Objective: To assess the clinical significance of nonpalpable localized prostate cancers with relatively favorable six sextant biopsy features in Japanese men.
Patients and methods: 136 nonpalpable prostate cancers of which biopsy features confined to (1) a Gleason score of 6 or less, (2) one or two positive cores per six sextant cores, and (3) 50% or less involvement of any positive core were collected. The Gleason score, tumor extension, and cancer volume were compared with preoperative serum PSA and PSA density for the patients who underwent radical prostatectomy. PSA doubling time was measured for the patients who were treated expectantly.
Results: Treatments chosen for 136 patients with favorable biopsy features were radical prostatectomy alone for 48 and with preoperative androgen deprivation for 30, radiation to the prostate for 12, androgen deprivation therapy for 21, and watchful waiting for 25. Of 48 patients who underwent radical prostatectomy without androgen deprivation therapy, 25% had nonorgan-confined cancers. Seven cancers (14.6%) were Gleason score of 7, but no cancers were 8 or greater. Among 42 prostatectomy specimens for which cancer volume was measured, 22 (52.4%) had cancer volume >0.5 cm(3). Pretreatment serum PSA levels were correlated neither with the Gleason score, tumor extension nor cancer volume. There was only one nonorgan-confined cancer in the 23 cancers for which PSA density was <0.2 ng/ml/g. The ability of PSA density to predict cancer volume <0. 5 cm(3) was 0.61 using a cut-off of 0.2 ng/ml/g. Of the 25 patients treated expectantly, the PSA doubling time was less than 2 years for 3 patients, while it was stable or fluctuated for 13.
Conclusions: Tumor extension can be predicted based on PSA density in nonpalpable prostate cancer with favorable biopsy features, but predictability of cancer volume based on PSA or PSA density is not satisfactorily high. New parameters or biomarkers that complement needle biopsy findings are needed to predict clinical significance of T1c prostate cancer with favorable biopsy features.