Safety of Prostate Stereotactic Body Radiation Therapy after Transurethral Resection of Prostate (TURP): A Propensity Score Matched Pair Analysis

Genitourinary toxicity in patients receiving TURP prior to hypofractionated radiotherapy for clinically localized prostate cancer: A scoping review

BACKGROUND

When compared with conventional external beam radiotherapy, hypofractionated radiotherapy has led to less treatment sessions and improved quality of life without compromising oncological outcomes for men with prostate cancer. Evidence has shown transurethral prostatic resection prior to brachytherapy and external beam radiotherapy is associated with worsening genitourinary toxicity. However, there is no review of genitourinary toxicity when TURP occurs prior to definitive hypofractionated radiotherapy. In this review, we seek to illustrate the genitourinary outcomes for men with localized prostate cancer who underwent transurethral resection of the prostate prior to receiving definitive hypofractionated radiotherapy. Genitourinary outcomes are explored, and any predictive risk factors for increased genitourinary toxicity are described.

METHODS

PubMed, Medline (Ovid), EMBASE and Cochrane Library were all searched for relevant articles published in English within the last 25 years. This scoping review identified a total of 579 articles. Following screening by authors, 11 articles were included for analysis.

RESULTS

Five studies reported on acute and late toxicity. One article reported only acute toxicity while 5 documented late toxicity only. While most articles found no increased risk of acute toxicity, the risk of late toxicity, particularly hematuria was noted to be significant. Risk factors including poor baseline urinary function, prostate volume, number of prior transurethral prostatic resections, timing of radiotherapy following transurethral prostatic resection, volume of the intraprostatic resection cavity and mean dose delivered to the cavity were all found to influence genitourinary outcomes.

CONCLUSION

For those who have undergone prior TURP hypofractionated radiotherapy may increase the risk of late urinary toxicity, particularly hematuria. Those with persisting bladder dysfunction following TURP are at greatest risk and careful management of these men is required. Close collaboration between urologists and radiation oncologists is recommended to discuss the management of patients with residual baseline bladder dysfunction prior to commencing hypofractionated radiotherapy.

Extreme hypofractionated stereotactic radiotherapy for localized prostate Cancer: Efficacy and late urinary toxicity according to transurethral resection of the prostate history

Background and purpose

Extreme hypofractionated stereotactic body radiotherapy (SBRT) is a therapeutic alternative for localized low- or intermediate-risk prostate cancer. Despite the availability of several studies, the toxicity profile of SBRT has not been comprehensively described. This real-world evidence study assessed the efficacy and toxicities associated with this regimen, and potential prognosis factors for genitourinary toxicities.

Materials and methods

This retrospective study included 141 consecutive patients with localized prostatic adenocarcinoma treated with CyberKnife™ SBRT, as primary irradiation, at the Oscar Lambret Center between 2010 and 2020. The prescribed dose was 36.25 Gy in 5 fractions. Acute and late toxicities were graded according to the CTCAE (version 5.0). Biochemical recurrence-free survival (bRFS) and overall survival (OS) were estimated using the Kaplan-Meier method. The cumulative incidence of biochemical recurrence (cBR) was estimated using the Kalbfleisch-Prentice method.

Results

Among the included patients, 13.5 % had a history of transurethral resection of the prostate (TURP). The median follow-up was 48 months. At 5 years, bRFS, cBR, and OS were 72 % (95 %CI: 61-81), 7 % (95 %CI: 3-14), and 82 % (95 %CI: 73-89), respectively. Twenty-nine patients experienced at least one late toxicity of grade ≥ 2; genitourinary (N = 29), including 3 cases of chronic hematuria, and/or gastrointestinal (N = 1). The cumulative incidence of late urinary toxicity of grade ≥ 2 was 20.6 % at 5 years (95 %CI: 13.9-28.1). Multivariate analysis revealed that a history of TURP was significantly associated with late urinary toxicity of grade ≥ 2, after adjusting for clinical target volume (Odds Ratio = 3.06; 95%CI: 1.05-8.86; P = 0.04).

Conclusion

Extreme hypofractionated SBRT is effective for localized prostate cancer with a low risk of late toxicity. A history of TURP is associated with a higher risk of late urinary toxicity. These findings may contribute to the optimal management of patients treated with this regimen, particularly those with a history of TURP.

Stereotactic body radiation therapy for prostate cancer after surgical treatment of prostatic obstruction: Impact on urinary morbidity and mitigation strategies

In the past decade, stereotactic body radiation therapy (SBRT) has emerged as a valid treatment option for patients with localized prostate cancer. Despite the promising results of ultra-hypofractionation in terms of tolerance and disease control, the toxicity profile of SBRT for prostate cancer patients with a history of surgical treatment of benign prostate hyperplasia is still underreported. Here we present an overview of the available data on urinary morbidity for prostate cancer patients treated with SBRT after prior surgical treatments for benign prostate hyperplasia. Technical improvements useful to minimize toxicity and possible treatments for radiation-induced urethritis are discussed.

