Improving survival for patients with prostate cancer diagnosed in the prostate-specific antigen ERA

Although prostate-specific antigen (PSA) screening has not been demonstrated to reduce prostate cancer mortality in the clinical trial or population setting, the use of PSA for screening increased during the early 1990's. A clinical trial is currently underway to test the efficacy of PSA screening; however, the results will not be available for at least 10 years. To address concerns about the effectiveness of PSA screening in the near term, population-based assessments of PSA screenings are needed. To reduce mortality, PSA screening must first produce improved survival. In New Mexico, increased screening was associated with a stage migration from distant to earlier stages and an increase in 5-year relative survival, suggesting that PSA screening may be effective.

To further investigate early indicators of the effectiveness of PSA screening in New Mexico, we examined temporal trends in survival for the period 1983-1992, using proportional-hazard models to estimate the risk of death by year of diagnosis, adjusted for age, stage, grade, ethnicity, and initial treatment.

We found the risk of death following the diagnosis of local or regional-stage prostate cancer decreased in the 1987-1988 (relative-risk [RR] = 0.9 [95% confidence interval (CI) 0.8, 1.1]), 1989-1990 [RR = 0.9 [0.8, 1.0]), and 1991-1992 (RR =0.7 [0.6, 0.9]) periods compared with the 1983-1984 period. Men treated with radical prostatectomy were at increased risk between 1985 and 1990, compared with those treated in the 1983-1984 period. However, for men diagnosed and treated in the 1991-1992 period, risks were lower than in the 1983-1984 period (RR =0.8 [0.4, 1.5]).

The earlier stage at diagnosis and the improved survival during the period of increased PSA screening are consistent with changes expected from an effective screening test and treatment modality.