Radiorecurrent prostate cancer: an emerging and largely mismanaged epidemic

Local salvage therapies in patients with radio-recurrent prostate cancer following external beam radiotherapy: a systematic review and meta-analysis

INTRODUCTION

To date, radio-recurrent prostate cancer (PCa) ranks as the fourth most common urological malignancy when considering the number of men with localized PCa who undergo radiation treatment and subsequently experience a biochemical recurrence. This systematic review aimed to summarize available evidence about the outcomes of local salvage strategies in patients with local PCa recurrence following primary external-beam radiation therapy (EBRT).

METHODS

We conducted a comprehensive bibliographic search on MEDLINE, Scopus, and Web of Science Core Collection databases in October 2023 to identify studies published in the last 20 years evaluating outcomes of local salvage procedures in patients with locally radio-recurrent PCa following EBRT. The meta-analysis was performed using ProMeta 3 software when two or more studies reported the same outcome. The effect size (ES) was estimated using rates reported with its 95% confidence interval (CI).

RESULTS

Overall, 28 studies (6 prospective and 22 retrospective) including 1544 patients were included in the review. Two-year recurrence-free survival (RFS) was 84.0% (95% CI: 67.0-93.0%), 69.0% (95% CI: 42.0-87.0%), 58.0% (95% CI: 43.0-71.0%), and 45% (95% CI: 38.0-52.0%), for patients undergoing brachytherapy (BT), EBRT, Cryotherapy and High-Intensity Focused Ultrasound (HIFU), respectively. After salvage prostatectomy, RFS ranged from 75% to 78.5% at a median follow-up ranging from 18 to 35 months. Estimates for severe gastrointestinal toxicity were 2%, 3%, 3%, 4%, and 11% following cryotherapy, BT, HIFU, EBRT, and salvage radical prostatectomy, respectively.

CONCLUSIONS

In patients who underwent EBRT as primary treatment, prostate salvage re-irradiation through BT or EBRT represents the modality providing the best balance between efficacy and safety. Unfortunately, due to the low level of evidence, strong recommendations regarding the choice of any of these techniques cannot be made.

Re-irradiation to the prostate using stereotactic body radiotherapy (SBRT) after initial definitive radiotherapy - A systematic review and meta-analysis of recent trials

Background

There is increasing data on re-irradiation to the prostate using stereotactic body radiotherapy (SBRT) after definitive radiotherapy for prostate cancer, with increasing evidence on prostate re-irradiation using a C-arm LINAC or an MR LINAC in recent years. We therefore conducted this systematic review and meta-analysis on prostate re-irradiation including studies published from 2020 to 2023, to serve as an update on existing meta-analysis.

Methods

We searched the PubMed and Embase databases in October 2023 with queries including combinations of "repeat", "radiotherapy", "prostate", "re-irradiation", "reirradiation", "re treatment", "SBRT", "retreatment". Publication date was set to be from 2020 to 2023. There was no limitation regarding language. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. After data extraction, heterogeneity testing was done by calculating the I2. A random effects model with a restricted maximum likelihood estimator was used to estimate the combined effect. Funnel plot asymmetry was assessed visually and using Egger's test to estimate the presence of publication and/or small study bias.

Results

14 publications were included in the systematic review. The rates of acute ≥ grade 2 (G2) genitourinary (GU) and gastrointestinal (GI) toxicities reported in the included studies ranged from 0.0-30.0 % and 0.0-25.0 % respectively. For late ≥ G2 GU and GI toxicity, the ranges are 4.0-51.8 % and 0.0-25.0 %. The pooled rate of acute GU and GI toxicity ≥ G2 were 13 % (95 % CI: 7-18 %) and 2 % (95 % CI: 0-4 %). For late GU and GI toxicity ≥ G2 the pooled rates were 25 % (95 % CI: 14-35 %) and 5 % (95 % CI: 1-9 %). The pooled 2-year biochemical recurrence-free survival was 72 % (95 % CI: 64-92 %).

Conclusions

SBRT in the re-irradiation of radiorecurrent prostate cancer is safe and effective. Further prospective data are warranted.

Salvage high-intensity focused ultrasound (S-HIFU) for recurrence after primary radiotherapy of prostate cancer

OBJECTIVES

To evaluate functional and oncological outcomes of salvage high-intensity focal ultrasound (S-HIFU) after external beam radiotherapy (EBRT) failure in prostate cancer (PCa) patients.

METHODS

This single-center study included patients who underwent S-HIFU for local recurrence after EBRT between 2006 and 2023. Cancer-specific survival, metastasis-free survival and progression-free survival were illustrated using Kaplan-Meier curves. Disease progression was defined by one of the following criteria: increase of 2ng/mL or more above the PSA nadir, positive post-S-HIFU biopsy or initiation of androgen deprivation therapy (ADT). Multivariable Cox proportional hazards model was used to identify predictors of disease progression after S-HIFU.