Relationships between holmium laser enucleation of the prostate and prostate cancer

Holmium laser enucleation of the prostate (HoLEP) is a size-independent surgical option for treating benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS) with excellent, durable functional outcomes. The prevalence of LUTS secondary to BPH and prostate cancer both increase with age, although the two diseases develop independently. Urologists often face a diagnostic dilemma, as men with LUTS secondary to BPH might also present with an elevated PSA and, therefore, need a diagnostic work-up to exclude prostate cancer. Nevertheless, ~15% of men with a negative elevated PSA work-up will undergo HoLEP and will be diagnosed with incidental prostate cancer at the time of HoLEP. Indeed, prostate cancer is often found in men undergoing HoLEP, and this situation can be challenging to manage. Variables associated with the detection of incidental prostate cancer, strategies to reduce incidental prostate cancer, as well as the natural history and management of this condition have been extensively studied, but further work in this area is still needed.

Surgical Treatments of Benign Prostatic Hyperplasia and Prostate Cancer Stereotactic Radiotherapy: Impact on Long-Term Genitourinary Toxicity

AIMS

Although the results on acute and late toxicity of ultrahypofractionation are encouraging, data on safety in prostate cancer patients with a medical history of transurethral resection of the prostate (TURP) or adenomectomy remain scarce, especially in cases of repeated procedures. The aim of the present study was to report on long-term toxicities after stereotactic body radiotherapy (SBRT) of prostate cancer patients with previous surgical treatment of benign prostatic hyperplasia.

MATERIALS AND METHODS

Among 150 patients treated with SBRT (median dose 36.25 Gy in five fractions) realised from 2014 to 2019 in a single-centre institution, data of 24 men with a history of TURP (n = 19) or adenomectomy (n = 5) were analysed. Repeated TURP was carried out in three patients, with a median time between surgery and SBRT of 54 months. Genitourinary toxicity was assessed using the Common Terminology Criteria for Adverse Events v4.0 grading scale.

RESULTS

With a median follow-up of 45 months, 10 of 24 (42%) patients experienced at least one episode of transient haematuria. One patient (4%) with three previous TURP presented a grade 3 acute non-infective cystitis. Late grade 2 and 3 genitourinary toxicities were observed in eight (33%) and four patients (17%) (two treated with adenomectomy, one with multiple TURP and one with a 140 cm³ prostate size), respectively, with no grade ≥4 adverse events. A complete recovery of grade 3 genitourinary toxicities was observed for all patients after hyperbaric oxygen therapy.

CONCLUSION

Prostate SBRT is feasible and well-tolerated in patients with a medical history of surgical treatments of benign hyperplasia. Patients with prior adenomectomy or multiple TURP are at higher risk of developing severe genitourinary toxicity and should be carefully evaluated before SBRT treatments.

Ultrahypofractionated Radiotherapy for Localised Prostate Cancer: How Far Can We Go?

Following adoption of moderately hypofractionated radiotherapy as a standard for localised prostate cancer, ultrahypofractioned radiotherapy delivered in five to seven fractions is rapidly being embraced by clinical practice and international guidelines. However, the question remains: how low can we go? Can radiotherapy for prostate cancer be delivered in fewer than five fractions? The current review summarises the evidence that radiotherapy for localised prostate cancer can be safely and effectively delivered in fewer than five fractions using high dose rate brachytherapy or stereotactic body radiotherapy. We also discuss important lessons learned from the single-fraction high dose rate brachytherapy experience.

Moderately Hypofractionated Radiotherapy and Androgen Deprivation Therapy for High-risk Localised Prostate Cancer: Predictors of Long-term Biochemical Control and Toxicity

AIMS

There is a paucity of long-term data on outcomes of high-risk prostatic adenocarcinoma after moderately hypofractionated radiotherapy with elective nodal treatment and long-term androgen deprivation therapy (ADT). We report long-term control and toxicity outcomes and analyse the predictors of failure and toxicity.

MATERIALS AND METHODS

The records of 120 consecutive high-risk prostate cancer patients treated in a single institution between February 2012 and December 2016 were retrospectively analysed. A moderately hypofractionted radiotherapy (HypoRT) regimen of 60 Gy in 20 fractions over 4 weeks with simultaneous elective pelvic irradiation to 44 Gy in 20 fractions with intensity-modulated radiotherapy was used, together with long-term ADT with either orchiectomy or medical castration for a total duration of 2-3 years. We analysed biochemical control, metastasis-free survival and late toxicities and their predictive factors using survival analysis.

