Low-dose-rate brachytherapy for prostate cancer: A 15-year experience in Japan

Prostate-specific antigen (PSA) nadir and experience of PSA bounce after low-dose-rate brachytherapy for prostate cancer predicts clinical failure

OBJECTIVE

This study aimed to assess if prostate-specific antigen (PSA) threshold and PSA bounce are associated with oncological control after low-dose-rate brachytherapy (LDR-BT) alone or with external beam radiotherapy (EBRT), with or without androgen deprivation therapy (ADT), considering serum testosterone levels.

METHODS

This study enrolled 944 prostate cancer patients treated at a single institution with LDR-BT alone or LDR-BT combined with EBRT, with or without ADT. The Fine-Gray hazard model was used to evaluate factors related to clinical failure, including experience of PSA bounce between baseline and 2, 4, or 7 years after LDR-BT and PSA value (0.1, 0.2, or 0.5 ng/mL) with normal testosterone levels at 2, 4, and 7 years after LDR-BT, respectively.

RESULTS

Patients with normal testosterone levels and a PSA of 0.2 or 0.5 ng/mL at 2, 4, and 7 years after LDR-BT had a significantly better clinical failure free rate (CFFR) than those with PSA levels >0.2 or >0.5 ng/mL or low testosterone levels. Multivariate analysis revealed that PSA <0.1, 0.2, or 0.5 ng/mL with normal testosterone levels at 2, 4, and 7 years and experience of PSA bounce between baseline and 2 or 4 years after LDR-BT were significantly related to better CFFR.

CONCLUSIONS

Patients with normal serum testosterone levels who reached PSA of <0.1, 0.2, or 0.5 ng/mL after LDR-BT, or those who experienced PSA bounce, showed better oncological control.

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.

Identification of a novel signature based on M6a modification regulators related LncRNA for stratification of the prognosis of prostate cancer

Prostate cancer emerges as a life-threatening disease that affects approximately 1.3 million patients of male population globally. Various studies established lncRNAs as a critical role in prostate cancer progression by regulating multiple epigenetic pathways. Therefore, it is imperative to disclose the involvement of lncRNAs in prostate cancer and their usability as prognostic markers for the disease. The model was constructed using Cox and LASSO analysis. The accuracy of model was evaluated using various cohorts. Furthermore, the study assessed the correlative relationship of the model with tumor immunity, immunotherapy, SNV mutation, and drug sensitivity, among other factors. We developed an accurate and stable prognostic model for prostate cancer patients by screening out 11 m6A regulators related lncRNAs and integrating pathological features and age through a nomogram model. The model had satisfactory accuracy and stability in stratification of clinical outcomes of prostate cancer patients, as demonstrated by AUC values (higher than 0.7) at 3, 5, and 7 years in both internal and external cohorts. Moreover, we performed PCA analysis to confirm m6A-related lncRNAs as the best modeling strategy. We developed a prognosis predicting model based on 11 selected m6A modification related lncRNA, which displayed satisfactory potency in multiple cohorts.

Clinical Efficacy and Openness to New Challenges of Low Dose Rate Brachytherapy for Prostate Cancer

Over a century ago, low-dose-rate (LDR) brachytherapy was introduced to treat prostate cancer (PCa). Since then, it has been widely applied worldwide, including in East Asia. LDR brachytherapy has been performed in 88 institutes in Japan. Beneficial clinical outcomes of LDR brachytherapy for intermediate-to-high-risk PCa have been demonstrated in large clinical trials. These clinical outcomes were achieved through advances in methods, such as urological precise needle puncture and seed placement, and the quantitative decision making regarding radiological parameters by radiation oncologists. The combined use of LDR brachytherapy with other therapeutic modalities, such as external beam radiation and androgen deprivation therapy, for the clinical risk classification of PCa has led to better anticancer treatment efficacy. In this study, we summarized basic LDR brachytherapy findings that should remain unchanged and be passed down in urology departments. We also discussed the applications of LDR brachytherapy for PCa in various clinical settings, including focal and salvage therapies. In addition, we highlighted technologies associated with brachytherapy that are under development.

Prognostic Factors for Resolution Delay of Lower Urinary Tract Symptoms in Patients with Prostate Cancer after Low-Dose-Rate Brachytherapy

Urinary storage symptoms after low-dose-rate brachytherapy (LDR-BT) with iodine-125 have been noted to be less likely to improve to baseline compared to voiding symptoms. This study aimed to evaluate the chronological changes in the overactive bladder symptom score (OABSS) and the time-to-resolution of OABSS in patients undergoing LDR-BT. Patients with prostate cancer who underwent LDR-BT at Gifu University Hospital were enrolled. The OABSS was evaluated before and after LDR-BT. Patients were divided into the OABSS resolution and resolution delay groups, and the association between OABSS resolution delay and clinicopathological covariates was evaluated. In total, 237 patients were enrolled in this study, with a median follow-up of 88.3 months. The OABSS in both groups worsened at 3 months following operation and gradually recovered at 9 months; however, the OABSS in the resolution delay group tended to worsen again after that. In the multivariate analysis, preoperative OABSS and the change from baseline to maximal OABSS were associated with OABSS resolution. To our knowledge, this is the first study to evaluate the delayed resolution of OABSS after LDR-BT in patients with prostate cancer. A low baseline OABSS and significant changes in the OABSS from baseline were independent predictors of delayed OABSS resolution.

