diameters ranging from 1.5 to 5.5 mm (median diameter 3 cm). The Synchrony respiratory tracking system was used for 21 lesions in 20 patients, while the XSight spinal tracking system was used for 16 lesions in 16 patients. Local progression was evaluated based on contrast-enhanced computed tomography and/or magnetic resonance imaging. The Kaplan-Meier method was used to calculate local control (LC) and overall survival (OS) rates, and the log-rank test was used for survival comparison and univariate prognostic analysis. Results The median follow-up time was 12.7 months. The 1-and 2-year postoperative LC rates were 90% and 76%, respectively. The 1-year OS and progression-free survival (PFS) rates were 63% and 39%, respectively. The median OS and PFS times were 15.2 and 10 months, respectively. The incidence of grade 3 adverse reactions was 11%. Conclusions The CyberKnife SBRT is a safe and effective way to treat hepatic hilar cancer. Key words: Liver neoplasms/stereotactic radiotherapy; Stereotactic radiotherapy, CyberKnife; Treatment outcome

Impact of tumor size on outcome after stereotactic body radiation therapy for inoperable hepatocellular carcinoma.

Stereotactic body radiation therapy (SBRT) for inoperable hepatocellular carcinoma (HCC) offers excellent local control rates. This study retrospectively analyzed the influence of different tumor size on treatment outcomes after SBRT.Between December 2008 and February 2014, 141 HCC patients were treated with Cyberknife SBRT. Patients were divided into 3 groups namely small tumors (≤4 cm), intermediate-sized (>4–<10 cm), and large (≥10 cm) tumors. Treatment outcomes, prognoses, and safety at each tumor size were compared and analyzed.A total of 52 patients with small tumors, 55 with intermediate tumors, and 34 patients with large tumors were retrospectively analyzed with a median follow-up of 16 months. Objective responses were achieved at 96.15%, 90.90%, and 76.47% for small, intermediate, and large tumors, respectively (P ≤ .0001) and the 3-year local control rates were 97.85%, 71.99%, and 82.14%, respectively (P = .0035). The 3-year overall survival rates were 50.26%, 45.29%, and 33.38% for small, intermediate, and large tumors, respectively (P = .3757). No significant differences were found in overall-survival, intra-hepatic recurrence free survival, disease-progression free survival, or distant metastasis-free survival.SBRT offers the best effective local control rate and response rate for small HCCs. However, tumor size did not significantly affect the overall survival rate, intra-hepatic recurrence free rate, or disease-progression free rate.

Clinical outcomes of primary lung cancer treated with cyberknife stereotactic body radiotherapy: A prospective cohort study

Clinical outcomes of primary lung cancer treated with cyberknife stereotactic body radiotherapy: A prospective cohort study

Clinical outcomes of primary and metastatic lung cancer treated with cyberknife stereotactic body radiotherapy: A prospective cohort study

Clinical outcomes of primary and metastatic lung cancer treated with cyberknife stereotactic body radiotherapy: A prospective cohort study

Stereotactic Body Radiotherapy for Low-Risk Prostate Cancer: A Ten-Year Analysis.

ObjectiveThis study represents the first 10 year analysis of the efficacy and toxicity of stereotactic body radiotherapy (SBRT) in the treatment of early low-risk prostate cancer.Materials and methodsTwo hundred and thirty males were treated with Cyberknife SBRT to a dose of 35 Gray (Gy) or 36.25 Gy in five consecutive days. All patients had a Gleason score of six and a PSA < 10ng/ml. Median follow-up is nine years. The median age was 69.5 years and median prostate specific antigen (PSA) was 5.6ng/ml. The treatment was delivered with homogeneous planning with a dose prescription of 82-87% of the maximum dose to cover the planning target volume (PTV).ResultsTen-year biochemical disease free survival was 93% with either dose. Local control was 98.4%. Median prostate specific antigen (PSA) dropped to 0.1 by five years and has remained there. Toxicity was mild with 10% of patients having Grade two-three late urinary toxicity and 4% having the late grade two rectal toxicity. Mean Expanded Prostate Cancer Index Composite (EPIC) Quality of Life (QOL) scores declined initially for bowel and urinary domains, but recovered to baseline, where they remain. EPIC sexual scores have declined by 40%.Discussion/ConclusionsStereotactic body radiotherapy to a dose of 35 Gy-36.25 Gy is an effective treatment for early low-risk prostate cancer, with acceptably low toxicity. There appears to be no benefit to increasing the dose beyond 35 Gy. Ten-year biochemical disease free survival appears to be higher than with standard intensity modulated radiotherapy (IMRT).

