78th Annual Meeting Abstracts

BACKGROUND: Radical prostatectomy (RP) is the treatment of choice for localized prostate cancer in appropriate patients and its benefits for long-term cancer control have been proven. Robotic-assisted laparoscopic prostatectomy (RALP) is steadily replacing the open and laparoscopic prostatectomy (LRP) as the surgical modality of choice despite lack of level I evidence of its superiority. Its advantages in reducing the learning curve over its pure laparoscopic counterpart are significant, however, even with prior laparoscopic training; a learning curve must be surmounted. In this retrospective study we examine the RALP learning curve on perioperative outcomes and complications of a robotics fellowship-trained surgeon.
METHODS: Data on 553 consecutive patients who underwent RALP at our institution were collected and recorded in an IRB-approved registry. Independent variables included age, BMI, tumor characteristics, and comorbidity by the Charleson Index (CI), dependent variables included operative time, estimated blood loss, pre to postoperative hematocrit difference, transfusion rate, complications, length of hospital stay, time to catheter removal, and pathologic tumor characteristics. Peri-operative complications were graded according to the modified Clavien classification. We stratified our series into 5 groups of 100 and a final group of 53 to assess outcomes relative to surgeon learning curve effects.
RESULTS: Demographic, operative, complication, and pathologic data are listed in Table 1. The mean age and BMI were 58.3 years and 28.6, respectively. CI was 0 in 83.6%, 1 in 12.3%, and 2 or greater in 4% of patients. Mean operative time was 171.1 minutes, mean EBL was 203.5cc, and the average pre to postoperative hematocrit change was 5.19dg/mL. All 3 of these outcomes improved significantly with increasing experience (all p≤0.01, respectively). Mean length of hospilization became shorter with increasing surgeon experience: 1.6 vs. 1.2 days in group 1 vs. group 6 (p<0.01). Moreover, the rate of peri-operative complications decreased over time (p=0.03). There were no conversions to open surgery. The mean gland volume was 54.8cc and pathology revealed 12.8% p2a, 1.0% p2b, 68.4% p2c, 10.7% p3a, and 3.5% p3b.The overall positive surgical margin rate was 13.7% and there was no difference in margin rate between groups.

Table 1: Demographic and Operative Variables
Group #	1	2	3	4	5	6	Ave (Range)	P value
Demographic Data:
Ave Age (Years)	58.3	58.2	59.7	58.9	57.2	57.2	58.3 (37-79)	0.0606
BMI (mean)	29.07	29.03	28.31	28.52	28.44	28.13	(520)/28.6 (18-55.8)	0.76837
Operative Variables:
Mean Operative Time (min)	225.5	194.8	163.7	149.1	152.5	133.4	171.7 (77-360)	<0.0001
Mean EBL (cc)	270.1	228.9	196.5	175.6	175.1	160.4	203.5 (50-900)	<0.0001
Hct difference (preop-PACU) (dg/mL)	5.98	5.41	4.62	5.43	4.91	4.60	5.19 (+2.3-16.5)	0.01226
Mean Hospital Stay (Days)	1.6	1.3	1.1	1.1	1.2	1.2	1.2 (1-13)	<0.0001
Ave Time to Catheter Removal (Days)	8.12	7.56	7.93	8.74	7.34	7.22	7.81 (4-43)	0.052872
Complications by Clavien Classification
Clavien I	4	0	3	1	3	1	(12)/2.17%	0.0308
Clavien Id	3	6	1	10	2	3	(25)/4.52%
Clavien II	3	2	1	3	3	2	(14)/2.53%
Clavien IId	0	0	1	0	0	0	(1)/0.18%
Clavien IIIa	1	2	0	0	1	0	(4)/0.72%
Clavien IIIb	6	0	1	1	2	0	(10)/1.81%
Clavien IVa	2	0	0	0	0	0	(1)/0.18%
Clavien V	1	0	0	0	0	0	(1)/0.18%
Overall	21	10	8	15	11	6	12.29%
Positive Margin (% yes)	16	9	21	13	12	(7)/10.14	(78)/13.71	0.1651

CONCLUSION: Surgeons with prior laparoscopic and robotic surgery fellowship training experience a learning curve that continues beyond several hundred procedures.