Watchful Waiting or Watchful Progression? Prostate Specific Antigen Doubling Times and Clinical Behavior in Patients with Early Untreated Prostate Carcinoma

Duncan B, McLaren, F.R.C.R.
Michael McKenzie, F.R.C.P.C.
Graeme Duncan, F.R.C.P.C.
Tom Pickles, F.R.C.P.C.

Department of Radiation Oncology, British Columbia Cancer Agency, Vancouver, British Columbia, Canada.


BACKGROUND, Prostate specific antigen doubling time (PSAdt) is a dynamic modelof prostate tumor biology. It predicts aggressive disease and subsequent clinical recurrence after radical treatment. However, as yet there is only limited evidence for its validity in the watchful waiting population.

METHODS, One hundred and thirteen previously untreated patients with adenocarcinoma of the prostate who were referred to the British Columbia Cancer Agency for a management opinion subsequently were placed into a prospective watchful waiting program. The reasons for watchful waiting, previous medical history, serial PSA, and histopathologic data were recorded.

RESULTS. The median age of patients was 75 years (range, 49-85 years). The median follow-up from the time of the first appointment was 14 months (range, 0-58 months). The reasons for watchful waiting were correlated highly with T classification (P = 0.003) and past medical history (P = 0.002). Approximately 40% of T1 patients and 51% ofT2 patients had clinical progression by 2 years, increasing to 60~b at 3 years. On multivariate analysis PSAdt strongly correlated with clinical progression (P < 0.0001), stage progression (P = 0.01), and time to treatment (P= 0.0001); tumor grade and initial stage were not found to be predictive for any of the endpoints studied. Initial PSA only was significant in predicting for time to treatment (P = 0.03). Approximately 50% of patients with a PSAdt of <18 months progressed within 6 months. At last follow-up, no deaths from prostate carcinoma had been recorded. Overall survival at 2 and 5 years was 92% and 68%, respectively.

CONCLUSIONS. Using digital rectal examination, the findings of this study demonstrated high rates of clinical tumor progression within the watchful waiting population. PSAdt rather than standard histopathologic criteria was found to be the most powerful indicator of disease activity.

Cancer1998;82:342-8. 1998 American Cancer Society.