Institutional long-term outcomes at the first Canadian center performing intraoperatively planned low-dose-rate brachytherapy alone in low- and intermediate-risk prostate cancer

Eligibility criteria according to EAU/ESTRO/SIOG guidelines for exclusive iodine-125 brachytherapy for intermediate-risk prostate adenocarcinoma patients: impact on relapse-free survival

Purpose

Iodine-125 (¹²⁵I) brachytherapy (BT) alone for intermediate-risk (IR) prostate adenocarcinoma (PCA) is controversial. The purpose of the study was to investigate potential predictive factors in selected IR-PCA patients treated with BT.

Material and methods

Among 547 patients treated with ¹²⁵I BT between 2003 and 2013, 149 IR-PCA cases were selected according to NCCN classification after an additional exclusion of patients with prostate specific antigen (PSA) > 15 ng/ml and ISUP group 3. A relapse was defined as a biochemical failure, using ASTRO Phoenix definition, or a relapse identified on imaging. Survival curves were estimated with Kaplan-Meier method. Potential prognostic variables including EAU/ESTRO/SIOG guidelines eligibility criteria were analyzed using univariate and Cox’s proportional hazards regression analysis.

Results

Of the 149 IR patients, 112 were classified as favorable, with 69 cases eligible to BT according to EAU/ESTRO/SIOG guidelines, and 37 patients were identified as unfavorable as per NCCN. Androgen deprivation therapy (ADT) was applied in 6 patients only. Percentage of positive biopsy cores were ≤ 33% and ≥ 50% for 119 and 11 patients, respectively. With a median follow-up of 8.5 years, 30 patients experienced a relapse. 10-year overall survival, progression-free survival (PFS), and relapse-free survival (RFS) were 84% (95% CI: 75-90%), 66% (95% CI: 56-75%), and 77% (95% CI: 67-84%), respectively. Failure to meet EAU/ESTRO/SIOG criteria was significantly associated with a lower RFS (p = 0.0267, HR = 2.37 [95% CI: 1.10-5.08%]).

Conclusions

Brachytherapy is an effective treatment for selected IR-PCA cases. Patients who were not eligible according to EAU/ESTRO/SIOG guidelines demonstrated a lower RFS.

Excessive waitlists and delays to treatment with low-dose-rate brachytherapy predict an increased risk of recurrence and metastases in intermediate-risk prostatic carcinoma

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Resource constraints have led to prolonged wait-times for prostate brachytherapy.

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Increased wait times predict a significant increase in recurrence and metastases.

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Better resource planning is needed to reduce management delays & improve outcomes.

Purpose

It has previously been shown that increased wait times for prostatectomy are associated with poorer outcomes in intermediate-risk prostatic carcinoma (PCa). However, the impact of wait times on PCa outcomes following low-dose-rate brachytherapy (LDR-BT) are unknown.

Methods and Materials

We retrospectively reviewed 466 intermediate-risk PCa patients that underwent LDR-BT at a single comprehensive cancer center between 2003 and 2016. Wait times were defined as the time from biopsy to LDR-BT. The association of wait times with outcomes was evaluated using Cox and Fine-Gray regression in both univariate and multivariate models.

Results

Median (interquartile range) follow-up and wait time for all patients were 8.1 (6.3–10.4) years and 5.1 (3.9–6.9) months, respectively. Among NCCN unfavourable intermediate-risk (UIR) patients (n = 170; 36%), increased wait times predicted both a greater cumulative incidence of recurrence [MHR = 1.01/month of wait time (95% CI: 1.00–1.03); P = 0.044] and metastases [MHR = 1.04/month of wait time (95% CI: 1.02–1.06); P < 0.001] in multivariate modeling. In NCCN favourable intermediate-risk (FIR) patients, there was no significant association between wait time and recurrence or metastases risk. Among all intermediate-risk patients, wait time was associated with an increase in the incidence of metastases [MHR = 1.03/month of wait time (95% CI: 1.02–1.05); P < 0.001], but not recurrence in multivariate models. There was no association between wait time and overall survival in the UIR, FIR, or all intermediate-risk cohorts.

