The value of percentage free prostate specific antigen (PSA) in the detection of prostate cancer among patients with intermediate levels of total PSA (4.0-10.0 ng/mL) in Nigeria

Objectives

To assess the value of percentage free prostate-specific antigen (%fPSA) in the detection of prostate cancer among Nigerian men with an intermediate total PSA level (4–10 ng/mL), and to show if the optimum threshold for biopsy is different from Caucasian values when the widely used (six-core, digitally directed) prostate biopsy protocol in Nigerians is applied.

Patients and methods

The study included 105 patients aged >50 years, with a palpably benign prostate gland and intermediate levels of total PSA (4–10 ng/mL). These patients had a free PSA assay and a transrectal digitally directed six-core biopsy of the prostate. The %fPSA was calculated and the optimum threshold value for detecting prostate cancer was determined.

Results

The mean (SD) age of the patients was 64.4 (6.6) years and their mean (SD) total PSA level was 6.6 (1.7) ng/mL. Of these men 14 (13.3%) had cancer of the prostate detected by the prostate biopsy. The %fPSA level related directly to sensitivity values but inversely to the specificity and the positive predictive values. The best threshold of %fPSA for detecting cancer in these men was <40%, with a sensitivity of 100%, specificity of 93.4% and a positive predictive value of 70% (P < 0.05).

Conclusions

In evaluating Nigerian patients with a palpably benign prostate gland and within the intermediate total PSA range, when digitally directed biopsy protocol is adopted, a %fPSA threshold of <40% will detect significant percentage of those with prostate cancer, with a minimal number of unnecessary biopsies. This value differs from that reported in western studies in which transrectal ultrasonography-directed biopsy was used.

Management of anterior caliceal stones >15 mm

Anterior caliceal stones represent a challenge to endourologist to select the best modality of management with the least morbidity. To study different treatment modalities of management of anterior caliceal stones >15 mm. It is an observational prospective study of patients with anterior caliceal stones more than 15 mm. Inclusion criteria were patients with isolated anterior caliceal stones, or branched anterior caliceal stones with posterior caliceal extension. Patients were evaluated using non-contrast CT preoperatively. They were divided into three groups: group 1 underwent PCNL through posterior caliceal puncture in cases with wide anterior calyx infundibulum or obtuse infundibulopelvic pelvic, group 2 underwent PCNL through anterior caliceal access in cases with narrow infundibulum or acute infundibulopelvic angel and group 3 underwent flexible ureteroscopy and laser lithotripsy. Intraoperative and postoperative findings were recorded and compared. Eighty eight patients were included in this study, Group 1 (44 patients) group 2 (28 patients), and group 3 (16 patients). Operative time was not significantly different across the three groups (68 ± 11.5, 72 ± 9 and 74 ± 11 min in group 1, 2 and 3, respectively, P = 0.053). Fluoroscopy time was significantly shorter for group 3 (2 ± 0.5 m, P = 0.0001) compared to group 1 and 2 (5.6 ± 4.6 and 4.5 ± 1.4 min), respectively. There were no significant differences in stone-free rates after initial treatment between the three groups; 84, 82, and 69 %, in groups 1, 2 and 3, respectively (P = 0.4). Postoperative hemoglobin drop was noted to be highest for group 2 and lowest for group 3 which was significantly different (1.7 ± 0.8, 2.2 ± 1.1, and 0.3 ± 0.3 g/dl, for patients in groups 1, 2 and 3 respectively, P = 0.0001). Group 2 showed the highest post-operative complication rate (21 %) in comparison to group 1 (11 %) and group 3 (6 %), however, differences were not statistically significant (P = 0.3). PCNL through posterior or anterior caliceal puncture is an excellent modality to treat anterior caliceal stones with high stone clearance rate. Despite the higher chance of bleeding with anterior caliceal puncture, it is still inevitably needed in difficult anterior caliceal stones with unfavorable anatomy. RIRS is a good alternative to PCNL with the advantage of less radiation exposure and less bleeding.