Objectives: Routine sextant biopsies have proven useful in the diagnosis and local staging of prostate cancer. A single positive biopsy is more frequently associated with a smaller tumor and a low risk of positive margins. Nevertheless, the risk of positive margins in patients with 1 positive sextant biopsy remains high (20%). A better assessment of local invasion is therefore needed. In addition to standard sextant biopsies, we routinely obtain 3 additional mid biopsies from the apex to the base of the prostate. The aim of this study is to analyze the contribution of these 3 additional mid biopsies to local staging.
Methods: From 1988 to 1996, 177 men underwent sextant biopsies plus 3 additional mid biopsies prior to radical prostatectomy; 59 men had 1 positive sextant biopsy, and 13 also had 1-3 positive mid biopsies. The pathological results of the prostatectomy specimens from these 13 men (group A) were compared with those of the 46 men with only 1 positive sextant biopsy (group B), by means of the Fisher and Mann-Whitney tests.
Results: The two groups were similar in terms of age, preoperative prostate-specific antigen, the Gleason score of positive biopsies, the weight of the specimen, the Gleason specimen score, tumor volume and pathological stage. Positive surgical margins were found in 53.8% of group A and 19.4% of group B patients (p = 0.002). The location of the positive additional biopsies matched that of the positive surgical margins.
Conclusions: Additional mid biopsies improve the local assessment of prostate cancer in patients with a single positive sextant biopsy, identifying significantly more positive margins when these additional mid biopsies are positive and indicating the location of the positive surgical margins. These informations could be helpful to avoid positive surgical margins during radical prostatectomy.