A New Risk Classification System for Therapeutic Decision Making with Intermediate-risk Prostate Cancer Patients Undergoing Dose-escalated External-beam Radiation Therapy

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• 作者：Zachary S. Zumsteg ; Daniel E. Spratt ; Isaac Pei ; Zhigang Zhang ; Yoshiya Yamada ; Marisa Kollmeier ; Michael J. Zelefsky
• 关键词：Prostate cancer ; Intermediate risk ; Dose escalation ; Androgen deprivation ; Risk stratification
• 刊名：European Urology
• 出版年：December, 2013
• 年：2013
• 卷：64
• 期：6
• 页码：895-902
• 全文大小：889 K

文摘

Background

The management of intermediate-risk prostate cancer (PCa) is controversial, in part due to the heterogeneous nature of patients falling within this classification.

Objective

We propose a new risk stratification system for intermediate-risk PCa to aid in prognosis and therapeutic decision making.

Design, setting, and participants

Between 1992 and 2007, 1024 patients with National Comprehensive Cancer Network intermediate-risk PCa and complete biopsy information were treated with definitive external-beam radiation therapy (EBRT) utilizing doses 鈮?1 Gy. Unfavorable intermediate-risk (UIR) PCa was defined as any intermediate-risk patient with a primary Gleason pattern of 4, percentage of positive biopsy cores (PPBC) 鈮?0%, or multiple intermediate-risk factors (IRFs; cT2b-c, prostate-specific antigen [PSA] 10-20, or Gleason score 7).

Intervention

All patients received EBRT with 鈮?1 Gy with or without neoadjuvant and concurrent androgen-deprivation therapy (ADT).

Outcome measurements and statistical analysis

Univariate and multivariate analyses were performed using a Cox proportional hazards model for PSA recurrence-free survival (PSA-RFS) and distant metastasis (DM). PCa-specific mortality (PCSM) was analyzed using a competing-risk method.

Results and limitations

Median follow-up was 71 mo. Primary Gleason pattern 4 (hazard ratio [HR]: 3.26; p < 0.0001), PPBC 鈮?0% (HR: 2.72; p = 0.0007), and multiple IRFs (HR: 2.20; p = 0.008) all were significant predictors of increased DM in multivariate analyses. Primary Gleason pattern 4 (HR: 5.23; p < 0.0001) and PPBC 鈮?0% (HR: 4.08; p = 0.002) but not multiple IRFs (HR: 1.74; p = 0.21) independently predicted for increased PCSM. Patients with UIR disease had inferior PSA-RFS (HR: 2.37; p < 0.0001), DM (HR: 4.34; p = 0.0003), and PCSM (HR: 7.39; p = 0.007) compared with those with favorable intermediate-risk disease, despite being more likely to receive neoadjuvant ADT. Short follow-up and retrospective study design are the primary limitations.

Conclusions

Intermediate-risk PCa is a heterogeneous collection of diseases that can be separated into favorable and unfavorable subsets. These groups likely will benefit from divergent therapeutic paradigms.