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

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.