Advantages of Evaluating Mean Nuclear Volume as an Adjunct Parameter in Prostate Cancer

BACKGROUND Efforts to improve the diagnosis, prognosis and surveillance of prostate cancer (PCa) are relevant. Gleason score (GSc) overestimation may subject individuals to unnecessary aggressive treatment. We aimed to use stereology in PCa evaluations and investigate whether mean nuclear volume (MNV) correlates with the Gleason primary pattern (Gpp) and to improve the subjective GSc to obtain an objective and reliable method without inter-observer dissension. METHODS We identified 74 radical prostatectomy specimens that were divided into six groups based on Gpp, from 3 to 5. Controls (C) were designed in paired non-tumor regions of the same specimens. MNV was estimated using the "point-sampled intercepts" method. Differences in MNV among the C groups and the Gpp groups were tested with the Kruskall-Wallis test and Dunn post-hoc test. Differences between each Gpp group and its control counterpart were tested with the Wilcoxon test. Correlations were evaluated with the Spearman rank correlation (R[Spearman]). RESULTS The correlations between prostate-specific antigen (PSA) and GSc (R[Spearman] of 0.76) and between PSA and MNV (R[Spearman] of 0.78) were moderately strong and highly significant, and the correlation between MNV and Gpp (R[Spearman] of 0.53) was moderate and highly significant. MNV was significantly greater in cancerous regions than in paired-control regions. Limitations included sample size. CONCLUSIONS Proper planning of a study, as well as the availability of equipment and software for morphological quantification, can provide incentive to quickly and accurately estimate MNV as an adjunct parameter in the assessment of PCa. Current data are in favor of the use of MNV associated with GSc and PSA in the assessment of PCa.