Management of prostate cancer recurrences after radiation therapy-brachytherapy as a salvage option

CDC20 promotes radioresistance of prostate cancer by activating Twist1 expression

Currently, radiotherapy is one of the most attractive treatments for prostate cancer (PCa) patients. However, radioresistance remains a challenging issue and the underlying mechanism is unknown. Growing evidence has demonstrated that CDC20 (Cell division cycle protein 20) plays a pivotal role in a variety of tumors, including PCa. Here, GEPIA database mining and western blot analysis showed that higher expression of CDC20 was observed in PCa tissues and cells. We demonstrated that the expression of CDC20 was increased in PCa cells by irradiation, and knockdown of CDC20 resulted in inhibition of cell proliferation, migration, tumor formation, induced cell apoptosis and increased radiosensitivity in PCa in vitro and in vivo. Furthermore, we observed that CDC20 regulated Twist1 pathway, influencing cell proliferation and migration. These results suggest that targeting CDC20 and Twist1 may be an effective way to improve the radiosensitivity of PCa.

Senescence-associated secretory phenotype constructed detrimental and beneficial subtypes and prognostic index for prostate cancer patients undergoing radical prostatectomy

BACKGROUND

Cellular senescence is growing in popularity in cancer. A dual function is played by the senescence-associated secretory phenotype (SASP) that senescent cells produce in the development of pro-inflammatory niches, tissue regeneration or destruction, senescence propagation, and malignant transformation. In this study, we conducted thorough bioinformatic analysis and meta-analysis to discover detrimental and beneficial subtypes and prognostic index for prostate cancer (PCa) patients using the experimentally confirmed SASP genes.

METHODS

We identified differentially expressed and prognosis-related SASP genes and used them to construct two molecular subtypes and risk score. Another two external cohorts were used to confirm the prognostic effect of the above subtypes and risk score and meta-analysis was further conducted. Additionally, functional analysis, tumor stemness and heterogeneity and tumor microenvironment were also evaluated. We completed analyses using software R 3.6.3 and its suitable packages. Meta-analysis was performed by software Stata 14.0.

RESULTS

Through multivariate Cox regression analysis and consensus clustering analysis, we used VGF, IGFBP3 and ANG to establish detrimental and beneficial subtypes in the TCGA cohort, which was validated through other two independent cohorts. Meta-analysis showed that detrimental SASP group had significantly higher risk of biochemical recurrence (BCR) than beneficial SASP group (HR: 2.48). Moreover, we also constructed and validated risk score based on these genes to better guide clinical practice. DNA repair, MYC target, oxidative phosphorylation, proteasome and ribosome were highly enriched in detrimental SASP group. Detrimental SASP group had significantly higher levels of B cells, CD8+ T cells, homologous recombination deficiency, loss of heterozygosity, microsatellite instability, purity, tumor mutation burden, mRNAsi, differentially methylated probes and epigenetically regulated RNA expression than beneficial SASP group. The top mutation genes between detrimental and beneficial SASP groups were SPOP, FOXA1, KMT2C, APC, BSN, DNAH17, MYH6, EPPK1, ZNF536 and ZC3H13 with statistical significance.

CONCLUSIONS

From perspective of SASP, we found detrimental and beneficial tumor subtypes which were closely associated with BCR-free survival for PCa patients, which might be important for the furture research in the field of PCa.

Linac-based stereotactic salvage reirradiation for intraprostatic prostate cancer recurrence: toxicity and outcomes

BACKGROUND

The rates of local failure after curative radiotherapy for prostate cancer (PC) remain high despite more accurate locoregional treatments available, with one third of patients experiencing biochemical failure and clinical relapse occurring in 30-47% of cases. Today, androgen deprivation therapy (ADT) is the treatment of choice in this setting, but with not negligible toxicity and low effects on local disease. Therefore, the treatment of intraprostatic PC recurrence represents a challenge for radiation oncologists. Prostate reirradiation (Re-I) might be a therapeutic possibility. We present our series of patients treated with salvage stereotactic Re‑I for intraprostatic recurrence of PC after radical radiotherapy, with the aim of evaluating feasibility and safety of linac-based prostate Re‑I.

MATERIALS AND METHODS

We retrospectively evaluated toxicities and outcomes of patients who underwent salvage reirradiation using volumetric modulated arc therapy (VMAT) for intraprostatic PC recurrence. Inclusion criteria were age ≥ 18 years, histologically proven diagnosis of PC, salvage Re‑I for intraprostatic recurrence after primary radiotherapy for PC with curative intent, concurrent/adjuvant ADT with stereotactic body radiation therapy (SBRT) allowed, performance status ECOG 0-2, restaging choline/PSMA-PET/TC and prostate MRI after biochemical recurrence, and signed informed consent.

RESULTS

From January 2019 to April 2022, 20 patients were recruited. Median follow-up was 26.7 months (range 7-50). After SBRT, no patients were lost at follow-up and all are still alive. One- and 2‑year progression free survival (PFS) was 100% and 81.5%, respectively, while 2‑year biochemical progression-free survival (bFFS) was 88.9%. Four patients (20%) experienced locoregional lymph node progression and were treated with a further course of SBRT. Prostate reirradiation allowed the ADT start to be postponed for 12-39 months. Re‑I was well tolerated by all patients and none discontinued the treatment. No cases of ≥ G3 genitourinary (GU) or gastrointestinal (GI) toxicity were reported. Seven (35%) and 2 (10%) patients experienced acute G1 and G2 GU toxicity, respectively. Late GU toxicity was recorded in 10 (50%) patients, including 8 (40%) G1 and 2 (10%) G2. ADT-related side effects were found in 7 patients (hot flashes and asthenia).

CONCLUSION

Linac-based SBRT is a safe technique for performing Re‑I for intraprostatic recurrence after primary curative radiotherapy for PC. Future prospective, randomized studies are desirable to better understand the effectiveness of reirradiation and the still open questions in this field.

