BACKGROUND: Watchful waiting (WW) or deferred treatment (DT) is an accepted management strategy for selected men with prostate cancer. Although this approach is commonly utilized, the initial outcome studies were performed prior to the PSA era. The majority of recent series are single-institution or from referral centers. As a result, in the medical literature there is a paucity of national, community-acquired data concerning the use of WW or DT during the PSA era. We gathered data from a large, prospective, multiregional cohort study to examine clinical and demographic profiles of men who elected to pursue WW or DT.
METHODS: We conducted a retrospective analysis of 2304 men with pathologically confirmed incident prostate cancer, identified in the prospective nationwide Health Professionals Follow-up Study (HPFS) cohort of 51,529 men through participant self-report on biennial follow-up. These participants and/or their physicians have provided treatment information since diagnosis, collected from 2000-2007. Those who deferred treatment for at least one year were compared across categories of demographic indicators, tumor characteristics, and clinical characteristics to those who received immediate treatment, using the Fisher exact test and t-test. Among DT cases, Cox proportional hazards models adjusted for calendar time were used to calculate hazard ratios and 95% confidence intervals for time to eventual treatment.
RESULTS: Of the 2304 prostate cancer cases, 165 (7.2%) had DT as their principal management. Compared to cases treated within 1 year of diagnosis, DT cases were significantly older at diagnosis (mean 72.6 vs. 67.3, p<0.05), and had a significantly lower stage, Gleason grade, and PSA at diagnosis (mean 10.2 vs.12.1). Of the 165 DT cases, 82 (49.7%) remained untreated throughout follow-up (mean 6.9 years) and the remaining 50.3% received treatment 3.0 years post-diagnosis, on average. Factors predicting progression to treatment include younger age at diagnosis (HR=1.7, 95% CI=1.1, 2.8), and higher stage (T2/T3 vs. T1) (HR=1.9, 95% CI=1.7, 3.1), PSA level (≥10 vs. <4 ng/mL) (HR=3.0, 95% CI=1.3, 6.7), Gleason grade (≥6 vs. ≤5) (HR=4.8, 95% CI=2.7, 8.5), modified D’Amico score (intermediate/high vs. low) (HR=3.1, 95% CI=1.9, 4.9), and number of biopsy cores with cancer (≥2 vs. 1) (HR=3.6, 95% CI=1.2, 10.9).
CONCLUSIONS: Watchful waiting or deferred treatment was successfully utilized in this contemporary, American nationwide cohort, wherein half of men who opted for watchful waiting remained on watchful waiting, without progression to treatment, for more than 6 years after diagnosis. Older men with lower cancer severity measures were more likely to avoid progression to treatment. These findings contrast recent single-institution, referred-sample studies that had suggested that most deferred treatment patients progress to treatment within 3 years following diagnosis.