Multiregion sampling of de novo metastatic prostate cancer reveals complex polyclonality and augments clinical genotyping

Defining oligometastatic state in uro-oncological cancers

PURPOSE OF REVIEW

Oligometastatic tumors illustrate a distinct state between localized and systematic disease and might harbor unique biologic features. Moreover, these tumors represent a different clinical entity, with a potential of long-term disease control or even cure, therefore they receive growing attention in the field of urologic oncology.

RECENT FINDINGS

Currently, there is no consensus on the definition of oligometastatic prostate cancer, most experts limit it to a maximum of three to five lesions and involvement of no more than two organs, excluding visceral metastases. Quality data on oligometastatic bladder cancer is scarce, however, a consensus of experts defined it as a maximum of three metastatic lesions, either resectable or suitable for stereotactic therapy, without restrictions to the number of organs involved. As for kidney cancer, a maximum number of five metastases, without limitations to the location are defined as oligometastatic, with an important implication of timing of developing metastases since diagnosis of the primary tumor.

SUMMARY

Defining oligometastatic state among urological tumors reflecting their distinct biological and clinical behavior is crucial to establish a sound framework for future clinical trials, and to facilitate guideline and policy formulation for improved patient care. Advancements in molecular imaging are expected to transform the field of oligometastatic urologic tumors in the future.

Impact of disease volume on survival efficacy of triplet therapy for metastatic hormone-sensitive prostate cancer: a systematic review, meta-analysis, and network meta-analysis

BACKGROUND

Triplet therapy, androgen receptor signaling inhibitors (ARSIs) plus docetaxel plus androgen-deprivation therapy (ADT), is a novel guideline-recommended treatment for metastatic hormone-sensitive prostate cancer (mHSPC). However, the optimal selection of the patient most likely to benefit from triplet therapy remains unclear.

METHODS

We performed a systematic review, meta-analysis, and network meta-analysis to assess the oncologic benefit of triplet therapy in mHSPC patients stratified by disease volume and compare them with doublet treatment regimens. Three databases and meeting abstracts were queried in March 2023 for randomized controlled trials (RCTs) evaluating patients treated with systemic therapy for mHSPC stratified by disease volume. Primary interests of measure were overall survival (OS). We followed the PRISMA guideline and AMSTAR2 checklist.

RESULTS

Overall, eight RCTs were included for meta-analyses and network meta-analyses (NMAs). Triplet therapy outperformed docetaxel plus ADT in terms of OS in both patients with high-(pooled HR: 0.73, 95%CI 0.64-0.84) and low-volume mHSPC (pooled HR: 0.71, 95%CI 0.52-0.97). There was no statistically significant difference between patients with low- vs. high-volume in terms of OS benefit from adding ARSI to docetaxel plus ADT (p = 0.9). Analysis of treatment rankings showed that darolutamide plus docetaxel plus ADT (90%) had the highest likelihood of improved OS in patients with high-volume disease, while enzalutamide plus ADT (84%) had the highest in with low-volume disease.

CONCLUSIONS

Triplet therapy improves OS in mHSPC patients compared to docetaxel-based doublet therapy, irrespective of disease volume. However, based on treatment ranking, triplet therapy should preferably be considered for patients with high-volume mHSPC while those with low-volume are likely to be adequately treated with ARSI + ADT.

Optimal systemic therapy in men with low-volume prostate cancer

PURPOSE OF REVIEW

Low-volume prostate cancer is an established prognostic category of metastatic hormone-sensitive prostate cancer. However, the term is often loosely used to reflect the low burden of disease across different prostate cancer states. This review explores the definitions of low-volume prostate cancer, biology, and current evidence for treatment. We also explore future directions, including the impact of advanced imaging modalities, particularly prostate-specific membrane antigen (PSMA) positron emission tomography (PET) scans, on refining patient subgroups and treatment strategies for patients with low-volume prostate cancer.

RECENT FINDINGS

Recent investigations have attempted to redefine low-volume disease, incorporating factors beyond metastatic burden. Advanced imaging, especially PSMA PET, offers enhanced accuracy in detecting metastases, potentially challenging the conventional definition of low volume. The prognosis and treatment of low-volume prostate cancer may vary by the timing of metastatic presentation. Biomarker-directed consolidative therapy, metastases-directed therapy, and de-escalation of systemic therapies will be increasingly important, especially in patients with metachronous low-volume disease.

SUMMARY

In the absence of validated biomarkers, the management of low-volume prostate cancer as defined by CHAARTED criteria may be guided by the timing of metastatic presentation. For metachronous low-volume disease, we recommend novel hormonal therapy (NHT) doublets with or without consolidative metastasis-directed therapy (MDT), and for synchronous low-volume disease, NHT doublets with or without consolidative MDT and prostate-directed radiation. Docetaxel triplets may be a reasonable alternative in some patients with synchronous presentation. There is no clear role of docetaxel doublets in patients with low-volume disease. In the future, a small subset of low-volume diseases with oligometastases selected by genomics and advanced imaging like PSMA PET may achieve long-term remission with MDT with no systemic therapy.