Conclusions

Resource constraints within this center’s public healthcare system have contributed to waitlists exceeding 5-months in length. This study finds that patients with UIR PCa experience a 1% increase in the risk of recurrence and 4% increase in the risk of metastases with each additional month of delay in definitive disease management. Preventing such extended management delays in LDR-BT may improve disease-related outcomes in patients with PCa.

Prostate brachytherapy intraoperative dosimetry using a combination of radiographic seed localization with a C-arm and deformed ultrasound prostate contours

PURPOSE

The purpose of the study was to assess the feasibility of performing intraoperative dosimetry for permanent prostate brachytherapy by combining transrectal ultrasound (TRUS) and fluoroscopy/cone beam CT [CBCT] images and accounting for the effect of prostate deformation.

METHODS AND MATERIALS

13 patients underwent TRUS and multiview two-dimensional fluoroscopic imaging partway through the implant, as well as repeat fluoroscopic imaging with the TRUS probe inserted and retracted, and finally three-dimensional CBCT imaging at the end of the implant. The locations of all the implanted seeds were obtained from the fluoroscopy/CBCT images and were registered to prostate contours delineated on the TRUS images based on a common subset of seeds identified on both image sets. Prostate contours were also deformed, using a finite-element model, to take into account the effect of the TRUS probe pressure. Prostate dosimetry parameters were obtained for fluoroscopic and CBCT-dosimetry approaches and compared with the standard-of-care Day-0 postimplant CT dosimetry.

RESULTS

High linear correlation (R² > 0.8) was observed in the measured values of prostate D_90%, V_100%, and V_150%, between the two intraoperative dosimetry approaches. The prostate D_90% and V_100% obtained from intraoperative dosimetry methods were in agreement with the postimplant CT dosimetry. Only the prostate V_150% was on average 4.1% (p-value <0.05) higher in the CBCT-dosimetry approach and 6.7% (p-value <0.05) higher in postimplant CT dosimetry compared with the fluoroscopic dosimetry approach. Deformation of the prostate by the ultrasound probe appeared to have a minimal effect on prostate dosimetry.

CONCLUSIONS

The results of this study have shown that both of the proposed dosimetric evaluation approaches have potential for real-time intraoperative dosimetry.

Analysis of outcomes after non-contour-based dose painting of dominant intra-epithelial lesion in intra-operative low-dose rate brachytherapy

Purpose

To compare the outcomes of patients with intermediate risk prostate cancer (IR-PCa) treated with low-dose rate I-125 seed brachytherapy (LDR-BT) and targeted dose painting of a histologic dominant intra-epithelial lesion (DIL) to those without a DIL.

Methods

455 patients with IR-PCa were treated at a single center with intra-operatively planned LDR-BT, each following the same in-house dose constraints. Patients with a DIL on pathology had hot spots localized to that region but no specific contouring during the procedure.

Results

396 (87%) patients had a DIL. Baseline tumor characteristics and overall prostate dosimetry were similar between patients with and without DIL except the median number of biopsy cores taken: 10 (10–12) vs 12 (10–12) (p = 0.002).

19 (5%) and 18 (5%) of patients with and 1 (2%) and 0 (0%) of those without DIL experienced CTCAE grade 2 and 3 toxicity respectively. Overall, toxicity grade did not significantly correlate with presence of DIL (p = 0.10).

Estimated 7-year freedom from biochemical failure (FFBF) was 84% (95% confidence interval: 79–89) and 70% (54–89) in patients with and without a DIL (log-rank p = 0.315). In DIL patients, cox regression revealed location of DIL (“Base” vs “Apex” HR: 1.03; 1.00–1.06; p = 0.03) and older age (70 vs 60 HR: 1.62; 1.06–2.49; p = 0.03) was associated with poor FFBF.

Conclusions

Targeting DIL through dose painting during intraoperatively planned LDR-BT provided no statistically significant change in FFBF. Patients with DILs in the prostate base had slightly lower FFBF despite DIL boost.

Incidence of subsequent primary cancers and radiation-induced subsequent primary cancers after low dose-rate brachytherapy monotherapy for prostate cancer in long-term follow-up

BACKGROUND

As aging is the most significant risk factor for cancer development, long-term prostate cancer (PCa) survivors have an evident risk of developing subsequent primary cancers (SPCs). Radiotherapy itself is an additional risk factor for cancer development and the SPCs appearing beyond 5 years after radiotherapy in the original treatment field can be considered as radiation-induced subsequent primary cancers (RISPCs).

