Maximum tumor diameter: a simple independent predictor for biochemical recurrence after radical prostatectomy.

Previous studies have suggested that maximum tumor diameter (MTD) is a predictor of PSA recurrence or biochemical recurrence (BCR) in prostate cancer after radical prostatectomy (RP). The significance of MTD in BCR prediction was evaluated using RP specimens of 364 patients with a BCR of 18% (n=66) during a mean follow-up of 37.4 months (range: 10-109 months). MTD was defined as the largest diameter of the largest tumor, and its median MTD was 15 mm (range: 0.9-50 mm). MTD was significantly associated with pre-operative PSA levels, pathological T stage, Gleason's score and positive surgical margin. In a univariate analysis, pathological T stage, Gleason's score, positive surgical margin and MTD were associated significantly with the risk of BCR. Patients with >20 mm MTD had a significantly higher risk of BCR than did those with < or =20 mm MTD (P<0.001). Cox multivariate models indicated that pathological stage, Gleason's score, positive surgical margin and MTD were independent prognostic factors for BCR. MTD would be a useful tool for predicting BCR, as calculation of MTD is a simple and reliable measure.