Clinical Significance of a Single-Core Positive Prostate Cancers Detected on Extended Prostate Needle Biopsy

Purpose: The widespread use of serum prostate specific antigen and extended needle biopsy of the prostate as screening procedures for prostate cancer has not only led to an increase of detecting prostate cancer as a whole, but also to an increase of detecting small low grade tumors. Still, the clinical significance of small, low grade, single-core positivity on prostate biopsy hasn't yet been determined. So, we tried to investigate the clinicopathological features of prostate cancers that showed only singlecore positivity on extended prostate needle biopsy. Materials and Methods: 144 patients were managed with radical prostatectomy during 2003-2005 at our institution. Insignificant prostate cancer on biopsy specimens was defined as a single-core positive biopsy containing a focus of 3mm or less of moderately differentiated prostate cancer (Gleason score≤6) and clinical insignificant cancer in the radical specimens was defined as a low volume (<0.5cc) of moderately differentiated organconfined prostate cancer. We analyzed the clinicopathological features and the clinical significance in regards to the number of positive cores and the biopsy significance. Results: Of 144 patients, 46 (31.9%) patients were diagnosed on the basis on single-core positive prostate cancer. Of these 114 patients, 32 (69.6%) patients had insignificance prostate cancer on biopsy. Although the single core positive group had more favorable pathologic features than the multiple core positive group, only 5 (10.9%) were found to have clinically insignificant cancer at radical prostatectomy. Also, in the biopsy insignificant group, only 5 patients (15.6%) were found to have clinically insignificant cancer. However, there were no features that could accurately predict insignificant prostate cancer preoperatively. Conclusions: Although the clinicopathological features of the prostate cancers that were detected in only a single-core on prostate needle biopsy were observed to be suggestive of less advanced disease, most of such single-core positive cancers may be clinically significant disease. (Korean J Urol 2006;47:475-481)