Uroncor consensus statement: Management of biochemical recurrence after radical radiotherapy for prostate cancer: From biochemical failure to castration resistance

Evaluation of Recurrent Disease after Radiation Therapy for Patients Considering Local Salvage Therapy: Past vs. Contemporary Management

Recurrent prostate cancer after primary treatment with radiation therapy is a common problem. Patients with localized recurrence may benefit from salvage therapy, but careful patient selection is crucial because not all patients will benefit from local salvage therapy, and salvage therapy has increased morbidity compared to primary treatments for prostate cancer. This review aims to provide an overview of the evaluation of patients with recurrent disease after radiation therapy and how it is continuing to evolve with increasing data on outcomes, as well as improving technologies and techniques. Our enhanced understanding of treatment outcomes and risk stratification has influenced the identification of patients who may benefit from local salvage treatment. Advances in imaging and biopsy techniques have enhanced the accuracy of locating the recurrence, which affects treatment decisions. Additionally, the growing interest in image-targeted ablative therapies that have less morbidity and complications than whole-gland therapies for suitable patients influences the evaluation process for those considering focal salvage therapy. Although significant changes have been made in the diagnostic evaluation of patients with recurrent disease after radiation therapy, it remains unclear whether these changes will ultimately improve patient outcomes.

Comparison between MRI and choline-PET trans-perineal target biopsies and saturation biopsies for detection and topography of intra-prostatic recurrence after primary radiation therapy for prostate cancer

INTRODUCTION

Biochemical recurrence of prostate cancer after radiation therapy occurs in 5 to 50% of cases depending on the radiation technique used. The diagnosis of recurrence of prostate adenocarcinoma must be made accurately. The aim of this study was to compare transperineal saturation and target biopsies to index lesion (IL) as defined on MRI and 18FCholine PET-CT (PETc) for detection of intra-prostatic recurrence after primary radiation therapy for prostate cancer.

MATERIALS AND METHODS

Thirty-eight patients with an history of prostate radiation for prostate cancer and biochemical recurrence were retrospectively included between March 2013 and June 2017. All patients had PETc and multiparametric MRI (MRI) defining IL. All patients had transperineal saturation biopsies and target biopsies the IL.

RESULTS

Among 38 patients with biochemical recurrence, 33 (87%) had biopsy proven recurrence in the prostate. The sensitivity and specificity of MRI were 32% (SD:19%) and 91% respectively (SD:7%). The sensitivity and specificity of PETc were 33% (SD:22%) and 78% respectively (SD:12%). Saturation trans-perineal and target biopsies allowed detection of disease recurrence in 79% and 84% of patients, respectively.

CONCLUSION

In case of positive imaging, both trans-perineal prostate saturation and target biopsies offer good performance to confirm intraprostatic recurrence. However, MRI and PETc low sensitivity to detect all sites of local recurrence of prostate cancer after radiation still justify the completion of systematic saturation biopsies.

LEVEL OF EVIDENCE

3.

PP2A and tumor radiotherapy

Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase that serves as a key regulator of cellular physiology in the context of apoptosis, mitosis, and DNA damage responses. Canonically, PP2A functions as a tumor suppressor gene. However, recent evidence suggests that inhibiting PP2A activity in tumor cells may represent a viable approach to enhancing tumor sensitivity to chemoradiotherapy as such inhibition can cause cells to enter a disordered mitotic state that renders them more susceptible to cell death. Indeed, there is evidence that inhibiting PP2A can slow tumor growth following radiotherapy in a range of cancer types including ovarian cancer, liver cancer, malignant glioma, pancreatic cancer, and nasopharyngeal carcinoma. In the present review, we discuss current understanding of the role of PP2A in tumor radiotherapy and the potential mechanisms whereby it may influence this process.

Are all prostate cancer patients "fit" for salvage radiotherapy?

