Evaluating the Effectiveness of Cytoreductive Surgery in Oligometastatic Prostate Cancer

Academic Background

Prostate cancer is the second most common malignancy among men globally, particularly in its advanced stages, where it is often accompanied by metastases, significantly impacting patients’ quality of life and prognosis. Oligometastatic prostate cancer (OMPCa) represents an intermediate state between localized disease and widespread metastasis, characterized by a limited number of metastatic lesions confined to a few organs. In recent years, treatment strategies for oligometastatic prostate cancer have garnered significant attention, particularly the application of cytoreductive surgery (CRP). However, the effectiveness of cytoreductive surgery in this specific clinical scenario remains controversial. This study aims to evaluate the effectiveness of cytoreductive surgery in the treatment of oligometastatic prostate cancer through quantitative analysis and retrospective cohort studies, providing evidence for clinical decision-making.

Source of the Paper

This paper was co-authored by Bisheng Cheng, Bingheng Li, Jianhan Fu, and others, affiliated with multiple institutions including Sun Yat-sen Memorial Hospital, Nanfang Hospital of Southern Medical University, and Sun Yat-sen University Cancer Center. The paper was published online on July 15, 2024, in the International Journal of Surgery, with the DOI 10.1097/js9.0000000000001968.

Study Design and Methods

Research Objectives

This study aims to evaluate the effectiveness of cytoreductive surgery in the treatment of oligometastatic prostate cancer, focusing on the following clinical outcome measures: overall survival (OS), progression-free survival (PFS), cancer-specific survival (CSS), and castration-resistant prostate cancer-free survival (CRPCFS).

Study Process

1. Literature Search and Screening
   The research team systematically searched databases such as PubMed, Embase, Web of Science, and CNKI for studies published up to December 2023 on the application of cytoreductive surgery in oligometastatic prostate cancer. A total of 18 studies were included, comprising 2 randomized controlled trials (RCTs) and 16 non-randomized controlled studies, involving 1,733 patients.

2. Data Extraction and Quality Assessment
   Two researchers independently screened the literature and extracted data, including patient demographics (e.g., age, Gleason score), tumor characteristics (e.g., number of metastatic lesions), surgical outcomes, and survival metrics. Study quality was assessed using the Cochrane Risk of Bias tool and the Newcastle-Ottawa Scale (NOS).

3. Quantitative Analysis
   A random-effects model was used for meta-analysis to calculate hazard ratios (HRs) and their 95% confidence intervals (CIs). Heterogeneity among studies was assessed using the I² test.

4. Retrospective Cohort Study
   The research team also conducted a multicenter retrospective cohort study, including 64 patients with oligometastatic prostate cancer treated at Nanfang Hospital and Sun Yat-sen University Cancer Center between January 2008 and June 2018. Of these, 32 patients underwent cytoreductive surgery combined with androgen deprivation therapy (ADT), while the other 32 received ADT alone.

Key Findings

Quantitative Analysis Results

1. Overall Survival (OS)
   The cytoreductive surgery group showed significantly better overall survival compared to the non-surgical group (HR 0.50, 95% CI 0.40–0.60). Both RCTs and non-RCTs demonstrated better OS outcomes in the cytoreductive surgery group.

2. Progression-Free Survival (PFS)
   The cytoreductive surgery group had significantly better PFS compared to the non-surgical group (HR 0.39, 95% CI 0.27–0.51).

3. Cancer-Specific Survival (CSS)
   The cytoreductive surgery group showed significantly better CSS compared to the non-surgical group (HR 0.44, 95% CI 0.23–0.65).

4. Castration-Resistant Prostate Cancer-Free Survival (CRPCFS)
   The cytoreductive surgery group had significantly better CRPCFS compared to the non-surgical group (HR 0.48, 95% CI 0.36–0.59).

Retrospective Cohort Study Results

1. Overall Survival (OS)
   The median OS in the cytoreductive surgery group was 60.0 months, significantly better than the 36.3 months in the ADT group (p=0.0182).

2. Progression-Free Survival (PFS)
   The median PFS in the cytoreductive surgery group was 44 months, significantly better than the 21 months in the ADT group (p=0.0297).

3. Castration-Resistant Prostate Cancer-Free Survival (CRPCFS)
   The median CRPCFS in the cytoreductive surgery group was 44.5 months, significantly better than the 21.5 months in the ADT group (p=0.0125).

4. Surgical Complications
   In the cytoreductive surgery group, 25% of patients experienced perioperative complications, with urinary incontinence being the most common (9.4%).

Conclusions and Significance

Through quantitative analysis and retrospective cohort studies, this study confirmed the significant advantages of cytoreductive surgery in the treatment of oligometastatic prostate cancer. Cytoreductive surgery combined with ADT significantly improved patients’ overall survival, progression-free survival, and castration-resistant prostate cancer-free survival. These findings provide new insights into the treatment of oligometastatic prostate cancer, highlighting the potential value of local therapy in this specific patient population.

Research Highlights

1. Large Sample Size: The study included 1,733 patients, the largest sample size in research of this kind to date.
2. Multidimensional Assessment: The study not only focused on overall survival but also evaluated progression-free survival, cancer-specific survival, and castration-resistant prostate cancer-free survival, providing comprehensive clinical outcome data.
3. Retrospective Cohort Validation: The multicenter retrospective cohort study further validated the results of the quantitative analysis, enhancing the credibility of the findings.

Future Prospects

Although this study provides strong evidence for the application of cytoreductive surgery in oligometastatic prostate cancer, further prospective randomized controlled trials are needed to verify its long-term efficacy and safety. Additionally, future research should explore the combined application of cytoreductive surgery with other treatment modalities (e.g., radiotherapy, immunotherapy) to optimize treatment strategies for oligometastatic prostate cancer.