METHODS

During the years 1999-2008, 241 patients with localized PCa who underwent low dose-rate brachytherapy (LDR-BT) with I125 and were followed-up in Kuopio University Hospital, were included in this study. In this study the incidences and types of SPCs and RISPCs with a very long follow-up time after LDR-BT were evaluated.

RESULTS

During the median follow-up time of 11.4 years, a total of 34 (14.1%) patients developed a metachronous SPC. The most abundant SPCs were lung and colorectal cancers, each diagnosed in six patients (16.7% out of all SPCs). The crude incidence rate of RISPC was 1.7% (n = 4). Half of the SPC cases (50%) were diagnosed during the latter half of the follow-up time as the risk to develop an SPC continued throughout the whole follow-up time with the actuarial 10-year SPC rate of 7.0%. The crude death rates due to metachronous out-of-field SPCs and RISPCs were 50 and 50%, respectively.

CONCLUSION

The crude rate of SPC was in line with previously published data and the incidence of RISPC was very low. These results support the role of LDR-BT as a safe treatment option for patients with localized PCa.

A Systematic Review of Sexual Satisfaction in Prostate Cancer Patients

INTRODUCTION

Prostate cancer (PCa) treatment has a significant negative impact on sexual function. Because research to this date has mostly focused on the impact of PCa on erectile function, very little is known about the impact of PCa on other relevant sexual outcomes, such as sexual satisfaction.

AIM

To conduct a literature review of studies that have examined sexual satisfaction in men diagnosed with and treated for PCa.

METHODS

A systematic review was conducted using Scopus and PubMed databases to identify studies that had assessed sexual satisfaction in men with PCa. The main characteristics of each study and results regarding the impact of PCa on sexual satisfaction were extracted and examined.

MAIN OUTCOME MEASURE

The main outcome measure was studies that assessed general sexual satisfaction in men with PCa.

RESULTS

Thirty-eight articles were found regarding sexual satisfaction in PCa. Most studies did not focus on sexual satisfaction specifically, and methodologic limitations produced very mixed results. Overall, PCa treatments had a low to moderate impact on sexual satisfaction, and psychosocial interventions were more successful at improving sexual satisfaction than medical interventions. Sexual satisfaction was correlated to a large number of sexual, relational, psychological, and medical variables.

CONCLUSION

This literature review shows very mixed results about the sexual satisfaction in men with PCa. Differences in research designs, methodologic limitations, and studies conducted atheoretically limit our understanding of the mechanisms that impact sexual satisfaction in men with PCa. We propose an alternative way of conducting research on sexual satisfaction by using solid theoretical models of sexual satisfaction. Santos-Iglesias P, Rana M, Walker L. A Systematic Review of Sexual Satisfaction in Prostate Cancer Patients. Sex Med Rev 2020;8:450-465.

Long-term efficacy and urological toxicity of low-dose-rate brachytherapy (LDR-BT) as monotherapy in localized prostate cancer

PURPOSE

The purpose of this study was to evaluate the incidence of late severe (≥Grade 3) urinary toxicity and the long-term efficacy after low-dose-rate brachytherapy (LDR-BT) in patients with localized prostate cancer (PCa).

METHODS AND MATERIALS

During the years 1999-2008, 241 patients with PCa who underwent LDR-BT with I¹²⁵ and were followed up in Kuopio University Hospital were included to this analysis. The incidence of late severe (Grade 3) urinary toxicity and the long-term efficacy results were analyzed.

RESULTS

All D'Amico risk groups were represented, as 58.9%, 35.3%, and 5.8% of the patients were classified as low-, intermediate-, and high-risk patients, respectively. With a median followup of 11.4 years after implantation, the incidence of severe urinary toxicity increased throughout the followup period. The risk of Grade 3 urinary toxicity was highest among patients with higher Gleason scores (p = 0.016) and higher initial urine residual volumes (p = 0.017) and the cumulative incidence of severe urinary toxicity was 10.0%. The crude rate for transurethral prostatic resection was 5.8%. The relapse-free survival, the cause-specific survival, and the overall survival were 79.3%, 95.0%, and 66.4%, respectively.

