Prostate saturation biopsy in the reevaluation of microfocal prostate cancer.

PURPOSE: We evaluated the ability of an extended, 32-core repeat transrectal ultrasound prostate biopsy protocol to improve the characterization of low volume, well differentiated disease in men with a diagnosis of potentially insignificant microfocal prostate cancer, as defined by 1 single focus positive core of 10 with less than 5 mm of Gleason score 6 or less tumor on primary biopsy. MATERIALS AND METHODS: A total of 35 consecutive patients, who were 62 to 75 years old, had a median serum prostate specific antigen of 8 ng/ml (range 0.5 to 14) and a diagnosis of minimal prostate cancer, and were willing to consider observation with delayed treatment at progression, were offered repeat saturation prostate biopsy with a median of 32 cores (range 18 to 36) under local anesthesia. This biopsy was to determine whether more extensive prostate sampling would confirm or disprove the initial diagnosis of microfocal, well differentiated prostate cancer. RESULTS: The procedure was aborted in 1 patient because of massive rectal hemorrhage. Another patient had acute prostatitis with gram-negative sepsis. Of 34 evaluable biopsy sets 11 (32%) were negative for cancer, suggesting that tumor detected at the primary biopsy was probably of low volume and amenable to observation with delayed treatment. Of the biopsies 23 (68%) were positive, 17 were at multiple sites and 7 were upgraded to Gleason score 7 or greater. These patients were then considered to have significant tumors and were offered active treatment. CONCLUSIONS: This study is to our knowledge the first to describe the clinical use of prostate saturation biopsies for re-evaluating potentially insignificant prostate cancer. Of patients with minimal disease on standard 10-core biopsy, results show that this technique may be helpful for distinguishing the 30% who probably have minimal disease based on negative repeat saturation biopsy from the 70% who almost certainly have a significant tumor, as characterized by multiple positive cores, with or without an increased Gleason score. The latter patients should be offered active therapy.

Micro-focal prostate cancer: a comparison of biopsy and radical prostatectomy specimen features.

OBJECTIVES: To study the pathologic features of radical prostatectomy (RP) specimens of patients operated on the basis of a potentially "Insignificant" prostate cancer (Ca P) characterized by one single focus (less than 3mm) of moderately differentiated adenocarcinoma - Gleason score < or =6, out of 6-10 biopsies and to determine which characteristics, if any, are predictive of the presence of a "non significant" prostate cancer in the specimen characterized by a low volume (<0.5 ml) moderately differentiated organ confined, cancer (Gleason score less than 6). PATIENTS AND METHODS: PSA, biopsy features, and surgical specimens of a series of 56 patients submitted to RP for "insignificant Ca P" on TRUS prostate biopsies between 1988 and 2004 were compared regarding the number of tumor foci, Gleason grade and score, tumor volume determined by the cylinder method, as well as extraprostatic extension (EPE) and positive surgical margins (P.SM.). RESULTS: 70% of the patients had multifocal microfocal cancer apart from the index tumor. The presence of grade 4 was ignored by the biopsy in 50% of the cases, however the primary grade was correctly evaluated in more than 70% of the biopsy sets. 42% of the patients had a cancer volume less than 0.5 ml and 29% met the definition of insignificant/unimportant cancer characterized by a moderately differentiated (Gleason score < or =6) of low volume (less than 0.5 ml) however no feature accurately predictive of insignificant cancer could be individualized. In this whole series, only 8% of the patients had EPE. When the pre-operative PSA was <10 ng/ml, 98% of the patients had an organ confined tumor. CONCLUSION: Patients diagnosed with prostate cancer on the basis of one single focus less than 3 mm of moderately differentiated (Gleason < or =6) prostate cancer have 30% of chances of harboring an insignificant tumor in their prostate and are therefore, at risk of being overtreated, however there is at this time no specific feature able to identify these patients pre operatively.