Fiducial Marker Insertion Research Articles

Transperineal versus transrectal prostate fiducial insertion in radiation treatment of prostate cancer: a systematic review and meta-analysis.

To provide more accurate and definitive conclusions regarding the clinical and technical complications associated with the transperineal (TP) and transrectal (TR) approaches, a comprehensive review of observational studies and randomized controlled trials was conducted. This systematic review covered all eligible studies to facilitate a thorough comparison of complications linked to the two fiducial marker insertion methods, TP and TR. A comprehensive search of the literature was conducted, encompassing databases such as PubMed, Embase, and the Cochrane Library, up to July 7, 2023. The relative risk and 95% confidence interval were utilized to evaluate the diagnosis and complication rates. The final selection for the methodological quality analysis included 13 observational studies that utilized TP and TR gold fiducial insertion approaches. The meta-analysis revealed significantly lower risks of urinary tract infections (UTI) and rectal bleeding with the TP approach. The use of both TP and TR techniques for placing gold seed fiducial markers has proven to be an effective, safe, and well-tolerated method for image-guided radiation therapy in prostate cancer patients. A significant benefit of the TP technique is its ability to avoid rectal puncture, thereby reducing the risk of UTIs. Although the incidence of UTIs and rectal bleeding associated with the TR method is relatively low, these complications can disrupt patient wellbeing and potentially cause delays in treatment.

End-to-end validation of fiducial tracking accuracy in robotic radiosurgery using MRI-only simulation imaging.

Image-guided radiation-therapy (IGRT)-based robotic radiosurgery using magnetic resonance imaging (MRI)-only simulation could allow for improved target definition with highly conformal radiotherapy treatments. Fiducial marker (FM)-based alignment is used with robotic radiosurgery treatments of sites such as the prostate because it aids in accurate target localization. Synthetic CT (sCT) images are generated in the MRI-only workflow but FMs used for IGRT appear as signal voids in MRIs and do not appear in MR-generated sCTs, hindering the ability to use sCTs for fiducial-based IGRT. In this study we evaluate the fiducial tracking accuracy for a novel artificial fiducial insertion method in sCT images that allows for fiducial marker tracking in robotic radiosurgery, using MRI-only simulation imaging (MRI-only workflow). Artificial fiducial markers were inserted into sCT images at the site of the real marker implantation as visible in MRI. Two phantoms were used in this study. A custom anthropomorphic pelvis phantom was designed to validate the tracking accuracy for a variety of artificial fiducials in an MRI-only workflow. A head phantom containing a hidden target and orthogonal film pair inserts was used to perform end-to-end tests of artificial fiducial configurations inserted in sCT images. The setup and end-to-end targeting accuracy of the MRI-only workflow were compared to the computed tomography (CT)-based standard. Each phantom had six FMs implanted with a minimum spacing of 2cm. For each phantom a bulk-density sCT was generated, and artificial FMs were inserted at the implantation location. Several methods of FM insertion were tested including: (1) replacing HU with a fixed value (10000HU) (voxel-burned); (2) using a representative fiducial image derived from a linear combination of fiducial templates (composite-fiducial); (3) computationally simulating FM signal voids using a digital phantom containing FMs and inserting the corresponding signal void into sCT images (simulated-fiducial). All tests were performed on a CyberKnife system (Accuray, Sunnyvale, CA). Treatment plans and digital-reconstructed-radiographs were generated from the original CT and sCTs with embedded fiducials and used to align the phantom on the treatment couch. Differences in the initial phantom alignment (3D translations/rotations) and tracking parameters between CT-based plans and sCT-based plans were analyzed. End-to-end plans for both scenarios were generated and analyzed following our clinical protocol. For all plans, the fiducial tracking algorithm was able to identify the fiducial locations. The mean FM-extraction uncertainty for the composite and simulated FMs was below 48% for fiducials in both the anthropomorphic pelvis and end-to-end phantoms, which is below the 70% treatment uncertainty threshold. The total targeting error was within tolerance (<0.95mm) for end-to-end tests of sCT images with the composite and head-on simulated FMs (0.26, 0.44, and 0.35mm for the composite fiducial in sCT, head-on simulated fiducial in sCT, and fiducials in original CT, respectively. MRI-only simulation for robotic radiosurgery could potentially improve treatment accuracy and reduce planning margins. Our study has shown that using a composite-derived or simulated FM in conjunction with sCT images, MRI-only workflow can provide clinically acceptable setup accuracy in line with CT-based standards for FM-based robotic radiosurgery.

