Predictive factors for urinary toxicity after iodine-125 prostate brachytherapy with or without supplemental external beam radiotherapy

Duration of α-1 adrenergic antagonist administration after low-dose-rate brachytherapy for prostate cancer

BACKGROUND

Urinary dysfunction is an adverse event of low-dose-rate brachytherapy (LDR-BT) in patients with prostate cancer. We aimed to examine the time to α-1 adrenergic antagonist withdrawal after LDR-BT initiation.

METHODS

We retrospectively evaluated 1663 patients who underwent LDR-BT at our hospital during 2004-2022.

RESULTS

Overall, 1485/1663 (89.3%) patients were able to stop using α-1 adrenergic antagonists, 1111 (66.8%) of them within 1 year of LDR-BT. Risk factors for prolonged time to withdrawal were age ≥70 years, taking agents for lower urinary tract symptoms prior to LDR-BT, an International Prostate Symptom Score ≥8, an Overactive Bladder Symptom Score ≥3 and a residual urine volume ≥20 ml. Of the patients who were able to stop taking α-1 adrenergic antagonists, 357/1485 (24.0%) required resumption, 218 (61.1%) of whom did so between 1 and 3 years after LDR-BT. This period matched the period of transient worsening of the urinary symptom score. Finally, multivariable analysis identified supplemental external beam radiotherapy and an Overactive Bladder Symptom Score ≥3 as independent risk factors for α-1 adrenergic antagonist resumption.

CONCLUSIONS

Withdrawal of α-1 adrenergic antagonists was possible in 66.8% of patients within 1 year of LDR-BT. Our results suggest that patients who are older or have pre-treatment LUTS may have prolonged deterioration of urinary dysfunction after treatment. Resumption of α-1 adrenergic antagonists 1-3 years after treatment may be associated with urinary symptom flares, and close attention is necessary for patients with supplemental external beam radiotherapy and a high pretreatment Overactive Bladder Symptom Score.

Japanese clinical practice guidelines for prostate cancer 2023

This fourth edition of the Japanese Clinical Practice Guidelines for Prostate Cancer 2023 is compiled. It was revised under the leadership of the Japanese Urological Association, with members selected from multiple academic societies and related organizations (Japan Radiological Society, Japanese Society for Radiation Oncology, the Department of EBM and guidelines, Japan Council for Quality Health Care (Minds), Japanese Society of Pathology, and the patient group (NPO Prostate Cancer Patients Association)), in accordance with the Minds Manual for Guideline Development (2020 ver. 3.0). The most important feature of this revision is the adoption of systematic reviews (SRs) in determining recommendations for 14 clinical questions (CQs). Qualitative SRs for these questions were conducted, and the final recommendations were made based on the results through the votes of 24 members of the guideline development group. Five algorithms based on these results were also created. Contents not covered by the SRs, which are considered textbook material, have been described in the general statement. In the general statement, a literature search for 14 areas was conducted; then, based on the general statement and CQs of the Japanese Clinical Practice Guidelines for Prostate Cancer 2016, the findings revealed after the 2016 guidelines were mainly described. This article provides an overview of these guidelines.

Significance of androgen-deprivation therapy for intermediate- and high-risk prostate cancer treated with high-dose radiotherapy: A literature review

The real-world benefits of adding androgen-deprivation therapy (ADT) and its optimal duration when combined with current standard high-dose radiation therapy (RT) remain unknown. We aimed to assess the efficacy of and toxicities associated with ADT in the setting of combination with high-dose RT for intermediate-risk (IR) and high-risk (HR) prostate cancer (PCa). This article is a modified and detailed version of the commentary on Clinical Question 8 described in the Japanese Clinical Practice Guidelines for Prostate Cancer (ver. 2023). A qualitative systematic review was performed according to the Minds Guide. All relevant published studies between September 2010 and August 2020, which assessed the outcomes of IR or HR PCa treated with high-dose RT, were screened using two databases (PubMed and ICHUSHI). A total of 41 studies were included in this systematic review, mostly consisting of retrospective studies (N = 34). The evidence basically supports the benefit of adding ADT to high-dose RT to improve tumor control. Regarding IR populations, many studies suggested the existence of a subgroup for which adding ADT had no impact on either overall survival or the BF-free duration. On the other hand, regarding HR populations, several studies suggested the positive impact of adding ADT for ≥1 year on overall survival. Adding ADT increases not only the risk of sexual dysfunction but also that of cardiovascular toxicities or bone fracture. Although the benefit of adding ADT was basically suggested for both IR and HR populations, further investigations are warranted to identify subgroups of patients for whom ADT has no benefit, as well as the appropriate duration of ADT for those who do derive benefit.

