Results
For a total of 116 patients with the finding of PSM after radical prostatectomy, median follow-up was 31.4 months (range 6–69). Of this cohort 55 (47%) patients experienced BCR. Median patient age at operation was 64 years (range 49–76). Median duration of time to BCR was 12 months (range 2–66). Median preoperative value of PSA was 9.2 ng/ml (range 2.8–38.2). Considering the clinical stage the distribution of the patients was as follows: T1c (n = 64), T2a (n = 28), T2b (14) and T2c (n = 10). The frequency of BCR did not differ significantly (p = 0.08) between clinical T categories: T1c (38%), T2a (54%), T2b (71%) and T2c (60%). Pathological examination of the species revealed Gleason score ≥7 in 59 (51%) patients, extraprostatic extension in 51 (43.9%) patients and seminal vesicle invasion in 11 (9.48%) patients. Except at day 14, postoperative PSA levels were identified to be significantly associated with observation of BCR (P < 0.001), while other conventional clinicopathologic variables failed to reveal significance (Table 1). Of all PSM locations, 15 (13%) were apical, 20 (17%) at the bladder neck and 81 (70%) at the posterolateral site. A total of 46 patients (40%) had PSM ≤ 1 mm. Neither the location (p = 0.216) nor the extent of PSM (p = 0.405) had any significant impact on the frequency of BCR. There were 36 men with the combination of all the adverse pathologic features (PSM and Gleason score ≥7 and extraprostatic extension) and these patients did not experienced significantly different rate of BCR (55%) in the comparison with the rest of the cohort (44%, P = 0.293). Calculated cut-off values for particular PSA measurement on day 14, 30, 60, 90 and 180 were 0.707 ng/ml, 0.073 ng/ml, 0.041 ng/ml, 0.012 ng/ml and 0.021 ng/ml, respectively.
The ability of postoperative PSA values to predict surgical failure was tested in the Cox proportional model. Apart from non-significant result for PSA at day 14, the risk of surgical failure predicted by PSA was increasing gradually with the time distance from the surgery (Table 2). Correlation between the preoperative PSA and postoperative ultrasensitive PSA was significant only on day 14 (r = 0.64, P < 0.001) and day 30 (r = 0.22, P < 0.01), while at day 60 (r = 0.05, P = 0.61), day 90 (r = 0.013, P = 0.89) and day 180 (r = 0.16, P = 0.10) no significance was found.
Calculated AUC values for PSA cut-offs on day 14, 30, 60, 90 and 180 were 0.58 (95% CI: 0.45–0.69; P = 0.259), 0.74 (95% CI: 0.64–0.82; P < 0.001), 0.84 (95% CI: 0.75–0.91; P < 0.001), 0.84 (95% CI: 0.75–0.90; P < 0.001) and 0.91 (95% CI: 0.84–0.96; P < 0.001), respectively. ROC curves and calculated AUC values are depicted in Figure 1. Positive/negative predictive values for particular PSA cut-offs on day 14, 30, 60, 90 and 180 were 73%/63%, 81%/72%, 96%/67%, 73%/90% and 83%/87%. Calculated PSA decline adjusted for preoperative baseline (PSA on particular measurement day/preoperative PSA) did not improve the prediction of BCR. Calculated AUC values for PSA decline cut-offs on day 14, 30, 60, 90 and 180 were 0.52 (95% CI: 0.40–0.64; P = 0.745), 0.72 (95% CI: 0.62–0.80; P < 0.001), 0.82 (95% CI: 0.73–0.89; P < 0.001), 0.82 (95% CI: 0.73–0.88; P < 0.001) and 0.88 (95% CI: 0.81–0.94; P < 0.001), respectively.
Figure 1.
Receiver operating characteristics (ROC) curves and calculated area under the curve (AUC) values for PSA at particular postoperative measurement day, devised for predicting biochemical recurrence.
Applying the PSA cut-off at day 30 as the indicator for adjuvant radiotherapy would result in the decrease of overtreatment from 61 patients (53%) to 8 patients (19%). From 21 patients (28%) who would stay undertreated, 18 patients would reveal the PSA progression at day 90 while only 2 patients would stay undertreated to late appearance of BCR after 39 and 48 months. Only 1 out of 16 patients who presented at day 30 with PSA ≤0.01 ng/ml developed BCR during the follow-up.
BMC Urol. 2014;14(79) © 2014 BioMed Central, Ltd.
