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EDITORIAL COMMENT

The authors have attempted to address an important aspect of thecurrent clinical staging system regarding prostate cancer, specifi-cally whether patients with nonpalpable tumors differ in outcomesbased on normal versus abnormal transrectal ultrasound. The majorfindings were that among patients with normal digital rectal exam-ination there were differences with respect to pathological findingsand disease-free survival of those with abnormal versus normaltransrectal ultrasound. In contrast, abnormal transrectal ultrasoundhad outcomes similar to those with palpable tumors (abnormal dig-ital rectal examination). Therefore, the authors conclude that trans-rectal ultrasound findings are justified in staging clinical T2 tumors,which are distinct from T1c tumors that are also not palpable butdistinguished by the lack of visibility on imaging in the present TNMstaging system.

Several important points are noteworthy. In the multivariate anal-ysis only PSA and Gleason score were predictive of disease-freesurvival, while transrectal ultrasound findings were not predictive(table 4 in article). There were statistically significant differences inmean serum PSA between the T1c, and abnormal transrectal ultra-sound and digital rectal examination groups (table 2 in article).Collectively, these findings suggest that pretreatment PSA andGleason score are the major clinical factors predictive of outcomeand, furthermore, significantly minimize any additional predictivevalue of the more subjective transrectal ultrasound findings. Furtherquestions arising from this provocative article include what addi-tional value abnormal transrectal ultrasound findings might contrib-ute compared to T1c tumors after adjusting for preoperative PSA.Also, it would have been interesting to know the correlation betweenabnormal transrectal ultrasound findings and biopsy results.

The authors appropriately argue that future refinements in theTNM staging system should incorporate objective values, such asserum PSA and biopsy Gleason score, which is particularly problem-atic in the clinical T1c category, when stratification based on preop-erative PSA might significantly enhance prediction of pathologicalstaging and disease-free outcomes. I would also suggest that futureefforts continue to define additional objective factors available fromneedle biopsy, such as number or percentage of cores positive andlaterality of positive cores, which may be reflective of tumor biologyand ultimately patient outcome. While the TNM staging system forprostate cancer particularly as it relates to the primary tumor hasseveral major shortcomings, it continues to be the standard of careand use should be encouraged. However, clinical medicine is in astate of constant evolution and only through continued reexamina-tion will the TNM staging system remain clinically useful.

Michael S. CooksonDepartment of Urologic SurgeryVanderbilt University Medical CenterNashville, Tennessee

SIGNIFICANCE OF PROSTATE ULTRASOUND1490