The indication for salvage radiotherapy (RT) (SRT) in patients with biochemically-recurrent prostate cancer after surgery is based on prostate-specific antigen (PSA) levels at the time of biochemical recurrence. Although there are clear criteria (pT3-pT4 disease and/or positive margins) for the use of adjuvant radiotherapy, no specific clinical or tumour-related criteria have yet been defined for SRT. In retrospective series, 5-year biochemical progression-free survival (PFS) ranges from 35%-85%, depending on the PSA level at the start of RT. Two phase 3 trials have compared SRT with and without androgen deprivation therapy (ADT), finding that combined treatment (SRT+ADT) improves both PFS and overall survival. Similar to adjuvant RT, the indication for ADT is based on tumour-related factors such as PSA levels, tumour stage, and surgical margins. The number of patients referred to radiation oncology departments for SRT continues to rise. In the present article, we define the clinical, therapeutic, and tumour-related factors that we believe should be evaluated before prescribing SRT. In addition, we propose a decision algorithm to determine whether the patient is fit for SRT. This algorithm will help to identify patients in whom radiotherapy is likely to improve survival without significantly worsening quality of life.

Management algorithms for prostate-specific antigen progression in prostate cancer: Biochemical recurrence after definitive therapy and progression to non-metastatic castrate-resistant prostate cancer

INTRODUCTION

Current prostate cancer (PCa) guidelines primarily focus on localized or metastatic PCa. A multidisciplinary genitourinary oncology panel determined that additional guidance focusing on monitoring and management of biochemical recurrence (BCR) following radical therapy and non-metastatic castration-resistant prostate cancer (nmCRPC) was warranted.

METHODS

The most up-to-date national and international guidelines, consensus statements, and emerging phase 3 trials were identified and used to inform development of algorithms by a multidisciplinary genitourinary oncology panel outlining optimal monitoring and treatment for patients with non-metastatic PCa.

RESULTS

A total of eight major national and international guidelines/consensus statements published since 2015 and three phase 3 trials were identified. Working group discussions among the multidisciplinary genitourinary oncology panel led to the development of two algorithms: the first addressing management of patients with BCR following radical therapy (post-BCR), and the second addressing management of nmCRPC. The post-BCR algorithm suggests consideration of early salvage treatment in select patients and provides guidance regarding observation vs. intermittent or continuous androgen-deprivation therapy (ADT). The nmCRPC algorithm suggests continued ADT and monitoring for all patients, with consideration of treatment with apalutamide or enzalutamide for patients with high-risk disease (prostate-specific antigen [PSA] doubling time of ≤ 10 months).

CONCLUSIONS

Two treatment algorithms have been developed to guide the management of non-metastatic PCa and should be considered in the context of local guidelines and practice patterns.

Consensus on management of castration-resistant prostate cancer on behalf of the Urological Tumours Working Group (URONCOR) of the Spanish Society of Radiation Oncology

BACKGROUND

The knowledge in the field of castration-resistant prostate cancer (CRPC) is developing rapidly, with emerging new therapies and advances in imaging. Nonetheless, in multiple areas there is still a lack of or very limited evidence, and clear guidance from clinicians regarding optimal strategy is required.

METHODS

A modified Delphi method, with 116 relevant questions divided into 7 different CRPC management topics, was used to develop a consensus statement by the URONCOR group.

RESULTS

A strong consensus or unanimity was reached on 93% of the proposed questions. The seven topics addressed were: CRPC definition, symptomatic patients, diagnosis of metastasis, CRPC progression, M0 management, M1 management and sequencing therapy, and treatment monitoring.

CONCLUSIONS

The recommendations based on the radiation oncology experts' opinions are intended to provide cancer specialists with expert guidance and to standardise CRPC patient management in Spain, facilitating decision-making in different clinically relevant issues regarding CRPC patients.