CT-guided Transgluteal Prostate Fiducial Marker Insertion for Localized Radiation Therapy.

To Evaluate the safety and technical success of transgluteal CT-guided fiducial marker implantation into the prostate as an alternative method to transperineal and transrectal approaches. We retrospectively identified all patients who had undergone CT-guided transgluteal fiducial marker insertion between 2020 and 2022. Four patients with confirmed prostate cancer were identified. One radiologist performed all procedures via a bilateral transgluteal approach under the guidance of real-time CT-fluoroscopy. Twenty cm long pre-waxed 18G guiding needles, preloaded with smooth gold fiducial markers, were used to implant markers. Technical success was defined as the successful placement of the fiducial markers into the planned positions. The mean age of patients was 70years. The mean procedure time was 19.25 (SD: 6.75)min, and the mean total dose length product (DLP) was 801.75 (SD: 291.17) mGycm, which is compatible with the 12mSv estimated effective dose. All procedures were technically successful (100%). All patients tolerated the procedure and did not require any analgesia for pain, and there were no requests to stop or pause the procedure. Only one patient reported hematuria one day after the procedure, which required no treatment. Transgluteal CT-guided fiducial marker implantation into the prostate is an alternative method to transperineal and transrectal approaches. In this technique, the risk of septic complications is minor, and general anesthesia is not required. Thus, transgluteal CT-guided marker insertion is a feasible and well-tolerated method for image-guided radiation therapy (IGRT) in patients with prostate cancer.

Computed Tomography-Guided Prostate Sampling and Fiducial Marker Insertion in Patients With Absent Rectums.

We aimed to present our experience and the outcomes of a novel technique, computed tomography (CT)-guided prostate biopsy and fiducial marker insertion in patients with absent rectums. Patients who underwent CT-guided prostate biopsy at a single institution from November 2010 to November 2022 were retrospectively reviewed. Patients were included if they had a clinical suspicion of prostate cancer and had absent rectums from previous surgical resection. Contrast-enhanced CT scan was used to perform transgluteal prostate biopsy. Patient demographics, multiparametric magnetic resonance imaging, and biopsy details were recorded. Thirteen biopsy procedures and 1 CT-guided fiducial marker insertion were performed on 12 unique patients. The reasons for the absence of rectums included surgical resection for rectal cancer (n = 10) and surgical resection for inflammatory bowel disease (n = 2). Clinically significant cancer was found in 7 of 13 biopsy results (52.8%), clinically insignificant cancer in 3 of 13 (23.1%), and benign cancer in 3 of 13 (23.1%). No complications were recorded. Our data support CT-guided prostate biopsy as an accurate and effective technique for investigating prostate cancer that requires tissue sampling in patients with absent rectums.

Intra-prostatic gold fiducial marker insertion for image-guided radiotherapy (IGRT): five-year experience on 795 patients

IntroductionProstate cancer is the second most commonly diagnosed cancer in males. The use of intra-prostatic fiducial markers (FM) for image-guided radiotherapy (IGRT) has become widespread due to their accuracy, relatively safe use, low cost, and reproducibility. FM provides a tool to monitor prostate position and volume changes. Many studies reported low to moderate rates of complications following FM implantation. In the current study, we present our five years’ experience regarding the insertion technique, technical success, and rates of complication and migration of intraprostatic insertion of FM gold marker.MethodsFrom January 2018 to January 2023, 795 patients with prostate cancer candidate for IGRT (with or without a history of radical prostatectomy) enrolled in this study. We used three fiducial markers (3*0.6 mm) inserted through an 18-gauge Chiba needle under transrectal ultrasonography (TRUS) guidance. The patients were observed for complications up to seven days after the procedure. Besides, the rate of marker migration was recorded.ResultsAll procedures were completed successfully, and all patients tolerated the procedure well with minimal discomfort. The rate of sepsis after the procedure was 1%, and transient urinary obstruction was 1.6%. Only two patients experienced marker migration shortly after insertion, and no fiducial migration was reported throughout radiotherapy. No other major complication was recorded.DiscussionTRUS-guided intraprostatic FM implantation is technically feasible, safe, and well-tolerated in most patients. The FM migration can seldom occur, with negligible effects. This study can provide convincing evidence that TRUS-guided intra-prostatic FM insertion is an appropriate choice for IGRT.

