Location, extent, and multifocality of positive surgical margins for biochemical recurrence prediction after radical prostatectomy.

PURPOSE: To study the prognostic value of extent, number, and location of positive surgical margins (PSM).
METHODS: A total of 1,504 consecutive adjuvant treatment naive and node-negative radical prostatectomy men were included in a prospective database including extent, number, and location of PSM. Mean follow-up was 33 months. Endpoint was biochemical progression-free (bPFS) survival. The impact of margin status and characteristics was assessed in time-dependent analyses using Cox regression and Kaplan-Meier methods.
RESULTS: PSM was reported in 26.7 % of patients. The predominant PSM locations were apex and posterior locations. Median PSM length was 4.0 mm. The 2-year bPFS was 73.7 % in PSM patients as compared to 93.0 % in NSM patients (p < 0.001). The rate and extent of PSM increased significantly with pathologic stage (p < 0.001). The extent of PSM length was linearly correlated with bPFS (p = 0.017, coefficient: -0.122). In univariable analysis, extent and number of PSM were significantly linked to outcomes. None of PSM subclassifications significantly influenced the bPFS rates in the subgroup of pT2 disease patients. Conversely, stratification by PSM location (apex vs. other locations, p = 0.008), by PSM number (p = 0.006), and by PSM length (p < 0.001) showed significant differences in pT3-4 cancer patients. In that subgroup, PSM length also added to bPFS prediction using PSM status only in multivariable models (p = 0.005).
CONCLUSIONS: PSM subclassifications do not improve the biochemical recurrence prediction in organ-confined disease. In non-organ-confined disease, PSM length (≥3 mm), multifocality (≥3 sites), and apical location are significantly linked to poorer outcomes and could justify a more aggressive adjuvant treatment approach.