Tumor amount in prostatic tissues in relation to patient outcome and management.

The clinical significance of prostate cancer extent in prostatic tissue is dependent on the prostatic tissue sample type. For prostate needle core tissue and prostatic chips from transurethral resection of the prostate (TURP), the amount of cancer is of established clinical significance, whereas the intraglandular extent of cancer in radical prostatectomy tissues, although prognostic, is not routinely used for patient management. In the December 2008 and January 2009 issues of the Journal, Vollmer1,2 contributes important knowledge on the relationship of the amount of prostate cancer in needle core tissue1 and radical prostatectomy tissue2 with patient outcome. Prominent strengths of these investigations include the rigorous statistical analyses, the size of the characterized patient populations (>400 patients in each), and the facts that these were prospective studies and the clinical end point was overall survival. Prospective research studies reduce the capacity for selection bias that is a striking feature of retrospective studies. The pathology literature would benefit by inclusion of more studies that were designed as prospective. Commonly used end points in prostate cancer research studies are pathologic stage and Gleason grade and elevation of the serum prostatespecific antigen (PSA) level after treatment (so-called PSA or biochemical failure). However, PSA failure is a surrogate for survival, and not all men who experience a rising PSA level after treatment will have diminished life expectancy. Survival is often considered the “gold standard” end point for cancer treatment trials and should be the gold standard in characterization of the clinical significance of pathologic features in prostatic tissues, including tumor extent. Overall survival and cancer-specific survival have been used. Cancer-specific survival can be instructive in older patient groups that generally have a high incidence of comorbidities and intercurrent deaths. Few studies have linked tumor extent in prostatic tissue to overall survival like the studies by Vollmer1,2 have.