Infection after prostatic transrectal fiducial marker implantation for image guided radiation therapy

PurposeThe aim of this retrospective study is to assess the risk of infection after transrectal ultrasound-guided fiducial marker insertion for image-guided radiotherapy of prostate cancer. Material and methodsBetween January 2016 and December 2020, 829 patients scheduled for intensity-modulated radiotherapy for prostate cancer had an intraprostatic fiducial marker transrectal implantation under ultrasound guidance by radiation-oncologists specialized in brachytherapy. Patients received standard oral prophylactic antibiotic with quinolone. If Gram negative bacteria resistant to quinolone were detected at the time of the prostate cancer biopsies, the antibioprophylaxis regimen was modified accordingly. The resistance to quinolone screening test was not repeated before fiducial marker insertion. Infectious complications were assessed with questionnaires at the time of CT-planning and medical record reviewed. Toxicity was evaluated according to CTCAE v5.0. ResultsThe median time between fiducial marker implantation and evaluation was 10 days (range: 0–165 days). Four patients (0.48%) developed urinary tract infection related to the procedure, mostly with Gram-negative bacteria resistant to quinolone (75%). Three had a grade 2 infection, and one patient experienced a grade 3 urosepsis. The quinolone-resistance status was known for two patients (one positive and one negative) and was unknown for the other two patients prior to fiducial marker implantation. ConclusionIntraprostatic transrectal fiducial marker implantation for image-guided radiotherapy is well tolerated with a low rate of infection. With such a low rate of infection, there is no need to repeat the search of Gram-negative bacteria resistant to quinolone before fiducial marker implantation if it was done at the time of prostate biopsies. Optimal antibioprophylaxis should be adapted to the known status of Gram-negative bacteria resistant to quinolone.

Minimally Invasive Navigation-Guided Quad Zygomatic Implant Placement: A Comparative In Vitro Study.

Purpose: Zygomatic implants (ZIs) have been considered a reliable alternative treatment for patients with maxillary atrophy and/or maxillary defects. The use of a navigation system for assisting ZI placement could be a reliable approach for enhancing accuracy and safety. The purpose of this in vitro study was to evaluate the accuracy of a new dynamic surgical navigation system with its minimally invasive registration guide for quad zygomatic implant placement in comparison with a gold standard navigation approach. Materials and Methods: A total of 40 zygomatic implants were placed in 10 3D-printed models based on the CBCT scans of edentulous patients. For registration, a surgical registration guide with a quick response plate was used for the test group, and five hemispheric cavities as registered miniscrews in the intraoral area were used for the control group. In each model, a split-mouth approach was employed (two ZIs in bilateral zygomata) to test both systems. After ZI placement, a CBCT scan was performed and merged with pre-interventional planning. The deviations between planned and placed implants were calculated as offset basis, offset apical, and angular deviation and compared between the systems. Results: The offset basis, offset apical, and angular deviation were 1.43 ± 0.55 mm, 1.81 ± 0.68 mm, and 2.32 ± 1.59 degrees in the test group, respectively. For the control group, values of 1.48 ± 0.57 mm, 1.76 ± 0.62 mm, and 2.57 ± 1.51 degrees were measured without significant differences between groups (all P < .05). The accuracy of ZI positions (anterior and posterior) were measured without significant differences between groups. Conclusion: Two navigation systems with different registration techniques seem to achieve comparable acceptable accuracy for dynamic navigation of zygomatic implant placement. With the test group system, additional pre-interventional radiologic imaging and invasive fiducial marker insertion could be avoided.

Prostatic urinary tract visualization with super-resolution deep learning models.