Chronological Changes of Lower Urinary Tract Symptoms in Elderly Patients with Prostate Cancer after Low-Dose-Rate Prostate Brachytherapy

BACKGROUND

To compare chronological changes in lower urinary tract symptoms (LUTS) after low-dose-rate prostate extended-release therapy (LDR-BT) using the overactive bladder symptom score (OABSS) in patients aged ≥ 75 years (elderly group) versus those aged < 75 years (control group).

MATERIALS AND METHODS

Patients with prostate cancer who underwent LDR-BT at Gifu University Hospital were included in this study. The International Prostate Symptom Score (IPSS), OABSS, and quality of life-based on urinary symptoms (IPSS-QOL) were evaluated before and after LDR-BT. We compared chronological changes in IPSS, OABSS, and IPSS-QOL in the elderly group with those in the control group and assessed the association between the resolution of OABSS and clinicopathological covariates.

RESULTS

A total of 484 patients were enrolled in this study. In the elderly group, the total IPSS, OABSS, and frequency scores increased at 1 month postoperatively, whereas the control group showed an increase at 3 months postoperatively. Multivariate analysis identified changes from baseline to the maximum OABSS and pre-treatment OABSS as significant predictors of delayed resolution of OABSS after LDR-BT.

CONCLUSIONS

Changes in pre-treatment OABSS and pre- and post-LDR-BT OABSS values were independent predictors of delayed resolution of OABSS; however, no correlation was found with age.

Seed Density as a New Predictive Index of Seed Migration in Brachytherapy for Prostate Cancer Using Iodine-125 Loose Seed

AIM

This study aimed to examine the usefulness of seed density as a predictor of seed migration in patients with prostate cancer who received brachytherapy using Iodine-125 loose seed.

METHODS

From May 2006 to April 2016, 320 patients with localized prostate cancer underwent transperineal brachytherapy using iodine-125 loose seeds. Among them, 202 (63.1%) patients received brachytherapy monotherapy and 118 (36.9%) received combined brachytherapy and external beam radiotherapy. Seed density was calculated using the following formula: seed density = implanted seed number/prostate volume. All patients underwent radiography of the chest, abdomen and pelvis, and computed tomography at 1 day, 1 month, and 1 year after brachytherapy to evaluate the presence of seed migration.

RESULTS

In total, the number of implanted seeds was 21,876. Seed migration was detected in 92 (28.8%) patients. Of a total of 21,876 seeds, 144 (0.66%) showed migration. The number of needles, number of seeds, and seed density were significantly higher in the group with migration than in the group without migration (p = 0.05). The ROC cutoff values for prostate volume, number of needles, number of seeds, and seed density were 20.9 cc, 21, 65, and 3.0, respectively. In the univariate analysis, prostate volume, number of needles, number of seeds, seed density, and treatment modality were all significant factors in predicting migration (p = 0.05). In the multivariate analysis, seed density and treatment modality were significant factors in predicting migration (p = 0.05).

CONCLUSION

Seed density is useful for predicting seed migration. In cases with seed density > 3.0, it is necessary to take measures such as considering the use of stranded seeds.

Chronological changes of lower urinary tract symptoms after low-dose-rate brachytherapy for prostate cancer using SpaceOAR® system

Background

The aim of this study is to investigate chronological changes of lower urinary tract symptoms (LUTS) in patients with prostate cancer who underwent low-dose-rate brachytherapy (LDR-BT) followed by the insertion of SpaceOAR® system (SpaceOAR).

Methods

In this retrospective study, 483 patients with localized prostate cancer underwent LDR-BT at the Gifu University Hospital between August 2004 and December 2020. SpaceOAR was inserted in 30 patients after LDR-BT (SpaceOAR group), and 453 patients received LDR-BT alone (non-SpaceOAR group). The International Prostate Symptom Score (IPSS), Overactive Bladder Symptom Score (OABSS), quality of life due to urinary symptoms (IPSS-QOL), and uroflowmetry (UFM), including maximum flow rate (Qmax), voided volume, and post-voided residual urine (PVR), were evaluated before LDR-BT, and at 1, 3, 6, 9, and 12 months after LDR-BT. The outcomes were chronological changes in IPSS, OABSS, and IPSS-QOL compared to pretreatment values and those of covariates in relation to UFM.