JNJ-64619178 radiosensitizes and suppresses fractionated ionizing radiation-induced neuroendocrine differentiation (NED) in prostate cancer

Background

Radiation therapy (RT) is a standard treatment regimen for locally advanced prostate cancer; however, its failure results in tumor recurrence, metastasis, and cancer-related death. The recurrence of cancer after radiotherapy is one of the major challenges in prostate cancer treatment. Despite overall cure rate of 93.3% initially, prostate cancer relapse in 20-30% patients after radiation therapy. Cancer cells acquire radioresistance upon fractionated ionizing radiation (FIR) treatment, eventually undergo neuroendocrine differentiation (NED) and transform into neuroendocrine-like cells, a mechanism involved in acquiring resistance to radiation therapy. Radiosensitizers are agents that inhibit the repair of radiation-induced DNA damage. Protein arginine methyltransferase 5 (PRMT5) gets upregulated upon ionizing radiation treatment and epigenetically activates DNA damage repair genes in prostate cancer cells. In this study, we targeted PRMT5 with JNJ-64619178 and assessed its effect on DNA damage repair gene activation, radiosensitization, and FIR-induced NED in prostate cancer.

Methods

γH2AX foci analysis was performed to evaluate the DNA damage repair after radiation therapy. RT-qPCR and western blot were carried out to analyze the expression of DNA damage repair genes. Clonogenic assay was conducted to find out the surviving fraction after radiation therapy. NED was targeted with JNJ-64619178 in androgen receptor (AR) positive and negative prostate cancer cells undergoing FIR treatment.

Results

JNJ-64619178 inhibits DNA damage repair in prostate cancer cells independent of their AR status. JNJ-64619178 impairs the repair of ionizing radiation-induced damaged DNA by transcriptionally inhibiting the DNA damage repair gene expression and radiosensitizes prostate, glioblastoma and lung cancer cell line. It targets NED induced by FIR in prostate cancer cells.

Conclusion

JNJ-64619178 can radiosensitize and suppress NED induced by FIR in prostate cancer cells and can be a potential radiosensitizer for prostate cancer treatment.

Case Report: Adaptive radiotherapy in the radiation salvage of prostate cancer

Adaptive radiotherapy has the potential to reduce margins, improve target coverage, and decrease toxicity to organs at risk (OARs) by optimizing radiation delivery to daily anatomic changes. Salvage for locally recurrent prostate cancer after definitive radiation remains a challenging clinical scenario given the risks to normal tissue in a setting of re-irradiation. Here, we present a case series of five patients with locally recurrent prostate cancer treated with an adaptive online linear accelerator or a 3-T MR-based linear accelerator to demonstrate excellent target coverage. All patients completed the planned treatment course with acceptable acute toxicities but a short follow-up time does not inform subacute/late toxicities.

A Ferroptosis-Related Gene Prognostic Index Associated With Biochemical Recurrence and Radiation Resistance for Patients With Prostate Cancer Undergoing Radical Radiotherapy

Background: Ferroptosis is a new type of programmed cell death which has been reported to be involved in the development of various cancers. In this study, we attempted to explore the possible links between ferroptosis and prostate cancer (PCa), and a novel ferroptosis-related gene prognostic index (FGPI) was constructed to predict biochemical recurrence (BCR) and radiation resistance for PCa patients undergoing radical radiotherapy (RRT). Moreover, the tumor immune microenvironment (TME) of PCa was analyzed.

Methods: We merged four GEO datasets by removing batch effects. All analyses were conducted with R version 3.6.3 and its suitable packages. Cytoscape 3.8.2 was used to establish a network of transcriptional factor and competing endogenous RNA.

Results: We established the FGPI based on ACSL3 and EPAS1. We observed that FGPI was an independent risk factor of BCR for PCa patients (HR: 3.03; 95% CI: 1.68–5.48), consistent with the result of internal validation (HR: 3.44; 95% CI: 1.68–7.05). Furthermore, FGPI showed high ability to identify radiation resistance (AUC: 0.963; 95% CI: 0.882–1.00). LncRNA PART1 was significantly associated with BCR and might modulate the mRNA expression of EPAS1 and ACSL3 through interactions with 60 miRNAs. Gene set enrichment analysis indicated that FGPI was enriched in epithelial–mesenchymal transition, allograft rejection, TGF beta signaling pathway, and ECM receptor interaction. Immune checkpoint and m6A analyses showed that PD-L2, CD96, and METTL14 were differentially expressed between BCR and no BCR groups, among which CD96 was significantly associated with BCR-free survival (HR: 1.79; 95% CI: 1.06–3.03). We observed that cancer-related fibroblasts (CAFs), macrophages, stromal score, immune score, estimate score, and tumor purity were differentially expressed between BCR and no BCR groups and closely related to BCR-free survival (HRs were 2.17, 1.79, 2.20, 1.93, 1.92, and 0.52 for cancer-related fibroblasts, macrophages, stromal score, immune score, estimate score, and tumor purity, respectively). Moreover, cancer-related fibroblasts (coefficient: 0.20), stromal score (coefficient: 0.14), immune score (coefficient: 0.14), estimate score (coefficient: 0.15), and tumor purity (coefficient: −0.15) were significantly related to FGPI, among which higher positive correlation between cancer-related fibroblasts and FGPI was observed.

Conclusion: We found that FGPI based on ACSL3 and EPAS1 might be used to predict BCR and radiation resistance for PCa patients. CD96 and PD-L2 might be a possible target for drug action. Besides, we highlighted the importance of immune evasion in the process of BCR.

Outcomes and toxicities of re-irradiation for prostate cancer: A systematic review on behalf of the Re-Irradiation Working Group of the Italian Association of Radiotherapy and Clinical Oncology (AIRO)

AIMS

The best therapeutic approach for local relapses of previously irradiated prostate cancer (PC) is still not defined. Re-irradiation (Re-I) could offer a chance of cure for highly selected patients, although high quality evidences are lacking. The aim of our study is to provide a literature review on efficacy and safety of Re-I.

METHODS

Only studies where Re-I field overlaps with previous radiotherapy were considered. To determine 2 and 4 years overall mortality (OM), 2 and 4 years biochemical failure (BF) and pooled acute and late G ≥ 3 toxicities rate, a meta-analysis over single arm study was performed.