RESULTS

A total of 52 S-HIFU sessions for 48 patients were performed. Median time between EBRT and S-HIFU was 6.5 years. Median PSA before S-HIFU was 3.2ng/mL and median PSA nadir after S-HIFU was 0.58ng/mL. A total of 39 (81.3%) complications was recorded, including 3 (6.3%) high grade complications according to the Clavien-Dindo classification. After a median follow-up period of 6 years, 14 (29.2%) patients developed metastatic disease. Eighteen (37.5%) patients had no recurrence, whereas 30 (62.5%) patients received ADT for disease progression. The estimated 5-yr cancer-specific survival (CSS), metastasis-free survival (MFS) and progression-free survival rates (PFSR) were 100%, 79.9% (95% CI 67-92) and 41.2% (95% CI 74-96), respectively. The estimated 10-yr CSS, MFS and PFSR were 80% (95% CI 45-100), 50.7% (95% CI 19.4-82.1) and 14% (95% CI 10.8-45), respectively. The hazard of progression increased with the intermediate (HR 3.8; 95% CI 0.99 to 15; p=0.049) and high pre-EBRT d'Amico-s risk group (HR 4.1; 95% CI 0.98 to 16.2; p=0.050). Also, the time between EBRT and S-HIFU was significantly associated with risk of progression (HR 0.61; 95% CI 0.43 to 0.86; p=0.004). No significant difference linked to the disease progression (DP) risk was found between focal vs whole-gland treatment (p=0.70).

CONCLUSION

Physicians should consider HIFU as a local salvage treatment after failed EBRT, thus avoiding or delaying palliative androgen deprivation therapy. Further studies are needed to improve patient selection for this therapy.

LEVEL OF EVIDENCE: 4

Recurrent Gleason Score 6 Prostate Cancer After Radiotherapy or Ablation: Should We Observe Them All? Results from a Large Multicenter Salvage Radical Prostatectomy Consortium

BACKGROUND

Salvage radical prostatectomy (sRP) yields poor functional outcomes and relatively high complication rates. Gleason score (GS) 6 prostate cancer (PCa) has genetic and clinical features showing little, if not absent, metastatic potential. However, the behavior of GS 6 PCa recurring after previous PCa treatment including radiotherapy and/or ablation has not been investigated.

OBJECTIVE

To evaluate the oncological outcomes of sRP for radio- and/or ablation-recurrent GS 6 PCa.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective data of sRP for recurrent PCa after local nonsurgical treatment were collected from 14 tertiary referral centers from 2000 to 2021.

INTERVENTION

Prostate biopsy before sRP and sRP.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

A survival analysis was performed for pre-sRP biopsy and sRP-proven GS 6. Concordance between PCa at pre-sRP biopsy and sRP histology was assessed.

RESULTS AND LIMITATIONS

We included GS 6 recurrent PCa at pre-sRP biopsy (n = 142) and at sRP (n = 50), as two cohorts. The majority had primary radiotherapy and/or brachytherapy (83.8% of GS 6 patients at pre-sRP biopsy; 78% of GS 6 patients at sRP) and whole-gland treatments (91% biopsy; 85.1% sRP). Biopsy GS 6 10-yr metastasis, cancer-specific survival (CSS), and overall survival (OS) were 79% (95% confidence interval [CI] 61-89%), 98% (95-99%), and 89% (78-95%), respectively. Upgrading at sRP was 69%, 35.5% had a pT3 stage, and 13.4% had positive nodes. The sRP GS 6 10-yr metastasis-free survival, CSS, and OS were 100%, 100%, and 90% (95% CI 58-98%) respectively; pT3 and pN1 disease were found in 12% and 0%, respectively. Overall complications, high-grade complications, and severe incontinence were experienced by >50%, >10%, and >15% of men, respectively (in both the biopsy and the sRP cohorts). Limitations include the retrospective nature of the study and absence of a centralized pathological review.

CONCLUSIONS

GS 6 sRP-proven PCa recurring after nonsurgical primary treatment has almost no metastatic potential, while patients experience relevant morbidity of the procedure. However, a significant proportion of GS 6 cases at pre-sRP biopsy are upgraded at sRP. In the idea not to overtreat, efforts should be made to improve the diagnostic accuracy of pre-sRP biopsy.

PATIENT SUMMARY

We investigated the oncological results of salvage radical prostatectomy for recurrent prostate cancer of Gleason score (GS) 6 category. We found a very low malignant potential of GS 6 confirmed at salvage radical prostatectomy despite surgical complications being relatively high. Nonetheless, biopsy GS 6 was frequently upgraded and had less optimal oncological control. Overtreatment for recurrent GS 6 after nonsurgical first-line treatment should be avoided, and efforts should be made to increase the diagnostic accuracy of biopsies for recurrent disease.

Salvage Radical Prostatectomy for Recurrent Prostate Cancer: A Systematic Review (French ccAFU)