Results

The IPSS, OABSS, IPSS-QOL, Qmax, and voided volume were not significantly associated with either group. According to the PVR interaction effect, the insertion of SpaceOAR was significantly affected by chronological changes in PVR (P = 0.001). Three months after LDR-BT, PVR in the SpaceOAR group was significantly higher than that in the non-SpaceOAR group (49.8 mL vs. 30.5 mL; P = 0.002).

Conclusion

SpaceOAR use may temporally increase PVR; however, IPSS, OABSS, IPSS-QOL, Qmax, and voided volume were not significantly associated with LUTS before and after LDR-BT. The combination of LDR-BT and SpaceOAR may be acceptable for treating patients with prostate cancer regarding the chronological changes in LUTS after brachytherapy.

Erectile dysfunction and sexual quality of life in patients who underwent low-dose-rate brachytherapy alone for prostate cancer

This study evaluated erectile function and sexual quality of life (QoL), and predictive factors for erectile dysfunction (ED) and the deterioration of sexual QoL in 70 patients who underwent low-dose-rate brachytherapy (LDR-BT) alone for prostate cancer without androgen deprivation therapy. Erectile function and sexual QoL were evaluated before and 1, 3, 6, 12, 24, 36, 48 and 60 months after LDR-BT. Binary logistic regression analysis was used to determine whether age, prostate volume, hypertension, diabetes, Brinkman's index, testosterone, baseline Sexual Health Inventory for Men (SHIM) score and post-implant dosimetry parameters could predict ED and deterioration of sexual QoL at 24 and 60 months after LDR-BT. After 24 and 60 months, ED was noted in 39 of 70 patients and 42 of 64 patients respectively. Furthermore, sexual QoL worsened in 42 of 70 and 43 of 64 patients respectively. Baseline SHIM score was identified as a significant predictor of ED (24 months: odds ratio [OR]: 0.83, p = 0.02; 60 months: OR: 0.83, p = 0.03) and the deterioration of sexual QoL (24 months: OR: 0.84, p = 0.03). LDR-BT for prostate cancer promoted decreased erectile function and sexual QoL, with high preimplant potency being a significant predictor of ED and the deterioration of sexual QoL.

Stereotactic Ablative Brachytherapy: Recent Advances in Optimization of Radiobiological Cancer Therapy

Brachytherapy (BT), a type of focal anti-cancer radiotherapy, delivers a highly focused radiation dose to localized tumors, sparing surrounding normal tissues. Recent technological advances have helped to increase the accuracy of BT and, thus, improve BT-based cancer treatment. Stereotactic ablative brachytherapy (SABT) was designed to improve the ablative effect of radiation, which was achieved via improved image guidance, and calculation of ablative dose, shorter treatment duration, and better organ preservation. Recently collected data characterized SABT as having the potential to cure various early-stage cancers. The method provides higher tumor control rate levels that were previously achievable only by surgical resection. Notably, SABT is suitable for application with unresectable malignancies. However, the pathological assessment of SABT irradiated tumors is limited due to difficulties in specimen acquisition. Prostate, lung, liver, and gynecological cancers are the most commonly reported SABT-treated malignancies. This study will give an overview of SABT, focusing on the advances in SABT optimization, and provide insights on the future benefits of the combined application of SABT with cancer immunotherapies.

A prospective study of oral 5-aminolevulinic acid to prevent adverse events in patients with localized prostate cancer undergoing low-dose-rate brachytherapy: Protocol of the AMBER study

Background

Radiotherapy is one of the most frequently selected treatment options for patients with prostate cancer. However, adverse effects related to the irradiated surrounding normal organs are significant clinical concerns. Specifically, genitourinary and gastrointestinal toxicities can lead to a dramatically reduced quality of life. The aim of this clinical trial is to determine the efficacy of oral 5-aminolevulinic acid (ALA) phosphate with sodium ferrous citrate (SFC) in patients treated with low-dose-rate brachytherapy (LDR-BT) using an iodine-125 seed source.

