Interpretation
Until now, studies highlighting the impact of learning curve on
oncological outcomes in gynaecology mainly focused on conventional
laparoscopy. A recent retrospective cohort study by Liu et al. showed
that the adoption of conventional laparoscopy for the treatment of
cervical cancer initially resulted in a significant reduction of DFS
survival rates.32 In the years thereafter the survival
rates in that study gradually improved up to the level before the
adoption of conventional laparoscopy which strongly suggests an effect
of a learning curve.32
Compared with conventional laparoscopy, the learning process of
robot-assisted surgery was originally perceived as shorter. After the
adoption of the robot-assisted approach, it was stated that the 3D view
of robotic laparoscopy allows for a significantly better performance and
faster improvement in learning curve than conventional laparoscopy with
2D view.33 Which specific part of robot-assisted
radical hysterectomy (RRH) or robot-assisted PLND contributes to the
learning curve the most, remains to be established. From their data on
the different parts of robot-assisted surgery in endometrial cancer,
Seamon et al. concluded that hysterectomies – and in particular the
closure of the vaginal cuff – had the longest learning
curve.34
Another recent study suggested an impact of the learning curve on
oncological outcomes after robot-assisted surgery in cervical cancer
patients.35 Chong et al. reported inferior OS after
RRH during the learning period compared with conventional laparoscopic
radical hysterectomy (LRH) performed by experienced surgeons, though not
significant (P- value of 0.07).35 Given the
small study size (n = 65) and the absence of a CUSUM analysis,
the exact length of the learning curve could not be defined in that
study.
With the use of RA-CUSUM analysis we approached the absolute number of
procedures needed for a single surgical team to obtain robotic
proficiency. More importantly, we were able to demonstrate the impact of
the learning curve on the oncological outcomes of early stage cervical
cancer patients. Our results underscore the necessity of a validated
learning curriculum to make the learning process of an innovative
surgical technique as effective and short as
possible.20,33 Nowadays, simulation training should be
mandatory and followed by robot-assisted procedures using dual consoles.
This allows for direct supervision of new trainees by a certified
proctor. Further research in larger populations and other centres is
needed to be able to determine to what extent the length of the initial
learning phase will be universally applicable.
Furthermore, we propose that the learning curve effect on oncological
outcomes should be included in the design of future studies – including
posthoc analyses of existing trials – comparing the safety of
innovative and common surgical treatments.