Redefining bladder neck dose in low-dose-rate prostate brachytherapy-Can we improve urinary toxicity without impacting disease control?

BACKGROUND

We sought to assess the impact of bladder neck dose (BND) on patient reported urinary toxicity, and feasibility of relative urethral sparing technique in prostate brachytherapy (PB).

METHODS AND MATERIALS

We retrospectively identified bladder neck as a point dose on post-implant CT scans in patients treated with 131Cs PB. Urinary symptoms were assessed through EPIC questionnaires. Patient cohorts were identified based on mean BND as a percentage of prescription dose with toxicity assessment at each time point.

RESULTS

In our cohort of 542 patients, BND was associated with clinically significant acute urinary symptoms and chronic symptoms, as patients receiving >70% of the prescription dose had significantly worse overall EPIC scores than patients receiving ≤70% of prescription dose. There was no difference in bDFS between patients receiving BND ≤70% (96% bDFS) and >70% (94% bDFS) at a median follow up of 57 months.

CONCLUSIONS

BND has a significant impact on both acute and chronic urinary symptoms, with reduced symptoms reported with BND <70% of prescription dose. With a median follow up of 4.7 years, excellent bDFS has thus far been achieved with relative urethral and bladder neck sparing. Utilizing this constraint should improve urinary symptoms without impacting disease control.

Associations of Clinical and Dosimetric Parameters with Urinary Toxicities after Prostate Brachytherapy: A Long-Term Single-Institution Experience

To examine the association of clinical, treatment, and dose parameters with late urinary toxicity after low-dose-rate brachytherapy (LDR-BT) for prostate cancer, we retrospectively studied patients with prostate cancer who underwent LDR-BT from January 2007 through December 2016. Urinary toxicity was assessed using the International Prostate Symptom Score (IPSS) and Overactive Bladder (OAB) Symptom Score (OABSS). Severe and moderate lower urinary tract symptoms (LUTS) were defined as IPSS ≥ 20 and ≥ 8, respectively; OAB was defined as a nocturnal frequency of ≥ 2 and a total OABSS of ≥ 3. In total, 203 patients (median age: 66 years) were included, with a mean follow-up of 8.4 years after treatment. The IPSS and OABSS worsened after 3 months of treatment; these scores improved to pretreatment levels after 18-36 months in most patients. Patients with a higher baseline IPSS and OABSS had a higher frequency of moderate and severe LUTS and OAB at 24 and 60 months, respectively. LUTS and OAB at 24 and 60 months were not correlated with the dosimetric factors of LDR-BT. Although the rate of long-term urinary toxicities assessed using IPSS and OABSS was low, the baseline scores were related to long-term function. Refining patient selection may further reduce long-term urinary toxicity.

Biochemical outcomes and toxicities in young men with prostate cancer after permanent iodine-125 seed implantation: Prospective cohort study in 6662 patients

PURPOSE

We evaluated the effect of age, <60 and ≥60 years, on biochemical outcomes and toxicities in patients with prostate cancer who underwent permanent seed implantation (PI) ± external beam radiation therapy ± hormone therapy in a national Japanese prospective cohort study (J-POPS).

METHODS AND MATERIALS

The safety and efficacy analyses included 6721 and 6662 patients, respectively. We categorized patients into two age groups: <60 (n = 716) and ≥60 (n = 6,005) years. We used propensity score matching (PSM) to estimate the marginal effect of age on biochemical freedom from failure (bFFF) using a Phoenix definition and Cox proportional hazard models.

