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Cost-Effectiveness Analysis of Robotically Assisted Laparoscopy for Newly Diagnosed Uterine Cancers

Leitao, Mario M. Jr MD; Bartashnik, Aleksandra MA; Wagner, Isaac MS; Lee, Stephen J. MD; Caroline, Ari MS, MBA; Hoskins, William J. MD; Thaler, Howard T. PhD; Abu-Rustum, Nadeem R. MD; Sonoda, Yukio MD; Brown, Carol L. MD; Jewell, Elizabeth L. MD; Barakat, Richard R. MD; Gardner, Ginger J. MD

doi: 10.1097/AOG.0000000000000223
Contents: Original Research

OBJECTIVE: To assess the direct costs of three surgical approaches in uterine cancer and the cost-effectiveness of incorporating robot-assisted surgery.

METHODS: A cost system that allocates the actual cost of resources used to treat each patient, as opposed to borrowing cost data from a billing system, was used to determine direct costs for patients who underwent surgery for uterine cancer from 2009 to 2010. These costs included all aspects of surgical care up to 6 months after discharge. Total amortized direct costs included the capital cost of three dual-console robotic platforms with 5 years of service contracts. Nonamortized costs were also calculated (excluded capital costs). Modeling was performed to estimate the mean cost of surgical care for patients presenting with endometrial cancer from 2007 to 2010.

RESULTS: Of 436 cases (132 laparoscopic, 262 robotic, 42 laparotomy), total mean amortized direct costs per case were $20,489 (laparoscopy), $23,646 (robot), and $24,642 (laparotomy) (P<.05 [robot compared with laparoscopy]; P=.6 [robot compared with laparotomy]). Total nonamortized costs per case were $20,289, $20,467, and $24,433, respectively (P=.9 [robot compared with laparoscopy]; P=.03 [robot compared with laparotomy]). The planned surgical approach in 2007 was laparoscopy, 68%; robot, 8%; and laparotomy, 24% compared with 26%, 64%, and 9%, respectively, in 2010 (P<.001). The modeled mean amortized direct costs per case were $21,738 in 2007 and $22,678 in 2010 (+$940). Nonamortized costs were $21,298 in 2007 and $20,573 in 2010 (−$725).

CONCLUSION: Laparoscopy is least expensive when including capital acquisition costs. Laparoscopy and robotic surgery are comparable if upfront costs are excluded. There is cost neutralization with the robot when it helps decrease laparotomy rates.

The costs of robotically assisted laparoscopic surgery can be attenuated once learning curves are overcome and are less than the costs of laparotomy.

Gynecology Service, Department of Surgery, Strategic Planning and Innovation, Quantitative Analysis and Strategic Initiatives, and the Department of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York.

Corresponding author: Mario M. Leitao Jr, MD, Gynecology Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10065; e-mail:

Funded in part by the cancer center core grant P30 CA008748. The core grant provides funding to institutional cores such as Biostatistics, which was used in this article.

Financial Disclosure Dr. Leitao is a surgical proctor and consultant for Intuitive Surgical. Dr. Jewell is a speaker for Covidien and Intuitive Surgical. The other authors did not disclose any potential conflicts of interest.

Uterine cancer is the most common gynecologic malignancy with nearly 50,000 new cases annually.1 Surgery at the time of diagnosis is the cornerstone of initial treatment and involves, at a minimum, total hysterectomy.2 The Gynecologic Oncology Group confirmed that laparoscopy results in lower complications, decreased length of stay, and improved patient quality of life as compared with laparotomy, without an adverse effect on survival.3–5 Similar findings have been reported in patients undergoing hysterectomy for benign indications.6,7 A recently published meta-analysis reported that total laparoscopic hysterectomy was associated with reduced postoperative pain scores and hospital stay compared with vaginal hysterectomy.8 Every effort to reduce laparotomy rates for patients with malignant indications should be the goal.

