RARP was performed in 308 patients during the study period. The PD group was comprised of 231 patients and the no PD (ND) group was comprised of 77. Table 1 shows the patient characteristics of the groups. The median age at time of surgery was significantly lower in the PD group than the ND group (66 years and 68 years, respectively; p = 0.007). Furthermore, the median preoperative PSA level was significantly lower in the PD group than the ND group (6.8 ng/mL and 5.8 ng/mL, respectively, p = 0.03). There were no significant differences between the two groups in median BMI, biopsy Gleason score (GS), clinical stage, D'Amico risk classification, history of abdominal surgery, proportion of patients receiving neoadjuvant androgen deprivation therapy, or median estimated PV.
Table 1
Variable | PD | ND | P |
Number of patients | 231 | 77 | |
Median age at surgery, years (range) | 66 (50–76) | 68 (57–76) | 0.007 |
Median BMI, kg/m2 (range) | 23.6 (17.4–31.5) | 23.5 (17.8–29.7) | 0.73 |
Preoperative PSA level, ng/mL (range) | 6.8 (1.8–90.1) | 5.8 (2.4–74.2) | 0.03 |
Biopsy GS (%) | | | 0.81 |
≤ 6 | 75 (32.5) | 22 (28.6) | |
7 | 104 (45) | 37 (48.1) | |
≥ 8 | 52 (22.5) | 18 (23.4) | |
Clinical stage (%) | | | 1 |
≤T2 | 219 (94.8) | 73 (94.8) | |
≥T3 | 12 (5.2) | 4 (5.2) | |
D’amico risk classification (%) | | | 0.98 |
Low | 62 (26.8) | 21 (27.3) | |
Intermediate | 91 (39.4) | 31 (40.3) | |
High | 78 (33.8) | 25 (32.5) | |
History of abdominal surgery (%) | | | 0.6 |
+ | 94 (40.7) | 34 (44.2) | |
- | 137 (59.3) | 43 (55.8) | |
Neoadjuvant ADT (%) | | | 0.12 |
+ | 46 (19.9) | 9 (11.7) | |
- | 185 (80.1) | 68 (88.3) | |
Median estimate PV, ml (range) | 24.5 (3.6–78.9) | 24.3 (7.3–97) | 0.29 |
PD: pelvic drain; ND: no pelvic drain; BMI: body mass index; PSA: prostate specific antigen; GS: Gleason score; ADT: androgen deprivation therapy; PV: prostate volume |
Table 2 shows the perioperative and pathological outcomes of the two groups. The PD group had a significantly higher proportion of patients who underwent pelvic lymph node dissection (PLND) (48.1% vs. 24.7%, p < 0.001) and higher median estimated blood loss (100 mL vs. 80 mL, p = 0.03). The median length of hospital stay was significantly longer in the PD group (6.8 days vs. 5.8 days, p < 0.001). There were no significant differences between the two groups in median operation time, pathological GS, pathological stage, median volume of resected prostate, median length of urinary catheter placement period, or proportion of patients who underwent nerve-sparing surgery, received a complete resection, or had extraprostatic extension. The incidence of complications, including ileus, urinary tract infection (UTI) with fever and anastomotic leak, did not significantly differ between the two groups; nor did the incidence of asymptomatic and symptomatic lymphocele at 2 weeks and 1 year after surgery.