RESULTS

Thirty-eight studies with 1194 patients were included. Median follow-up from Re-I was 30 months (10-94 months). Brachytherapy (BRT) was the most used Re-I technique (27 studies), followed by Stereotactic Body Radiotherapy (SBRT) (9) and External Beam Radiation Therapy (EBRT) (2). Re-I prescription doses ranged from 19 Gy in single HDR fraction to 145 Gy (interstitial BRT). The pooled 2 and 4 years OM rates were 2.1% (95%CI:1.1-3.7%, P < 0.001) and 12.5% (95%CI:8.1-19.5%; P < 0.001). The pooled 2 years BF rate was 24% (95% CI: 19.1-30.2%, P < 0.001). The pooled 4 years BF was 35.6% (95% CI: 28.7-44.3%, P < 0.001). The pooled result of G ≥ 3 acute toxicity was 1.4% (95%CI: 0.7-3%, P < 0.001). One hundred and three G ≥ 3 late adverse events were reported, with a pooled result of G ≥ 3 late toxicity of 8.7% (95%CI: 5.8-13%, P < 0.001).

CONCLUSIONS

Re-I of local failures from PC showed promising OM and biochemical control rates with a safe toxicity profile.

Focal Salvage MR Imaging-Guided Cryoablation for Localized Prostate Cancer Recurrence after Radiotherapy: 12-Month Follow-up

PURPOSE

To evaluate safety, quality of life (QoL), and local cancer control after focal salvage MR imaging-guided cryoablation in patients with local recurrence of prostate cancer (PCa) after radiotherapy.

MATERIALS AND METHODS

A retrospective, single-center study was performed in 62 patients with radiorecurrent PCa who underwent MR imaging-guided cryoablation since May 2011 with a follow-up ≥12 months in December 2017. Rates and descriptions of adverse events were reported. Ablation complications were classified according to the Clavien and SIR systems. Validated questionnaires were used to observe functional outcomes and QoL before therapy and 6 and 12 months after therapy. Cancer control was defined as no biochemical failure according to Phoenix criteria and no other clinical evidence for local or metastatic disease.

RESULTS

All procedures were technically feasible. The number of complications requiring major therapy (Clavien grade 3b/4 or SIR grade D/E/F) was low (2 [3.2%] and 1 [1.6%], respectively). After 12 months, the International Consultation of Incontinence Questionnaire-Short Form (P < .001) and 5-item International Index of Erectile Function (P = .001) scores became significantly worse, indicating increased symptoms of incontinence and diminished erectile function, without compromising QoL. Six patients developed metastases within 6 months. After 12 months, 36 patients (63%) were disease-free.

CONCLUSIONS

Focal salvage MR imaging-guided cryoablation is safe and is associated with a high technical success rate, preservation of QoL, and local PCa control. This treatment can be a reasonable alternative to salvage radical prostatectomy in properly selected patients with low morbidity and preservation of QoL; however, longer follow-up is needed.

Neuroendocrine Differentiation of Prostate Cancer-An Intriguing Example of Tumor Evolution at Play

Our understanding of neuroendocrine prostate cancer (NEPC) has assumed a new perspective in light of the recent advances in research. Although classical NEPC is rarely seen in the clinic, focal neuroendocrine trans-differentiation of prostate adenocarcinoma occurs in about 30% of advanced prostate cancer (PCa) cases, and represents a therapeutic challenge. Even though our knowledge of the mechanisms that mediate neuroendocrine differentiation (NED) is still evolving, the role of androgen deprivation therapy (ADT) as a key driver of this phenomenon is increasingly becoming evident. In this review, we discuss the molecular, cellular, and therapeutic mediators of NED, and emphasize the role of the tumor microenvironment (TME) in orchestrating the phenotype. Understanding the role of the TME in mediating NED could provide us with valuable insights into the plasticity associated with the phenotype, and reveal potential therapeutic targets against this aggressive form of PCa.

Salvage High Dose Rate Brachytherapy after Primary External Beam Irradiation in Localized Prostate Cancer: A Case Report

No standard treatment exists for locally relapsed prostate cancer after primary external beam radiotherapy with no evidence of distant metastases. Radical prostatectomy, brachytherapy, cryotherapy and high-intensity focused ultrasound are currently used as local salvage treatments. Data on the safety and effectiveness of high dose rate (HDR) brachytherapy in this scenario are limited. We report on a patient who has no evidence of disease and no late urinary or gastrointestinal toxicity 33 months after receiving HDR treatment for recurrent prostate cancer.

Image-Guided Robotic Radiosurgery as Salvage Therapy for Locally Recurrent Prostate Cancer after External Beam Irradiation: Retrospective Feasibility Study on Six Cases

Aims and background

Technological advances in treatment planning and execution are providing new potential opportunities in the treatment of recurrent prostate cancer. This study was conducted to evaluate the feasibility and safety of reirradiation with image-guided radiosurgery using CyberKnife, a robotic arm-driven compact linear accelerator, for intraprostatic recurrence after external beam radiotherapy (EBRT).

Methods

Between September 2007 and May 2008, 6 patients diagnosed with locally recurrent prostate cancer after EBRT were treated using the CyberKnife system. The total reirradiation dose was 30 Gy in five fractions. Prior to radiosurgery four patients were treated with androgen-deprivation therapy. Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria and the Houston-Phoenix definition (PSA nadir + 2 ng/mL) were used for toxicity and biochemical failure evaluation, respectively.

Results

After a median follow-up of 11.2 months (range, 9.6–18.6 months), all patients are alive with no evidence of severe urinary or rectal acute morbidity. Local control cannot be exactly determined due to the short follow-up and the bias of the use of androgen ablation. Four patients had biochemical failure, three of them with clinical failure evidence (lymph node, bone and lung metastasis, respectively): none of these patients had clinical evidence of tumor persistence in the prostate.

Conclusions

Salvage radiosurgery with CyberKnife after irradiation is feasible with low urinary and rectal morbidity. A longer follow-up and a larger number of patients are necessary to evaluate its effectiveness and optimal patient selection criteria.

