Transperineal gold marker implantation for image-guided external beam radiotherapy of prostate cancer: A single institution, prospective study

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.

The role of a radiopaque peri-rectal hydrogel spacer in aiding accurate daily image-guidance for prostate stereotactic radiotherapy

Introduction

Precise patient positioning with image guidance (IGRT) is essential for safe prostate radiotherapy. We present the first report of utilizing a CT-visible hydrogel spacer, used to decrease rectal radiation dose, as a surrogate fiducial marker to aid in daily IGRT with cone-beam CT (CBCT) in stereotactic radiotherapy (SABR) for prostate cancer.

Materials and methods

Prior to CT simulation, patients underwent placement of three intraprostatic gold fiducial markers and radiopaque hydrogel spacer per standard practice. At treatment, after initial setup, a CBCT was acquired and fused to the planning CT based on 3-dimensional matching of the spacer. A second alignment was then performed based on the fiducial markers. The six directional shifts (three linear and three rotational) were recorded, and the differences compared.

Results

140 individual fractions across 41 consecutive patients were evaluated. Mean/median differences between hydrogel spacer-based and fiducial-based alignment in linear (vertical, longitudinal, lateral) and rotational (rotation, pitch, roll) shifts were 0.9/0.6mm, 0.8/0.5mm, and 0.6/0.4mm, and 0.38/0, 0.62/0, and 0.35/0 degrees, respectively. No difference was observed in 9.9%, 22.9%, and 22.14% of linear shifts, and 65.7%, 65%, and 66.4% rotational shifts, respectively. Significantly smaller differences were observed in the latter 70 fractions vs. the former, and results were consistent across evaluators.

Conclusions

For precise daily IGRT with CBCT for prostate SABR, alignment using a radiopaque hydrogel spacer was highly comparable to intraprostatic fiducial markers. This represents the first report supporting an additional indication of IGRT for a CT-visible hydrogel spacer, to further enhance treatment accuracy and potentially obviate the need for the additional fiducial marker procedure.

Acute side effects after definitive stereotactic body radiation therapy (SBRT) for patients with clinically localized or locally advanced prostate cancer: a single institution prospective study

Background

The aim of the study was to evaluate acute side effects after extremely hypofractionated intensity-modulated radiotherapy (IMRT) with stereotactic body radiation therapy (SBRT) for definitive treatment of prostate cancer patients.

Patients and methods

Between February 2018 and August 2019, 205 low-, intermediate- and high-risk prostate cancer patients were treated with SBRT using “CyberKnife M6” linear accelerator. In low-risk patients 7.5–8 Gy was delivered to the prostate gland by each fraction. For intermediate- and high-risk disease a dose of 7.5–8 Gy was delivered to the prostate and 6–6.5 Gy to the seminal vesicles by each fraction with a simultaneous integrated boost (SIB) technique. A total of 5 fractions (total dose 37.5–40 Gy) were given on every second working day. Acute radiotherapy-related genitourinary (GU) and gastrointestinal (GI) side effects were assessed using Radiation Therapy Oncology Group (RTOG) scoring system.

Results

Of the 205 patients (28 low-, 115 intermediate-, 62 high-risk) treated with SBRT, 203 (99%) completed the radiotherapy as planned. The duration of radiation therapy was 1 week and 3 days. The frequencies of acute radiotherapy-related side effects were as follows: GU grade 0 – 17.1%, grade I – 30.7%, grade II – 50.7%, grade III – 1.5%; and GI grade 0 – 62.4%, grade I–31.7%, grade II–5.9%, grade III–0%. None of the patients developed grade ≥ 4 acute toxicity.

Conclusions

SBRT with a total dose of 37.5–40 Gy in 5 fractions appears to be a safe and well tolerated treatment option in patients with prostate cancer, associated with slight or moderate early side effects. Longer follow-up is needed to evaluate long-term toxicity and biochemical control.

Impact of bladder volume on acute genitourinary toxicity in intensity modulated radiotherapy for localized and locally advanced prostate cancer

BACKGROUND AND PURPOSE

To evaluate the effect of changes in bladder volume during high-dose intensity-modulated-radiotherapy (IMRT) of prostate cancer on acute genitourinary (GU) toxicity and prospectively evaluate a simple biofeedback technique for reproducible bladder filling with the aim of reducing acute GU toxicity.