In urethra-sparing radiation therapy, prostatic urinary tract visualization is important in decreasing the urinary side effect. A methodology has been developed to visualize the prostatic urinary tract using post-urination magnetic resonance imaging (PU-MRI) without a urethral catheter. This study investigated whether the combination of PU-MRI and super-resolution (SR) deep learning models improves the visibility of the prostatic urinary tract. We enrolled 30 patients who had previously undergone real-time-image-gated spot scanning proton therapy by insertion of fiducial markers. PU-MRI was performed using a non-contrast high-resolution two-dimensional T2-weighted turbo spin-echo imaging sequence. Four different SR deep learning models were used: the enhanced deep SR network (EDSR), widely activated SR network (WDSR), SR generative adversarial network (SRGAN), and residual dense network (RDN). The complex wavelet structural similarity index measure (CW-SSIM) was used to quantitatively assess the performance of the proposed SR images compared to PU-MRI. Two radiation oncologists used a 1-to-5 scale to subjectively evaluate the visibility of the prostatic urinary tract. Cohen's weighted kappa (k) was used as a measure of agreement of inter-operator reliability. The mean CW-SSIM in EDSR, WDSR, SRGAN, and RDN was 99.86%, 99.89%, 99.30%, and 99.67%, respectively. The mean prostatic urinary tract visibility scores of the radiation oncologists were 3.70 and 3.53 for PU-MRI (k = 0.93), 3.67 and 2.70 for EDSR (k = 0.89), 3.70 and 2.73 for WDSR (k = 0.88), 3.67 and 2.73 for SRGAN (k = 0.88), and 4.37 and 3.73 for RDN (k = 0.93), respectively. The results suggest that SR images using RDN are similar to the original images, and the SR deep learning models subjectively improve the visibility of the prostatic urinary tract.

A value-based approach to prostate cancer image-guidance in a regional radiation therapy centre: a cost-minimisation analysis.

Usual practice for the insertion of prostate fiducial markers involves at least one week delay between insertion and simulation. An evidence-based practice change was implemented whereby fiducial marker insertion occurred on the same day as radiotherapy simulation. The aim of this study was to quantify the health service costs and clinical outcomes associated with this practice change. A cost-minimisation analysis was undertaken from the perspective of the local health service. A retrospective chart audit was conducted to collect data on 149 patients in the pre-implementation cohort and 138 patients in the post-implementation cohort. Associated costs with insertion and simulation were calculated and compared across the two cohorts; this included subsided travel costs for rural and remote patients. Fiducial marker positions on planning CT and first treatment CBCT were measured for all patients as the surrogate clinical outcome measure for oedema. The health service saved an average of AU$ 361 (CI $311 - $412) per patient after the practice change. There was no significant difference in fiducial marker position pre- and post- implementation (p<0.05). The practice change to perform insertion and radiotherapy simulation on the same day resulted in substantial savings to the health system, without compromising clinical outcomes. The decrease in number of required patient attendances is of real consequence to rural and remote populations. The practice change increases both the value and accessibility of best-practice health care to those most at risk of missing out.

The Use of HA as Rectal Spacer in Prostate Cancer Patients Undergoing Hypofractionated RT: An Australian Experience

<h3>Purpose/Objective(s)</h3> To report the feasibility, post-operative complications and recto-prostatic separation achieved with hyaluronic acid (HA) inserted into the perirectal fat before definitive prostate radiotherapy (RT). <h3>Materials/Methods</h3> Fifty-seven patients with clinical stage T1-3 prostate cancer underwent transrectal ultrasound guided transperineal insertion of fiducial markers and HA into the perirectal space before volumetric arc RT between 7/2020 to 7/2021. Post insertion computerized tomography (CT) and magnetic resonance imaging (MRI) scans were obtained for treatment planning. HA feasibility, safety and recto-prostatic separation were assessed. The prescribed dose to the planning target volume (PTV) ranged from 60-62Gy in 20 fractions. <h3>Results</h3> The mean age was 74.7 years. The median PSA was 8.1 [Interquartile range (IQR)6.2-10.0]. The majority of patients had ISUP 2 adenocarcinoma (60%). The rest had ISUP 1 (11%) and ISUP 3 (30%). The disease risk was staged as early in 11%, favorable intermediate in 30%, unfavorable intermediate in 58% and high in 2%. Androgen deprivation therapy was delivered in 63%. HA insertion was completed with a 100% success rate. This was rated as ‘easy' to ‘very easy' 100% of the time. There were no device related complications, rectal perforation, serious bleeding, infections or allergic reactions. The mean prostate size was 43cc (IQR 30-55cc). Recto-prostatic separation at the base (measured 5mm below the prostate base), mid gland and apex (measured 5mm above the prostate apex) were 12mm (0.2), 11mm (0.2) and 0.9mm (0.1) respectively. The HA was also symmetrically placed in breadth at the mid gland in all patients. The mean rectal volume receiving 53Gy (rV53) was 3.2% (IQR 1.3-5.5) for patients receiving 60-62Gy. The median follow up was 13.5 months (IQR 9.5-17.5). The risk of any acute GU toxicity was 81%. The majority had grade 1 GU toxicity at 67% with urinary frequency, urgency and obstruction being the commonest reported side effects. The risk of any grade 2 GU toxicity was 14% with urinary obstruction (13%) and urgency (7%). The risk of any acute GI toxicity was 2%. Only 1 patient developed grade 1 GI toxicity with diarrhea. The risk of any late GU toxicity was 43%. The majority had grade 1 GU toxicity at 32% with urinary frequency, urgency and obstruction. The risk of any grade 2 GU toxicity was 11% with urinary obstruction (5%), urgency (5%) and incontinence (2%). The risk of any late GI toxicity was 2%. Only 1 patient had grade 1 GI toxicity with diarrhea. <h3>Conclusion</h3> HA was successfully inserted in all patients and was well tolerated. Recto-prostatic separation was symmetrical in length from the base to the apex and in breadth at the midgland. The risk of developing any acute GI toxicity was minimal at 2% with the use of HA. In addition, the risk of late GI toxicity was 2%, albeit with short follow up.

