Do the current subclassifications of stage T3 adenocarcinoma of the prostate have clinical relevance?

Objectives: To compare the outcome of patients with T3a and T3c adenocarcinoma of the prostate and determine the utility of these substages as defined in the current American Joint Committee on Cancer and the International Union Against Cancer (AJCC/UICC) staging system.

Methods: An analysis was performed of patients with T3 (clinical) prostate cancer treated with definitive irradiation at the Fox Chase Cancer Center between 1986 and 1993. The series was composed of 66 patients with T3a tumors and 44 patients with T3c tumors. The endpoints studied included freedom from biochemical relapse (bNED) and rates of clinical local and distant failure.

Results: No statistically significant differences in freedom from biochemical relapse were observed when comparing patients with T3a and T3c disease (3 years bNED, 41%; difference not significant). Similarly, there was no difference in the patterns of clinical failure at 3 years when comparing patients with T3a and T3c disease (21% clinically detected distant metastases; < 10% local failure in either group). In a multivariate analysis, only a low baseline prostate-specific antigen (PSA) (eg, 20 ng/mL or less) independently predicted the likelihood of remaining biochemically free of disease.

Conclusions: Anatomic substaging that is based on the findings of the digital rectal examination does not distinguish meaningful prognostic substages among patients with T3 disease. PSA should be used to establish biochemical substaging of patients who present with T3 prostate cancer.