Contemporary trends in low risk prostate cancer: risk assessment and treatment

Abstract

Purpose: We updated national risk trends in prostate cancer with a focus on low risk tumors, reexamined trends in primary treatment for low risk tumors and substratified patients at low risk based on pretreatment clinical data.

Materials and methods: Data were abstracted from the CaPSURE registry. A total of 10,385 men were diagnosed between 1990 and 2006 with localized disease. Low risk was defined as prostate specific antigen 10 ng/ml or less, Gleason score 6 or less and clinical T stage 2a or less. Temporal trends were assessed for patient distribution among risk groups and in the low risk group for individual risk factors, Kattan nomogram prediction, Cancer of the Prostate Risk Assessment score and primary treatment. The ability of the Cancer of the Prostate Risk Assessment score to substratify low risk prostatectomy cases was evaluated with survival analysis.

Results: The proportion of low risk tumors in CaPSURE almost doubled from 27.5% in 1990 to 1994, to 46.4% in 2000 to 2001 but it has been relatively constant since then. A growing proportion of low risk tumors are cT1c and virtually all are Gleason score 6. Prostate specific antigen and the percent of positive biopsies decreased throughout the study period, as did the mean Cancer of the Prostate Risk Assessment score. The use of active surveillance increased from a nadir of 6.2% in 2000 to 2001, to 10.2% in 2004 to 2006. The use of prostatectomy also increased, whereas the use of androgen deprivation and radiation decreased. The likelihood of recurrence increased significantly with increasing Cancer of the Prostate Risk Assessment scores.

Conclusions: Patients at low risk can be further substratified to identify those at very low risk based on clinical variables. The use of surveillance is increasing but overtreatment remains a concern in these patients.

Figure 1

Trends in patient clinical risk stratification at time of diagnosis. Percentage of men stratified to low-, intermediate-, and high-risk groups in each year group. Numbers indicate aggregate totals for each group in each time period: 1990-1994, 1995-1999, 2000-2001, 2002-2003, and 2004-2006. The trend toward more low- and less high-risk disease at diagnosis was significant (P<0.001).

Figure 2

Time trends in individual risk characteristics among low-risk patients. Distribution over time of clinical T stages (A), Gleason scores (B), serum prostate-specific antigen (PSA) levels (C), and percentage of positive biopsy cores (PPB) (D). Trends in distribution of each risk characteristic were statistically significant at P<0.001. On panels C and D, the mean PSA and PPB, respectively, are plotted on the secondary y-axis for each time period.

Figure 2

Time trends in individual risk characteristics among low-risk patients. Distribution over time of clinical T stages (A), Gleason scores (B), serum prostate-specific antigen (PSA) levels (C), and percentage of positive biopsy cores (PPB) (D). Trends in distribution of each risk characteristic were statistically significant at P<0.001. On panels C and D, the mean PSA and PPB, respectively, are plotted on the secondary y-axis for each time period.

Figure 3

Biochemical survival among radical prostatectomy patients with low-risk prostate cancer. Kaplan-Meier curves for biochemical recurrence-free survival among patients with low-risk prostate cancer undergoing radical prostatectomy, stratified by Cancer of the Prostate Risk Assessment (CAPRA) score.