ROBOT-ASSISTED VERSUS LAPAROSCOPIC RECTAL RESECTION FOR CANCER IN A SINGLE SURGEON’S EXPERIENCE: A COST-ANALYSIS, COVERING THE INITIAL 50 ROBOTIC CASES

PURPOSE Since the introduction of the da Vinci® Surgical System, several studies have been published regarding the clinical and surgical benefits of robot-assistance in colon-rectal surgery, however only few reports have conducted a structured cost-analysis. The aim of the present study is to compare surgical parameters and costs of robotic surgery with those of laparoscopic approach in rectal cancer based on a single surgeon’s early robotic experience. METHODS Data from the first 50 robotic (ROB) and from 25 laparoscopic (LAP), rectal resections performed at our institution by an experienced laparoscopic surgeon (>500 minimally invasive procedures) between 2009 to 2014, were collected, retrospectively analyzed and compared. Patient demographics, procedures and outcome data were gathered. Financial costs of the two procedures were collected and categorized into fixed and variable costs. The robotic learning curve was analyzed using the cumulative sum statistical method (CUSUM). RESULTS Based on CUSUM analysis, the ROB group was divided into three phases (ROB1: 1-19th cases; ROB2: 20-40; ROB3: 41-50). Overall median operating time was significantly lower in LAP than in ROB (270 min vs 312.5 min, P=0.006) and regression analysis showed a borderline significant interaction effect between type of surgery and year (P=0.058) suggesting a significant reduction of operating time only in ROB group. Length of hospital stay did not differ between groups (P=0.567). Overall mean costs associated with LAP procedures were significantly lower than that of ROB (P<0.001). A statistically significant reduction in variable and fixed costs were found between ROB3 and ROB1 (P<0.05). If we exclude fixed costs, the difference between laparoscopic and ROB3 were no longer statistically significant. DISCUSSION Robotic surgery has two main drawbacks compared with laparoscopy widely quoted in literature: the greater operative time and the higher costs. According to other works, we used the CUSUM to analyse the operative time and the learning curve of robotic assisted rectal cancer resection. In our study, in accordance with previous reports, the learning curve of robotic surgery for rectal cancer was divided into three phases: the initial learning period (1st–19th case) in which there is a rapid decrease of operative time, the competent period (20th–40th case) showing stabilization of operative time, and finally the challenging period (40th–50th case) comprising the most difficult cases (inter-sphincteric resection, higher rates of preoperative chemio-radiotherapy, more cases with totally robotic approach and a tendency towards lower incidence of complications). We reported a different median operative time in these three phases with statistically significant reduction with robotic experience and primary technical competence in reducing the operational time achieved after the initial learning period. However, despite the increased operative time and the presence of difficult cases recruited in ROB 3, we noted that costs were higher in ROB1 compared to ROB3. This fact may be partially explained by adding extra costs such as laparoscopic energy devices used in hybrid laparoscopic-robotic rectal resection during the initial period. Regarding costs of robotic surgery the literature published to date concludes that it is more expensive compared with laparoscopy. The overall median costs associated to laparoscopic procedures were significant lower than robotic colon-rectal procedures with a statistically significant difference. However, we have broken down the overall costs into different items and we noticed that costs related only to hospital stay were similar in the two groups according to similar post-operative course in both group while consumables’ costs and personnel costs were the principle the causes of higher costs related to robotic colorectal surgery. Direct hospital costs were significantly improved over time and the reasons for this decrease in costs were multi-factorial, nonetheless the reduction of operating time, due to an abbreviated learning curve, and length of stay are probably two major contributors. The most important finding of our study was that, excluding fixed costs, the difference between LAP and the last robotic phase (Rob 3) turn out to be no longer statistically significant; suggesting an optimization of costs of robotic surgery and a flattening of differences with standard laparoscopy with an ongoing experience. CONCLUSIONS Even if our results suggest a significant optimization of costs with increased experience, robotic rectal surgery has significantly greater expenditures and operating times compared to standard laparoscopy. The dominant costs are fixed costs, and efforts to reduce it include accurate patient selection and use in high volume, multidisciplinary center.