Methods

The AMBER study is a prospective, single-center trial in patients with localized prostate cancer undergoing LDR-BT. Patients who undergo supplementary extra-beam radiotherapy are excluded, whereas those who undergo pre-implantation short-term (4–6 months) androgen deprivation therapy to decrease the prostate volume and/or improve oncological outcomes are included. After the screening and registration, the patients will be instructed to take capsules of ALA-SFC twice a day (200 mg and 229.42 mg per day) for 6 months from the day of seed implantation (prescribed radiation dose of 160 Gy). Patient data will be collected before the implantation; during oral ALA-SFC treatment; and 1, 3, 6, 9, and 12 month(s) after seed implantation. The primary endpoint of this trial is the urinary frequency 3 months after seed implantation. At each visit, the 24-h urinary frequency, total voided volume, and mean voided volume on a frequency volume chart and other patient-reported outcomes are recorded. The data of the trial cases will be compared with those of historical controls, who are consecutive patients undergoing LDR-BT without supplementary extra-beam radiotherapy between January 2016 and January 2019. The number of subjects has been set to be 50 for trial cases and 150 for the historical control cases. Pre- and post-treatment clinicopathologic factors are compared between two groups.

Discussion

The goal of this trial is to determine the potential benefit of ALA-SFC in patients who undergo LDR-BT. To the best of our knowledge, this is the first study investigating the potential clinical benefit of oral ALA-SFC after radiotherapy. More evidence from a further randomized controlled trial is needed to change the standard of care and lead to better post-radiotherapy management.

Trial registration

This clinical trial was prospectively registered with the Japan Registry of Clinical Trials on 5 December 2019. The reference number is jRCTs051190077, nara0013 (Certified Review Board of Nara Medical University).

Predictive factors of rectal hemorrhage in patients with localized prostate cancer who underwent low-dose-rate brachytherapy

BACKGROUND

This study aimed to evaluate the association between clinical covariates or the prescribed radiation dose for the prostate and rectal hemorrhage in patients with prostate cancer (PCa) who received iodine-125 low-dose-rate brachytherapy (LDR-BT group) or the combination of LDR-BT and external beam radiation therapy (CMT group).

METHODS AND MATERIALS

In this retrospective study, we reviewed the clinical records of 298 consecutive PCa patients with clinical stage T1c/T2 who underwent LDR-BT between August 2004 and August 2016 at a single institution. The prescribed minimum peripheral doses were 145 Gy for the LDR-BT group and 104 Gy for the CMT group. The dosimetric parameters analyzed were minimal dose received by 90% of the prostate gland, biologically effective dose, and rectal volume receiving 100% (RV100) or 150% of the prescribed dose. The endpoint of this study was the onset of any-grade clinical rectal hemorrhage after treatment.

RESULTS

The median follow-up period was 6.8 years. The 5-year overall survival rate was found to be 98.3%, and two patients (0.7%) reported biochemical recurrence during follow-up period. A total of 33 patients (11%) experienced rectal hemorrhage. However, ≥ grade 2 rectal hemorrhage occurred in eight patients (2.7%). On multivariate analysis, CMT, RV100 ≥ 0.66 mL, and hemorrhoids before treatment were identified as predictors of rectal hemorrhage after radiation therapy.

CONCLUSIONS

Maximal reduction of the rectal dose seems very important to prevent serious rectal hemorrhage. In addition, we should consider the risk of rectal toxicities in patients with abnormalities in the rectal mucosa, especially hemorrhoids.

Radical prostatectomy versus brachytherapy for clinically localized prostate cancer on oncological and functional outcomes: a meta-analysis

Background

Prostate cancer (PCa) is a form of malignancy that harms the health status of elderly men worldwide. It is unclear which of radical prostatectomy (RP) or brachytherapy (BT) is the more effective treatment for PCa. This study presents the first highly comprehensive and up-to-date comparative analysis of the overall outcomes of RP versus BT.

Methods

We conducted a systematic literature search for studies published on PubMed, EMBASE, and the Cochrane Library on the outcomes of RP versus BT in clinically localized PCa. The cumulative analysis was performed using Review Manager Version 5.3 software, and the Chi-square test was employed to test the statistical heterogeneity. The summary odds ratio (OR) and standard mean difference (SMD) was estimated using random effects models at 95% confidence intervals (CIs).

Results

In total, 2 randomized, 2 prospective, and 21 retrospective comparative studies were included. No significant differences in biochemical recurrence rate (BCR) (OR: 1.24; 95% CI: 0.91, 1.68) and prostate cancer-specific mortality (PCSM) (OR: 1.62; 95% CI: 0.86, 3.04) between RP and BT were noted. With erectile dysfunction and urinary incontinence, BT was more protective than RP in both short-term post-operative reports (OR: 2.06; 95% CI: 1.15, 3.70 and OR: 4.62; 95% CI: 2.33, 9.16) and long-term patient outcome reports (SMD: -5.62; 95% CI: -13.81, 2.57 and SMD: -11.52; 95% CI: -18.32, -4.72).

Conclusions

BT and RP for PCa therapy pose comparable risks of PCSM and BCR, while BT is associated with a lower incidence of erectile dysfunction and urinary incontinence. This study tentatively confirms that BT is an alternative to RP for patients seeking a curative treatment with minimal risks of urinary incontinence and sexual dysfunction.