Objectives: The number of biopsy samples for a proper prostate cancer diagnosis has not yet been established. We report our experience with the 10-sample extended biopsy.
Methods: We collected the results of a group of 222 patients undergoing extended ultrasound guided prostate biopsy with 10 samples. In addition to the sextant biopsies 2 extra samples were obtained from the dorsal-apex area on each lobe. Results of this group were compared with a control group of 552 patients undergoing sextant biopsy in 2002 with the same inclusion in criteria.
Results: 60 patients had cancer (27.15%). The extra samples gave the diagnosis in 5 out of 60 patients, 8.33% of the tumors and 2.25% of all patients. Control group showed cancer in 24.5%, not having the difference statistical significance. The incidence in prostates smaller than 20 cc was 69.2%, 11.6% in prostates bigger than 50 cc. 80% of the patients with prostate cancer only in the extra samples have a volume smaller than 35 cc. Multivariate logistic regression study for the probability of prostate cancer only showed association with serum PSA and prostate volume but not with the number of samples.
Conclusions: The extended biopsy is not indicated as an initial diagnostic technique, being reserved for specific cases such as repeated biopsies in patients with high risk pathology reports. Neither it is indicated in the bigger volume prostates.