The aim of this study was to systematically review the current evidence regarding the oncological and functional outcomes of salvage radical prostatectomy (sRP) for recurrent prostate cancer. A systematic review was conducted throughout September 2022 using the PubMed, Science Direct, Scopus, and Embase databases. Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were followed to identify eligible studies. A total of 55 studies (3836 patients) met our eligibility criteria. The vast majority of men included had radiation therapy (including brachytherapy) as their first-line treatment (n = 3240, 84%). Other first-line treatments included HIFU (n = 338, 9%), electroporation (n = 59, 2%), proton beam therapy (n = 54, 1.5%), cryotherapy (n = 34, 1%), focal vascular targeted photodynamic therapy (n = 22, 0.6%), and transurethral ultrasound ablation (n = 19, 0.5%). Median preoperative PSA, at the time of recurrence, ranged from 1.5 to 14.4 ng/mL. The surgical approach was open in 2300 (60%) cases, robotic in 1465 (38%) cases, and laparoscopic in 71 (2%) cases. Since 2019, there has been a clear increase in robotic versus conventional surgery (1245 versus 525 cases, respectively). The median operative time and blood loss ranged from 80 to 297 min and 75 to 914 mL, respectively. Concomitant lymph node dissection was performed in 2587 cases (79%). The overall complication rate was 34%, with a majority of Clavien grade I or II complications. Clavien ≥ 3 complications ranged from 0 to 64%. Positive surgical margins were noted in 792 cases (32%). The median follow-up ranged from 4.6 to 94 months. Biochemical recurrence after sRP ranged from 8% to 51.5% at 12 months, from 0% to 66% at 22 months, and from 48% to 59% at 60 months. The specific and overall survival rates ranged from 13.4 to 98% and 62 to 100% at 5 years, respectively. Urinary continence was maintained in 52.1% of cases. sRP demonstrated acceptable oncological outcomes. These results, after sRP, are influenced by several factors, and above all by pre-treatment assessment, including imaging, with the development of mpMRI and metabolic imaging. Our results demonstrated that SRP can be considered a suitable treatment option for selected patients, but the level of evidence remains low.

Intermediate-term oncological and functional outcomes of salvage cryotherapy for the management of prostate cancer recurrence after primary brachytherapy versus primary cryotherapy: A propensity score-matched analysis

BACKGROUND

Salvage cryotherapy (SCT) is widely used to treat prostate cancer (PCa) recurrence after radiotherapy (RT). We studied the intermediate oncological and functional outcomes of patients who underwent SCT following cryotherapy (CRYO-SCT) recurrence and compare it to recurrence after brachytherapy (BT-SCT).

METHODS

An IRB-approved retrospective cohort study utilizing patient data from the Cryo On-Line Data Registry and the Duke PCa database between 1992 and 2016. Biochemical recurrence (BCR) using Phoenix criteria was the primary endpoint assessed at 2- and 5-years post-SCT. Secondary endpoints assessed functional outcomes including urinary continence, erectile function, and recto-urethral fistula. Association between treatment and biochemical progression-free survival was assessed using inverse probability weighted (IPTW) Cox proportional hazards regression. The differences in the secondary functional outcomes were assessed by Pearson's χ2 test or Fisher's exact test, corrected for IPTW.

RESULTS

A total of 194 patients met inclusion criteria. The BCR rate for BT-SCT and CRYO-SCT was 23 (20.4%) and 17 (21%) at 2 years and 30 (26.5%) and 22 (27.2%) at 5 years according to Phoenix criteria. There was no statistical difference in 2 years (hazard ratio [HR] 0.9; 95% confidence interval [CI], 0.5-1.7, p = 0.7) or 5-year BCR (HR: 0.86; 95% CI, 0.5-1.5, p = 0.6) between the groups. The functional outcomes like urinary continence (p = 0.4), erectile function (p = 0.1), and recto-urethral fistula (p = 0.3) were not statistically different.

CONCLUSION

CRYO-SCT appears to be well tolerated, with comparable oncological and functional outcomes to patients failing primary BT. The findings also demonstrated that SCT can render a significant number of patients biochemically free of disease after initial CRYO with minimal morbidity. SCT is a viable treatment option to salvage local PCa recurrence following either BT or cryoablation failure.

Salvage Radical Prostatectomy for Recurrent Prostate Cancer After Primary Nonsurgical Treatment: An Updated Systematic Review

Salvage radical prostatectomy (sRP) has historically been associated with high morbidity, whilst recently published multicentre series suggested a trend towards improved outcomes. Hence, we performed a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses criteria to investigate the oncological and functional results and morbidity of sRP. We included 20 retrospective articles comprising 4175 men. Robotic procedures were performed in 40% and nerve sparing in up to 36% of men. Postoperative continence was preserved in 40.4% of patients and erectile function in <16%. High-grade complications were described in 6.6% of patients (rectal injuries 0.9%). At final sRP pathology, surgical margins were positive in 26.1%, 32.8% had seminal vesicle invasion, and International Society of Urological Pathology grade was >3 in 26.6%. Ten-year metastasis-free survival ranged from 72% to 77% and 5-yr cancer-specific survival ranged from 86.6% to 97.7%. Salvage radical prostatectomy shows durable oncological control and morbidity improved over recent years, despite remaining significant compared to and higher than that of primary radical prostatectomy. PATIENT SUMMARY: Salvage radical prostatectomy (sRP) shows improving oncological control and morbidity over time. The complications associated with sRP and its functional results seem to be acceptable and are continuously improving.

Topography of Prostate Cancer Recurrence: A Single-centre Analysis of Salvage Radical Prostatectomy Specimens and Implications for Focal Salvage Treatments

Background

Most prostate cancer (PCa) recurrences after nonsurgical first-line treatment are managed with androgen deprivation therapy (ADT). When local treatment is indicated, salvage focal treatment (FT) may achieve outcomes similar to those after salvage radical prostatectomy (sRP), with lower morbidity. However, descriptions of the topography of PCa recurrence are scarce.

Objective

To describe the characteristics and topography of recurrent PCa at sRP.

Design setting and participants

We performed a review of the final pathology for consecutive men undergoing sRP at a single centre between 2007 and 2021.

