Association of biopsy core number and location with pain in patients undergoing a transperineal prostate biopsy under local anaesthesia: a secondary analysis of the APROPOS trial

Background: APROPOS was a multicentre, randomized, blinded trial focus on investigating the perineal nerve block versus the periprostatic block in pain control for men undergoing a transperineal prostate biopsy. In the analysis reported here, the authors aimed to evaluate the association of biopsy core count and location with pain outcomes in patients undergoing a transperineal prostate biopsy under local anesthesia. Methods: APROPOS was performed at six medical centers in China. Patients with suspected prostate cancer were randomized to receive either a perineal nerve block or a periprostatic block (1:1), followed by a transperineal prostate biopsy. The secondary analysis outcomes were the worst pain experienced during the prostate biopsy and postbiopsy pain at 1,6, and 24 h. Results: Between 12 August 2020 and 20 July 2022, a total of 192 patients were randomized in the original trial, and 188 were involved in this analysis, with 94 patients per group. Participants had a median (IQR) age of 68 (63–72) and a median (IQR) prostate volume of 42.51 (30.04–62.84). The patient population had a median (IQR) number of biopsy cores of 15 (12–17.50), and 26.06% of patients had a biopsy cores count of more than 15. After adjusting the baseline characteristics, the number of biopsy cores was associated with the worst pain during the biopsy procedure in both the perineal nerve block group ( β 0.19, 95% CI: 0.12–0.26, P <0.001) and the periprostatic block group ( β 0.16, 95% CI: 0.07–0.24, P <0.001). A similar association was also evident for the postbiopsy pain at 1, 6, and 24 h. A lesser degree of pain in both groups at any time (r range −0.57 to −0.01 for both groups) was associated with biopsy cores from the peripheral zone of the middle gland, while other locations were associated with a higher degree of pain. In addition, the location of the biopsy core had less of an effect on pain during the biopsy (r range −0.01–0.25 for both groups) than it did on postbiopsy pain (r range −0.57–0.60 for both groups). Conclusions: In this secondary analysis of a randomized trial, biopsy core count and location were associated with pain in patients undergoing a transperineal prostate biopsy under local anesthesia. These results may be helpful for making clinical decisions about the anesthetic approach for scheduled transperineal prostate biopsies.