RESULTS

Patients had locally advanced cancers (cT3 77.5%, median pretreatment prostate-specific antigen 30 ng/ml, Gleason score 8-10 in 45.8%). The median follow-up time was 70 months. The 3- and 5-year probability of freedom from biochemical progression was 93% and 80%, respectively. The 5-year probability of freedom from local relapse/intra-pelvic nodal relapse/distant metastases as the site of first failure was 96%/97%/86%, respectively. Gleason score 8-10 and medical ADT for 2-3 years (as opposed to orchidectomy) were independent risk factors for distant metastases. A total of 18 grade 2 and above late gastrointestinal toxicity events and a total of 23 grade 2 and above late genitourinary toxicity events were documented. Patients who underwent a transurethral resection of prostate prior to radiotherapy had worse urological toxicity.

CONCLUSIONS

HypoRT with elective nodal treatment results in excellent pelvic control. Distant metastases are the primary mode of failure. Risk of metastases is associated with Gleason score and the duration of ADT. Late urinary toxicities are more common in those with prior transurethral resection of prostate.

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.

Urinary Outcomes for Men With High Baseline International Prostate Symptom Scores Treated With Prostate SBRT

Purpose

There are limited data regarding high-dose stereotactic body radiation therapy (SBRT) for prostate cancer in patients with poor baseline urinary function. The purpose of this study was to evaluate genitourinary (GU) toxicity and changes in patient-reported symptom severity scores after prostate SBRT in men with a high pretreatment International Prostate Symptom Score (IPSS).

Methods and Materials

Seven hundred fifty-three patients treated with prostate SBRT at our institution from 2012 to 2019 were identified, of whom 72 consecutive patients with baseline IPSS ≥15 were selected for this study. GU toxicity according to Common Terminology Criteria for Adverse Events (CTCAE) v3.0 and IPSS were prospectively documented at each follow-up visit. Univariable logistic regression was used to evaluate for potential predictors of GU toxicity.

Results

Median follow-up in survivors was 26.8 months. The rates of acute grade 2 and 3 GU toxicity were 20.8% and 1.4%, respectively. The rates of late grade 2 and 3 GU toxicity were 37.5% and 5.6%, respectively. The majority of grade 2+ toxicities resolved by last follow-up, and when toxicities were regraded per CTCAE v5.0, there were no longer any grade 3 adverse events. Total IPSS and individual symptom subscores improved over time. Compared with baseline, median total IPSS at 24 ± 6 months was significantly lower (18 vs 12; P < .001) and the proportion of patients with severe scores (IPSS ≥20) decreased from 29.2% to 13.9%. Pretreatment urinary urgency was associated with late grade 2+ GU toxicity (odds ratio, 2.10; 95% confidence interval, 1.33-3.31; P = .001).

Conclusions

In men with baseline IPSS ≥15 managed with prostate SBRT, the rate of severe GU toxicity was low and patient-reported symptoms generally improved over time. Thus, high pretreatment IPSS should not deter clinicians from offering prostate SBRT.

Development and Validation of a Comprehensive Multivariate Dosimetric Model for Predicting Late Genitourinary Toxicity Following Prostate Cancer Stereotactic Body Radiotherapy

Purpose: Dosimetric predictors of toxicity after Stereotactic Body Radiation Therapy (SBRT) are not well-established. We sought to develop a multivariate model that predicts Common Terminology Criteria for Adverse Events (CTCAE) late grade 2 or greater genitourinary (GU) toxicity by interrogating the entire dose-volume histogram (DVH) from a large cohort of prostate cancer patients treated with SBRT on prospective trials.

Methods: Three hundred and thirty-nine patients with late CTCAE toxicity data treated with prostate SBRT were identified and analyzed. All patients received 40 Gy in five fractions, every other day, using volumetric modulated arc therapy. For each patient, we examined 910 candidate dosimetric features including maximum dose, volumes of each organ [CTV, organs at risk (OARs)], V100%, and other granular volumetric/dosimetric indices at varying volumetric/dosimetric values from the entire DVH as well as ADT use to model and predict toxicity from SBRT. Training and validation subsets were generated with 90 and 10% of the patients in our cohort, respectively. Predictive accuracy was assessed by calculating the area under the receiver operating curve (AROC). Univariate analysis with student t-test was first performed on each candidate DVH feature. We subsequently performed advanced machine-learning multivariate analyses including classification and regression tree (CART), random forest, boosted tree, and multilayer neural network.

Results: Median follow-up time was 32.3 months (range 3–98.9 months). Late grade ≥2 GU toxicity occurred in 20.1% of patients in our series. No single dosimetric parameter had an AROC for predicting late grade ≥2 GU toxicity on univariate analysis that exceeded 0.599. Optimized CART modestly improved prediction accuracy, with an AROC of 0.601, whereas other machine learning approaches did not improve upon univariate analyses.