Outcome measurements and statistical analysis

Clinical and pathological outcomes and recurrence localisation (standardised map) were recorded. Suitability for salvage FT was evaluated using criteria defined a priori.

Results and limitations

We included 41 men who underwent sRP after whole-gland treatment (82.9% primary radiotherapy). Of these, 68.3% had grade group ≥3 and 46.3% had pT3 disease, including nine men (22%) with seminal vesicle involvement >1 cm. The pN+ rate was 29.3%. Surgical margins were positive in 39% (mostly at the apex, 21.9%). PCa was located at <3 mm from the apex in 68% of cases. The segment most frequently involved was the mid-gland (93%). The median prostate and index lesion (IL) volume was 31.4 cm³ (interquartile range [IQR] 23-37) and 2 cm³ (IQR 0.5-6), respectively. A solitary IL was present in 63.4% of cases, while 7.3% had whole-gland PCa involvement. Overall, 56% of the men (n = 23) were deemed suitable for salvage FT (although seven had pN+ disease). The sample size, single-centre retrospective design, and unavailability of magnetic resonance imaging data are the main limitations.

Conclusions

According to sRP pathology, radiorecurrent PCa is an aggressive disease, frequently showing extraprostatic extension, positive margins, and apical involvement. The majority of cases still harbour a solitary index lesion and a consistent proportion may be suitable for a gland-preserving strategy.

Patient summary

In this report we looked at the location of prostate cancer recurrence within the prostate gland after radiotherapy or ablation, in which energy (such as heat, cold, or laser energy) is used to kill cells. We found that although these recurrences are often high-grade locally advanced disease, around half of cases might be suitable for a gland-preserving salvage treatment.

Targeting the radiation-induced ARv7-mediated circNHS/miR-512-5p/XRCC5 signaling with Quercetin increases prostate cancer radiosensitivity

Background

Radiation therapy (RT) with androgen deprivation therapy (ADT) is an effective therapy to suppress the locally advanced prostate cancer (PCa). However, we unexpectedly found that RT could also induce the androgen receptor splice variant 7 (ARv7) expression to decrease the radiosensitivity.

Methods

The study was designed to target ARv7 expression with Quercetin or ARv7-shRNA that leads to enhancing and increasing the radiation sensitivity to better suppress the PCa that involved the modulation of the circNHS/miR-512-5p/XRCC5 signaling.

Results

Mechanism studies revealed that RT-induced ARv7 may function via altering the circNHS/miR-512-5p/XRCC5 signaling to decrease the radiosensitivity. Results from preclinical studies using multiple in vitro cell lines and in vivo mouse models concluded that combining RT with the small molecule of Quercetin to target full-length AR and ARv7 could lead to better efficacy to suppress PCa progression.

Conclusion

Together, these results suggest that ARv7 may play key roles to alter the PCa radiosensitivity, and targeting this newly identified ARv7 mediated circNHS/miR-512-5p/XRCC5 signaling with Quercetin may help physicians to develop a novel RT to better suppress the progression of PCa.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02287-4.

The SAFE Pilot Trial—SAlvage Focal Irreversible Electroporation—For Recurrent Localized Prostate Cancer: Rationale and Study Protocol

Introduction

Currently, the majority of prostate cancer (PCa) recurrences after non-surgical first-line treatment are managed with androgen-deprivation therapy (ADT). Salvage radical prostatectomy (sRP) is a curative alternative to ADT but yields significant morbidity. Preliminary evidence from focal salvage treatments shows similar oncological control but lower morbidity compared to sRP. Among available ablative focal energies, irreversible electroporation (IRE) is a treatment modality that proved promising, especially in treating apical lesions, where PCa most often recurs. Our aim is to test the safety of salvage IRE for recurrent PCa.

Methods

We performed a single-arm pilot feasibility study (IDEAL stage 2a): SAFE, SAlvage Focal irreversible Electroporation for recurrent localized PCa. Twenty patients with biopsy-proven PCa recurrence after primary non-surgical (radiation or ablation) treatment were included. All men will undergo mpMRI ± targeted biopsies, pre-operative PSMA-PET staging before inclusion and sIRE. Outcomes will be evaluated through internationally validated questionnaires and morbidity scales. All men will undergo a control biopsy at one year.

Results

Primary objectives were the evaluation of the safety of sIRE (and patients’ quality of life) after treatment. Secondary objectives were the evaluation of functional outcomes, namely, continence and erectile function changes and evaluation of short-term oncological efficacy.

Conclusions

SAFE is the second pilot study to evaluate sIRE and the first one performed according to the most recent diagnostic and staging imaging standards. sIRE may provide a curative option for recurrent PCa together with lower comorbidities compared to sRP.