Tip60 is associated with resistance to X-ray irradiation in prostate cancer

Tip60, an oncogene, accelerates cell growth by regulating androgen receptor translocation into the nucleus in prostate cancer. However, the mechanism of Tip60 in the response of prostate cancer to radiotherapy, and radioresistance, has not been studied. Using human prostate cancer samples and two human prostate cancer cell lines (LNCaP and DU145), Tip60 protein expression and the acetylation of ataxia telangiectasia mutant (ATM) were analysed by western blotting and immunoprecipitation. Tip60 was downregulated with small interfering RNA. Cells were irradiated using X‐rays at 0.25 Gy·min⁻¹. Cell viability was assessed by the MTT assay. The expression of Tip60 protein was increased in radioresistant prostate cancer tissues in comparison with radiosensitive tissues, which was also confirmed in both irradiated DU145 and LNCaP cells. Furthermore, the acetylation of ATM was also upregulated in a time‐dependent manner after irradiation of both DU145 and LNCaP cells. Additionally, depletion of Tip60 decreased the survival of LNCaP and DU145 cells by inducing apoptosis, reduced the acetylation of ATM and decreased the expression of phosphorylated ATM, Chk2 and cdc25A in both DU145 and LNCaP cells after X‐ray irradiation. The results of this study demonstrated that the expression of Tip60 may be related to the radioresistance of prostate cancer and could serve as a promising predictive factor for prostate cancer patients receiving radiotherapy.

Focal or whole-gland salvage prostate brachytherapy with iodine seeds with or without a rectal spacer for postradiotherapy local failure: How best to spare the rectum?

PURPOSE

Salvage prostate permanent implant (sPPI) for postradiation local failure provides high rates of biochemical control. The cumulative dose delivered to the prostate and the rectum is still unknown.

METHODS AND MATERIALS

We reviewed the postimplant CT-based dosimetry of 18 selected patients who underwent sPPI with (125)I seeds for isolated biopsy-proven local failure several years after external beam radiation therapy. Ten patients had whole-prostate sPPI, and 8 patients had multiparametric MRI-based focal sPPI. In 8 patients, hyaluronic acid (HA) gel was injected into the prostate-rectum space.

RESULTS

The median cumulative biological effective dose after EBRT + sPPI for the prostate and the rectum was higher in patients treated with whole-gland sPPI than in patients treated with focal sPPI (313.5 Gy2 vs. 174.4 Gy2; p = 0.06 and 258.1 Gy3 vs. 172.6 Gy3; p < 0.01, respectively). The median D0.1cc for the rectum was significantly lower in patients who had HA gel: 63.3 Gy (29.0-78.3) vs. 83.9 Gy (34.9-180.0) (p = 0.04).

CONCLUSIONS

Cumulative prostate and rectum biological effective doses were lower with focal sPPI. D0.1cc delivered to the rectum was significantly lower with HA gel, while there was no difference between focal or whole-gland plans.

The evolution of brachytherapy for prostate cancer

Brachytherapy (BT), using low-dose-rate (LDR) permanent seed implantation or high-dose-rate (HDR) temporary source implantation, is an acceptable treatment option for select patients with prostate cancer of any risk group. The benefits of HDR-BT over LDR-BT include the ability to use the same source for other cancers, lower operator dependence, and - typically - fewer acute irritative symptoms. By contrast, the benefits of LDR-BT include more favourable scheduling logistics, lower initial capital equipment costs, no need for a shielded room, completion in a single implant, and more robust data from clinical trials. Prospective reports comparing HDR-BT and LDR-BT to each other or to other treatment options (such as external beam radiotherapy (EBRT) or surgery) suggest similar outcomes. The 5-year freedom from biochemical failure rates for patients with low-risk, intermediate-risk, and high-risk disease are >85%, 69-97%, and 63-80%, respectively. Brachytherapy with EBRT (versus brachytherapy alone) is an appropriate approach in select patients with intermediate-risk and high-risk disease. The 10-year rates of overall survival, distant metastasis, and cancer-specific mortality are >85%, <10%, and <5%, respectively. Grade 3-4 toxicities associated with HDR-BT and LDR-BT are rare, at <4% in most series, and quality of life is improved in patients who receive brachytherapy compared with those who undergo surgery.

Single-institution comparative study on the outcomes of salvage cryotherapy versus salvage robotic prostatectomy for radio-resistant prostate cancer

BACKGROUND

Although primary treatment of localized prostate cancer provides excellent oncologic control, some men who chose radiotherapy experience a recurrence of disease. There is no consensus on the most appropriate management of these patients after radiotherapy failure. In this single-institution review, we compare our oncologic outcome and toxicity between salvage prostatectomy and cryotherapy treatments.

METHODS

From January 2004 to June 2013, a total of 23 salvage procedures were performed. Six of those patients underwent salvage prostatectomy while 17 underwent salvage cryotherapy by two high-volume fellowship-trained urologists. Patients being considered for salvage therapy had localized disease at presentation, a prostate-specific antigen (PSA) < 10 ng/mL at recurrence, life expectancy > 10 years at recurrence, and a negative metastatic workup. Patients were followed to observe cancer progression and toxicity of treatment.

RESULTS

Patients who underwent salvage cryotherapy were statistically older with a higher incidence of hypertension than our salvage prostatectomy cohort. With a mean follow up of 14.1 months and 7.2 months, the incidence of disease progression was 23.5% and 16.7% after salvage cryotherapy and prostatectomy, respectively. The overall complication rate was also 23.5% versus 16.7%, with the most frequent complication after salvage cryotherapy being urethral stricture and after salvage prostatectomy being severe urinary incontinence. There were no rectal injuries with salvage prostatectomy and one rectourethral fistula in the cohort after salvage cryotherapy.

CONCLUSION

While recurrences from primary radiotherapy for prostate cancer do occur, there is no consensus on its management. In our experience, salvage procedures were generally safe and effective. Both salvage cryotherapy and salvage prostatectomy allow for adequate cancer control with minimal toxicity.

