Survival following primary androgen deprivation therapy among men with localized prostate cancer

Abstract

Context: Despite a lack of data, increasing numbers of patients are receiving primary androgen deprivation therapy (PADT) as an alternative to surgery, radiation, or conservative management for the treatment of localized prostate cancer.

Objective: To evaluate the association between PADT and survival in elderly men with localized prostate cancer.

Design, setting, and patients: A population-based cohort study of 19,271 men aged 66 years or older receiving Medicare who did not receive definitive local therapy for clinical stage T1-T2 prostate cancer. These patients were diagnosed in 1992-2002 within predefined US geographical areas, with follow-up through December 31, 2006, for all-cause mortality and through December 31, 2004, for prostate cancer-specific mortality. Instrumental variable analysis was used to address potential biases associated with unmeasured confounding variables.

Main outcome measures: Prostate cancer-specific survival and overall survival.

Results: Among patients with localized prostate cancer (median age, 77 years), 7867 (41%) received PADT, and 11,404 were treated with conservative management, not including PADT. During the follow-up period, there were 1560 prostate cancer deaths and 11,045 deaths from all causes. Primary androgen deprivation therapy was associated with lower 10-year prostate cancer-specific survival (80.1% vs 82.6%; hazard ratio [HR], 1.17; 95% confidence interval [CI], 1.03-1.33) and no increase in 10-year overall survival (30.2% vs 30.3%; HR, 1.00; 95% CI, 0.96-1.05) compared with conservative management. However, in a prespecified subset analysis, PADT use in men with poorly differentiated cancer was associated with improved prostate cancer-specific survival (59.8% vs 54.3%; HR, 0.84; 95% CI, 0.70-1.00; P = .049) but not overall survival (17.3% vs 15.3%; HR, 0.92; 95% CI, 0.84-1.01).

Conclusion: Primary androgen deprivation therapy is not associated with improved survival among the majority of elderly men with localized prostate cancer when compared with conservative management.

Figure 1

Figure 1A. Adjusted prostate cancer-specific survival in high- and low-use areas by cancer grade Results were adjusted for age, race, income, marital status, urban residence, comorbidity status, year of diagnosis and cancer stage. Prostate cancer-specific survival was lower in high-PADT use areas compared with low-PADT use areas among men with moderately-differentiated cancer (P <0.001). Prostate cancer-specific survival was borderline statistically different between high- and low-PADT use areas among men with poorly-differentiated cancer (P =0.0498). Error bars represent 95% confidence intervals. Figure 1B. Adjusted overall survival in high- and low-use areas by cancer grade Overall survival was similar in high- and low-PADT use areas among men with moderately-differentiated cancer; median overall survival was 89 and 90 months for high- and low-use areas (P =0.671). Differences in overall survival between high- and low-PADT use areas among men with poorly-differentiated cancer did not reach statistical significance (P =0.127). Median overall survival was 57 and 54 months for high- and low-PADT use areas. The difference in median overall survival between high- and low-PADT use areas was 3 months (95% CI –1 to 7 months).

Figure 1

Figure 1A. Adjusted prostate cancer-specific survival in high- and low-use areas by cancer grade Results were adjusted for age, race, income, marital status, urban residence, comorbidity status, year of diagnosis and cancer stage. Prostate cancer-specific survival was lower in high-PADT use areas compared with low-PADT use areas among men with moderately-differentiated cancer (P <0.001). Prostate cancer-specific survival was borderline statistically different between high- and low-PADT use areas among men with poorly-differentiated cancer (P =0.0498). Error bars represent 95% confidence intervals. Figure 1B. Adjusted overall survival in high- and low-use areas by cancer grade Overall survival was similar in high- and low-PADT use areas among men with moderately-differentiated cancer; median overall survival was 89 and 90 months for high- and low-use areas (P =0.671). Differences in overall survival between high- and low-PADT use areas among men with poorly-differentiated cancer did not reach statistical significance (P =0.127). Median overall survival was 57 and 54 months for high- and low-PADT use areas. The difference in median overall survival between high- and low-PADT use areas was 3 months (95% CI –1 to 7 months).