Purpose: We compared biochemical progression rates measured by increasing prostate specific antigen (PSA) levels using a standard definition of biochemical recurrence among patients with screen detected prostate cancer treated with radical prostatectomy (RP) or radiotherapy (RT).
Materials and methods: A total of 1,939 patients diagnosed with clinically localized prostate cancer in a community based screening study from 1989 to 1998, followed through 2001, were treated with RP or RT and agreed to enroll in a followup study. This prospective cohort study (median followup 62 months, range 0.2 to 141) used adjusted Cox proportional hazards models to examine time to progression. Selection bias was addressed with propensity scores. Biochemical evidence of cancer progression was defined as PSA greater than 0.2 ng/ml in patients who underwent RP and 3 consecutive PSA increases as recommended by the American Society for Therapeutic Radiology and Oncology criteria for radiotherapy.
Results: Of the patients 17% had evidence of cancer progression. The percentage with progression-free survival at 5 and 9 years for RP was 84% and 76%, respectively, and for RT 80% and 70%, respectively. Cox proportional hazards models produced a hazard ratio of 1.63 (95% CI, 1.12, 2.38) for RT compared with RP, adjusting for clinical stage, Gleason grade, preoperative PSA, biopsy age, treatment year and propensity for treatment type.
Conclusions: With intermediate term followup, patients treated with RT were more likely to have cancer progression than with RP adjusting for demographics, clinical factors, selection bias and treatment year.