The T classification of clinically localized prostate cancer. An appraisal based on disease outcome after radiation therapy

Abstract

Background: This study was performed to evaluate the use of the 1992 International Union Against Cancer (UICC)/American Joint Committee on Cancer (AJCC) T categories for localized prostate cancer treated with radiation therapy and to compare the prognostic power of this system with the Whitmore-Jewett scheme.

Methods: The outcome for 427 men with Stages A2-C or T1a-T4b prostate cancers, followed for a mean of 32 months after treatment, was evaluated for relapse or rising prostate-specific antigen (PSA) levels, disease relapse, metastatic failure, and local recurrence relative to the two staging systems. Univariate and multivariate analysis was used to compare the two staging systems. The T categories were based on digital rectal examination.

Results: At 5 years, the actuarial incidence of relapse or rising PSA level was as follows: Stage A2, 29%; Stage B, 41%; Stage C, 62%. The corresponding results according to T category were as follows: T1a, 0%; T1b, 37%; T1c, 23%; T2a, 39%; T2b, 38%; T2c, 42%; T3a, 53%; T3c, 68%; T4b, greater than 75%. Too few patients were in the T3b and T4a categories. The following five-category grouping was significantly superior prognostically to the Whitmore-Jewett system: T1a, T1c, T1b/T2, T3, T4. The actuarial incidences of relapse or rising PSA at 5 years were as follows: T1a, 0%; T1c, 23%; T1b/T2, 41%; T3, 61%; and T4, 75%. No differences were evident within the T2 or T3 categories.

Conclusions: The current UICC/AJCC system appears to be a valid method for categorizing a primary prostate carcinoma. This system defines a greater number of meaningful tumor categories and is prognostically superior to the traditional Whitmore-Jewett scheme.