The implementation of minimally invasive surgery has been hindered by the limitations of available laparoscopic instrumentation, especially for more complex and difficult hysterectomies. In the United States, only 14% of all hysterectomies performed for benign indications are completed laparoscopically.9 One of the barriers to performing laparoscopy is the associated technical difficulty.10 Computer-based (“robotic”) platforms may allow surgeons to increase the rate of laparoscopy.11,12

There are many criticisms of the robotic platform. Recently reported analyses of the Perspective database concluded that robotic hysterectomy is associated with an incremental cost per case of $1,291 to $2,189 over laparoscopy.13,14 These data compared successfully completed laparoscopic and robotic cases without taking into consideration the experience of the surgeons or the drivers of cost. The effect on laparotomy rates with the introduction of the robotic platform was also not taken into account. The introduction of the robotic platform has been reported to significantly reduce laparotomy rates, leading to an actual reduction in overall hospital costs.11 We sought to analyze the costs of incorporating the robotic platform in patients with newly diagnosed uterine cancers at an experienced laparoscopic center after an initial robotic learning and development period.

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Laparoscopy has been offered at our institution since 1993. A robotics program was initiated in 2007. The Memorial Sloan-Kettering Cancer Center institutional review board granted approval to analyze this data set. Direct costs were abstracted for all patients who underwent primary surgical therapy for newly diagnosed uterine cancer at our institution from January 1, 2009, to December 31, 2010. We chose this time period to have concurrent cases to analyze and to overcome any learning curves associated with the robot. These costs included direct costs for all aspects of care during the initial surgical event, immediate postoperative stay, and costs incurred up to 6 months postoperatively (Table 1). Direct costs were obtained using a cost system that allocates the cost of resources used to treat each patient as opposed to borrowing cost data from the hospital billing system, providing a more accurate assessment of true direct costs. The amortized costs included the capital cost of three dual-console robotic (Da Vinci Si) platforms as well as 5 years of service contracts for each of the three platforms amortized over 5 years assessed to each case based on a total robotic case volume of 751 cases in 2009 and 886 cases in 2010 as well as the summation of all the direct costs of the other resources used to treat each patient. The total robotic case volume includes all surgical cases performed across all gynecologic and nongynecologic services using the platform. Capital equipment purchases for standard laparoscopic instrumentation were also calculated. Nonamortized costs were the amortized costs minus the capital equipment costs of the robotic platforms and laparoscopic capital purchases.

Table 1

Table 1

The primary analysis was based on intent to treat, ie, cost for cases converted to laparotomy from planned laparoscopic or robotic approaches were included in the laparoscopic or robotic cohorts, respectively. Nine laparoscopically trained surgeons contributed to the total number of cases. “Laparoscopically trained” indicates that the surgeon received formal training in laparoscopy either postfellowship in a structured outside program or during fellowship. Additionally, all demonstrated sufficient competency to be granted institutional privileges in laparoscopic approaches, and all had been routinely performing standard laparoscopy. The reasons for planned laparotomy were based on individual surgeon choice and do not reflect a particular institutional policy or guideline.

χ2 square or Fisher's exact tests were used as appropriate to compare nominal data between the surgical approaches. The Mann-Whitney U test was used to compare continuous baseline data when two-group analyses were performed. The Kruskal-Wallis test was used to compare continuous baseline data when three-group analyses were performed. The Student's t test was used to compare mean costs between the planned laparoscopic and robotic cohorts.

Modeling was then performed to estimate the mean cost of surgical care for patients presenting to our institution for newly diagnosed uterine cancer based on the rate distribution of planned laparoscopy, robotic, and laparotomy from 2007 to 2010, which we have previously published.12 This model was created by calculating weighted projections of total endometrial surgical cost on retrospective case data. The actual costs from 2009 and 2010 were projected onto the 2007–2008 cases weighted by surgical method and caseload. We did not adjust for inflation because this should have a limited effect on such a short time period and would have equally affected costs for all three planned approaches. Similar modeling methodology was then performed based on currently reported national rates of laparotomy9 and the estimated potential reduction of laparotomy rates, which we have previously reported with the introduction of robotics. In this theoretical model, we chose to keep the rates of laparoscopy stable over the theoretical time period because the rates of laparoscopy have been reported to both decrease13 or increase14 in various publications. Any set of assumptions could be chosen in this theoretical model.

