Clinical and pathological characteristics of unstageable prostate cancer: analysis of the CaPSURE database

The new and older clinical staging systems for prostate cancer overlook a group of patients in whom abnormal digital rectal examinations (DREs) do not correlate with prostate biopsy findings. These cases are clinically unstageable. We evaluated the prevalence and pathological characteristics of these patients and stratified them into the 1997 American Joint Committee on Cancer clinical staging categories.

Using the CaPSURE database, a longitudinal disease registry of patients with various stages of prostate cancer, the unstageable cohort was identified. The postoperative pathological stage distribution of the unstageable cohort was used to assign the appropriate preoperative clinical stages in retrograde fashion. Pearson product moment correlation was used to establish the best clinical stage for this unstageable group.

A total of 5,543 patients with recorded DREs were evaluated, of whom 2,610 (47%) had an isolated unilateral abnormality on DRE. A total of 235 patients (9%) had prostate needle biopsies positive only on the contralateral side, yielding an unstageable prevalence of 4.2%. Of the cohort 102 patients (44%) underwent radical prostatectomy and 96 had adequate pathological staging data available for review and correlation. Pathological staging revealed pT2a cancers in 26%, pT2b in 53%, pT3a in 19%, pT3b and pT0 in 1% of patients. This distribution indicated that the unstageable cohort correlated most precisely with clinical stage T1c (r = 0.99).

Thus, the prevalence of unstageable prostate cancer is low but significant and it can be accurately classified into clinical stage T1c.