RESULTS

The median followup period was 60.0 months. Without PSM, men <60 years demonstrated similar 5-year bFFF (96.3%) compared with men ≥60 years (95.6%; p = 0.576); percent positive biopsies, biologically effective dose, Gleason score, risk classification, and supplemental external beam radiation therapy (p <0.001, <0.001, <0.001, 0.008, and <0.001) were significantly associated with bFFF while age was not (p = 0.576). With PSM, bFFF was not significantly different between age groups (p = 0.664); however, men <60 years showed a significantly lower incidence of declining erectile function, grade ≥2 all urinary toxicities, urinary frequency/urgency, and rectal bleeding (p <0.001, 0.024, 0.031, and 0.010) than men ≥60 years.

CONCLUSIONS

After PI, men <60 years achieved a comparable 5-year biochemical control rate and showed a lower incidence of several toxicities compared to men ≥60 years. This suggests that PI should be an excellent treatment option for men <60 years with prostate cancer.

Sarcopenia and excess visceral fat accumulation negatively affect early urinary function after I‐125 low‐dose‐rate brachytherapy for localized prostate cancer

OBJECTIVES

To evaluate the effects of sarcopenia and excess visceral fat accumulation on early urinary function after I-125 low-dose-rate brachytherapy for prostate cancer.

METHODS

We retrospectively reviewed consecutive patients who underwent brachytherapy for prostate cancer. Pre-treatment computed tomography was used to measure skeletal muscle index at the L3 level to assess sarcopenia and visceral fat area at the umbilical level. The International Prostate Symptom Score and the University of California Los Angeles Prostate Cancer Index were used to assess quality of life during the 24 months after brachytherapy. Logistic regression analysis was used to examine whether sarcopenia and excess visceral fat accumulation had clinically significant effects on post-treatment quality of life.

RESULTS

Among 246 patients, 92 (37.4%) were stratified into the sarcopenia group and 141 (57.3%) into the excess visceral fat accumulation group. The sarcopenia group had significantly lower University of California Los Angeles Prostate Cancer Index urinary function than the non-sarcopenia group 24 months post-brachytherapy. The excess visceral fat accumulation group had significantly poorer International Prostate Symptom Score total, storage, and voiding scores than the non-excess accumulation group 12 months post-brachytherapy. In the multivariate analysis, sarcopenia had a clinically significant adverse effect on the University of California Los Angeles Prostate Cancer Index urinary function at 12 months. Excess visceral fat accumulation had a clinically significant adverse effect on the International Prostate Symptom Score voiding and storage scores at 12 months.

CONCLUSIONS

Sarcopenia and excess visceral fat accumulation negatively affect urinary function early after I-125 low-dose-rate brachytherapy for prostate cancer.

Acute and late side-effects after low dose-rate brachytherapy for prostate cancer; incidence, management and technical considerations

PURPOSE

To review common reported side effects and complications after primary LDR-BT (monotherapy) and discuss some of the technical aspects that could impact the treatment outcomes.

METHODS AND MATERIALS

A literature search was undertaken using medical subject headings (MeSH) complemented by the authors' personal and institutional expertise.

RESULTS

The reported incidence of acute and late grade 2 or above urinary, bowel and sexual side effects is very variable across the literature. The learning curve and the implant quality have a clear impact on the toxicity outcomes. Being aware of some of the technical challenges encountered during the procedure and ways to mitigate them could decrease the incidence of side effects. Careful planning of seed placement and seed deposition allow sparing of the organs at risk and a lower incidence of urinary and gastro-intestinal toxicity.

CONCLUSIONS

Low dose-rate brachytherapy remains a standard monotherapy treatment in the setting of favorable-risk prostate cancer. High disease control and low long-term toxicities are achievable in expert hands with a good technique.

Effect of adding androgen deprivation therapy to permanent iodine-125 implantation with or without external beam radiation therapy on the outcomes in patients with intermediate-risk prostate cancer: A propensity score-matched analysis

PURPOSE

The purpose of the study was to evaluate the effect of adding androgen deprivation therapy (ADT) to brachytherapy with or without external beam radiation therapy on oncological outcomes in prostate cancer.

METHODS AND MATERIALS

Overall, 1,171 patients with intermediate-risk prostate cancer treated with brachytherapy with or without external beam radiation therapy with or without ADT between 2003 and 2013 were identified. Propensity score matching was used to counter biases between the ADT and non-ADT groups. The biochemical failure-free rate (bFFR), local recurrence-free rate, and overall survival rate were evaluated using Kaplan-Meier curves, and predictors were identified using Cox proportional hazards regression models.