Hyaluronic acid rectal spacer in EBRT: Usability, safety and symmetry related to user experience

ObjectivesTo report on the usability, safety, symmetry, and effectiveness of hyaluronic acid (HA) injected between the prostate and the rectum for patients undergoing treatment for prostate cancer with external beam radiotherapy (EBRT), and present a novel definition of rectal spacer symmetry that is reproducible and independent of patient anatomy. Patients and Methods102 consecutive patients with clinical stage of T1c-3b prostate cancer underwent general anaesthesia for fiducial marker insertion and injection of HA into the perirectal space before EBRT. HA safety, symmetry, separation, and usability based on user experience were assessed. ResultsHA insertion was completed with a 100% success rate independent of user experience, rated as ‘easy’ or ‘very easy’ in all cases. There were no postoperative complications reported. The mean (SD) recto-prostatic separation for all patients at the base, midgland and apex were 12 (±2) mm, 11 (±2) mm, and 9 (±1) mm respectively. The mean sagittal length of the implant was 43 (±5) mm. The implant was rated as symmetrical in 98% of cases. The mean rV70Gy was 1.6% (IQR 0.8-3.3%) for patients receiving 78-80Gy. The mean rV53Gy was 2.8% (IQR 1.2-4.8%) for patients receiving 60-62Gy. The median prostate size was 43.5 cc (IQR 32-57). ConclusionInjection of HA was able to achieve highly symmetrical recto-prostatic separation, with new users able to produce excellent separation, particularly at the apex, achieving similar dosimetry outcomes as competent and experienced users. HA is safe, easy to use, and significantly reduced mean rV70Gy and rV53Gy compared to non-spacer patients.

Clinical Evaluation of Fiducial Marker Pre-Planning for Virtual Bronchoscopic Navigation Implantation in Lung Tumour Patients Treated With CyberKnife.

PurposeFor the treatment of invisible lung tumours with CyberKnife (CK), fiducial markers (FMs) were implanted as an internal surrogate under virtual bronchoscopic navigation (VBN). This research aims to study the benefits of introducing an additional procedure in assigning the optimal FM positions using a pre-procedure planning system and performing virtual simulation before implantation. The objectives were 1) to reduce the duration of the FM implantation procedure, 2) to reduce the radiation exposure in dose area product (DAP) (dGy*cm2) to patients, and 3) to increase the number of FMs implanted around the tumour.Methods and MaterialsThis study is retrospective, single-centre, and observational in nature. A total of 32 patients were divided into two groups. In Group 1, 18 patients underwent conventional VBN FM implantation. In Group 2, 14 patients underwent additional pre-procedure planning and simulation. The steps of pre-procedure planning include 1) importing CT images into the treatment planning system (Eclipse, Varian Medical Systems, Inc.) and delineating five to six FMs in their ideal virtual positions and 2) copying the FM configuration into VBN planning software (LungPoint Bronchus Medical, Inc.) for verification and simulation. Finally, the verified FMs were deployed through VBN with the guidance of the LungPoint planning software.ResultsA total of 162 FMs were implanted among 35 lesions in 32 patients aged from 37 to 92 (median = 66; 16 men and 16 women). Results showed that 1) the average FM insertion time was shortened from 41 min (SD = 2.05) to 23 min (SD = 1.25), p = 0.00; 2) the average absorbed dose of patients in DAP was decreased from 67.4 cGy*cm2 (SD = 14.48) to 25.3 cGy*cm2 (SD = 3.82), p = 0.01 (1-tailed); and 3) the average number of FMs implanted around the tumour was increased from 4.7 (SD = 0.84) to 5.6 (SD = 0.76), p = 0.00 (1-tailed).ConclusionPre-procedure planning reduces the FM implantation duration from 41.1 to 22.9 min, reduces the radiation exposure in DAP from 67.4 to 25.3 dGy*cm2, and increases the number of FMs inserted around the tumour from 4.7 to 5.6.