Clinical outcomes and prognostic factors of stereotactic body radiation therapy for intrahepatic cholangiocarcinoma.

Stereotactic body radiation therapy (SBRT) has been an emerging non-invasive treatment modality for patients with intrahepatic cholangiocarcinoma (ICC) when surgical treatment cannot be applied. The CyberKnife® is a SBRT system that allows for real-time tracking of the tumor. The purpose of this study was to evaluate the clinical outcomes and prognostic factors for ICC patients receiving this treatment. Twenty-eight patients with ICC were enrolled in the present study. The median prescription dose was 45 Gy (range, 36-54 Gy), fractionated 3 to 5 times with a 70% to 92% isodose line. Local control, overall survival, progression-free survival and toxicity were studied. The median follow-up time was 16 months (3-42 months). Based on modified Response Evaluation and Criteria in Solid Tumors (mRECIST), response rate and disease control rate of SBRT in ICC were 46.4% (13/28) and 89.3% (25/28), respectively. Median overall survival was 15 months (95% CI, 7.22-22.78). 1- and 2-years survival rates were 57.1% and 32.1%, and 1- and 2- years Progression-free Survival rates were 50.0 % and 21.4 %. Multivariate analysis revealed that number of lesions (solitary vs. multiple nodules), CA19-9 levels (≤37 U/mL vs. 37-600/>600) and TNM stage (AJCC stage) were independent prognostic factors for ICC patients treated with SBRT. Toxicity was mostly transient and tolerable. No greater than grade 3 toxicity was observed. These results suggested that CyberKnife SBRT might be a good alternative treatment for unresectable ICC.

Demystifying CyberKnife Stereotactic Body Radiation Therapy for Interventional Radiologists

Stereotactic body radiation therapy (SBRT) using CyberKnife system is a relatively new radiation therapy that has demonstrated feasibility, safety, and efficacy with a high local control of various extracranial unresectable primary cancer and oligometastasis. It involves accurate delivery of very high dose of radiation to the target or tumor volume with high precision and conformity, while minimizing the radiation exposure of nontargeted tissue. Radiopaque fiducial markers (FMs) implantation in and around the tumors is required to track the selected tumor during CyberKnife SBRT, especially in those organs moving with respiration. They act as internal radiographic landmarks that maintain a fixed relationship within the tumor and with each other. Although their implantation can be technically demanding, it can be performed using various techniques with varying success; however, percutaneous implantation under image guidance by interventional radiologists is the most common method. Close collaboration between interventional radiologists and radiation oncologists with understanding of the technical aspects of CyberKnife SBRT and FMs implantation has important implications for optimal delivery of therapy and direct impact on the interventional radiology practice in selected patients proposed for CyberKnife SBRT.

The application of CyberKnife stereotactic body radiotherapy in treatment of oligometastatic prostate cancer