RESULTS

After propensity score matching, 405 patients were included in each group. The median followup duration was 9.1 years; the median ADT duration was 6 months. In the ADT versus non-ADT groups, the 9-year bFFR, local recurrence-free rate, and overall survival rate were 93.4% versus 87.8% (p = 0.016), 96.9% versus 98.1% (p = 0.481), and 88.1% versus 90.4% (p = 0.969), respectively. On multivariate analyses, Gleason score (hazard ratio [HR]: 2.52, 95% confidence interval [CI]: 1.58-4.03) and ADT use (HR: 0.55, 95% CI: 0.34-0.89) were associated with biochemical failure. Supplemental external beam radiation therapy use (HR: 0.38, 95% CI: 0.16-0.91) was associated with lower local recurrence rates. Age (HR: 1.12, 95% CI: 1.08-1.16) and comorbidities (HR: 1.56, 95% CI: 1.04-2.34) were associated with all-cause mortality.

CONCLUSIONS

A risk-benefit assessment between bFFR improvement and the potential side effects of adding ADT to brachytherapy-based radiotherapy is warranted before incorporating ADT as routine practice.

Predictors of urinary toxicity with MRI-assisted radiosurgery for low-dose-rate prostate brachytherapy

PURPOSE

MRI-assisted radiosurgery (MARS) is a modern technique for prostate brachytherapy that provides superior soft tissue contrast. The purpose of this analysis was to evaluate treatment planning factors associated with urinary toxicity, particularly damage to the membranous urethra (MUL) and external urethral sphincter (EUS), after MARS.

MATERIAL AND METHODS

We retrospectively reviewed 227 patients treated with MARS. Comparisons were made between several factors including preimplantation length of the MUL and EUS dosimetric characteristics after implantation with longitudinal changes in American Urological Association (AUA) urinary symptom score.

RESULTS

Rates of grade 3 urinary incontinence and obstructive urinary symptoms were 4% and 2%. A piecewise mixed univariate model revealed that MUL and V₂₀₀, V₁₅₀, V₁₂₅, and D₅ to the EUS were all associated with increased rates of urinary toxicity over time. On univariate logistic regression, MUL >14.2 mm (odds ratio [OR] 2.03 per cm³, 95% confidence interval [CI] 1.10-3.77, p = 0.025), V₁₂₅ to the EUS (OR 3.21 cm³, 95% CI 1.18-8.71, p = 0.022), and use of the I-125 isotope (OR 3.45, 95% CI 1.55-7.70, p = 0.001) were associated with subacute urinary toxicity (i.e., that occurring at 4-8 months). Optimal dose-constraint limits to the EUS were determined to be V₂₀₀ < 0.04 cm³ (p = 0.002), V₁₅₀ < 0.12 cm³ (p = 0.041), V₁₂₅ < 0.45 cm³ (p = 0.033), D₃₀ < 160 Gy (p = 0.004), and D₅ < 218 Gy (p = 0.016).

CONCLUSIONS

MARS brachytherapy provides detailed anatomic information for treatment planning, implantation, and quality assurance. Overall rates of urinary toxicity are low; however, several dosimetric variables associated with the EUS were found to correlate with urinary toxicity.

Assessment of Long-term Changes in Lower Urinary Tract Symptoms in Patients With Prostate Cancer Who Underwent Low-dose-rate Prostate Brachytherapy

OBJECTIVE

To investigate long-term changes in lower urinary tract symptoms in patients with prostate cancer (PCa) who underwent low-dose-rate brachytherapy with iodine-125 (LDR-BT).

PATIENTS AND METHODS

In this retrospective study, 313 patients with localized PCa underwent LDR-BT at Gifu University hospital between August 2004 and December 2013. The International Prostate Symptom Score (IPSS), Overactive Bladder Symptom Score (OABSS), and quality of life due to urinary symptoms (IPSS-QOL) were measured before LDR-BT; at 1, 3, 6, 9, 12, 24, 36, 48, and 60 months after LDR-BT; and annually thereafter. Study endpoints were chronological changes in IPSS, OABSS, and IPSS-QOL compared to pretreatment values. A multivariable nonlinear regression model with robust sandwich estimator evaluated association between outcomes and time with adjustment for covariates.