Evolution of Salvage Radical Prostatectomy from Open to Robotic and Further to Retzius Sparing Surgery

Salvage radical prostatectomy (sRP) has evolved from open to minimally invasive approaches. sRP can be offered to patients with local recurrence to improve biochemical recurrence (BCR)-free and overall survival. We evaluate oncological outcome and continence after retropubic (RRP), conventional (cRARP), and Retzius-sparing robotic (rsRARP) surgery. Materials/methods: A total of 53 patients undergoing sRP between 2010 and 2020 were included. Follow-up included oncological outcome and continence. Results: sRP was done as RRP (n = 25), cRARP (n = 7), or rsRARP (n = 21). Median blood loss was 900 mL, 500 mL, and 300 mL for RRP, cRARP, and rsRARP, respectively. At 12 months, 5 (20%), 0, and 4 (19%) patients were continent, 9 (36%), 3 (43%), and 7 (33%) had grade 1 incontinence, 5 (20%), 2 (29%), and 3 (14%) had grade 2 incontinence, and 3 (12%), 2 (29%), and 4 (19%) had grade 3 incontinence for RRP, cRARP, or rsRARP, respectively. During a mean follow-up of 52.6 months, 16 (64%), 4 (57%), and 3 (14%) developed BCR in the RRP-, cRARP-, and rsRARP-group, respectively. Conclusions: Over the years, sRP has shifted from open to laparoscopic/robotic surgery. RARP shows good oncological and functional outcome. rsRARP ensures direct vision on the rectum during preparation and can therefore increase safety and surgeon’s confidence, especially in the salvage setting.

Minimally invasive strategies for the treatment of prostate cancer recurrence after radiation therapy: a systematic review

INTRODUCTION

The aim of this review was to conduct a comprehensive analysis of the role of minimally invasive salvage modalities in radio-recurrent prostate cancer and the associated clinical outcomes and toxicity profiles.

EVIDENCE ACQUISITION

A systematic review of the current literature was conducted through the Medline and NCBI PubMed, Scopus databases in January 2020. All papers published after 2000, concerning studies conducted on humans for radio-recurrent prostate cancer were considered for the review.

EVIDENCE SYNTHESIS

Overall, 545 studies were identified. After duplicate exclusion, initial screening, and eligibility evaluation, a total of 80 studies were included in the qualitative analysis, corresponding to a cohort of 6681 patients. The median age at initial diagnosis ranged from 59 to 75.5. Pre-treatment PSA ranged from 6.2 to 27.4 ng/mL. All patients underwent primary radiotherapy for localized prostate cancer. Cryotherapy, Brachytherapy, EBRT, HIFU were the minimally invasive options mostly used as salvage therapy. They showed to be promising approaches for recurrent prostate cancer (PCa) control, with acceptable toxicities.

CONCLUSIONS

Minimally invasive therapeutic options offer promising results in terms of biochemical control in the local recurrence setting. Unfortunately, the absence of high quality and comparative studies makes it difficult to establish which method is the best in terms of oncological and safety outcomes.

Ralaniten Sensitizes Enzalutamide-Resistant Prostate Cancer to Ionizing Radiation in Prostate Cancer Cells that Express Androgen Receptor Splice Variants

Blocking androgen receptor (AR) transcriptional activity by androgen deprivation therapy (ADT) improves the response to radiotherapy for intermediate and high risk prostate cancer. Unfortunately, ADT, antiandrogens, and abiraterone increase expression of constitutively active splice variants of AR (AR-Vs) which regulate DNA damage repair leading to resistance to radiotherapy. Here we investigate whether blocking the transcriptional activities of full-length AR and AR-Vs with ralaniten leads to enhanced sensitivity to radiotherapy. Combination therapies using ralaniten with ionizing radiation were evaluated for effects on proliferation, colony formation, cell cycle, DNA damage, and Western blot analyses in human prostate cancer cells that express both full-length AR and AR-Vs. Ralaniten and a potent next-generation analog (EPI-7170) decreased expression of DNA repair genes whereas enzalutamide had no effect. FACS analysis revealed a dose-dependent decrease of BrdU incorporation with increased accumulation of γH2AX with a combination of ionizing radiation with ralaniten. An additive inhibitory effect on proliferation of enzalutamide-resistant cells was achieved with a combination of ralaniten compounds with ionizing radiation. Ralaniten and EPI-7170 sensitized prostate cancer cells that express full-length AR and AR-Vs to radiotherapy whereas enzalutamide had no added benefit.

Helical tomotherapy re-irradiation for patients affected by local radiorecurrent prostate cancer

Background

Salvage re-irradiation in patients affected by radiorecurrent prostate cancer might be a valid as well as challenging treatment option. The aim of this study was to evaluate feasibility and toxicity of salvage external beam radiotherapy (EBRT) re-treatment in patients affected by radiorecurrent prostate cancer within the prostate gland or the prostate bed.

Materials and Methods

15 patients underwent EBRT re-treatment using helical tomotherapy (HT), with daily Megavolt computed tomography image-guidance. We registered toxicity according to Common Terminology Criteria for Adverse Events (CTCAE) v4.0. Biochemical relapse was defined as a PSA increase > 20% compared with the pre-EBRT re-treatment value. Survival curves were calculated using the Kaplan-Meier method.

Results

All patients received a total dose of 50 Gy (25 × 2 Gy), and 7 (46.6%) had concomitant androgen deprivation therapy (median duration of 12 months). With a median follow-up of 40.9 months, the 2-year and 4-year biochemical relapse-free survival were 55% and 35%, respectively. Acute and late genito-urinary (GU) toxicity ≥2 were recorded in 4 (26.6%) and 5 (33.3%) patients, respectively, and the 4-year late GU toxicity was 30%. Acute gastrointestinal toxicity ≥2 was recorded in 2 (13.3%) cases, whereas no patient experienced late toxicity.