Current evidence on local therapy in oligometastatic prostate cancer

PURPOSE OF REVIEW

Metastatic prostate cancer (PCa) continues to be an invariably fatal condition. While historically, de-novo metastatic PCa was primarily treated with androgen deprivation therapy (ADT) and systemic therapy, there is a growing trend toward incorporating local treatments in the early management of the disease. This is particularly applicable to men with oligometastatic PCa (OMPC), which represents an 'intermediate phase' between localized and disseminated metastatic disease. Local treatment offers an opportunity for disease control before it progresses to a more advanced stage. This review discussed the current evidence for local treatment options for OMPC.

RECENT FINDINGS

Currently, it has been suggested that men with OMPC may have a more indolent course and, therefore, favorable outcomes may be observed with metastasis-directed therapy (MDT). This review will not address the role of MDT to patients with OMPC but will focus on local treatments of the primary disease. The three main forms of local therapy employed for OMPC are cryotherapy, radiation therapy, and cytoreductive prostatectomy (CRP). Whole gland cryotherapy, either with ADT or with ADT and systemic chemotherapy, has shown some limited promising results. Radiation therapy combined with ADT has also demonstrated improvements in progression-free survival in clinical trials (primarily STAMPEDE Arm G and HORRAD). CRP often combined with ADT has emerged as a potential strategy for managing OMPC, with promising findings primarily from retrospective studies. Currently, several randomized controlled trials are underway to further investigate the role of CRP in the oligometastatic setting.

SUMMARY

OMPC has become a unique category of disease with specific therapeutic implications. Lack of robust clinical data renders treatment selection controversial. Further studies with long follow up are necessary to identify men with oligometastatic disease who will benefit from local treatment.

[Local therapies for oligometastatic hormone-sensitive prostate cancer]

BACKGROUND

Oligometastatic, hormone-sensitive prostate cancer (omHSPC) is increasingly diagnosed due to the implementation of molecular imaging. OmHSPC is mostly defined as a maximum of four bone metastases without visceral metastases on conventional imaging.

OBJECTIVES

This study highlights the existing evidence regarding local treatment of omHSPC, taking into account molecular imaging and modern therapies.

MATERIALS AND METHODS

Narrative review article based on expert consensus and national/international guideline recommendations, supported by a nonsystematic literature search in PubMed (MEDLINE). The authors consider the cited studies as the most significant works in this regard and these were selected to illustrate developments and fundamental concepts, without claiming completeness.

RESULTS

Initially, the STAMPEDE study prospectively demonstrated an oncologic benefit of radiotherapy (RT) to the prostate in addition to androgen deprivation therapy for omHSPC. At 3 years, overall survival (OS) was 81% with RT versus 73% without RT (hazard ratio [HR] 0.68; 95% confidence interval [CI] 0.52-0.90; p = 0.007). However, this benefit was not observed in polymetastatic HSPC (HR 1.07; 95% CI 0.90-1.28; p = 0.4). In a study by Dai et al., local therapy for omHSPC was performed surgically in 85% of cases, also demonstrating an OS advantage (HR 0.44; 95% CI 0.24-0.81; p = 0.008).

CONCLUSION

OmHSPC should be treated using adjunctive RT. Preliminary prospective evidence shows comparable efficacy with prostatectomy. Modern systemic combination therapies challenge the role of local therapy.

Prostate cancer: Molecular aspects, consequences, and opportunities of the multifocal nature

Prostate cancer is unique compared to other major cancers due to the presence of multiple primary malignant foci in the majority of patients at the time of diagnosis. Each malignant focus has distinct somatic mutations and gene expression patterns, which represents a challenge for the development of prognostic tests for localized prostate cancer. Additionally, the molecular heterogeneity of advanced prostate cancer has important implications for management, particularly for patients with metastatic and locally recurrent cancer. Studies have shown that prostate cancers with mutations in DNA damage response genes are more sensitive to drugs inhibiting the poly ADP-ribose polymerase (PARP) enzyme. However, testing for such mutations should consider both spatial and temporal heterogeneity. Here, we summarize studies where multiregional genomics and transcriptomics analyses have been performed for primary prostate cancer. We further discuss the vast interfocal heterogeneity and how prognostic biomarkers and a molecular definition of the index tumor should be developed. The concept of focal treatments in prostate cancer has been evolving as a demand from patients and clinicians and is one example where there is a need for defining an index tumor. Here, biomarkers must have proven value for individual malignant foci. The potential discovery and implementation of biomarkers that are agnostic to heterogeneity are also explored as an alternative to multisample testing. Thus, deciding upon whole-organ treatment, such as radical prostatectomy, should depend on information from biomarkers which are informative for the whole organ.