RESULTS

All scores worsened immediately after LDR-BT compared to preoperative scores. However, symptoms improved with time and returned to baseline in 18-36 months. After a 5-year follow-up after LDR-BT, OABSS significantly worsened in almost all patients compared to baseline although there were gradual improvements in less than 5 years after LDR-BT.

CONCLUSIONS

Our results may be of clinical importance in selecting treatment modalities for patients with localized PCa and long-term survival after definitive therapy.

Evaluation of the urethral α/β ratio and tissue repair half-time for iodine-125 prostate brachytherapy with or without supplemental external beam radiotherapy

PURPOSE

To assess the correlation between postimplant dosimetric quantifiers and the genitourinary (GU) toxicity of low-dose rate brachytherapy for prostate cancer.

METHODS AND MATERIALS

The minimum urethral dose (UD10, 30, and 90) and the percent volume of the urethra receiving the prescription dose (V100, V150) were calculated from the postimplant dose-volume histograms of 182 patients. We then calculated various urethral biologically equivalent doses (uBEDs) using different values of the α/β ratio and tissue repair half-time (t1/2) and examined the correlations with GU toxicity.

RESULTS

Common dosimetric quantifiers, such as UD90 (brachytherapy) + UD50 (external beam radiotherapy), showed no correlation with Grade ≥ 2 GU toxicity. There was a significant correlation between Grade ≥2 GU toxicity and uBED when the α/β value was 0.5 or 1 Gy and t1/2 was 0.5-2.5 h. An uBED (α/β = 1.0, t1/2 = 0.5) had the largest hazard ratio for GU toxicity, and it was also significantly correlated with Grade ≥ 2 GU toxicity according to multivariate analysis.

CONCLUSIONS

We observed a significant correlation of uBED with GU toxicity when α/β was 0.5 or 1.0 Gy and t1/2 was 0.5-2.5 h. As the simple formula we used has not been verified in basic experiments, more data are needed to validate our results.

Institutional patient accrual volume and the treatment quality of I‑125 prostate seed implantation in a Japanese nationwide prospective cohort study

PURPOSE

It is unclear whether experience at high-volume institute improves the treatment quality of prostate seed implantation. The aim of this study was to evaluate the effect of institutional experience on postimplant dosimetric parameters in a nationwide prospective cohort study.

METHODS

From July 2005 to June 2007, 2354 patients were registered in the Japanese Prostate Cancer Outcome Study of Permanent I‑125 Seed Implantation (J-POPS), and 1126 patients treated with seed implantation alone were evaluated. As a surrogate for institutional experience, we classified the J‑POPS institutions as high-volume (patient accrual volume was ≥120 patients per institution) or low-volume institutions (patient accrual volume was <120 patients per institution). To compare treatment quality between institutions, we evaluated the postimplant dosimetric parameters including D90, V100/150 (prostatic dose parameters), UD5/90, U200 (urethral dose parameters), and rectum R100/150 (rectal dose parameters).

RESULTS

In the 5 high-volume institutions (n = 601 patients), most of the patients were treated with >144 Gy of D90, whereas in the 20 low-volume institutions (n = 525) some of the patients were treated with <144 Gy. The V100 of most of the high-volume institution patients were >90%, whereas in the low-volume institutions a considerable percentage of patients showed lower V100. Although there was no correlation between D90 and rectal dose parameters, UD90 had a moderate positive correlation with D90 in both the high- and low-volume institutions. U200 varied more widely in the low-volume institutions.

CONCLUSIONS

Our findings indicate that the institutional patient accrual volume is associated with the treatment quality of I‑125 prostate seed implantation.

Permanent seed implant brachytherapy in low-risk prostate cancer: Preoperative planning with 145 Gy versus real-time intraoperative planning with 160 Gy

Aim

The present retrospective study was to compare toxicity and survival outcomes in a group of low-risk PCa patients treated with either the preoperative planning technique (145 Gy) or the real-time IoP technique (160 Gy).

Background

The two most common permanent seed implantation techniques are preoperative planning (PP) with 145 Gy and real-time intraoperative planning (IoP) with 160 Gy. Although IoP has largely replaced PP at many centres in recent years, few studies have directly compared these two techniques.