Conclusions

Despite the inherent bias of a retrospective analysis, our long-term results showed a low toxicity profile with a relatively low rate of biochemical control for HT re-treatment in patients affected by local radiorecurrent prostate cancer. Prospective trials are needed to investigate the role of EBRT in this setting.

Nonsurgical Salvage Local Therapies for Radiorecurrent Prostate Cancer: A Systematic Review and Meta-analysis

CONTEXT

Different nonsurgical therapeutic strategies can be adopted for intraprostatic relapse of prostate cancer after primary radiotherapy, including re-irradiation (with brachytherapy [BT] or external beam radiotherapy [EBRT]), high-intensity focused ultrasound (HIFU), and cryotherapy. The main issues to consider when choosing nonsurgical salvage local therapies are local tumor control and significant genitourinary toxicity.

OBJECTIVE

To conduct a systematic review and meta-analysis of the role of nonsurgical salvage modalities in patients with radiorecurrent prostate cancer and associated clinical outcomes and toxicity profiles.

EVIDENCE ACQUISITION

We performed a critical review of the Medline, Scopus, and ClinicalKey databases from January 1, 2000 through February 1, 2018 according to the Preferred Reporting Items and Meta-Analyses statement. To assess the overall quality of the literature reviewed, we used a modified Delphi tool for case-series studies.

EVIDENCE SYNTHESIS

A total of 64 case-series studies were included, corresponding to a cohort of 5585 patients. The modified Delphi checklist evidenced high methodological quality overall (mean quality score of 80.6%). Biochemical control rates were lowest for patients treated with HIFU (58%, 95% confidence interval [CI] 47-68%) and highest for patients treated with BT (69%, 95% CI 62-76%) and EBRT (69%, 95% CI 53-83%). The lowest prevalence of incontinence was for patients treated with BT (3%, 95% CI 0-6%; I²=63.4%) and the highest was among patients treated with HIFU (28%, 95% CI 19-38%; I²=89.7%).

CONCLUSIONS

Nonsurgical therapeutic options, especially BT, showed good outcomes in terms of biochemical control and tolerability in the local recurrence setting.

PATIENT SUMMARY

The current analysis demonstrated that nonsurgical salvage local therapies offer a chance of a curative local approach in radiorecurrent prostate cancer. However, high-quality data from prospective trials are needed to validate long-term outcomes from nonsurgical strategies for the treatment of intraprostatic recurrence after previous radiotherapy.

Androgen Receptor Variants Mediate DNA Repair after Prostate Cancer Irradiation

In prostate cancer, androgen deprivation therapy (ADT) enhances the cytotoxic effects of radiotherapy. This effect is associated with weakening of the DNA damage response (DDR) normally supported by the androgen receptor. As a significant number of patients will fail combined ADT and radiotherapy, we hypothesized that DDR may be driven by androgen receptor splice variants (ARV) induced by ADT. Investigating this hypothesis, we found that ARVs increase the clonogenic survival of prostate cancer cells after irradiation in an ADT-independent manner. Notably, prostate cancer cell irradiation triggers binding of ARV to the catalytic subunit of the critical DNA repair kinase DNA-PK. Pharmacologic inhibition of DNA-PKc blocked this interaction, increased DNA damage, and elevated prostate cancer cell death after irradiation. Our findings provide a mechanistic rationale for therapeutic targeting of DNA-PK in the context of combined ADT and radiotherapy as a strategy to radiosensitize clinically localized prostate cancer. Cancer Res; 77(18); 4745-54. ©2017 AACR.

Salvage high-intensity focused ultrasound (HIFU) for locally recurrent prostate cancer after failed radiation therapy: Multi-institutional analysis of 418 patients

OBJECTIVE

To report the oncological outcome of salvage high-intensity focused ultrasound (S-HIFU) for locally recurrent prostate cancer after external beam radiotherapy (EBRT) from a multicentre database.

PATIENTS AND METHODS

This retrospective study comprises patients from nine centres with local recurrent disease after EBRT treated with S-HIFU from 1995 to 2009. The biochemical failure-free survival (bFFS) rate was based on the 'Phoenix' definition (PSA nadir + 2 ng/mL). Secondary endpoints included progression to metastasis and cancer-specific death. Kaplan-Meier analysis was performed examining overall (OS), cancer-specific (CSS) and metastasis-free survival (MFS). Adverse events and quality of life status are reported.

RESULTS

In all, 418 patients with a mean (SD) follow-up of 3.5 (2.5) years were included. The mean (SD) age was 68.6 (5.8) years and the PSA level before S-HIFU was 6.8 (7.8) ng/mL. The median PSA nadir after S-HIFU was 0.19 ng/mL. The OS, CSS and MFS rates at 7 years were 72%, 82% and 81%, respectively. At 5 years the bFFS rate was 58%, 51% and 36% for pre-EBRT low-, intermediate- and high-risk patients, respectively. The 5-year bFFS rate was 67%, 42% and 22% for pre-S-HIFU PSA level ≤4, 4-10 and ≥10 ng/mL, respectively. Complication rates decreased after the introduction of specific post-RT parameters: incontinence (grade II or III) from 32% to 19% (P = 0.002); bladder outlet obstruction or stenosis from 30% to 15% (P = 0.003); recto-urethral fistula decreased from 9% to 0.6% (P < 0.001). Study limitations include being a retrospective analysis from a registry with no control group.