Fiducial markers for stereotactic lung radiation therapy: review of the transthoracic, endovascular and endobronchial approaches.

Stereotactic body radiation therapy is an alternative to surgery for early-stage, inoperable peripheral non-small cell lung cancer. As opposed to linear accelerator (linac)-based (e.g. gating) and free-breathing techniques, CyberKnife® with Synchrony® technology allows accurate radiation delivery by means of a real-time respiratory motion tracking system using, in most cases, metal fiducial markers (FMs) placed in the vicinity of the target. The aims of this review are as follows. First, to describe the safety and efficacy of the transthoracic, endovascular and endobronchial FM insertion techniques for peripheral pulmonary lesions (PPLs). Second, to analyse performance in terms of the migration and tracking rates of different FM types. Recent developments in FM tracking for central lesions will also be reviewed. In conclusion, for PPLs, the endobronchial approach provides a low rate of pneumothorax, offers the possibility of concurrent diagnostic sampling for both the PPL and the lymph nodes, and, finally, reduces the intervention time compared to other techniques. In this context, coil-tailed and coil-spring FMs have shown the lowest migration rate with a consequently high tracking rate.

EUS-guided fiducial marker insertion for radiotherapy in advanced esophageal carcinoma: submucosal insertion may lead to less migration when compared to intratumoral insertion.

The use of radiotherapy is frequently required in the treatment of locally advanced esophageal squamous cell carcinoma. However, the margins of the tumor are often difficult to ascertain on computed tomography. Thus, EUS-guided fiducial marker insertion can aid the localization of the margins of the tumor. However, the optimal technique of the procedure is still uncertain. This was a retrospective study of all patients that received EUS-guided fiducial marker insertion between March 2015 and December 2018. All patients suffering from esophageal squamous cell carcinoma scheduled for radiotherapy underwent the procedure within one week of the scheduled appointment. Gold fiducial markers were inserted under EUS guidance either intratumorally or within the submucosa just proximal and distal to the tumor. Outcome parameters included tumor characteristics, early and late migration rates, and tumor response rates. During the study period, 40 patients were recruited. 10 fiducial markers were placed intratumorally and 30 markers were placed submucosally. When comparing fiducials that were placed in the submucosa versus intratumorally, significantly more fiducials had early (40% vs 0%, RR = 0.6, 95% CI 0.36, 1.00) and late migration (60% vs 0%, RR = 0.33, 95% CI 0.13, 0.84) in the intratumoral group. The submucosal group had significantly more patients intended for curative intent (96.7% vs 70%, RR = 0.34, 95%CI 0.003, 0.361) and more patients with partial and complete response. There was no difference between the gross tumor volume, the clinical target volume, and the total radiation dose. In esophageal carcinomas planned for radiotherapy, fiducial markers placed in the submucosa may lead to less migration.

PH-0430 The benefits of pre-procedure planning in fiducial marker insertion for CyberKnife treatment

PH-0430 The benefits of pre-procedure planning in fiducial marker insertion for CyberKnife treatment

Australasian Gastro-Intestinal Trials Group (AGITG) MASTERPLAN: Randomized phase II study of modified neoadjuvant FOLFIRINOX alone or in combination with stereotactic radiotherapy (SBRT) for patients with high-risk and locally advanced pancreatic cancer.

