Prospective study of determinants and outcomes of deferred treatment or watchful waiting among men with prostate cancer in a nationwide cohort.

PURPOSE: To examine consequences of deferred treatment (DT) as initial management of prostate cancer (PCa) in a contemporary, prospective cohort of American men diagnosed with PCa. PARTICIPANTS AND METHODS: We evaluated deferred treatment for PCa in the Health Professionals Follow-up Study, a prospective study of 51,529 men. Cox proportional hazards models were used to calculate hazard ratios (HRs) for time to eventual treatment among men who deferred treatment for more than 1 year after diagnosis. HRs for time to metastasis or death as a result of PCa were compared between patients who deferred treatment and those who underwent immediate treatment within 1 year of diagnosis.
RESULTS: From among 3,331 cohort participants diagnosed with PCa from 1986 to 2007, 342 (10.3%) initially deferred treatment. Of these, 174 (51%) remained untreated throughout follow-up (mean 7.7 years); the remainder were treated an average of 3.9 years after diagnosis. Factors associated with progression to treatment among DT patients included younger age, higher clinical stage, higher Gleason score, and higher prostate-specific antigen at diagnosis. We observed similar rates for development of metastases (n = 20 and n = 199; 7.2 v 8.1 per 1,000 person-years; P = .68) and death as a result of PCa (n = 8 and n = 80; 2.4 v 2.6 per 1,000 person-years; P = .99) for DT and immediate treatment, respectively.
CONCLUSION: In this nationwide cohort, more than half the men who opted for DT remained without treatment for 7.7 years after diagnosis. Older men and men with lesser cancer severity at diagnosis were more likely to remain untreated. PCa mortality did not differ between DT and active treatment patients.