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Direct costs were assessed for 436 cases, which included 132 planned laparoscopic, 262 planned robotic, and 42 planned laparotomy cases, for patients with newly diagnosed uterine cancer undergoing surgery at our institution in 2009 and 2010. Table 2 summarizes select characteristics of our cohorts. Median age was the same across all three cohorts. The conversion to laparotomy rate was the same for the laparoscopic and robotic cohorts. The median body mass index (calculated as weight (kg)/[height (m)]2) was higher in the robotic cohort compared with the laparoscopic cohort. Importantly, stage distribution was the same across all three cohorts. The choice of approach was surgeon-dependent, the most common reasons for planned laparotomy being obesity and uterine anatomy, accounting for more than half of the laparotomy cases. Additional details are described in a previous publication.12 Tumor histologies and grades were similar.12 Robotic cases were associated with longer operating room and operative times but shorter length of stay.12 There were more grade 1–2 complications among laparoscopic (12%) compared with robotic (7%) cases.12 The rate of planned laparotomy was similar during these 2 years (11% and 9%). However, the rate of planned laparotomy decreased by approximately 60%, from 24% in 2007 to 9% in 2010 (P<.001).

Table 2

Table 2

Table 3 describes the results of our primary analyses. The mean amortized cost total was $3,157 more for robotic compared with laparoscopic cases (P<.05) when accounting for the capital purchase and maintenance fees of three dual-console platforms used for 1,637 total robotic cases in 2009–2010. The mean amortized cost total was $996 less for robotic cases compared with laparotomy cases (P=.6). Excluding the capital costs of the platforms and laparoscopy, the mean nonamortized cost total was $178 more for robotic compared with laparoscopic cases (P=.9). The nonamortized total cost was $3,966 less for the robotic compared with laparotomy cases (P=.03). Cost differences for other parameters can be seen in Table 3.

Table 3

Table 3

Table 4 describes our cost modeling analysis using our mean cost results per planned surgical approach depicted in Table 3 based on the distribution of planned surgical approaches from 2007 to 2010 as previously published.12 There was a 63% reduction in laparotomy rates from 2007 to 2010 with an eightfold increase in robotic and 62% decrease in laparoscopic cases. The mean amortized cost total increased by $940 per patient presenting with newly diagnosed uterine cancer and undergoing surgery from 2007 to 2010. However, excluding capital equipment costs, the mean nonamortized total cost decreased by $725 from 2007 to 2010.

Table 4

Table 4

Table 5 describes cost modeling based on one theoretical scenario, recognizing that this model can be modified in multiple ways. This chosen model uses a Year 1 laparotomy rate of 66% based on published national data.9 It assumes a laparoscopic rate of 34% and robotic rate of 0% in Year 1 with subsequent changes in surgical rates based on a 63% reduction in laparotomy rates without a decrease in laparoscopy. We used our amortized cost data, which include the purchase of three dual-console platforms. The amortized costs would change if only one platform, or more than three, were to be amortized. Reducing laparotomy rates by 63% from an initial rate of 66% would result in a reduction in mean amortized cost total by $418 per case. The mean nonamortized cost total would be reduced by $1,666 per patient.

Table 5

Table 5

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The key conclusion from our data, in conjunction with other published data, is that the costs of robotics must take into account how it affects the rate of laparotomy and not just comparing successfully completed robotic to laparoscopic cases, because these are both laparoscopic (ie, minimally invasive) approaches using different instrumentation. Also, it is important to take into account postdischarge cost outcomes. Our data further validate and support the data from Lau and colleagues.11 The enhancement of laparoscopic programs with the introduction of the robotic platform and a concomitant decrease in laparotomy rates leads to cost neutralization of the robotic platform and potentially a cost savings overall. These effects will be greatest among surgeons and hospitals that have struggled with adopting laparoscopy and have a high laparotomy rate. This may also help experienced laparoscopic centers further develop their programs as they expand their ability to offer minimally invasive surgery to even more patients. Surgeons and hospitals that feel they can offer the highest possible rates (greater than 70–80%) of minimally invasive surgery with standard laparoscopic instrumentation may not derive benefits from acquiring or incorporating the robotic platform.