Objective To determine the effectiveness and safety of stereotactic body radiotherapy (SBRT)-CyberKnife for oligometastatic prostate cancer. Methods From May 2012 to February 2017, 31 patients treated by CyberKnife were retrospectively reviewed, with a median age of 67 years(range 52 to 83 years), including 50 oligometastatic and 2 primary prostate cancer patients. The median PSA level was 8.4 ng/ml(range 0 to 300.0 ng/ml) and PSA test was performed every month. PSA progression-free survival (PSA-PFS), time to initiation of androgen deprivation therapy (ADT) and local control rate (LCR) were measured as the main outcomes. Results SBRT was well tolerated and were performed as planned in all patients. No SBRT related acute or late toxicities were observed. No bone fracture was observed in patients treated by bony targeted radiotherapy. The median follow-up after SBRT was 20.7 months (range 1.2-58.3 months). The median PSA-PFS was 5.3 months (range 0-58.3 months). 1-year, 2-year, and 4-year PSA-PFS was 52.0%, 36.7% and 36.7% respectively. PSA level decrease was observed in 21 oligometastatic prostate cancer patients after SBRT, with median PSA-PFS of 12.3 months (range 1.2-58.3 months). PSA level increase was observed in 29 oligometastatic prostate cancer patients after SBRT. Six local recurrence were observed resulting in an actuarial 1-year, 2-year and 3-year LCR of 90.4%, 86.9% and 82.6%, respectively. Twelve patients treated without ADT after SBRT, with median follow-up of 8.6 months (range 2.9-58.3 months) in this subgroup. Seven patients were added ADT after SBRT, with the median time from SBRT to initiation of ADT of 13.3 months (range 3.0-24.0 months) in this subgroup. Twelve patients were treated with ADT continuously after SBRT. Conclusions CyberKnife seems to be a safe and effective treatment with tolerated adverse events and good local control for patients with oligometastatic prostate cancer. Key words: Prostate cancer; Oligometastatic; CyberKnife; Stereotactic body radiotherapy; Prostate specific antigen(PSA)

Prostate clinical outlook visualization for patients and clinicians considering cyberknife treatment: A personalized approach.

e16549 Background: When a patient presents with localized prostate cancer, referral for radiation oncology consultation includes a discussion of likely outcomes of therapy. Among current radiation treatments for prostate cancers, hypo-fractionated stereotactic body radiation therapy (SBRT) has gained clinical acceptance based on efficacy, short duration of treatment and potential radiobiological advantages. The prostate Clinical Outlook (PCO) visualization system was developed to provide the patient and the clinician with a tool to visualize probable treatment outcomes using institutional, patient specific data for comparing results of treatment. Methods: We calculated the prostate cancer outlooks for each prospective patient using the EPIC-26 quality of life parameters based on clinical outcomes data of 580 cyberknife SBRT treated prostate cancer patients. We applied Kaplan-Meier analysis using the ASTRO method for disease free likely outcome and the PCO nomogram to calculate parameters for quality of life. Open source R, R/Shiny, and MySQL were used to develop a modularized architecture system. Results: PCO presents patient specific risk scores in a gauge chart style and risk free probability bar plots to compare treatment data of cyberknife patients. PCO generates reports, in PDF and HTML, which consist of a comparison chart of risk free probabilities and gauge charts of risk scores. This system is now being expanded as a web-based service to patients. Conclusions: PCO visualized patient specific likely outcomes were compared to treatment data from a single department, helping the patient and the clinician to visualize likely outcomes. The PCO approach can be expanded to other specialties of oncology with the flexible, modularized architecture which can be customized by changing parameter variables for the modules.

Dosimetric impacts of endorectal balloon in CyberKnife stereotactic body radiation therapy (SBRT) for early-stage prostate cancer.

PurposeIn SBRT for prostate cancer, higher fractional dose to the rectum is a major toxicity concern due to using smaller PTV margin and hypofractionation. We investigate the dosimetric impact on rectum using endorectal balloon (ERB) in prostate SBRT.Materials and MethodsTwenty prostate cancer patients were included in a retrospective study, ten with ERB and 10 without ERB. Optimized SBRT plans were generated on CyberKnife MultiPlan for 5 × 7.25 Gy to PTV under RTOG‐0938 protocol for early‐stage prostate cancer. For the rectum and the anterior half rectum, mean dose and percentage of volumes receiving 50%, 80%, 90%, and 100% prescription dose were compared.ResultsUsing ERB, mean dose to the rectum was 62 cGy (P = 0.001) lower per fraction, and 50 cGy (P = 0.024) lower per fraction for the anterior half rectum. The average V50%, V80%, V90%, and V100% were lower by 9.9% (P = 0.001), 5.3% (P = 0.0002), 3.4% (P = 0.0002), and 1.2% (P = 0.005) for the rectum, and lower by 10.4% (P = 0.009), 8.3% (P = 0.0004), 5.4% (P = 0.0003), and 2.1% (P = 0.003) for the anterior half rectum.ConclusionsSignificant reductions of dose to the rectum using ERB were observed. This may lead to improvement of the rectal toxicity profiles in prostate SBRT.