Transperineal implantation of gold fiducial markers (gold seeds) for prostate image-guided radiation therapy: a feasible technique associated with a low risk of complications

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

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

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

OBJECTIVES

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Impact of Dose Perturbations Around Brachytherapy Seeds in External-Beam Radiotherapy Planning: A Fundamental and Clinical Validation Using Treatment Planning System-Based Monte Carlo Simulations

Background This study evaluates dose perturbations caused by nonradioactive seeds in clinical cases by employing treatment planning system-based Monte Carlo (TPS-MC) simulation. Methodology We investigated dose perturbation using a water-equivalent phantom and 20 clinical cases of prostate cancer (10 cases with seeds and 10 cases without seeds) treated at Fujita Health University Hospital, Japan. First, dose calculations for a simple geometry were performed using the RayStation MC algorithm for a water-equivalent phantom with and without a seed. TPS-independent Monte Carlo (full-MC) simulations and film measurements were conducted to verify the accuracy of TPS-MC simulation. Subsequently, dose calculations using TPS-MC were performed on CT images of clinical cases of prostate cancer with and without seeds, and the dose distributions were compared. Results In clinical cases, dose calculations using MC simulations revealed hotspots around the seeds. However, the size of the hotspot was not correlated with the number of seeds. The maximum difference in dose perturbation between TPS-MC simulations and film measurements was 3.9%, whereas that between TPS-MC simulations and full-MC simulations was 3.7%. The dose error of TPS-MC was negligible for multiple beams or rotational irradiation. Conclusions Hotspots were observed in dose calculations using TPS-MC performed on CT images of clinical cases with seeds. The dose calculation accuracy around the seeds using TPS-MC simulations was comparable to that of film measurements and full-MC simulations, with differences within 3.9%. Although the clinical impact of hotspots occurring around the seeds is minimal, utilizing MC simulations on TPSs can be beneficial to verify their presence.

UroLift implants as surrogate fiducial markers for cone-beam CT-based prostate image-guided radiotherapy

Introduction:

UroLift implants are a novel treatment for the obstructive lower urinary tract symptoms arising from benign prostatic hyperplasia. This case study aimed to assess their effectiveness as fiducial marker (FM) surrogates in prostate image-guided radiotherapy (IGRT).

Method:

Cone-beam CT images from a patient receiving prostate radiation therapy underwent manual alignment using UroLift implants and also prostate soft-tissue matching by five experienced therapeutic radiographers. The match values of both methods were compared using Bland–Altman analysis. All five observers were also asked to score the ease of matching using both approaches.

Results:

The 95% mean level of agreement for the UroLift matches were within a 2-mm threshold in all dimensions. Comparison of UroLift and prostate matches had 95% limit of agreement values of −0·98 to 1·78, −0·58 to 0·49 and −1·83 to 1·04 mm in the vertical, longitudinal and lateral planes, respectively. All of the UroLift matches were rated as ‘very easy’ or ‘possible with little difficulty’ by the five observers.

Conclusion:

A small difference between the CBCT UroLift and CBCT prostate match was found. It has been shown that IGRT to the prostate with the aid of the UroLift system implants and CBCT is feasible and can eliminate the need for FM implants. Wider evaluation in a large cohort is recommended.

Towards an Implantable Fluorescence Image Sensor for Real-Time Monitoring of Immune Response in Cancer Therapy

Real-time monitoring of cellular-level changes inside the body provides key information regarding disease progression and therapy assessment for critical care including cancer therapy. Current state-of-the-art oncological imaging methods impose unnecessary latencies to detect small cell foci. Invasive methods such as biopsies, on the other hand, cause disruption if deployed on a repeated basis. Therefore, they are not practical for real-time assessments of the tumor tissue. This work presents a proof-of-concept design for an implantable fluorescence lensless image sensor to address the pervasive challenge of real-time tracking of the immune response in immunotherapy. The 2.4x4.7 mm² integrated circuit (IC) prototype consists of a 36 by 40 pixel array, a laser driver and a power management unit harvesting power and transferring 11.5 kbits/frame through a wireless ultrasound link while implanted 2 cm deep inside the body. Compared to prior art, this is the first full-fledged wireless system implementing chip-scale fluorescence microscopy to the best of our knowledge.Clinical relevance- This prototype can be used to personalize immunotherapy for the 50% of cancer patients who do not initially respond to the therapy.

