Probability based diagnostic biopsy specimens as predictors of tumor grade and stage found

The Gleason score of prostatic adenocarcinoma in biopsy specimens was compared with the Gleason score of corresponding radical prostatectomy specimens from 78 patients with localized prostate cancer. Grading errors were found to be significant for well-differentiated (Gleason score 2-4) tumors. The accuracy was 6 (23%) for Gleason scores of 2-4 on needle biopsy. All of the Gleason scores of 8-10 on needle biopsy were graded correctly. When the preoperative Gleason score was <7, 20 (37%) patients had organ-confined lesions, while when preoperative Gleason score > or = 7, 5 (21%) patients were confined to the prostate. Discrepancies between the Gleason score of the biopsy material and prostatectomy specimens were larger for biopsy specimens with low Gleason scores than for biopsy specimens with high Gleason scores. Large differences existed between the Gleason histologic scores of the biopsy and prostatectomy specimens when only a single microscopic focus of the tumor in the biopsy specimen is low grade. Consequently, when tumor grade influences the clinical management of prostate cancer, patients with limited biopsy material, provided this material is not poorly differentiated, should probably undergo repeated biopsy to reduce the likihood of tumor sampling error. This awareness influences treatment policy, particularly for the watchful waiting criteria of prostate cancer.