TPS4172 Background: Eighty per cent of patients with non-metastatic pancreatic cancer have high-risk, borderline resectable (BRPC) or locally advanced pancreas cancer (LAPC), conferring a 5-year overall survival of only 12%. MASTERPLAN evaluates the safety and activity of stereotactic body radiotherapy (SBRT) added to neoadjuvant chemotherapy in these patient cohorts. Methods: MASTERPLAN is an investigator-initiated prospective multi-centre randomized phase II trial. Inclusion criteria include histologically confirmed high-risk, BRPC or LAPC. High risk is defined as tumour &gt; 4cm, extrapancreatic extension or node positive. Randomisation is 2:1 to chemotherapy + SBRT (investigational arm) or chemotherapy (control arm) by minimisation with stratification by operability (potentially operable - high risk; BRPC versus inoperable – LAPC; medically inoperable), planned chemotherapy and institution. Both treatment arms receive 6 x 2 weekly cycles of modified FOLFIRINOX (mFOLFIRINOX). Gemcitabine and nab-paclitaxel is permitted if mFOLFIRINOX is unsuitable. The investigational arm receives SBRT (40Gy in 5 fractions) with real time quality assurance. Resectability will be evaluated following initial chemotherapy +/- SBRT. Adjuvant chemotherapy is 6 cycles (12 weeks) of mFOLFIRINOX, or the same duration of gemcitabine and capecitabine (GEMCAP) if neoadjuvant gemcitabine/ nab-paclitaxel given. SBRT adverse events (AEs) will be recorded until study cessation. The primary endpoint is 12-month locoregional control. Secondary endpoints: safety, surgical morbidity and mortality, radiological response rate, progression free survival, pathological response rate, surgical resection rate, R0 resection rate, quality of life, deterioration free survival and overall survival. Biospecimens are collected for translational research for potential prognostic/predictive biomarkers of clinical endpoints and include serial tumour tissue collection from patients undergoing fiducial marker insertion and/or surgery, biopsy at disease progression, serial blood collection and serial buccal and faecal sample collection. An interim analysis will review locoregional failure, distant metastasis and rate of death on the first 40 patients after completion of 12 months follow up. The sample size is 120 patients (80 intervention:40 control), balanced for BRPC/LAPC (60 in each cohort). The minimum follow up is 12 months. The first site opened in October 2019 and 10 patients have been recruited from five sites at 17 Feb 2021. Overall 15 sites in Australia and New Zealand are planned to open to recruitment. Australian Clinical Trials Registry Number: ACTRN12619000409178. Clinical trial information: ACTRN12619000409178.

EUS-guided placement of fiducial markers for stereotactic body radiation therapy in pancreatic cancer: feasibility, security and a new quality score

Background and study aims In borderline resectable/locally advanced pancreatic ductal adenocarcinoma (PDAC), stereotactic body radiation therapy (SBRT) is an emerging neoadjuvant treatment option. Endoscopic ultrasound (EUS)-guided insertion of fiducial markers being a prerequisite, our aim was to assess its feasibility and safety and also to evaluate its success, from both the endoscopist’s and radiotherapist’s perspectives. Patients and methods We prospectively collected data concerning PDAC patients submitted to EUS-guided fiducial placement, from February 2018 to November 2019. Technical success was defined as at least one marker presumed inside the tumor. Quality success was assessed at pre-SBRT computed tomography, accordingly to the number of markers inside or < 1 cm from the tumor, number of markers at the tumor extremity, their location in different planes, the distance between them, and their distance from the biliary stent (if present). A new quality score was then proposed and high-quality success defined as at least six of 12 points. Results Thirty-seven patients were enrolled. A total of 97 fiducials were implanted, with a median of three fiducials per patient (0–4). The technical success rate was 92 %, with failure of fiducial placement in three patients. Three patients (8 %) had adverse events (fever, mild acute pancreatitis, and biliary stent migration). At pre-SBRT evaluation, two patients’ markers had migrated. The high-quality success rate was 62.5 %. Conclusions Our results contribute to demonstrating the feasibility and safety of EUS-guided fiducial placement for SBRT treatment in PDAC. It is hoped that the newly proposed quality score will pave the way for improving fiducial positioning and SBRT delivery.

Patient perceptions and preferences about prostate fiducial markers and ultrasound motion monitoring procedures in radiation therapy treatment.