Comparative Oncologic and Toxicity Outcomes of Salvage Radical Prostatectomy Versus Nonsurgical Therapies for Radiorecurrent Prostate Cancer: A Meta-Regression Analysis

CONTEXT

In the absence of randomised controlled trials comparing the oncologic, toxicity, and functional outcomes of salvage radical prostatectomy (SRP), salvage high-intensity focused ultrasound (SHIFU), salvage brachytherapy (SBT), and salvage cryotherapy (SCT), controversy exists as to the optimal salvage modality in radiorecurrent prostate cancer.

OBJECTIVE

We carried out a meta-regression analysis to determine whether there is a difference in oncologic, toxicity, and functional outcomes using data from original publications of salvage modalities in the postradiation setting.

EVIDENCE ACQUISITION

We performed a systematic review of PubMed/Medline citations according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement. We included 63 articles in the analysis (25 on SRP, 8 on SHIFU, 16 on SCT, 14 on SBT).

EVIDENCE SYNTHESIS

Median values of the following variables were extracted from each study: patient age, length of follow-up, prostate-specific antigen (PSA) before radiotherapy (RT), PSA before salvage therapy, Gleason score before RT, and time interval between RT and salvage therapy. Functional, toxicity, and oncologic outcomes were measured according to rates of impotence, incontinence, fistula formation, urethral strictures, and biochemical recurrence. Meta-regression adjusting for confounders found no significant difference in oncologic outcomes between SRP and nonsurgical salvage modalities. SBT, SCT, and SHIFU appeared to have better continence outcomes than SRP. No significant difference in toxicity outcomes between modalities was found, although limitations such as reporting, selection, and publication bias and between-study heterogeneity must also be considered with these conclusions.

CONCLUSIONS

Oncologic outcomes are comparable for SRP and all three nonsurgical salvage modalities. We found no significant differences in toxicity outcomes among modalities; however, SRP appears to be associated with worse rates of urinary incontinence than SBT, SCT, and SHIFU.

PATIENT SUMMARY

We performed a meta-regression analysis to compare oncologic, functional, and toxicity outcomes between salvage radical prostatectomy and nonsurgical salvage modalities. Oncologic and toxicity outcomes appear to be similar; however, all nonsurgical salvage modalities may be associated with better continence outcomes.

Salvage radical prostatectomy after external beam radiation therapy: a systematic review of current approaches

BACKGROUND

Radical external beam radiotherapy (EBRT) is a standard treatment for prostate cancer patients. Despite this, the rate of intraprostatic relapses after primary EBRT is still not negligible. There is no consensus on the most appropriate management of these patients after EBRT failure. For these patients, local salvage therapy such as radical prostatectomy, cryotherapy, and brachytherapy may be indicated.

OBJECTIVE

The objectives of this review were to analyze the eligibility criteria for careful selection of appropriate patients and to evaluate the oncological results and complications for each method.

METHODS

A review of the literature was performed to identify studies of local salvage therapy for patients who had failed primary EBRT for localized prostate cancer.

RESULTS

Most studies demonstrated that local salvage therapy after EBRT may provide long-term local control in appropriately selected patients, although toxicity is often significant.

CONCLUSIONS

Our results suggest that for localized prostate cancer recurrence after EBRT, the selection of a local treatment modality should be made on a patient-by-patient basis. An improvement in selection criteria and an integrated definition of biochemical failure for all salvage methods are required to determine which provides the best oncological outcome and least comorbidity.

Targeted radiotherapy with gold nanoparticles: current status and future perspectives

Radiation therapy (RT) is the treatment of cancer and other diseases with ionizing radiation. The ultimate goal of RT is to destroy all the disease cells while sparing healthy tissue. Towards this goal, RT has advanced significantly over the past few decades in part due to new technologies including: multileaf collimator-assisted modulation of radiation beams, improved computer-assisted inverse treatment planning, image guidance, robotics with more precision, better motion management strategies, stereotactic treatments and hypofractionation. With recent advances in nanotechnology, targeted RT with gold nanoparticles (GNPs) is actively being investigated as a means to further increase the RT therapeutic ratio. In this review, we summarize the current status of research and development towards the use of GNPs to enhance RT. We highlight the promising emerging modalities for targeted RT with GNPs and the corresponding preclinical evidence supporting such promise towards potential clinical translation. Future prospects and perspectives are discussed.

Salvage brachytherapy in prostate local recurrence after radiation therapy: predicting factors for control and toxicity

Purpose

To evaluate efficacy and toxicity after salvage brachytherapy (BT) in prostate local recurrence after radiation therapy.

Methods and materials

Between 1993 and 2007, we retrospectively analyzed 56 consecutively patients (pts) undergoing salvage brachytherapy. After local biopsy-proven recurrence, pts received 145 Gy LDR-BT (37 pts, 66%) or HDR-BT (19 pts, 34%) in different dose levels according to biological equivalent doses (BED_{2 Gy}). By the time of salvage BT, only 15 pts (27%) received ADT. Univariate and multivariate analyses were performed to identify predictors of biochemical control and toxicities. Acute and late genitourinary (GU) and gastrointestinal (GI) toxicities were graded using Common Terminology Criteria for Adverse Events (CTCv3.0).

Results

Median follow-up after salvage BT was 48 months. The 5-year FFbF was 77%. HDR and LDR late grade 3 GU toxicities were observed in 21% and 24%. Late grade 3 GI toxicities were observed in 2% (HDR) and 2.7% (LDR). On univariate analysis, pre-salvage prostate-specific antigen (PSA) > 10 ng/ml (p = 0.004), interval to relapse after initial treatment < 24 months (p = 0.004) and salvage HDR-BT doses BED_{2 Gy} level < 227 Gy (p = 0.012) were significant in predicting biochemical failure. On Cox multivariate analysis, pre-salvage PSA, and time to relapse were significant in predicting biochemical failure.

HDR-BT BED_{2 Gy} (α/β 1.5 Gy) levels ≥ 227 (p = 0.013), and ADT (p = 0.049) were significant in predicting grade ≥ 2 urinary toxicity.