Risks and Benefits of Fiducial Marker Placement in Tumor Lesions for Robotic Radiosurgery: Technical Outcomes of 357 Implantations

Simple Summary

Robotic radiosurgery (RRS) allows for the accurate treatment of primary tumors or metastases with high single doses. However, organ motion during or between fractions can lead to imprecise irradiation. We sought to evaluate the risks and advantages of fiducial marker (FM) implantation regarding clinical complications, marker migration, and motion amplitude. Complications were most common in Synchrony^®-tracked lesions affected by respiratory motion, particularly lung lesions. Pneumothoraces and pulmonary bleeding were the most common complications. An increased complication rate was associated with concomitant biopsy sampling and FM implantation. Most FM migration observed in this study occurred after CT-guided placements and clinical FM insertions. The largest motion amplitudes were observed in hepatic and lower lung lobe lesions. This study highlights the benefits of marker implantation, especially in lesions with a large motion amplitude, including hepatic lesions and lesions of the lower lobe of the lung located >100.0 mm from the spine.

Abstract

Fiducial markers (FM) inserted into tumors increase the precision of irradiation during robotic radiosurgery (RRS). This retrospective study evaluated the clinical complications, marker migration, and motion amplitude of FM implantations by analyzing 288 cancer patients (58% men; 63.1 ± 13.0 years) who underwent 357 FM implantations prior to RRS with CyberKnife, between 2011 and 2019. Complications were classified according to the Society of Interventional Radiology (SIR) guidelines. The radial motion amplitude was calculated for tumors that moved with respiration. A total of 725 gold FM was inserted. SIR-rated complications occurred in 17.9% of all procedures. Most complications (32.0%, 62/194 implantations) were observed in Synchrony^®-tracked lesions affected by respiratory motion, particularly in pulmonary lesions (46.9% 52/111 implantations). Concurrent biopsy sampling was associated with a higher complication rate (p = 0.001). FM migration occurred in 3.6% after CT-guided and clinical FM implantations. The largest motion amplitudes were observed in hepatic (20.5 ± 11.0 mm) and lower lung lobe (15.4 ± 10.5 mm) lesions. This study increases the awareness of the risks of FM placement, especially in thoracic lesions affected by respiratory motion. Considering the maximum motion amplitude, FM placement remains essential in hepatic and lower lung lobe lesions located >100.0 mm from the spine.

Prostate Fiducial Marker Placement in Patients on Anticoagulation: Feasibility Prior to Prostate SBRT

Background and Purpose: Fiducial marker placement is required in patients undergoing robotic-based Stereotactic Body Radiotherapy (SBRT) or image-guided radiation therapy (IGRT) for prostate cancer. Many patients take antiplatelet or anticoagulant medication due to other medical comorbidities. They are often required to temporarily discontinue these medications prior to invasive medical procedures as they are prone to bleed. Some patients are unable to discontinue therapy due to an elevated risk of thromboembolic events. The purpose of this study is to report this institution's experience placing fiducial markers in prostate cancer patients who are on chronic antiplatelet or anticoagulant medication. Materials and Methods: From August 2015-March 2019 57 patients on chronic antiplatelet or anticoagulation therapy who were not cleared to stop these medications underwent transrectal ultrasound guided (TRUS) fiducial marker placement for SBRT/IGRT. All patients were monitored by a registered nurse during the procedure for prolonged bleeding that required staff to hold pressure to the area with a 4 × 4 gauze until it resolved. All patients were also called the following day to assess for ongoing bleeding events. Treatment planning CT scan confirmed the ideal geometry of the marker placement. Results: All 57 patients on antiplatelet or anticoagulant medication who underwent fiducial marker placement were discharged home the same day of the procedure. Four patients experienced persistent bleeding that required a nurse to hold prolonged pressure to the area. No patient experienced significant bleeding the following day or any untoward cardiovascular event. Conclusions: This series suggests the use of antiplatelet or anticoagulant medication is not an absolute contraindication to fiducial marker placement in patients undergoing SBRT or IGRT for prostate cancer. These patients should be closely monitored after the procedure for bleeding complications. Practitioners may consider the patient's medical comorbidities, risk factors for thromboembolism, and overall functional status as there is no standardized protocol for discontinuing anticoagulant or antiplatelet therapy for fiducial marker placement.

Safety and efficacy of fiducial marker implantation for robotic stereotactic body radiation therapy with fiducial tracking

Purpose

The purpose of this study was to assess the feasibility, efficacy and toxicity of fiducial marker implantation and tracking in CyberKnife® stereotactic radiation therapy (SBRT) applied to extracranial locations.

Materials and method

This is a retrospective, single-centre, observational study to collect the data of all patients treated by stereotactic radiation therapy with fiducial marker tracking at extracranial locations, conducted between June 2014 and November 2017. Information regarding the implantation procedure, the types of toxicity related to marker implantation and the number of markers implanted/tracked during treatment were collected. Complication rates were evaluated using the CTCAE v4 [Common Terminology Criteria for Adverse Events] scale. The technical success rate was based on the ability to optimally track the tumor throughout all treatment fractions.