Identification of genes that predict the biochemical recurrence of prostate cancer

Prostate cancer (PCa) is one of the most prevalent cancer types in men. Biochemical recurrence continues to occur in a large proportion of patients after radical prostatectomy. Thus, prognostic biomarkers are required to determine which treatment is suitable. In the present study, RNA-sequencing gene expression data from The Cancer Genome Atlas was used in order to develop a risk-score staging system based on the expression of eight genes. Cox multivariate regression was used to predict the outcome of patients with PCa. The biomedical recurrence-free survival of patients with low-risk scores was significantly longer compared with patients with high-risk scores (P=5×10⁻⁷). This result was further validated using another dataset, GSE70769, from the National Center for Biotechnology Information. The prognostic values of other clinical information and risk scores were evaluated for 5-year biochemical recurrence. The prognostic value of the risk score was determined using an area under curve value of 0.819, predicting the 5-year biochemical recurrence of patients with PCa. The risk score was identified to be significantly associated with primary tumor stage (P<0.01), Gleason score (P<0.01), and lymph node invasion (P<0.05), but was independent of age. Cox multivariate regression revealed that the risk score was an indicator for prediction of biochemical recurrence. Thus, the risk score is a valuable and robust indicator for predicting the biochemical recurrence of patients with PCa.

Prognostic correlation of cell cycle progression score and Ki-67 as a predictor of aggressiveness, biochemical failure, and mortality in men with high-risk prostate cancer treated with external beam radiation therapy

OBJECTIVES

Ki-67 is a proliferation marker in prostate cancer. A prognostic RNA signature was developed to characterize prostate cancer aggressiveness. The aim was to evaluate prognostic correlation of CCP and Ki-67 with biochemical failure (BF), and survival in high-risk prostate cancer patients (pts) treated with radiation therapy (RT).

METHODS

CCP score and Ki-67 were derived retrospectively from pre-treatment paraffin-embedded prostate cancer tissue of 33 men diagnosed from 2002 to 2006. CCP score was calculated as an average expression of 31 CCP genes. Ki-67 was determined by IHC. Single pathologist evaluated all tissues. Factors associated to failure and survival were analyzed.

RESULTS

Median CCP score was 0.9 (-0-1 - 2.6). CCP 0: 1 pt; CCP 1: 19 pts; CCP 2: 13 pts. Median Ki-67 was 8.9. Ki-67 cutpoint was 15.08%. BF and DSM were observed in 21% and 9%. Ki-67 ≥ 15% predicted BF (p = 0.043). With a median follow-up of 8.4 years, 10-year BF, OS, DM and DSM for CCP 1 vs. CCP 2 was 76-71% (p = 0.83), 83-73% (p = 0.86), 89-85% (p = 0.84), and 94-78% (p = 0.66). On univariate, high Ki-67 was correlated with BF (p = 0.013), OS (p = 0.023), DM (p = 0.007), and DSM (p = 0.01). On Cox MVA, high Ki-67 had a BF trend (p = 0.063). High CCP score was not correlated with DSM.

CONCLUSIONS

High Ki-67 significantly predicted outcome and provided prognostic information. CCP score may improve accuracy stratification. We did not provide prognostic correlation of CCP and DSM. It should be validated in a larger cohort of pts.

Cognitive Function in Patients With Prostate Cancer Receiving Luteinizing Hormone-Releasing Hormone Analogues: A Prospective, Observational, Multicenter Study

PURPOSE

The effect of androgen deprivation therapy (ADT) on cognitive performance (CP) in prostate cancer (PCa) patients is not well understood. We evaluated changes in CP after 6 months of medical castration with luteinizing hormone-releasing hormone (LHRH) analogues.

METHODS AND MATERIALS

We performed a prospective, observational, multicenter, open-label study of PCa patients scheduled to receive LHRH analogues for ≥6 months. We assessed 4 domains of CP at baseline and after 6 months of ADT: (1) working memory, assessed with the Wechsler Adult Intelligence Scale III (WAIS III) Digit Span subtest; (2) visual memory, assessed with an ad hoc visual memory test; (3) visuospatial ability, assessed with the Judgment of Line Orientation test and Mental Rotation of Three-Dimensional Objects test; and (4) nonverbal analytical reasoning, assessed with the WAIS III Matrix Reasoning test. Changes outside the baseline 95% confidence intervals were considered significant.