Conclusions

Prostate BT is an effective salvage modality in some selected prostate local recurrence patients after radiation therapy. Even, we provide some potential predictors of biochemical control and toxicity for prostate salvage BT, further investigation is recommended.

A Phase II study of salvage high-dose-rate brachytherapy for the treatment of locally recurrent prostate cancer after definitive external beam radiotherapy

PURPOSE

We report the toxicity and biochemical tumor control outcome of a prospective Phase II study using high-dose-rate brachytherapy (HDR) alone as a salvage therapy for recurrent disease after external beam radiotherapy (EBRT).

METHODS

Forty-two patients with biopsy-proven recurrence were enrolled on a Phase II study of salvage HDR monotherapy using iridium-192. Median pretreatment EBRT dose was 8100 cGy (6840–8640 cGy) and the median time from completion of EBRT to salvage HDR was 73 months. The protocol prescription dose of 3200 cGy was delivered in four fractions over 30 hours in a single insertion. Median followup after salvage HDR was 36 months (6–67 months).

RESULTS

The actuarial prostate-specific antigen biochemical relapse-free survival and distant metastases-free survival rates at 5 years were 68.5% and 81.5%, respectively. Cause-specific survival was 90.3%. Late genitourinary Grade 1and 2 toxicities were found in 38% and 48%, respectively, and one patient developed Grade 3 urinary incontinence. Late Grade 1 and 2 gastrointestinal toxicity was noted in 17% and 8% of patients, respectively. Three patients (7%) developed Grade 2 late urinary toxicity (urethral stricture), which were corrected with urethral dilatation, and one patient developed Grade 3 urinary incontinence. No Grade 4 toxicities were observed.

CONCLUSIONS

Genitourinary toxicity was the most commonly encountered toxicity observed after salvage HDR but severe toxicities were uncommon. Salvage HDR is an effective and well-tolerated modality for locally recurrent prostate cancer and should be considered even for patients who have previously been treated with ultra-high dose levels of EBRT.

Focal low-dose rate brachytherapy for the treatment of prostate cancer

Whole-gland low-dose rate (LDR) brachytherapy has been a well-established modality of treating low-risk prostate cancer. Treatment in a focal manner has the advantages of reduced toxicity to surrounding organs. Focal treatment using LDR brachytherapy has been relatively unexplored, but it may offer advantages over other modalities that have established experiences with a focal approach. This is particularly true as prostate cancer is being detected at an earlier and more localized stage with the advent of better detection methods and newer imaging modalities.

The dilemma of a rising prostate-specific antigen level after local therapy: what are our options?

Prostate cancer is the most common solid tumor diagnosed in men in the United States and Western Europe. Primary treatment with radiation or surgery is largely successful at controlling localized disease. However, a significant number (up to one third of men) may develop biochemical recurrence (BR), defined as a rise in serum prostate-specific antigen (PSA) level. A general presumption is that BR will lead to overt progression in patients over subsequent years. There are a number of factors that a physician must consider when counseling and recommending treatment to a patient with a rising PSA. These include the following (1) various PSA-based definitions of BR; (2) source of PSA (ie, local or distant disease, residual benign prostate); (3) available modalities to treat the disease with the least morbidity; and (4) timing of therapy. In this article we review the current and future factors that clinicians should consider in the diagnosis and treatment of recurrent prostate cancer.

Extracellular microRNAs in urologic malignancies: chances and challenges

Small noncoding RNAs that are 19–23 nucleotides long, known as microRNAs (miRNAs), are involved in almost all biological mechanisms during carcinogenesis. Recent studies show that miRNAs released from live cells are detectable in body fluids and may be taken up by other cells to confer cell-cell communication. These released miRNAs (here referred to as extracellular miRNAs) are often protected by RNA-binding proteins or embedded inside circulating microvesicles. Due to their relative stability, extracellular miRNAs are believed to be promising candidates as biomarkers for diagnosis and prognosis of disease, or even as therapeutic agents for targeted treatment. In this review, we first describe biogenesis and characteristics of these miRNAs. We then summarize recent publications involving extracellular miRNA profiling studies in three representative urologic cancers, including: prostate cancer, bladder cancer, and renal cell carcinoma. We focus on the diagnostic, prognostic, and therapeutic potential of these miRNAs in biological fluids, such as serum, plasma, and urine. Finally, we discuss advantages and challenges of these miRNAs in clinical applications.

MR imaging-guided focal cryoablation in patients with recurrent prostate cancer

PURPOSE

To assess the feasibility of magnetic resonance (MR) imaging-guided focal cryoablation in patients with locally recurrent prostate cancer after radiation therapy.

MATERIALS AND METHODS

This was a prospective study, and informed consent was obtained from all patients. Ten consecutive patients with histopathologically proved recurrent prostate cancer after radiation therapy, without evidence of distant metastases, were treated while under general anesthesia in a 1.5-T MR unit. A urethral warmer was inserted. Cryoneedles were transperineally inserted under real-time MR imaging. Then, a rectal warmer was inserted. Ice ball growth was continuously monitored under MR imaging guidance. Two freeze-thaw cycles were performed. Follow-up consisted of a visit to the urologist, measurement of prostate-specific antigen level, and multiparametric MR imaging at 3, 6, and 12 months. Potential complications were recorded.

RESULTS

All patients were successfully treated. In one patient, the urethral warmer could not be inserted and the procedure was cancelled. Two months later, the procedure was successfully repeated. Another patient had urinary retention. Follow-up data were available for all patients. A local recurrence or remnant tumor was found in two patients after 6 months and in another patient after 12 months. These three patients underwent successful retreatment with MR imaging-guided focal cryoablation.

CONCLUSION

MR imaging-guided focal cryoablation of recurrent prostate cancer after radiation therapy is feasible and safe. Initial results are promising; however, longer follow-up is needed and more patients must be studied.

