COMPARISON OF POSITIVE SURGICAL MARGIN STATUS BETWEEN LAPAROSCOPIC
AND ROBOT-ASSISTED RADICAL PROSTATECTOMY: A MULTICENTRE STUDY
Authors: Rocco, De Lorenzis, Costa, Randi, Minervini, Serni, Lanciotti, Carini,
Falsaperla, Porreca, Antonelli, Celia, Bove, Parma, Crivellaro, Morlacco, Zaramella,
Cindolo
Aim of the study:
Positive surgical margins (PSMs) are a potential risk factor for recurrence after surgery for
prostate cancer (RP). Laparoscopy (LRP) and Robotics (RARP) failed to demonstrate
significant different in terms of PSMs, particularly in referral centers. Nevertheless, in
center with medium case-load the impact of the learning curve can lead to different results.
The aim of our study is to evaluate the status of PSMs comparing their incidence between
LPR and RARP in centers with medium case-load (50-150 cases/year). We also analyzed
the correlations between surgical technique, nerve-sparing approach (NS) and incidence
of PSMs, stratifying our results by pathological stage.
Materials and methods:
From December 2009 to February 2013, 1622 patients underwent RP in 10 urologic
centers, of those, 1308 were evaluable for this purpose. 391 (29.9%) patients were treated
with LRP and 917 (70.1%) underwent RALP. We evaluated the incidence of PSMs, and
then we compared the stage-related incidence of PSMs, for both the techniques.
Results:
Overall, PSMs were diagnosed in 330 patients (25.2%). The incidences of PSMs stratified
by pT stage and procedure are shown in Table 1. There was a significant difference in the
intention to perform NS surgery between the 2 groups: NS was performed in 84 cases
(40.0%) of LRP group and in 595 cases (79.3%) of RARP group (p<0.0001). Among pT2
patients, PSMs rate was 17% (16.2%-17.5%) in the LRP group and 17.6% (10.1%28.2%) in the RARP group. PSMs rate for pT3-4 was 47.4% (41.6%-57.1%) in LRP
patients and 49.4% in the RARP group (38.8%-54.6%). Pathological stages were evenly
distributed between LRP and RARP. We observed a PSM rate of 25% in the NS LPR
group and of 22% in the NS RARP group. At the stratified analysis of PSMs risk we found
a protective effect of NS on PSMs, even when this association is adjusted for procedure
and pT stage [OR (95%CI)= 0.66 (0.45-0.97)]; this protective effect is more evident in pT34 stage.
Discussion:
In our cohort, we observed an overall elevated PSM rate with no differences between LPR
and RARP, but a significant intercenter variability. This can be related to the impact of the
learning curves, included in the analysis; moreover the burden of extracapsular disease in
pT3 patients might be more extended in our series compared to centers in country with a
more extensive PSA screening. We found that performing NS during RP could play a
protective role in terms of lower PSMs, particularly in pT3 cases. A possible explanation is
the selection of NS candidates based on clinical stage and on percentage of positive
cores.
Conclusions:
In our retrospective study, we didn’t find any difference in terms of PSMs in RARP versus
LPR. Our PSMs were not negligible, particularly in pT3 stages, compared to high volume
centers; surgical experience and patients' selection can be a possible explanation.
Table 1. Distribution of 1308 patients by marginal status according to selected variables *
Variable
Type
procedure
LRP
RARP
pT stage
pT2
pT3-pT4
Nerve sparing
No
Yes
Positive surgical margins
(%)
Negative surgical margins
(%)
90 (23.0)
240 (26.2)
301 (77.0)
677 (73.8)
172 (17.5)
159 (49.4)
810 (82.5)
163 (50.6)
81 (33.5)
127 (22.3)
161 (66.5)
443 (77.7)
p-value
of
* missing data were excluded for each analysis
0.229
<0.0001
0.0008