Journal of the National Cancer Institute Advance Access published online on June 9, 2009
JNCI Journal of the National Cancer Institute, doi:10.1093/jnci/djp122
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© The Author 2009. Published by Oxford University Press.
ARTICLES |
Risk Assessment for Prostate Cancer Metastasis and Mortality at the Time of Diagnosis
Affiliation of authors: Department of Urology, University of California, San Francisco Helen Diller Family Comprehensive Cancer Center, San Francisco, CA
Correspondence to: Matthew R. Cooperberg, MD, MPH, Department of Urology, University of California, San Francisco, Box 1695, 1600 Divisadero St, A-607, San Francisco, CA 94143-1695 (e-mail: mcooperberg{at}urology.ucsf.edu).
Background: Although many tools for the assessment of prostate cancer risk have been published, most are designed to predict only biochemical recurrence, usually after a single specified treatment. We assessed the accuracy of the Cancer of the Prostate Risk Assessment (CAPRA) score, which was validated previously to predict pathological and biochemical outcomes after radical prostatectomy, to predict metastases, prostate cancer–specific mortality, and all-cause mortality.
Methods: We studied 10 627 men with clinically localized prostate cancer in the Cancer of the Prostate Strategic Urologic Research Endeavor registry, who underwent primary radical prostatectomy, radiation therapy (external beam or interstitial), androgen deprivation monotherapy, or watchful waiting/active surveillance, and had at least 6 months of follow-up after treatment. CAPRA scores were calculated at diagnosis from the prostate-specific antigen level, Gleason score, percentage of biopsy cores that were positive for cancer, clinical tumor stage, and age at diagnosis. Survival was studied with Kaplan–Meier analyses. Associations between increasing CAPRA scores and bone metastasis, cancer-specific mortality, and all-cause mortality were examined by use of proportional hazards regression, with adjustment for primary treatment; for all-cause mortality, the analysis also included adjustment for age and comorbidity. Accuracy of the CAPRA score was assessed with the concordance (c)-index.
Results: Among the 10 627 patients, 311 (2.9%) men developed bone metastases, 251 (2.4%) died of prostate cancer, and 1582 (14.9%) died of other causes. Each single-point increase in the CAPRA score was associated with increased bone metastases (hazard ratio [HR] for bone metastases = 1.47, 95% confidence interval [CI] = 1.39 to 1.56), cancer-specific mortality (HR for prostate cancer death = 1.39, 95% CI = 1.31 to 1.48), and all-cause mortality (HR for death = 1.13, 95% CI = 1.10 to 1.16). The CAPRA score was accurate for predicting metastases (c-index = 0.78), cancer-specific mortality (c-index = 0.80), and all-cause mortality (c-index = 0.71).
Conclusions: In a large cohort of patients with clinically localized prostate cancer who were managed with one of five primary modalities, the CAPRA score predicted clinical prostate cancer endpoints with good accuracy. These results support the value of the CAPRA score as a risk assessment and stratification tool for both research studies and clinical practice.
| CONTEXT AND CAVEATS Prior knowledge Most tools for the assessment of prostate cancer risk are designed to predict only biochemical recurrence, defined as increasing levels of prostate-specific antigen (PSA), usually after a single specified treatment. Study design Retrospective analysis of data from the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) registry, a diverse multi-institutional registry of patients with prostate cancer. Patients with localized prostate cancer were treated with primary radical prostatectomy, radiation therapy (external beam or interstitial), androgen deprivation monotherapy, or watchful waiting/active surveillance. The Cancer of the Prostate Risk Assessment (CAPRA) score was calculated at diagnosis from the PSA level, Gleason score, percentage of biopsy cores that were positive for cancer, clinical tumor stage, and age at diagnosis. Contribution Each single-point increase in the CAPRA score was associated with increased bone metastases, cancer-specific mortality, and all-cause mortality. The CAPRA score was accurate for predicting all three outcomes. Implications The CAPRA score warrants validation in independent cohorts of prostate cancer patients. Limitations The number of metastasis and cancer-specific mortality events was relatively small. Some data for cancer-specific mortality were obtained from death certificates, which may be inaccurate. CaPSURE sites were not chosen at random and so do not reflect the general population. From the Editors
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Manuscript received November 3, 2008; revised March 18, 2009; accepted April 9, 2009.
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J Natl Cancer Inst 2009 101: 835.