CONCLUSION

S-HIFU for locally recurrent prostate cancer after failed EBRT is associated with 7-year CSS and MFS rates of >80% at a price of significant morbidity. S-HIFU should be initiated early following EBRT failure.

Decision analytic cost-effectiveness model to compare prostate cryotherapy to androgen deprivation therapy for treatment of radiation recurrent prostate cancer

OBJECTIVE

To determine the cost-effectiveness of salvage cryotherapy (SC) in men with radiation recurrent prostate cancer (RRPC).

DESIGN

Cost-utility analysis using decision analytic modelling by a Markov model.

SETTING AND METHODS

Compared SC and androgen deprivation therapy (ADT) in a cohort of patients with RRPC (biopsy proven local recurrence, no evidence of metastatic disease). A literature review captured published data to inform the decision model, and resource use data were from the Scottish Prostate Cryotherapy Service. The model was run in monthly cycles for RRPC men, mean age of 70 years. The model was run over the patient lifetime, to assess changes in patient health states and the associated quality of life, survival and cost impacts. Results are reported in terms of the discounted incremental costs and discounted incremental quality-adjusted life years (QALYs) gained between the 2 alternative interventions. Probabilistic sensitivity analysis used a 10,000 iteration Monte Carlo simulation.

RESULTS

SC has a high upfront treatment cost, but delays the ongoing monthly cost of ADT. SC is the dominant strategy over the patient lifetime; it is more effective with an incremental 0.56 QALY gain (95% CI 0.28 to 0.87), and less costly with a reduced lifetime cost of £29,719 (€37,619) (95% CI -51,985 to -9243). For a ceiling ratio of £30,000, SC has a 100% probability to be cost-effective. The cost neutral point was at 3.5 years, when the upfront cost of SC (plus any subsequent cumulative cost of side effects and ADT) equates the cumulative cost in the ADT arm. Limitations of our model may arise from its insensitivity to parameter or structural uncertainty.

CONCLUSIONS

The platform for SC versus ADT cost-effective analysis can be employed to evaluate other treatment modalities or strategies in RRPC. SC is the dominant strategy, costing less over a patient's lifetime with improvements in QALYs.

TRIAL REGISTRATION NUMBER

This economic analysis was undertaken as part of the CROP RCT study

ISRCTN

72677390; it was a pre-trial economic model developed and analysed during the pre-results stage of the RCT.

Re-purposing cryoablation: a combinatorial 'therapy' for the destruction of tissue

It is now recognized that the tumor microenvironment creates a protective neo-tissue that isolates the tumor from the various defense strategies of the body. Evidence demonstrates that, with successive therapeutic attempts, cancer cells acquire resistance to individual treatment modalities. For example, exposure to cytotoxic drugs results in the survival of approximately 20-30% of the cancer cells as only dividing cells succumb to each toxic exposure. With follow-up treatments, each additional dose results in tumor-associated fibroblasts secreting surface-protective proteins, which enhance cancer cell resistance. Similar outcomes are reported following radiotherapy. These defensive strategies are indicative of evolved capabilities of cancer to assure successful tumor growth through well-established anti-tumor-protective adaptations. As such, successful cancer management requires the activation of multiple cellular 'kill switches' to prevent initiation of diverse protective adaptations. Thermal therapies are unique treatment modalities typically applied as monotherapies (without repetition) thereby denying cancer cells the opportunity to express defensive mutations. Further, the destructive mechanisms of action involved with cryoablation (CA) include both physical and molecular insults resulting in the disruption of multiple defensive strategies that are not cell cycle dependent and adds a damaging structural (physical) element. This review discusses the application and clinical outcomes of CA with an emphasis on the mechanisms of cell death induced by structural, metabolic, vascular and immune processes. The induction of diverse cell death cascades, resulting in the activation of apoptosis and necrosis, allows CA to be characterized as a combinatorial treatment modality. Our understanding of these mechanisms now supports adjunctive therapies that can augment cell death pathways.

Low-temperature plasma treatment induces DNA damage leading to necrotic cell death in primary prostate epithelial cells

Background:

In recent years, the rapidly advancing field of low-temperature atmospheric pressure plasmas has shown considerable promise for future translational biomedical applications, including cancer therapy, through the generation of reactive oxygen and nitrogen species.

Method:

The cytopathic effect of low-temperature plasma was first verified in two commonly used prostate cell lines: BPH-1 and PC-3 cells. The study was then extended to analyse the effects in paired normal and tumour (Gleason grade 7) prostate epithelial cells cultured directly from patient tissue. Hydrogen peroxide (H₂O₂) and staurosporine were used as controls throughout.

Results:

Low-temperature plasma (LTP) exposure resulted in high levels of DNA damage, a reduction in cell viability, and colony-forming ability. H₂O₂ formed in the culture medium was a likely facilitator of these effects. Necrosis and autophagy were recorded in primary cells, whereas cell lines exhibited apoptosis and necrosis.

Conclusions:

This study demonstrates that LTP treatment causes cytotoxic insult in primary prostate cells, leading to rapid necrotic cell death. It also highlights the need to study primary cultures in order to gain more realistic insight into patient response.

