Non-metastatic castration-resistant prostate cancer: current status and future directions

Physician preferences for nonmetastatic castration-resistant prostate cancer treatment in China

Introduction

The treatment preferences of Chinese physicians who treat nonmetastatic castration-resistant prostate cancer (nmCRPC) and how they weigh the benefits and risks of nmCRPC treatment are still unknown. This study aimed to evaluate Chinese physicians' benefit-risk treatment preferences for nmCRPC and assist in setting nmCRPC treatment goals.

Methods

A paper-based discrete choice experiment (DCE) survey was administered to 80 nmCRPC-treating physicians. DCE responses were analyzed to produce the preference weight and the relative importance score for each attribute level. The marginal rate of substitution (MRS) was used to quantify the amount of overall survival (OS) physicians were willing to trade for a reduction in treatment-related adverse events (AEs). We further conducted the exploratory analysis, stratifying physicians from 5 perspectives into different subgroups and examining the treatment preferences and OS trade-off in each subgroup.

Results

In terms of efficacy attributes, physicians placed greater emphasis on OS than time to pain progression. With regard to safety attributes, serious fracture was perceived as the most important AE by physicians, followed by serious fall, cognitive problems, skin rash, and fatigue. In the exploratory analysis, we found generally that physicians with less clinical practice experience and those from more economically developed regions placed more emphasis on AEs and were willing to give up more of their patients' OS to reduce the risk of AEs.

Conclusion

Physicians from mainland China value the importance of minimizing treatment-related AEs when considering different treatment options for patients with nmCRPC, and they are willing to trade a substantial amount of OS to avoid AEs.

How the Management of Biochemical Recurrence in Prostate Cancer Will Be Modified by the Concept of Anticipation and Incrementation of Therapy

Biochemical recurrence (BCR) after primary treatments for prostate cancer (PC) is an extremely heterogeneous phase and at least a stratification into low- and high-risk cases for early progression in metastatic disease is necessary. At present, PSA-DT represents the best parameter to define low- and high-risk BCR PC, but real precision medicine is strongly suggested to define tailored management for patients with BCR. Before defining management, it is necessary to exclude the presence of low-volume metastasis associated with PSA progression using new-generation imaging, preferably with PSMA PET/CT. Low-risk BCR cases should be actively observed without early systemic therapies. Early treatment of low-risk BCR with continuous androgen deprivation therapy (ADT) can produce disadvantages such as the development of castration resistance before the appearance of metastases (non-metastatic castration-resistant PC). Patients with high-risk BCR benefit from early systemic therapy. Even with overall survival (OS) as the primary treatment endpoint, metastasis-free survival (MFS) should be used as a surrogate endpoint in clinical trials, especially in long survival stages of the disease. The EMBARK study has greatly influenced the management of high-risk BCR, by introducing the concept of anticipation and intensification through the use of androgen receptor signaling inhibitors (ARSIs) and ADT combination therapy. In high-risk (PSA-DT ≤ 9 months) BCR cases, the combination of enzalutamide with leuprolide significantly improves MFS when compared to leuprolide alone, maintaining an unchanged quality of life in the asymptomatic phase of the disease. The possibility of using ARSIs alone in this early disease setting is suggested by the EMBARK study (arm with enzalutamide alone) with less evidence than with the intensification of the combination therapy. Continued use versus discontinuation of enzalutamide plus leuprolide intensified therapy upon reaching undetectable PSA levels needs to be better defined with further analysis. Real-world analysis must verify the significant results obtained in the context of a phase 3 study.

"Non-metastatic, Castration-resistant Prostate Cancer: Diagnostic and Treatment Recommendations by an Expert Panel from Brazil"

INTRODUCTION

Non-metastatic, castration-resistant prostate cancer (nmCRPC) is an important clinical stage of prostate cancer, prior to morbidity and mortality from clinical metastases. In particular, the introduction of novel androgen-receptor signaling inhibitors (ARSi) has changed the therapeutic landscape in nmCRPC. Given recent developments in this field, we update our recommendations for the management of nmCRPC.