Radiosensitivity of human prostate cancer cells can be modulated by inhibition of 12-lipoxygenase

Nearly 30% of prostate cancer (PCa) patients treated with potentially curative doses relapse at the sites of irradiation. How some tumor cells acquire radioresistance is poorly understood. The platelet-type 12-lipoxygenases (12-LOX)-mediated arachidonic acid metabolism is important in PCa progression. Here we show that 12-LOX confers radioresistance upon PCa cells. Treatment with 12-LOX inhibitors baicalein or BMD122 sensitizes PCa cells to radiation, without radiosensitizing normal cells. 12-LOX inhibitors and radiation, when combined, have super additive or synergistic inhibitory effects on the colony formation of both androgen-dependent LNCaP and androgen-independent PC-3 PCa cells. In vivo, the combination therapy significantly reduced tumor growth.

M-HIFU inhibits tumor growth, suppresses STAT3 activity and enhances tumor specific immunity in a transplant tumor model of prostate cancer

Objective

In this study, we explored the use of mechanical high intensity focused ultrasound (M-HIFU) as a neo-adjuvant therapy prior to surgical resection of the primary tumor. We also investigated the role of signal transducer and activator of transcription 3 (STAT3) in M-HIFU elicited anti-tumor immune response using a transplant tumor model of prostate cancer.

Methods

RM-9, a mouse prostate cancer cell line with constitutively activated STAT3, was inoculated subcutaneously in C57BL/6J mice. The tumor-bearing mice (with a maximum tumor diameter of 5∼6 mm) were treated by M-HIFU or sham exposure two days before surgical resection of the primary tumor. Following recovery, if no tumor recurrence was observed in 30 days, tumor rechallenge was performed. The growth of the rechallenged tumor, survival rate and anti-tumor immune response of the animal were evaluated.

Results

No tumor recurrence and distant metastasis were observed in both treatment groups employing M-HIFU + surgery and surgery alone. However, compared to surgery alone, M-HIFU combined with surgery were found to significantly inhibit the growth of rechallenged tumors, down-regulate intra-tumoral STAT3 activities, increase cytotoxic T cells in spleens and tumor draining lymph nodes (TDLNs), and improve the host survival. Furthermore, M-HIFU combined with surgery was found to significantly decrease the level of immunosuppression with concomitantly increased number and activities of dendritic cells, compared to surgery alone.

Conclusion

Our results demonstrate that M-HIFU can inhibit STAT3 activities, and when combined synergistically with surgery, may provide a novel and promising strategy for the treatment of prostate cancers.

Long-term follow-up of prostate cancer patients treated with vaccine and definitive radiation therapy

BACKGROUND

Vaccine therapy in combination with radiation therapy may improve distant and/or local control in prostate cancer. We present long-term follow-up data on the secondary and exploratory endpoints of safety and biochemical failure, respectively, from patients with clinically localized prostate cancer treated definitively with a poxviral vector-based therapeutic vaccine combined with external beam radiation therapy (EBRT).

METHODS

Thirty-six prostate cancer patients received definitive EBRT plus vaccine. A total of 18 patients were treated with adjuvant standard-dose interleukin-2 (S-IL-2) (4 MIU m(-2)) and 18 were treated with very low-dose IL-2 (M-IL-2) (0.6 MIU m(-2)). Seven patients were treated with EBRT alone. Twenty-six patients treated with EBRT plus vaccine returned for follow-up, and we reviewed the most recent labs and clinical notes of the remaining patients.

RESULTS

Median follow-up for the S-IL-2, M-IL-2 and EBRT-alone groups was 98, 76 and 79 months, respectively. Actuarial 5-year PSA failure-free probability was 78%, 82% and 86% (P=0.58 overall), respectively. There were no significant differences between the actuarial overall survival and the prostate cancer-specific survival between the two vaccine arms. Of the 26 patients who returned for follow-up, Radiation Therapy Oncology Group grade ≥2 genitourinary (GU) and gastrointestinal (GI) toxicity was seen in 19% and 8%, respectively, with no difference between the arms (P=1.00 and P=0.48 for grade ≥2 GU and GI toxicity, respectively). In all, 12 patients were evaluated for PSA-specific immune responses, and 1 demonstrated a response 66 months post-enrollment.

CONCLUSIONS

We demonstrate that vaccine combined with EBRT does not appear to have significant differences with regard to PSA control or late-term toxicity compared with standard treatment. We also found limited evidence of long-term immune response following vaccine therapy.

mTOR is a selective effector of the radiation therapy response in androgen receptor-positive prostate cancer

Ionizing radiation (IR) is used frequently in the management of multiple tumor types, including both organ-confined and locally advanced prostate cancer (PCa). Enhancing tumor radiosensitivity could both reduce the amount of radiation required for definitive treatment and improve clinical outcome. Androgen suppression therapy improves clinical outcomes when combined with radiation therapy but is associated with significant acute and chronic toxicities; hence, there is a clear need for alternative means to increase the therapeutic window of radiotherapy. Herein, it is demonstrated that the mammalian target of rapamycin (mTOR) inhibitors rapamycin (sirolimus) and temsirolimus limit both hormone therapy (HT)-sensitive and castration-resistant PCa (CRPC) cell proliferation as single agents and have a profound radiosensitization effect when used in combination with IR. Importantly, the observed radiosensitization was influenced by the treatment schedule, in which adjuvant administration of mTOR inhibitors was most effective in limiting PCa cell population doubling. This schedule-dependent influence on in vitro treatment outcome was determined to be the result of relative effects on the cell cycle kinetics. Finally, adjuvant administration of either mTOR inhibitor tested after IR significantly decreased clonogenic cell survival of both HT-sensitive and CRPC cells compared with IR alone. Taken together, these data demonstrate that inhibition of mTOR confers a radiosensitization phenotype that is dependent on relative cell cycle kinetics and provide a foundation for clinical assessment.