Materials and methods

Retrospective study of 408 patients with low-risk PCa treated with permanent seed implant brachytherapy at our institution between October 2003 and December 2014. Of these, 187 patients were treated with PP at a dose of 145 Gy while 221 received real-time IoP with 160 Gy.

Results

At a median follow up of 90 months, 5- and 8-year rates of biochemical relapse-free survival (BRFS) were 94.8% and 86% with the IoP technique versus 90.8% and 83.9%, respectively, with PP. The maximum dose to the urethra was <217 Gy with both techniques. Despite the higher dose, IoP did not cause any significant increase in toxicity (p = 0.11).

Conclusions

The present study shows that real-time intraoperative brachytherapy at a dose of 160 Gy yield better biochemical control than preoperative planning at 145 Gy. In addition, urinary toxicity did not increase, despite the dose escalation, probably because the dose constraints to the urethra were met despite the increased dose escalation. These findings support the use of real-time IoP.

Does supplemental external beam radiation therapy impact urinary, bowel, and erectile function following permanent prostate brachytherapy?: results of two prospective randomized trials

Purpose

To evaluate the impact of supplemental external beam radiation therapy (EBRT) prior to permanent prostate brachytherapy on long term urinary, bowel, and erectile function.

Material and methods

Patient administered urinary, bowel, and erectile quality of life (QoL) instrument were obtained prior to treatment and following brachytherapy. The study population was comprised of the 457 patients who were alive as of June 2016, had been randomized to two markedly different supplemental EBRT dose regimens and a third arm without supplemental EBRT, and had completed the June 2016 QoL survey. The need for urinary or bowel surgical intervention was prospectively recorded during routine follow-up. Multiple parameters were evaluated for effect on outcomes.

Results

The urinary catheter was removed on day 0 in 92.1% of patients and 0.4% required a post-implant transurethral prostatic resection (TURP). On average, the International Prostate Symptom Score (IPSS) normalized at week 14. The 10-year rate of urethral strictures was 5.3%. No significant differences were discerned between baseline and post-implant rectal function assessment score (RFAS), and no patient developed a rectal ulcer or fistula. The 10-year potency preservation rate was 50.3%. Supplemental EBRT did not affect urinary, bowel, or erectile function. Urethral strictures were most closely related to bulbomembranous urethral brachytherapy doses, post-implant rectal function to pre-implant hemorroidal bleeding, and RFAS and erectile function to pre-brachytherapy international index of erectile function and age.

Conclusions

Supplemental EBRT did not significantly effect catheter dependency, IPSS resolution, urethral stricture rate, the need for post-implant TURP, bowel, or erectile function. Careful attention to brachytherapy dose distributions appears to be most important in minimizing post-brachytherapy morbidity.

Clinical outcomes of 125I brachytherapy with and without external-beam radiation therapy for localized prostate cancer: results from 300 patients at a single institution in Japan

The aim of this study was to determine the outcomes and adverse events for 300 men with prostate cancer treated with 125iodine (125I) brachytherapy with and without external-beam radiation therapy (EBRT) at a single institution in Japan. Between February 2005 and November 2011, 300 consecutive patients with clinically localized prostate cancer were treated with 125I brachytherapy at the Nagoya University Hospital. A total of 271 men were treated with implants with doses of 145 Gy, and 29 men were treated with implants with doses of 110 Gy combined with EBRT (40-50 Gy/20-25 fractions). The median patient age was 69 years (range, 53-83 years). The median follow-up period was 53 months (range, 5-99 months). According to the National Comprehensive Cancer Network risk classification, 132 men (44%) had low-risk, 147 men (29%) had intermediate-risk and 21 men (7%) had high-risk disease. The 5-year overall survival rate, biochemical relapse-free survival rate, and disease-specific survival rates were 93.5%, 97.3% and 98.5%, respectively. Two men (0.6%) died of prostate cancer and 10 men (3.3%) died of other causes. Seventeen men (5.6%) experienced Grade 2 rectal bleeding in all: 12 (41.4%) of 29 in brachytherapy with EBRT, and 5 (1.8%) of 271 in brachytherapy alone. The rates of Grade 2 and 3 genitourinary toxicity were 1.0% and 1.7%, respectively. Excellent local control was achieved at our hospital for localized prostate cancer with 125I brachytherapy with and without EBRT. Gastrointestinal and genitourinary toxicities were acceptable.

