Tumor volume as a predictor of adverse pathologic features and biochemical recurrence (BCR) in radical prostatectomy specimens: A tale of two methods

The prognostic value of tumor volume in predicting biochemical recurrence after prostatectomy has been debated. Our aim in this study was to (a) evaluate tumor volume as an independent predictor of adverse pathologic outcomes and BCR and (b) determine the effect of two different methods of tumor volume estimation. We reviewed the charts of 3,087 patients who underwent radical prostatectomy at Vanderbilt University Medical Center between 2000 and 2008; of which 1,747 patients had data sufficient for analysis. Prostate specimens were processed as whole mount between 2000 and 2003 and then via systematic sampling from 2003 to 2008, with tumor volume measured by planimetry in the whole-mount group and tumor volume estimated by percent tumor involvement in the systematic sampling group. Tumor volume estimates were higher with SS than with WM. There were significant associations between larger tumor volume and adverse pathological outcomes, regardless of pathologic method (all with P < 0.001). Controlling for other pathologic parameters, tumor volume was an independent predictor of PGS, EPE, and SM in logistic regression models (P < 0.001 for TV in all models). Tumor volume was demonstrated to be an independent predictor of BCR in the WM group (1.06, 95% CI 1.01-1.11, P = 0.013), though tumor volume was not a significant predictor of BCR in the SS group. Though the prognostic value of tumor volume is debated, our data demonstrate that tumor volume, when calculated via planimetry on whole-mount pathologic sectioning, is a significant predictor of biochemical recurrence after prostatectomy.