RESULTS

A total of 308 patients completed the study. Of these, 245 (79.6%) experienced no statistically significant changes on any test whereas 63 (20.4%) experienced significant changes on ≥1 test. Most of these patients showed a change on only 1 test, distributed evenly between improvement (58 patients, 18.8%) and worsening (56 patients, 18.2%). For individual tests, most patients (87.8%-91.8%) had no change from baseline; however, the significant changes (improvement vs deterioration) were as follows: WAIS III Digit Span subtest (6.3% vs 5.9%), visual memory (5.3% vs 5.7%), Judgment of Line Orientation test (5.3% vs 4.5%), Mental Rotation of Three-Dimensional Objects test (4.1% vs 4.1%), and WAIS III Matrix Reasoning test (4.8% vs 5.8%).

CONCLUSIONS

CP in patients with PCa does not appear to be adversely affected by 6 months of LHRH analogue administration.

International survey of androgen deprivation therapy (ADT) for non-metastatic prostate cancer in 19 countries

Background

Continuous androgen deprivation therapy (CADT) is commonly used for patients with non-metastatic prostate cancer as primary therapy for high-risk disease, adjuvant therapy together with radiation or for recurrence after initial local therapy. Intermittent ADT (IADT), a recently developed alternative strategy for providing ADT, is thought to potentially reduce adverse effects, but little is known about practice patterns relating to it. We aimed to describe factors related to physicians’ ADT use and modality for patients with non-metastatic prostate cancer.

Methods

A 45 min online survey was completed by urologists and oncologists responsible for treatment decisions for non-metastatic prostate cancer from 19 countries with high or increasing prevalence of non-metastatic prostate cancer.

Results

There were 441 treating physicians who completed the survey which represented 99 177 patients with prostate cancer under their care, of which 76 386 (77%) had non-metastatic prostate cancer. Of patients with non-metastatic prostate cancer, 38% received ADT (37% gonadotropin-releasing hormone (GnRH), 2% orchiectomy); among patients on GnRH, 54% received CADT (≥6 without >3 months interruption), 23% IADT and 23% <6 months. Highest rates of ADT were reported among oncologists (62%) and in Eastern Europe (Czech Republic, Hungary and Poland). Prostate-specific antigen (PSA) levels (65%), Gleason score (52%) and treatment guidelines (48%) were the most common reasons for CADT whereas PSA levels (54%), patient request (48%), desire to maintain sexual function (40%), patient age and comorbidities (38%) were cited most frequently as reasons for IADT.

Conclusions

This international survey with 441 treating physicians from 19 countries showed that ADT is commonly used in treating patients with non-metastatic prostate cancer, and type of ADT is influenced by high-risk criteria (PSA and Gleason), treatment guidelines and patient preferences. IADT use was primarily driven by PSA levels, patient request and patient age/comorbidities, likely reflecting an attempt to minimise adverse effects of ADT in patients with lower risk tumours.

Transcription Factor HBP1 Enhances Radiosensitivity by Inducing Apoptosis in Prostate Cancer Cell Lines

Radiotherapy for prostate cancer has been gradually carried out in recent years; however, acquired radioresistance often occurred in some patients after radiotherapy. HBP1 (HMG-box transcription factor 1) is a transcriptional inhibitor which could inhibit the expression of dozens of oncogenes. In our previous study, we showed that the expression level of HBP1 was closely related to prostate cancer metastasis and prognosis, but the relationship between HBP1 and radioresistance for prostate cancer is largely unknown. In this study, the clinical data of patients with prostate cancer was compared, and the positive correlation was revealed between prostate cancer brachytherapy efficacy and the expression level of HBP1 gene. Through research on prostate cancer cells in vitro, we found that HBP1 expression levels were negatively correlated with oncogene expression levels. Furthermore, HBP1 overexpression could sensitize prostate cancer cells to radiation and increase apoptosis in prostate cancer cells. In addition, animal model was employed to analyze the relationship between HBP1 gene and prostate cancer radiosensitivity in vivo; the result showed that knockdown of HBP1 gene could decrease the sensitivity to radiation of xenograft. These studies identified a specific molecular mechanism underlying prostate cancer radiosensitivity, which suggested HBP1 as a novel target in prostate cancer radiotherapy.