Results

Out of 2505 patients treated by stereotactic radiation therapy, 25% received treatment with fiducial marker tracking. The total number of implantation procedures was 616 and 1543 fiducial markers were implanted. The implantation-related complication rate was 3%, with 16 Grade 1 events and 4 Grade 2 events. The number of treated patients and the number of implanted markers has gradually increased since the technique was first implemented. The median treatment time was 27 min (range 10–76). 1295 fiducials were effectively tracked throughout all treatment fractions, corresponding to a technical success rate of 84%. The difference between the number of fiducials implanted and those tracked during treatment decreased significantly as the site’s experience increased.

Conclusion

Fiducial marker implantation and tracking is feasible, well-tolerated, and technically effective technique in SBRT for extracranial tumors.

Fiducial markers in prostate cancer image-guided radiotherapy

Background: Image-guided radiotherapy (IGRT) is recommended to reduce the risk of geometrical miss when modern radiotherapy technologies with high grades of conformity are used. The purpose of this study was to evaluate the efficacy of fiducial markers (FMs) for electronic portal imaging in prostate cancer radiotherapy in term of evaluating the complications associated with FMs implantation, quantifying inter-fraction prostate motion, and determination of optimal planning target volume (PTV) margins.

Methods: In this single institution, prospective, consecutive study, 27 patients underwent implantation of three-gold seed FMs into the prostate gland before prostate radiotherapy. Prior to computed tomography planning, all patients were asked to report any complication associated with FMs implantation that have experienced to date. Daily pre-treatment electronic portal images were captured, and prostate position errors were corrected if they were greater than 2 mm along three translational directions. Optimal PTV expansions were computed using van Herk formula [PTV-margin= 2.5Σ + 0.7σ].

Results: FMs implantation was successful with an acceptable toxicity profile in all patients. Without IGRT, margins of 5.4 mm, 5.8 mm and 5.5 mm, in vertical, longitudinal and lateral directions, respectively, are needed for a 95% confidence level of complete clinical target volume (CTV) coverage in each treatment session. The PTV margins of 3.0 mm, 3.3 mm and 4.0 mm in corresponding directions were calculated when FMs based electronic portal imaging was applied.

Conclusion: FMs based electronic portal imaging is an effective tool for prostate cancer IGRT.

Fiducial markers implantation for prostate image-guided radiotherapy: a report on the transperineal approach

INTRODUCTION

In the external beam prostate cancer radiation therapy, daily gland displacement could lead to a target missing. The use of intra-prostatic gold fiducial markers for daily prostate position verification and correction before and during treatment delivery (image-guided radiotherapy, IGRT) is widely used in the radiation therapy centers to accurately target the prostate. Usually, the fiducial markers are implanted through the rectum, with complications such as infections and rectal bleeding. We report our experience in prostate fiducial markers implantation through a transperineal approach.

PATIENTS AND METHODS

Between September 2011 and January 2018 at our center, 101 patients underwent gold seed fiducial marker transperineal ultrasound-guided implantation for prostate IGRT. We retrospectively reviewed their features and outcome. Twenty-two (21.8%) patients had previously been subjected to a transurethral prostate resection (TURP) for obstructive urinary symptoms because of benign prostatic hypertrophy. No antibiotic prophylaxis was used.

RESULTS

The procedure was well tolerated. In one patient, a single episode of self-limiting urinary bleeding occurred just after it. No other complication was recorded. All the patients, at the evaluation before discharge, reported no pain or dysuria. No rectal bleeding, hematospermia, urinary obstruction or infection were reported in the next days. No markers lost or migration occurred.

DISCUSSION AND CONCLUSION

According to our experience, prostate fiducial markers implantation through a transperineal approach is safe and should be recommended to limit the use of antibiotic therapy and patients morbidity. A previous TURP was not related to a higher risk of loss of seeds.

Internal Fusion: exact correlation of transrectal ultrasound images of the prostate by detailed landmarks over time for targeted biopsies or follow-up

PURPOSE

Innovative imaging modalities are applied for diagnosing and follow-up of prostate cancer (PCa). To perform authentic targeted biopsies and evaluate prostate changes, it is essential to reliably identify and hit targets in their true anatomical location over time. A newly described image correlation method (Internal Fusion) allows precise correlation of serial transrectal ultrasound (TRUS) images in vitro and vivo. Identifiable morphologic structures such as prostatic calcifications define internal anchor points (Internal Landmarks) to facilitate exact correlation.

METHODS

After verification of Internal Fusion in vitro, 83 patients were included from January to August 2017 with at least one prior series of 5-mm spaced TRUS images stored as computed tomographic (US-CT) online data set. Two experienced operators collected new images in correlation with each cross-section of the previous examinations based on Internal Landmarks.

