Maximum tumor diameter and the risk of prostate-specific antigen recurrence after radical prostatectomy

The aim of this study was to investigate whether the MTD could identify men at low risk of PSA recurrence after RP who might not benefit from ART despite other adverse features.

The study cohort consisted of 354 men with T1c to T2 prostate cancer diagnosed between September 2001 and December 2008 who underwent RP without adjuvant therapy. Multivariable Cox regression was used to assess the effect of MTD on the risk of PSA recurrence (> 0.1 ng/mL and verified), adjusting for known predictors.

After a median follow-up of 4.0 years, 34 men (9.6%) experienced PSA failure. In multivariable analysis, increasing MTD was significantly associated with an increased PSA recurrence risk (hazard ratio, 2.74; 95% confidence interval, 1.23-6.10; P = .01) within the interaction model. Estimates of PSA recurrence-free survival stratified around the median MTD value (1.2 cm) were significantly different in men with a pre-RP PSA > 4 ng/mL (P < .001; 5-year estimate: 74.5% vs. 99.0%) but not in men with PSA ≤ 4 ng/mL (P = .59; 5-year estimate: 89.6% vs. 92.6%), consistent with the significant interaction (P = .004) between PSA and MTD. Moreover, in men with a pre-RP PSA > 4 ng/mL these estimates were significantly different if at least 1 adverse feature (pT3, R1, or Gleason score ≥ 8) was present at RP (P = .01; 5-year estimate: 46.6% vs. 100%) versus none (P = .09; 5-year estimate: 93.4% vs. 98.9%).

Men with a low MTD (≤ 1.2 cm) appear to be at low risk of PSA recurrence despite adverse features at RP and might not benefit from ART.