IntroductionPatient experiences and preferences of image‐guidance procedures in prostate cancer radiotherapy are largely unknown. This study explored experiences and preferences of patients undergoing both fiducial marker (FM) insertion and Clarity ultrasound (US) procedures.MethodsA sequential explanatory mixed method approach was used. A questionnaire (n = 40) ranked experiences from 0 to 10 (worst) in the domains of invasiveness; pain; physical discomfort; and psychological discomfort. Responses were analysed with descriptive and inferential statistics. Semi‐structured interviews (n = 22) obtained further insights into their perspectives and preferences and were thematically analysed.ResultsPerceptions of invasiveness varied with 46% reporting FMs more invasive than US and 49% the same for the two procedures. The mean score for FM was 3.6 and 2.1 for US. Mean scores for pain, physical and psychological discomfort were higher for FMs with 3.3, 3.2 and 2.9, respectively, and 1.1, 1.2 and 1.7 respectively for US, only pain achieved significance (P < 0.05). Three themes emerged from the interviews: Expectations versus Experience; Preferences linked to Priorities; and Motivations. Eleven patients (50%) preferred US; however, 10 (45%) could not illicit a preference.ConclusionParticipants found both of the FM and US image‐guidance procedures tolerable and acceptable. Men’s preference was elusive, suggesting a more rigorous preference methodology is required to understand preferences in this population.

Prevention of Wrong-level Surgery in the Thoracic Spine: Preoperative Computer Tomography Fluoroscopy-guided Percutaneous Gold Fiducial Marker Placement in 57 Patients.

Retrospective review. The aim of this study was to evaluate the feasibility, safety,s and complications of computer tomography (CT) fluoroscopy-guided percutaneous transpedicular gold fiducial marker insertion to reduce incidence of wrong-level surgery in the thoracic spine. Intraoperative localization of the correct thoracic level can be challenging and time-consuming, especially in obese patients and patients with anatomical variations. In the literature there are very few studies containing low numbers of patients which assessed CT or CT fluoroscopy-guided fiducial marker placement of the thoracic spine. Description of this technique has been similarly scarce. All patients who underwent percutaneous CT fluoroscopy-guided gold fiducial marker placement of the thoracic spine were retrospectively reviewed. Indications for surgery included degenerative disc disease, infection, spinal metastasis, and intra- and extradural tumors. Gold fiducial markers were placed using a percutaneous CT fluoroscopy-guided transpedicular approach with local anesthesia. In addition, sex, age, body mass index (BMI), thoracic level, related pathology, and procedure-related complications were also recorded. A total of 57 patients (24 females, 33 males) were included. Mean age was 58.6 ± 15.5 years. No complications during CT fluoroscopy-guided gold fiducial marker placement were recorded. Intraoperative localization was successful in all patients. Mean BMI was 32.98 kg/m (range, 18.63-56.03 kg/m), and 63% of patients were obese (>30 kg/m). T7 (n = 11) was the most often marked vertebral body, followed by T10 (n = 10) and T6 (n = 7). The most cranial and most caudal levels marked were T2 and T12, respectively. Preoperative CT fluoroscopy-guided percutaneous gold fiducial marker placement is safe, feasible, and accurate. The resulting facilitated localization of the intended thoracic level of surgery can reduce the length of surgery and prevent wrong-level surgery. Further studies are needed to evaluate in the effect on exposure to radiation and quantify the difference in operating room time. 4.

Absence of prostate oedema obviates the need for delay between fiducial marker insertion and radiotherapy simulation.

IntroductionFiducial markers (FMs) are commonly inserted into the prostate for image guided radiation therapy. This study aimed to quantify prostate oedema immediately following FM insertion compared to prostate volumes measured a week later, at the time of simulation for radiation therapy.MethodsThirty patients underwent a verification computed tomography (VCT) scan in treatment position immediately after the fiducial insertion and their planning computed tomography scan (PCT) one week after. Patient data sets were retrospectively evaluated, comparing prostate volumes and planning target volumes (PTV). Volumes were delineated by a single radiation oncologist, blinded to whether the scan was VCT or PCT. Distances between the FMs were measured on both scans. Descriptive statistics described the data, DICE similarity co‐efficient (DSC) calculated, and paired t‐tests were used to compare paired data.ResultsThe median prostate volume was 35.09 cc and 36.31 cc for VCT and PCT data sets, respectively, and median PTV was 118.56 cc and 127.04 cc for VCT and PCT, respectively. There was no significant difference in prostate volumes (P = 0.3037) or PTV (P = 0.1279), with a DSC of 0.87 (range 0.76–0.91) and 0.91 (range 0.85 to 0.95), respectively. Similarly, there was no significant difference in distance between fiducial markers (P > 0.05).ConclusionThis study demonstrates no statistically significant difference in prostate or PTV volumes (P > 0.05) between the CT acquired at fiducial marker insertion compared with the CT acquired a week later. Therefore, oedema is not significant enough to justify a delay between FM insertion and simulation.