CONCLUSIONS

The treatment was well tolerated as 90% of patients avoided any Grade 3 urinary toxicity. LDR-BT for localized PCa achieved high and durable efficacy. These results support the role of LDR-BT monotherapy as one of the valid primary treatment options for low-risk and favorable intermediate-risk patients.

A single institution analysis of low-dose-rate brachytherapy: 5-year reported survival and late toxicity outcomes

Purpose

To report the 5-year biochemical relapse-free survival (BRFS), overall survival (OS), and long-term toxicity outcomes of patients treated with low-dose-rate (LDR) brachytherapy as monotherapy for low- to intermediate-risk prostate cancer.

Material and methods

Between 2004 and 2011, 371 patients were treated with LDR brachytherapy as monotherapy. Of these, 102 patients (27%) underwent transurethral resection of the prostate (TURP) prior to implantation. Follow-up was performed every 3 months for 12 months, then every 6 months over 4 years and included prostate specific antigen evaluation. The biochemical relapse-free survival (BRFS) was defined according to the Phoenix criteria. Acute and late toxicities were documented using the Common Terminology Criteria for Adverse Events version 4.0. The BRFS and OS estimates were calculated using Kaplan-Meier plots. Univariate and multivariate analyses were performed to evaluate outcomes by pre-treatment clinical prognostic factors and radiation dosimetry.

Results

The median follow-up of all patients was 5.45 years. The 5-year BRFS and OS rates were 95% and 96%, respectively. The BRFS rates for patients with Gleason score (GS) > 7 and GS ≤ 6 were 96% and 91% respectively (p = 0.06). On univariate analysis, T1 and T2 staging, risk-group classification, and prostate volumes had no impact on survival at 5 years (p > 0.1). Late grade 2 and 3 genitourinary (GU) toxicities were observed in 10% and 5% of patients respectively. Additionally, patients with prior TURP had a greater incidence of late grade 2 or 3 urinary retention (p = 0.001). There were 14 deaths in total; however, none were attributed to prostate cancer.

Conclusions

LDR brachytherapy is an effective treatment option in low- to intermediate-risk prostate cancer patients. We observed low biochemical relapse rates and minimal GU toxicities several years after treatment in patients with or without TURP. However, a small risk of urinary retention was observed in some patients.

Does Seed Migration Increase the Risk of Second Malignancies in Prostate Cancer Patients Treated With Iodine-125 Loose Seeds Brachytherapy?

PURPOSE

To evaluate the risk of second malignancies after migration of seeds (MS) in prostate cancer patients treated with ¹²⁵I loose seeds brachytherapy.

METHODS AND MATERIALS

Data from 2802 prostate cancer patients treated with ¹²⁵I loose seeds brachytherapy in 3 Canadian centers were reviewed. After seeds implant, all patients underwent postimplant pelvic radiography and computed tomography scan for postimplant dosimetry. These images were used to assess whether seed migration occurred. The incidence of second malignancies was determined through the review of patient charts. The 7- and 10-year cumulative incidences of second malignancies and their 95% confidence intervals (CIs) were calculated. Fine and Gray competing risk regression analysis was used to assess the factors associated with the development of second malignancies.

RESULTS

Mean age and median follow-up were 63.5 years and 74 (range, 12-246) months, respectively. Migration of seeds occurred in 263 of 2802 patients (9.4%). Second malignancy occurred in 87 patients (3.1%) for the entire cohort and was not different between patients who experienced MS (9, 3.4%) and those who did not (78, 3.1%) (P = .755). The 7-year cumulative incidence rates of second malignancies were 2.95% (95% CI 1.20%-6.00%) (with MS) versus 2.82% (2.10%-3.70%) (without MS) (P = .756). The corresponding values at 10 years were 6.16% (2.20%-12.3%) versus 4.51% (3.20%-5.50%) (P = .570). Migration of seeds did not seem to be a significant predictive factor for second malignancies development (adjusted hazard ratio 1.27 [95% CI 0.63-2.55]; P = .510). In both models, only advanced age was significantly associated with second malignancies development.

CONCLUSIONS

These results did not show an increased risk of second malignancies associated with MS after ¹²⁵I loose seeds brachytherapy for prostate cancer patients. Longer follow-up and more events are required to better correlate MS and second malignancies.