Population-based comparative effectiveness of salvage radical prostatectomy vs cryotherapy

OBJECTIVE

To characterize population-based practice patterns, disease-specific and overall mortality, and cost associated with salvage cryotherapy (SCT) vs salvage radical prostatectomy (SRP).

METHODS

We retrospectively identified 440 men who failed primary radiation therapy and subsequently underwent SCT (n = 341, 77.5%) or SRP (n = 99, 22.5%) between 1992 and 2009 from Surveillance, Epidemiology, and End Results-Medicare linked data. Propensity score analyses were used to compare overall and prostate cancer-specific mortality and associated Medicare expenditures for SRP vs SCT.

RESULTS

Men undergoing SCT were more likely to be white (P <.001), less likely to be high school graduates (P = .008), and experienced shorter median time from diagnosis to salvage therapy (44.1 vs 60.1, P <.001) and from primary radiotherapy to salvage therapy (38.7 vs 55.8 months, P <.001). In adjusted analyses, overall mortality was higher (21.6 vs 6.1 deaths/100 person years, P <.001) for SRP vs SCT. There was a trend for higher prostate cancer-specific death rates with SRP vs SCT (6.5 vs 1.4 deaths/100 person years, P = .061). Medicare expenditures for SRP vs SCT were more than 2-fold higher ($19,543 vs $8,088, P <.001).

CONCLUSION

SRP vs SCT is associated with higher overall mortality and greater health care expenditures. However, longer follow-up is needed to assess long-term functional outcomes and cancer control.

Low temperature plasma: a novel focal therapy for localized prostate cancer?

Despite considerable advances in recent years for the focal treatment of localized prostate cancer, high recurrence rates and detrimental side effects are still a cause for concern. In this review, we compare current focal therapies to a potentially novel approach for the treatment of early onset prostate cancer: low temperature plasma. The rapidly evolving plasma technology has the potential to deliver a wide range of promising medical applications via the delivery of plasma-induced reactive oxygen and nitrogen species. Studies assessing the effect of low temperature plasma on cell lines and xenografts have demonstrated DNA damage leading to apoptosis and reduction in cell viability. However, there have been no studies on prostate cancer, which is an obvious candidate for this novel therapy. We present here the potential of low temperature plasma as a focal therapy for prostate cancer.

HDAC inhibitor confers radiosensitivity to prostate stem-like cells

Background:

Radiotherapy can be an effective treatment for prostate cancer, but radiorecurrent tumours do develop. Considering prostate cancer heterogeneity, we hypothesised that primitive stem-like cells may constitute the radiation-resistant fraction.

Methods:

Primary cultures were derived from patients undergoing resection for prostate cancer or benign prostatic hyperplasia. After short-term culture, three populations of cells were sorted, reflecting the prostate epithelial hierarchy, namely stem-like cells (SCs, α₂β₁integrin^hi/CD133⁺), transit-amplifying (TA, α₂β₁integrin^hi/CD133⁻) and committed basal (CB, α₂β₁integrin^lo) cells. Radiosensitivity was measured by colony-forming efficiency (CFE) and DNA damage by comet assay and DNA damage foci quantification. Immunofluorescence and flow cytometry were used to measure heterochromatin. The HDAC (histone deacetylase) inhibitor Trichostatin A was used as a radiosensitiser.

Results:

Stem-like cells had increased CFE post irradiation compared with the more differentiated cells (TA and CB). The SC population sustained fewer lethal double-strand breaks than either TA or CB cells, which correlated with SCs being less proliferative and having increased levels of heterochromatin. Finally, treatment with an HDAC inhibitor sensitised the SCs to radiation.

Interpretation:

Prostate SCs are more radioresistant than more differentiated cell populations. We suggest that the primitive cells survive radiation therapy and that pre-treatment with HDAC inhibitors may sensitise this resistant fraction.

Differential cytotoxic activity of a novel palladium-based compound on prostate cell lines, primary prostate epithelial cells and prostate stem cells

The outcome for patients with advanced metastatic and recurrent prostate cancer is still poor. Therefore, new chemotherapeutics are required, especially for killing cancer stem cells that are thought to be responsible for disease recurrence. In this study, we screened the effect of a novel palladium-based anticancer agent (Pd complex) against six different prostate cancer cell lines, and primary cultures from seven Gleason 6/7 prostate cancer, three Gleason 8/9 prostate cancer and four benign prostate hyperplasia patient samples, as well as cancer stem cells selected from primary cultures. MTT and ATP viability assays were used to assess cell growth and flow cytometry to assess cell cycle status. In addition, immunofluorescence was used to detect γH2AX nuclear foci, indicative of DNA damage, and Western blotting to assess the induction of apoptosis and autophagy. The Pd complex showed a powerful growth-inhibitory effect against both cell lines and primary cultures. More importantly, it successfully reduced the viability of cancer stem cells as first reported in this study. The Pd complex induced DNA damage and differentially induced evidence of cell death, as well as autophagy. In conclusion, this novel agent may be promising for use against the bulk of the tumour cell population as well as the prostate cancer stem cells, which are thought to be responsible for the resistance of metastatic prostate cancer to chemotherapy. This study also indicates that the combined use of the Pd complex with an autophagy modulator may be a more promising approach to treat prostate cancer. In addition, the differential effects observed between cell lines and primary cells emphasise the importance of the model used to test novel drugs including its genetic background, and indeed the necessity of using cells cultured from patient samples.