Despite nearly 40 years of availability, laparoscopic hysterectomies still comprise only a small percentage of all hysterectomies in the United States and the world.9 There are gynecologic surgeons who provide safe and efficient laparoscopic surgery, and it is important to continue to support their efforts. Unfortunately, they only represent a minority of all gynecologic surgeons. The robotic platform is a device that overcomes some of the limitations of standard laparoscopic instrumentation and has increased minimally invasive approaches.11,12,15

The robotic platform has been criticized as being unnecessary and expensive.13,14 Comparative and cost-effectiveness analyses are highly complex. The manner in which the cost data are entered, the drivers of those costs, the experience of the surgeons performing laparoscopy and robotics, and the complexity of cases, often are not accounted for. Most importantly, the effect on laparotomy rates is rarely addressed. Laparotomy results in much higher rates of complications (both acute and long term), lengthier hospital stays and readmissions, more pain, and lengthier delays of patients returning to normal activities. Laparotomy is the most expensive surgical approach on a societal basis.16 Long-term adhesion-related and incisional hernia care after laparotomy is extremely costly.

Lau et al11 evaluated the effect of introducing a robotic program for uterine cancer surgery on cost and patient outcomes at their institution. They compared 143 patients after introducing robotics with 160 patients before this “robotic era.” They were able to increase their minimally invasive rates from 17% to 98% within 2 years simply by incorporating robotics. Overall complications decreased significantly from 42% to 13%. Mean cost decreased by $2,000 per patient even when including the amortization of one platform.11

Our incorporating the 6-month postoperative period captures the costs associated with surgical complications. Early on in our analysis, we recognized errors in the costs assigned by our financial managers and required extensive review by clinicians, highlighting the need for clear guidelines when entering cost data into public databases and access to that data. Surgical cost analyses should also include costs of postdischarge care, not just the immediate surgical event and length of stay. These include repeated office visits, home nursing, antibiotics, and delayed return to normal activities.

A potential limitation of our current analysis, beyond its retrospective nature, was that we did not perform a risk-adjusted analysis as a result of the small number of planned laparotomies, which is beyond the scope of this report. However, we did consider some of the potential risks of adversely affecting costs in laparotomy cases. Stage distribution was similar among the three surgical approaches. The percentage of stage III and IV cases was higher in the laparotomy cohort, but this was not significant with such a small group of planned laparotomies, and the only stage IV cases were in the laparoscopic and robotic cohort. Of note, we included cases converted to laparotomy in the laparoscopic and robotic cohorts as part of our intent-to-treat analysis. Excluding these cases or placing them in the laparotomy cohort would have further favored our laparoscopic and robotic cohorts over laparotomy. We also recognize that these are not data from a randomized protocol, which would truly provide more robust results. However, randomization of patients with uterine cancer to a protocol arm involving laparotomy will likely never be done again in light of the results of Gynecologic Oncology Group study LAP2.

Hospitals must take into account capital costs to decide on purchasing new equipment; therefore, amortized cost is relevant. However, amortized cost is highly dependent on the number of platforms purchased and how many years they are used. Our amortized costs factored in three dual-console platforms. The amortized cost for a single platform would obviously reduce this cost by two-thirds. Amortized costs per case will also decrease with an increasing number of cases performed. Our current analysis amortized the cost of more than 1,637 total cases performed in 2009 and 2010. Since then, our total number of cases has increased significantly, with more than1,400 cases performed in 2012 and an estimated 1,800 cases for 2013.

Many institutions will already have a robotic platform in place. Therefore, the calculated amortized cost does not actually reflect an additional actual cost each time the platform is used because that equipment has already been acquired. In reality, the amortized costs will decrease with increasing use, as described previously. The nonamortized cost reflects the actual cost of that case. Operative time and disposable equipment are two of the greatest drivers of cost beyond capital cost.17 We, and others, have reported a learning curve of approximately 20–50 robotic cases, after which operative times decrease significantly.12,18,19 Median operating room and actual operative times equal those of similar laparoscopic cases after this learning curve.12 Our current cost analysis demonstrates that in a time period after which most, but not all, surgeons had overcome this learning curve, use of the robotic platform did not translate into an incremental nonamortized cost.

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© 2014 by The American College of Obstetricians and Gynecologists. Published by Wolters Kluwer Health, Inc. All rights reserved.