RESULTS

Of the 83 patients, fifty (60%) had prior negative biopsies. Fourteen (17%) wished US-CT targeted biopsies and PCa were detected in 7/14 patients (50%). Overall, accurate imaging correlations were attained in 369/397 slices (93%). In initial and repeat biopsy, 31/31 and 35/35 images could be correlated detecting PCa in 5/8 (63%) and 2/6 patients (33%). The longest observation of prostate changes over time (Trend Monitoring) with accurate image correlation was 8 years and 6 months.

CONCLUSIONS

Internal Fusion by Internal Landmarks ensures exact correlation in long-term follow-up. It is possible to precisely monitor trends in prostate tissue changes. In case of PCa suspicion, biopsies could be targeted with high accuracy by Internal Fusion, even over time.

Classifying high-risk versus very high-risk prostate cancer: is it relevant to outcomes of conformal radiotherapy and androgen deprivation?

OBJECTIVE

To evaluate outcomes in prostate cancer patients classified as high-risk (HR) or very high-risk (VHR) who were treated with conformal radiation therapy (CRT) and androgen deprivation therapy (ADT).

METHODS

Between 11/2001 and 3/2012, 203 patients with HR disease received CRT to the prostate (78-82 Gy) and pelvic lymph nodes (46-50 Gy) with ADT (6 m-2 years). Median follow-up was 50 months (12 m-142 m). Biochemical failure was defined according to Phoenix definition. Imaging studies were used to identify local, regional or metastatic failure. Four different VHR/HR groupings were formed using the 2014 and revised 2015 NCCN guidelines. Differences were examined using Kaplan Meier (KM) estimates with log rank test and uni- and multivariate Cox regression analysis (MVA).

RESULTS

Failure occurred in 30/203 patients (15%). Median time to failure was 30 m (4 m-76 m). KM estimate of 4 year biochemical disease free survival (b-DFS) for the entire cohort was 87% (95%CI: 82-92%). Four year KM survival estimates for b-DFS, PCSS and OS were comparable for each NCCN subgroup. On univariate analysis, the NCCN subgroups were not predictive of b-DFS at 4 years, however, DMFS was worse for both VHR subgroups (p = .03and .01) respectively. Cox univariate analysis was also significant for: PSA ≥40 ng/ml p = 0.001; clinical stages T2c p = .004, T3b p = .02 and > 4 cores with Gleason score 8-10 p < .03. On MVA, only PSA ≥ 40 ng/ml was predictive for b-DFS or MFS at 4 years (HR: 3.75 and 3.25, p < 0.005).

CONCLUSION

Patients with HR and VHR disease treated with CRT and ADT had good outcomes. Stratification into HR and VHR sub-groups provided no predictive value. Only PSA ≥40 ng/ml predicted poor outcomes on MVA. Distant failure was dominant and local recurrence rare, suggesting that improved systemic treatment rather than intensification of local therapy is needed. Patients with high-risk prostate cancer are most often treated with conformal dose escalated radiation therapy with androgen deprivation. Stratification into high versus very high-risk subgroups using 2014 or revised 2015 National Comprehensive Cancer Network (NCCN) criteria did not impact treatment outcomes. Only Prostate Serum Antigen (PSA) ≥40 ng/ml was predictive of poor prognosis. Distant failure was dominant and local recurrence uncommon which challenges the notion that intensification of local therapy will further improve outcomes in patients with high-risk disease.

Transperineal implantation of gold fiducial markers (gold seeds) for prostate image-guided radiation therapy: a feasible technique associated with a low risk of complications

Introduction

The purpose is to describe the method, safety and efficacy of transperineal gold seed placement for image‐guided radiation therapy.

Methods

An ethics committee approved database was used to review records of consecutive patients from October 2008 through December 2013, who underwent transperineal implantation of three gold markers into the prostate using staged local anaesthesia and transrectal ultrasound. Seeds were counted on radiographs from CT simulation, first treatment and last treatment. Retention and use of at least three markers for kV/kV matching was considered a successful implant. A visual analogue scale (VAS) pain assessment was performed. SAS was used for data analysis.

Results

Fiducial marker placement was successful for kV/kV matching in 556/581 patients (95.7%). The procedure was aborted due to pain in two patients. Additional sedation during the procedure was required in two patients. Complications include urinary infections (2 patients, <0.5%) and transient haematuria (2 patients, <0.5%). There were no recorded calls requesting additional pain medication or delays in radiation due to complications. The number of seeds identified at simulation: 4 (2 patients), 3 (554 patients), 2 (21 patients), 1 (1 patient), 0 (1 patient). One patient with three seeds and two patients with <2 seeds had cone beam CT instead of kV/kV imaging for image guidance. No seeds were lost after simulation. The mean visual analogue pain score associated with transperineal gold seed insertion met patients' expectations (respectively 4.1 vs. 4.4 P = 0.19).

Conclusion

Outpatient transperineal insertion of fiducials avoids the rectum, is effective, convenient, well tolerated and has few side effects.