Table 2
Perioperative and pathological outcomes
Variable | PD | ND | P |
Number of patients | 231 | 77 | |
Median operating time, minute (range) | 234 (138–398) | 239 (177–352) | 0.3 |
Median console time, minute (range) | 180 (102–350) | 176 (123–306) | 0.74 |
Median estimated blood loss, mL (range) | 100 (0-1350) | 80 (0-510) | 0.03 |
Pathological GS (%) | | | 0.045 |
No malignancy | 10 (4.3) | 1 (1.3) | |
≤ 6 | 58 (25.1) | 11 (14.3) | |
7 | 126 (54.5) | 58 (75.3) | |
≥ 8 | 17 (7.4) | 7 (9.1) | |
Unknown | 20 (8.7) | 0 (0) | |
Pathological stage (%) | | | 0.18 |
≤ T2 | 191 (82.7) | 58 (75.3) | |
≥ T3 | 40 (17.3) | 19 (24.7) | |
Pelvic lymph node dissection (%) | | | < 0.001 |
None | 120 (51.9) | 58 (75.3) | |
Limited or extended | 111 (48.1) | 19 (24.7) | |
Nerve sparing (%) | | | 0.22 |
None | 42 (18.2) | 9 (11.7) | |
Limited or bilateral | 189 (91.8) | 68 (88.3) | |
Median hospital stay, days (range) | 15 (9–48) | 12 (9–25) | < 0.001 |
RM | | | 0.062 |
0 | 194 (84.0) | 57 (74.0) | |
1 | 37 (16.0) | 20 (26.0) | |
EPE | | | 0.19 |
0 | 199 (86.1) | 62 (80.5) | |
1 | 29 (12.6) | 15 (19.5) | |
X | 3 (1.3) | 0 (0) | |
Median removed PV, ml (range) | 37 (15–87) | 38 (18–113) | 0.3 |
Ileus (%) | 8 (3.5) | 1 (1.3) | 0.46 |
Febrile urinary tract infection (%) | 3 (1.3) | 0 (0) | 0.58 |
Anastomotic leak (%) | 10 (4.3) | 4 (5.2) | 0.76 |
Median urinary catheter placement period, day (range) | 7 (5–41) | 7 (6–21) | 0.055 |
Average liquid storage for 2 weeks after surgery, ml (range) | 8.9 (0-229) | 10.9 (0-210) | 0.55 |
Average liquid storage for 1 year after surgery, ml (range) | 1.4 (0-232) | 0 | n.d. |
Asymptomatic lymphocele for 2 weeks after surgery (%) | 29 (12.6%) | 12 (15.6%) | 0.56 |
Asymptomatic lymphocele for 1 year after surgery (%) | 3 (1.3%) | 0 | n.d. |
Symptomatic lymphocele (%) | 1 (0.4%) | 0 | n.d. |
GS: Gleason score; RM: resection margin; EPE: extraprostatic extension; PV: prostate volume |
Table 3 shows the results of the univariate and multivariate analyses for predictors of asymptomatic lymphocele 2 weeks after surgery. Significant univariate predictors included BMI < 25 kg/m2 (p = 0.04), biopsy GS ≥ 8 (p = 0.03), pelvic lymph node dissection (p < 0.001) and pathological GS ≥ 8 (p = 0.03). In the multivariate analyses, the only significant independent predictor was pelvic lymph node dissection (p < 0.001).
Table 3
Analyses for prediction of asymptomatic lymphocele for 2 weeks after surgery
| Univariable analysis | | Multivariable analysis |
| P | Odds ratio* | | P | Odds ratio* |
age (≥ 70 vs < 70 years) | 0.83 | 0.94 | | | |
BMI (≥ 25 vs < 25 kg/m2) | 0.09 | 0.57 | | 0.08 | 0.55 |
PSA (≥ 10 vs < 10 ng/ml) | 0.71 | 1.14 | | | |
Prostate volume (≥ 30 vs < 30 ml) | 0.52 | 0.81 | | | |
Biopsy GS (≥ 8 vs < 8) | 0.1 | 1.65 | | 0.351 | 1.37 |
Clinical stage (≥ cT3 vs < cT3) | 0.72 | 0.79 | | | |
Neoadjuvant ADT (yes vs no) | 0.41 | 0.73 | | | |
D’Amico’s risk classification (high vs low, intermediate) | 0.4 | 1.27 | | | |
History of abdominal surgery (yes vs no) | 0.46 | 0.81 | | | |
Operating time (≥ 240 vs < 240 minutes) | 0.28 | 1.35 | | | |
Console time (≥ 180 vs < 180 minutes) | 0.37 | 1.28 | | | |
Bleeding volume (≥ 150 vs < 150 ml) | 0.08 | 1.63 | | 0.054 | 1.75 |
Nerve sparing (yes vs no) | 0.6 | 1.22 | | | |
Lymph node dissection (yes vs no) | 0.001 | 2.47 | | 0.016 | 2.08 |
Pathological GS (≥ 8 vs < 8) | 0.07 | 2.27 | | | |
Pathological stage (≥ pT3 vs < pT3) | 0.34 | 1.38 | | | |
Pelvic drain (yes vs no) | 0.58 | 0.84 | | | |
Drainage volume the day before drain removal (≥ 100 vs < 100 ml) | 0.9 | 1.05 | | | |
BMI: body mass index; PSA: prostate specific antigen; ADT: androgen deprivation therapy; GS: Gleason score |
*The odd ratio was described using the latter in parentheses as a reference. |