National practice patterns and time trends in androgen ablation for localized prostate cancer

Abstract

Background: Recent reports have suggested that growing numbers of patients with localized prostate cancer are receiving androgen deprivation therapy as primary or neoadjuvant treatment, yet sparse clinical evidence supports the use of such treatment except among patients with high-risk or locally advanced disease receiving external beam radiotherapy. We describe national trends in the use of androgen deprivation therapy for localized disease.

Methods: CaPSURE is an observational database of 7195 patients with prostate cancer. This study included 3439 of these patients who were diagnosed since 1989, had clinical staging information available, and were treated with radical prostatectomy, radiation therapy, or primary androgen deprivation therapy (PADT). High-, intermediate-, and low-risk groups were defined by serum prostate-specific antigen level, Gleason score, and clinical tumor stage. Time trends in the use of PADT and neoadjuvant androgen deprivation therapy (NADT) were analyzed. All statistical tests were two-sided.

Results: Rates of PADT use rose sharply between 1989 and 2001, from 4.6% (95% confidence interval [CI] = 3.4% to 5.8%) to 14.2% (95% CI = 12.2% to 16.2%), from 8.9% (95% CI = 7.3% to 10.5%) to 19.7% (95% CI = 17.5% to 21.9%), and from 32.8% (95% CI = 29.9% to 35.7%) to 48.2% (95% CI = 45.1% to 51.3%) (all P<.001) in low-, intermediate-, and high-risk groups, respectively. NADT use also increased in association with radical prostatectomy (2.9% [95% CI = 2.1% to 3.7%] to 7.8% [95% CI = 6.5% to 9.1%] of patients, P =.003) and external beam radiotherapy (9.8% [95% CI = 7.5% to 12.1%] to 74.6% [95% CI = 70.8% to 78.4%], P<.001) across all risk levels combined. Rates of NADT use among patients treated with brachytherapy also increased but not statistically significantly (7.4% [95% CI = 3.5% to 11.3%] to 24.6% [95% CI = 18.2% to 31.0%], P =.100).

Conclusions: Rates of both PADT and NADT are increasing across risk groups and treatment types. Future clinical trials must define more clearly the appropriate role of hormonal therapy in localized prostate cancer, and their results should shape updated practice guidelines.

Fig. 1

Overall trends in primary treatments for prostate cancer. Within each time period (1989–1992, 1993–1995, 1996–1998, and 1999–2001), data are presented by clinical risk group. Each number on the graph refers to the total percentage of patients in each time and risk group receiving a given primary treatment: watchful waiting (WW), brachytherapy (Brachy), external-beam radiotherapy (EBRT), radical prostatectomy (RP), and primary androgen deprivation therapy (PADT). Within the Brachy, EBRT, and RP bars, cross-hatched areas represent patients receiving neoadjuvant androgen ablation therapy (NADT) before local treatment.

Fig. 2

Time trends in the use of primary hormonal therapy. Regression lines for low-, intermediate-, and high-risk patients are weighted at each year by total number of patients in that year. As discussed above, patients in 1998 were merged with 1999 because of the low total accrual to CaPSURE in 1998. Slopes are presented for the regression lines. P values are determined by the two-sided Mantel-Haenszel χ² test for trend.

Fig. 3

Time trends in the use of neoadjuvant hormonal ablation. Regression lines for radical prostatectomy (RP), brachytherapy, and external-beam radiotherapy (EBRT) patients are weighted at each year by total number of patients in that year in each treatment group. As discussed above, patients in 1998 were merged with 1999 because of the low total accrual to CaPSURE in 1998. Slopes are presented for the regression lines. P values are determined via the two-sided Mantel-Haenszel χ² test for trend.