Clinicopathological features of prostate cancer in Japanese men diagnosed on repeat transrectal ultrasound-guided biopsy

Abstract

Background

The objective of this study was to analyze the clinicopathological features of prostate cancer detected on repeat transrectal ultrasound-guided random biopsy in comparison with those detected on initial biopsy.

Methods

Between January 1999 and March 2004, 132 Japanese men underwent radical retropubic prostatectomy without neoadjuvant therapy at our institution. In 109 patients (group A) prostate cancer was detected on initial biopsy, while in the remaining 23 (group B), it was diagnosed on repeat biopsy. We retrospectively characterized differences in clinicopathological features between these two groups.

Results

There were no significant differences in age, serum prostate specific antigen (PSA) value, or biopsy Gleason score between groups A and B. However, prostate volume in group A was significantly smaller than that in group B, while PSA density, the percentage of positive biopsy cores, and the percentage of cancers in the biopsy set in group A were significantly higher than those in group B. Pathological examination of the radical prostatectomy specimens showed that there were no significant differences in the distribution of pathological T stage or in the Gleason score; or in the incidences of lymphatic invasion, vascular invasion, and perineural invasion between groups A and B. Despite there being a significantly larger tumor volume in the radical prostatectomy specimens in group A compared to that in group B, there was no significant difference in the incidence of insignificant disease between these two groups.

Conclusion

These findings suggest that missing the cancer on the initial needle biopsy may be due to a small cancer focus in a large prostate; however, there were no significant differences in the final pathological features of prostate cancers detected on the initial and repeat biopsies, suggesting similar biological behaviors. Thus performance of a repeat biopsy in cases negative for malignancy on the initial biopsy is advocated.

Missing prostate cancer on the initial biopsy may be due to a small cancer focus in a large prostate; however prostate cancers detected on initial and repeat biopsies may have similar biological behavior.