METHODS

One hundred ninety-three patients were trained via a biofeedback mechanism to maintain a partially filled bladder with a reproducible volume of 200-300 cc at planning CT and subsequently at each fraction of radiotherapy. We prospectively analyzed whether and to what extent the patients' ability to maintain a certain bladder filling influenced the degree of acute GU toxicity and whether cut-off values could be differentiated.

RESULTS

We demonstrated that the ability to reach a reproducible bladder volume above a threshold volume of 180 cc and maintain that volume via biofeedback throughout treatment predicts for a decrease in acute GU toxicity during curative high-dose IMRT of the prostate. Patients who were not able to reach a partial bladder filling to that cut-off value and were not able to maintain a partially filled bladder throughout treatment had a significantly higher risk of developing ≥grade 2 GU acute toxicity.

CONCLUSION

Our results support the hypothesis that a biofeedback training for the patient is an easy-to-apply, useful, and cost-effective tool for reducing acute GU toxicity in high-dose IMRT of the prostate. Patients who are not able to reach and maintain a certain bladder volume during planning and treatment-two independent risk factors-might need special consideration.

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.

Penile bulb sparing in prostate cancer radiotherapy : Dose analysis of an in-house MRI system to improve contouring

OBJECTIVE

This study aimed to assess the reduction in dose to the penile bulb (PB) achieved by MRI-based contouring following drinking and endorectal balloon (ERB) instructions.

PATIENTS AND METHODS

A total of 17 prostate cancer patients were treated with intensity-modulated radiation therapy (IMRT) and interstitial brachytherapy (IBT). CT and MRI datasets were acquired back-to-back based on a 65 cm³ air-filled ERB and drinking instructions. After rigid co-registration of the imaging data, the CT-based planning target volume (PTV) used for treatment planning was retrospectively compared to an MRI-based adaptive PTV and the dose to the PB was determined in each case. The adapted PTV encompassed a caudally cropped CT-based PTV which was defined on the basis of the MRI-based prostate contour plus an additional 5 mm safety margin.

RESULTS

In the seven-field IMRT treatment plans, the MRI-based adapted PTV achieved mean (D_mean) and maximum (D_max) doses to the PB which were significantly lower (by 7.6 Gy and 10.9 Gy, respectively; p <0.05) than those of the CT-contoured PTV. For 6 patients, the estimated PB D_max (seven-field IMRT and IBT) for the adapted PTV was <70 Gy, whereas only 1 patient fulfilled this criterium with the CT-based PTV.

CONCLUSION

MRI-based contouring and seven-field IMRT-based treatment planning achieved dose sparing to the PB. Whereas the comparison of MRI and CT contouring only relates to external beam radiotherapy (EBRT) sparing, considering EBRT and IBT shows the improvement in PB sparing for the total treatment.

Potential Applications of Nanotechnology in Urological Cancer

Nowadays, the potential scope of nanotechnology in uro-oncology (cancers of the prostate, bladder, and kidney) is broad, ranging from drug delivery, prevention, and diagnosis to treatment. Novel drug delivery methods using magnetic nanoparticles, gold nanoparticles, and polymeric nanoparticles have been investigated in prostate cancer. Additionally, renal cancer treatment may be profoundly influenced by applications of nanotechnology principles. Various nanoparticle-based strategies for kidney cancer therapy have been proposed. Partly due to the dilution of drug concentrations by urine production, causing inadequate drug delivery to tumor cells in the treatment of bladder cancer, various multifunctional bladder-targeted nanoparticles have been developed to enhance therapeutic efficiency. In each of these cancer research fields, nanotechnology has shown several advantages over widely used traditional methods. Different types of nanoparticles improve the solubility of poorly soluble drugs, and multifunctional nanoparticles have good specificity toward prostate, renal, and bladder cancer. Moreover, nanotechnology can also combine with other novel technologies to further enhance effectivity. As our understanding of nanotechnologies grows, additional opportunities to improve the diagnosis and treatment of urological cancer are excepted to arise. In this review, we focus on nanotechnologies with potential applications in urological cancer therapy and highlight clinical areas that would benefit from nanoparticle therapy.