Conclusions: CART-based machine learning multivariate analyses drawing from 910 dosimetric features and ADT use modestly improves upon clinical prediction of late GU toxicity alone, yielding an AROC of 0.601. Biologic predictors may enhance predictive models for identifying patients at risk for late toxicity after SBRT.

Urinary Morbidity in Men Treated With Stereotactic Body Radiation Therapy (SBRT) for Localized Prostate Cancer Following Transurethral Resection of the Prostate (TURP)

Background: Clinical data suggest that stereotactic body radiation therapy (SBRT) provides similar clinical outcomes as other radiation modalities for prostate cancer. However, data reporting on the safety of SBRT after TURP is limited. Herein, we report our experience using SBRT to deliver hypofractionated radiotherapy in patients with a history of TURP including physician-reported toxicities and patient-reported quality of life.

Methods: Forty-seven patients treated with SBRT from 2007 to 2016 at Georgetown University Hospital for localized prostate carcinoma with a history of prior TURP were included in this retrospective analysis. Treatment was delivered using the CyberKnife® (Accuray Incorporated, Sunnyvale, CA) with doses of 35 Gy or 36.25 Gy in 5 fractions without prostatic urethral sparing. Toxicities were recorded and scored using the CTCAE v.4. Cystoscopy findings were retrospectively reviewed. Urinary quality of life data was assessed using the International Prostate Symptom Scoring (IPSS) and Expanded Prostate Cancer Index Composite 26 (EPIC-26). A Wilcoxon signed-rank sum test was used to determine if there was a statistically significant increase or decrease in IPSS or EPIC scores between timepoints. Minimally important differences were calculated by obtaining half the standard deviation at time of start of treatment.

Results: Forty-seven patients at a median age of 72 years (range 63–84) received SBRT. The mean follow-up was 4.7 years (range 2–10 years). Late Grade 2 and grade 3 urinary toxicity occurred in 23 (48.9%) and 3 (6.4%) men, respectively. There were no Grade 4 or 5 toxicities. Approximately 51% of patients experienced hematuria following treatment. Mean time to hematuria was 10.5 months. Twenty-five cystoscopies were performed during follow-up and the most common finding was hyperemia, varices of the bladder neck/TURP defect, and/or necrotic tissue in the TURP defect. Baseline urinary QOL composite scores were low, but they did not clinically significantly decline in the first 2 years following treatment.

Conclusions: In patients with prior TURP, prostate SBRT was well-tolerated. GU toxicity rates were comparable to similar patients treated with conventionally fractionated radiation therapy. Urinary quality of life was poor at baseline, but did not worsen clinically over time. Stricter dosimetric criteria could potentially improve the rate of high-grade late toxicity, but may increase the risk of peri-urethral recurrence.

Study protocol of a randomised controlled trial of prostate radiotherapy in high-risk and node-positive disease comparing moderate and extreme hypofractionation (PRIME TRIAL)

INTRODUCTION

There has been an interest in studying the efficacy of extreme hypofractionation in low and intermediate risk prostate cancer utilising the low alpha/beta ratio of prostate. Its role in high-risk and node-positive prostate cancer, however, is unknown. We hypothesise that a five-fraction schedule of extreme hypofractionation will be non-inferior to a moderately hypofractionated regimen over 5 weeks in efficacy and will have acceptable toxicity and quality of life while reducing the cost implications during treatment.

METHODS AND ANALYSIS

This is an ongoing, non-inferiority, multicentre, randomised trial (NCT03561961) of two schedules for National Cancer Control Network high-risk and/or node-positive non-metastatic carcinoma of the prostate. The standard arm will be a schedule of 68 Gy/25# over 5 weeks while the test arm will be extremely hypofractionated radiotherapy with stereotactic body radiation therapy to 36.25 Gy/5# (7 to 10 days). The block randomisation will be stratified by nodal status (N0/N+), hormonal therapy (luteinizing hormone-releasing hormone therapy/orchiectomy) and centre. All patients will receive daily image-guided radiotherapy.The primary end point is 4-year biochemical failure free survival (BFFS). The power calculations assume 4-year BFFS of 80% in the moderate hypofractionation arm. With a 5% one-sided significance and 80% power, a total of 434 patients will be randomised to both arms equally (217 in each arm). The secondary end points include overall survival, prostate cancer specific survival, acute and late toxicities, quality of life and out-of-pocket expenditure.

DISCUSSION

The trial aims to establish a therapeutically efficacious and cost-efficient modality for high-risk and node-positive prostate cancer with an acceptable toxicity profile. Presently, this is the only trial evaluating and answering such a question in this cohort.

ETHICS AND DISSEMINATION

The trial has been approved by IEC-III of Tata Memorial Centre, Mumbai.

TRIAL REGISTRATION NUMBER

Registered with CTRI/2018/05/014054 (http://ctri.nic.in) on 24 May 2018.