ASSOCIATION BETWEEN TUMOR VOLUME AND UNFAVORABLE
PROSTATE CANCER CHARACTERISTICS:
IMPLICATIONS FOR PATIENT STRATIFICATION
Introduction. Previous studies showed that the tumor volume (TV) might increase
the ability to identify patients with insignificant prostate cancer (PCa). However,
these results were obtained using preoperative imaging modalities, which might lead
to an under- or overestimation of the actual TV. The aim of our study was to test the
role of pathological TV on the risk of unfavorable characteristics at final pathology in
patients
treated
with
radical
prostatectomy
(RP).
Methods. Overall, 3,193 patients with PCa treated with RP between February 2005
and August 2013 at a single tertiary referral center were identified. All patients had
available preoperative and pathological data. TV was calculated by visual inspection,
according to the College of American Pathologists guidelines. Uni- and multivariable
logistic regression analyses tested the impact of tumor volume (continuously coded)
on the risk of pathological Gleason score 8-10, seminal vesicle invasion (SVI), and
lymph node invasion (LNI) in the overall population, and after stratifying patients
according to the D’Amico risk groups. Covariates consisted of preoperative PSA,
clinical
stage,
and
biopsy
Gleason
score.
Results. Mean patient age was 62.5 years (median: 63). Mean tumor volume was 4.8
ml (median: 2.8). Overall, 1,200 (37.6%), 1,406 (44.0%), and 587 (18.4%) patients
had low-, intermediate- and high-risk PCa, respectively. Overall, 392 (12.3%), 367
(11.5%), and 325 (10.2%) patients had pathological Gleason score 8-10, SVI, and
LNI, respectively. In multivariate logistic regression analyses, TV was associated
with increased risk of pathological Gleason score 8-10, SVI, and LNI, after
accounting for confounders (all P<0.001). This held true after stratifying patients
according to the risk groups (all P<0.001). Particularly, TV represented an
independent predictor of pathological Gleason score 8-10, SVI, and LNI even in
patients with low-risk PCa, after accounting for preoperative PSA (all P<0.001).
Conclusions. Pathological TV represents an independent predictor of unfavorable
pathological characteristics in PCa patients. These results support the importance of
preoperative assessment of tumor volume in order to identify patients at higher risk of
more aggressive disease at final pathology.