METHODS

A panel of 51 invited medical oncologists and urologists convened in May of 2021 with the aim of discussing and providing recommendations regarding the most relevant issues concerning staging methods, antineoplastic therapy, osteoclast-targeted therapy, and patient follow-up in nmCRPC. Panel members considered the available evidence and their practical experience to address the 73 multiple-choice questions presented.

RESULTS

Key recommendations and findings include the reliance on prostate-specific antigen doubling time for treatment decisions, the absence of a clear preference between conventional and novel (i.e., positron-emission tomography-based) imaging techniques, the increasing role of ARSis in various settings, the general view that ARSis have similar efficacy. Panelists highlighted the slight preference for darolutamide, when safety is of greater concern, and a continued need to develop high-level evidence to guide the intensity of follow-up in this subset of prostate cancer.

DISCUSSION

Despite the limitations associated with a consensus panel, the topics addressed are relevant in current practice, and the recommendations can help practicing clinicians to provide state-of-the-art treatment to patients with nmCRPC in Brazil and other countries with similar healthcare settings.

Nonmetastatic Castration-Resistant Prostate Cancer: Current Challenges and Trends

Prostate carcinoma is a highly prevalent biologically and clinically diverse disease, generally associated with a consistent elevation of prostate-specific antigen levels. Castration-resistant prostate cancer represents a heterogeneous clinical setting that ranges from patients with an asymptomatic prostate-specific antigen elevation after hormone blockade failure and good performance status to patients with significant debilitating symptoms and rapidly progressive disease, leading to death. Nonmetastatic castration-resistant prostate cancer is a transient disease stage defined over specific criteria established within a sensitive time period. The majority of the patients with nonmetastatic castration-resistant prostate cancer will eventually develop metastatic lesions, associated with prostate cancer-specific morbidity and mortality. However, progression to metastatic disease is a heterogeneous process still not fully understood, with studies suggesting that younger age, high Gleason score (> 7), high prostate-specific antigen levels, reduced prostate-specific antigen doubling time (< 6 months), and a rapid alkaline phosphatase rise as potentially associated factors. Although the nonmetastatic castration-resistant prostate cancer treatment landscape has substantially evolved in recent years, the disease heterogeneity makes treatment decisions for this population challenging in the effort to achieve a balance between the risk of disease progression and the toxicity of new treatments in patients who often have associated comorbidities, yet are generally asymptomatic. The present article addresses the current main challenges in nonmetastatic castration-resistant prostate cancer management, including in diagnosis, owing to the development of new imaging modalities with a direct impact in disease detection, prognostic classification, as a result of the traditionally oversimplified definition of disease aggressiveness (mainly based on prostate-specific antigen doubling time), and patient selection for the most adequate treatment.

Management of Patients with Nonmetastatic Castration-Resistant Prostate Cancer: Recommendations of a Multidisciplinary Panel of Experts from South America

Most prostate cancer patients who undergo androgen-deprivation therapy or orchiectomy will eventually develop castration-resistant prostate cancer (CRPC), often preceded by a nonmetastatic CRPC state known as M0CRPC. The recent development of second-generation antiandrogens provides clinicians with efficacious and safe treatments for M0CRPC. However, the complexity of these patients, who typically have to deal with underlying comorbidities and polypharmacy, often challenges therapeutic decisions in this setting. The recent development of novel imaging techniques also provides clinicians with tools for detecting metastases with high sensitivity and specificity. However, the lack of evidence on the early detection of metastases and the corresponding impact on therapeutic decisions makes these techniques a double-edged sword that must be managed appropriately. Here, we present the expert view of the rapidly evolving concept of M0CRPC and provide recommendations for the identification of these patients, the appropriate use of the emerging imaging modalities, and patients’ management, particularly considering their clinical complexity and the recent development of next-generation antiandrogens.