Assessment of lower urinary symptom flare with overactive bladder symptom score and International Prostate Symptom Score in patients treated with iodine-125 implant brachytherapy: long-term follow-up experience at a single institute

Background

The aim of this study was to evaluate the combined use of the overactive bladder symptom score (OABSS) and International Prostate Symptom Score (IPSS) as an assessment tool for urinary symptom flare after iodine-125 (¹²⁵I) implant brachytherapy. The association between urinary symptom flare and prostate-specific antigen (PSA) bounce was investigated.

Methods

Changes in the IPSS and OABSS were prospectively recorded in 355 patients who underwent seed implantation. The percentage distribution of patients according to the difference between the flare peak and post-implant nadir was plotted to define significant increases in the scores. The clinicopathologic characteristics, treatment parameters, and post-implant dosimetric parameters were compared between the non-flare and flare groups. PSA bounce was defined as an elevation of ≥0.1 ng/mL or ≥0.4 ng/mL compared to the previous lowest value, followed by a decrease to a level at or below the pre-bounce value.

Results

A clinically significant increase required an IPSS increase of at least 12 points and an OABSS increase of at least 6 points based on a time-course analysis of total scores and the QOL index. Assessment only by IPSS failed to detect 40 patients (11%) who had urinary symptom flare according to the OABSS. Univariate and multivariate analyses revealed that patients treated with higher biologically effective doses and those without diabetes mellitus had higher risks of urinary flare. There was no statistical correlation between the incidence and time of urinary symptom flare onset and that of a PSA bounce.

Conclusions

To our knowledge, this is the first report to prove the clinical potential of the OABSS as an assessment tool for urinary symptom flare after seed implantation. Our findings showed that persistent lower urinary tract symptoms after seed implantation were attributed to storage rather than to voiding issues. We believe that assessment with the OABSS combined with the IPSS would aid in decision-making in terms of timing, selection of a treatment intervention, and assessment of the outcome.

Electronic supplementary material

The online version of this article (doi:10.1186/s12894-017-0251-1) contains supplementary material, which is available to authorized users.

Understanding Urinary Toxicity after Radiotherapy for Prostate Cancer: First Steps Forward

One of the most relevant achievements of Professor Gianni Bonadonna was the implementation of the methodology of controlled clinical trials in medical oncology. It is valid for all cancer types, oncological disciplines and clinical endpoints, both survival and toxicity. This narrative review reports on the status of the current knowledge of the radiation-induced urinary syndrome after external-beam radiotherapy for prostate cancer. In recent years, the syndrome has been the object of large-scale prospective observational trials specifically devoted to investigating the association of patient and treatment features with acute/late urinary toxicity. The first results of these trials allow initial attempts at predictive modeling, which can serve as a basis for the optimization of patient selection and treatment planning.

Variability of treatment planning of seed implantation: A Japanese multicenter simulation study

PURPOSE

This multicenter study was conducted to evaluate the current variability of treatment planning of seed implantation in Japanese centers and the feasibility of two virtual trials.

METHODS AND MATERIALS

Two types of contour data were sent to 12 radiation oncologists with a request letter that asked them to make treatment plans on the data in the same manner as in their own practice. Five of the 12 radiation oncologists were asked to participate in the two virtual trials in which the D90 (dose to the hottest 90% of prostate volume) was 1) required to be set at just 180 Gy and 2) increased as much as possible without violating other limitations.

RESULTS

A relatively high dose with a small deviation was irradiated to the prostate in Japanese centers (mean D90 = 188 Gy; SD = 10 Gy). In the virtual trials, all five physicians could achieve 180 Gy for the D90 with a very small deviation, although the urethral dose showed relatively large deviations. Dose escalation without increase of urethral dose or V150 was difficult, although the rectum could be spared by most of the physicians.

CONCLUSION

Our study showed a relatively high dose with a small deviation was prescribed to the prostate in Japanese centers. Consolidated protocols such as D90 = 180 Gy could be available for future trials. Meanwhile, our study suggested that some cautions might be needed for urethral dose and the V150, even when a relatively low D90 was requested.