Molecular targets for radiation oncology in prostate cancer

Recent selected developments of the molecular science of prostate cancer (PrCa) biology and radiation oncology are reviewed. We present potential targets for molecular integration treatment strategies with radiation therapy (RT), and highlight potential strategies for molecular treatment in combination with RT for patient care. We provide a synopsis of the information to date regarding molecular biology of PrCa, and potential integrated research strategy for improved treatment of PrCa. Many patients with early-stage disease at presentation can be treated effectively with androgen ablation treatment, surgery, or RT. However, a significant portion of men are diagnosed with advanced stage/high-risk disease and these patients progress despite curative therapeutic intervention. Unfortunately, management options for these patients are limited and are not always successful including treatment for hormone refractory disease. In this review, we focus on molecules of extracellular matrix component, apoptosis, androgen receptor, RUNX, and DNA methylation. Expanding our knowledge of the molecular biology of PrCa will permit the development of novel treatment strategies integrated with RT to improve patient outcome.

[Which modality for prostate brachytherapy?]

Brachytherapy techniques by permanent implant of radioactive sources or by temporary high-dose-rate (HDR) fractions are nowadays extensively used for the treatment of prostatic carcinoma. Long-term results (at 20 years) concerning large amount of patients have been published by major centers confirming both in terms of efficacy and toxicities that permanent implant of radioactive iodine-125 seeds yields at least the same good results of surgery and of external beam irradiation when proposed to patients affected by low-risk disease. For intermediate to high-risk tumors, HDR temporary implants are proposed as a boost for dose escalation. For both techniques, several topics still need to be clarified dealing with a recent enlargement of indications (HDR alone for low-risk, iodine-125 seeds boost for intermediate-high-risk cancers), or with technical aspects (loose seeds versus linked ones, number of fractions and dose for HDR protocols), while dosimetric issues have only recently been addressed by cooperatives groups. Last but not least, there is a real need to address and clearly characterize the correct definition of biochemical disease control both for iodine permanent implant and for HDR implant. New challenges are facing the prostate-brachytherapy community in the near future: local relapse after external beam radiotherapy are currently managed by several salvage treatments (prostatectomy, cryo, high intensity focused ultrasounds [HIFU]) but the role of reirradiation by brachytherapy is also actively investigated. Focal therapy has gained considerable interest in the last 5 years aiming at treating only the area of cancer foci inside the prostate and preserving nearby healthy tissues. Encouraging results have been obtained with the so-called "minimally invasive" approaches and both permanent seed implantation and HDR brachytherapy techniques may be worthwhile testing in this setting because of their capability of exactly sculpting the dose inside the prostatic gland.

Long-term outcomes and patient satisfaction of continent catheterizable limb and augmentation cystoplasty simultaneous with salvage prostatectomy

AIMS

We evaluated the long-term outcomes of augmentation cystoplasty and continent catheterizable limb formation in patients who underwent simultaneous salvage prostatectomy.

METHODS

Twelve men who underwent salvage prostatectomy with augmentation cystoplasty and either an appendicovesicostomy or Monti ileovesicostomy between October 2000 and February 2003 were assessed for long-term surgical complications, reoperations, continence rates, and patient satisfaction using the Incontinence Symptom Index (ISI) questionnaire and a self-designed catheterization questionnaire.

RESULTS

In addition to bladder augmentation, six patients underwent appendicovesicostomy, four had a Monti ileovesicostomy and two a spiral Monti ileovesicostomy. There were no intraoperative complications or surgical-related deaths. Four patients required revision surgery (33%) at a mean of 39 months. Minor revisions were performed for stomal stenosis in two patients with stomal relocation in two patients. Ten of 12 patients were dry (83.3%) with a catheterization frequency of between 3 and 8 hr. At a mean follow-up of 61 months (SD = 20.51), the mean ISI severity score was 1.86 (SD = 3.54) and the mean ISI bother score was 1 (SD 0.74). The majority (86%) would choose to undergo the surgery again.

CONCLUSIONS

Although surgically challenging and associated with significant morbidity, salvage prostatectomy with concomitant bladder augmentation and continent catheterizable reconstruction is a feasible and effective means of obtaining adequate long-term urinary continence, while preserving the native bladder. In comparison to similar historical patients with catheterizable limbs only, fewer of the augmented patients needed antimuscarinic medication and delayed augmentation was not necessary. Complications do not increase over time and the continence rates are stable.

Current salvage methods for recurrent prostate cancer after failure of primary radiotherapy

We reviewed the current salvage methods for patients with local recurrent prostate cancer after primary radiotherapy (RT), using a search of relevant Medline/PubMed articles published from 1982 to 2008, with the following search terms: 'radiorecurrent prostate cancer, local salvage treatment, salvage radical prostatectomy (RP), salvage cryoablation, salvage brachytherapy, salvage high-intensity focused ultrasound (HIFU)', and permutations of the above. Only articles written in English were included. The objectives of this review were to analyse the eligibility criteria for careful selection of appropriate patients and to evaluate the oncological results and complications for each method. There are four whole-gland re-treatment options (salvage RP, salvage cryoablation, salvage brachytherapy, salvage HIFU) for RT failure, although others might be in development or investigations. Salvage RP has the longest follow-up with acceptable oncological results, but it is a challenging technique with a high complication rate. Salvage cryoablation is a feasible option, especially using third-generation technology, whereby the average biochemical disease-free survival rate is 50-70% and there are fewer occurrences of severe complications such as recto-urethral fistula. Salvage brachytherapy, with short-term cancer control, is comparable to other salvage methods but depends on cumulative dosage limitation to target tissues. HIFU is a relatively recent option in the salvage setting. Both salvage brachytherapy and HIFU require more detailed studies with intermediate and long-term follow-up. As these are not prospective, randomized studies and the definitions of biochemical failure varied, there are limited comparisons among these different salvage methods, including efficacy. In the focal therapy salvage setting, the increased use of thermoablative methods for eligible patients might contribute to reducing complications and maintaining quality of life. The problem to effectively salvage patients with locally recurrent disease after RT is the lack of diagnostic examinations with sufficient sensitivity and specificity to detect local recurrence at an early curable stage. Therefore, a more strict definition of biochemical failure, improved imaging techniques, and accurate specimen mapping are needed as diagnostic tools. Furthermore, universal selection criteria and an integrated definition of biochemical failure for all salvage methods are required to determine which provides the best oncological efficacy and least comorbidity.