Robotic-Assisted Surgery for the Treatment of Breast and Cervical Cancers: Where is the Consensus?

Introduction
In 1983, the first surgical robot was introduced, a device that ultimately incorporated the development of robotic arms to complement ophthalmologic procedures [1]. The Zeus® system was initially utilized in gynecologic surgery to reconnect fallopian tubes in 1997 [2] and in 2000, the da Vinci Surgery System became the first robotic surgery system approved by the FDA; throughout 2016, there were approximately 1.75 million robotic surgeries (e.g., urology, gynecology, cardiology) conducted in the United States [3].

Robotic surgery enables the surgeon to achieve increased precision via intuitive instrument handling, tremor elimination, and motion scaling [4]. The advent of this technology was thus, envisioned as a clinical upgrade over conventional laparoscopic surgery, which previously obviated the large incisions inherent in open surgeries. However, despite the prevalence of robotic surgery, the approach is reportedly assailed because of the untenable assertion that patient clinical outcomes are further enhanced.

Aarts et al. evaluated the safety and efficacy data from randomized clinical trials involving abdominal hysterectomy, vaginal hysterectomy, laparoscopic hysterectomy and robotic-assisted hysterectomy for the treatment of benign gynecologic conditions [5]. The review indicated that vaginal hysterectomy was superior to laparoscopic hysterectomy and abdominal hysterectomy regarding the resumption of activities of daily living but there was no increased benefit from robotic hysterectomy compared to a laparoscopic hysterectomy. Ultimately, there was no evidence of an overall difference amongst the surgery groups.

In 2015, the American College of Obstetricians and Gynecologists (ACOG) published a committee opinion that impugned the pervasive acceptance of robotic surgery in gynecology, and advocated for randomized clinical trials to validate the procedure’s attendant benefits and risks, vis-à-vis traditional laparoscopic and open approaches [6]. The ACOG further criticized the high cost of a robotic hysterectomy, which incorporates the greater than $1.7 million per robot, the $125,000 in annual maintenance costs, and up to $2,000 per surgery for the single-use instruments [7].

Mendivil et al. retrospectively compared the outcomes for early-stage cervical cancer patients who underwent open or minimally invasive (i.e., robotic-assisted or laparoscopic) surgery [8]. They reported improved operative morbidity (e.g., estimated blood loss) and reduced hospital stay duration in association with the endoscopic procedures, compared to the subjects treated with an open procedure. Nevertheless, recent early-stage cervical cancer investigations have implicated the use of minimally invasive radical hysterectomy with an increased risk for patient disease recurrence and reduced mortality [9,10].

Ramirez et al. assessed the outcomes of a laparoscopic or robot-assisted radical hysterectomy compared to an open radical hysterectomy for the treatment of early-stage cervical cancer [10]. At 4.5 years, the disease-free survival rate was 86% for the minimally invasive surgery patients and 96.5% for the open surgery group. The minimally invasive surgery patients also exhibited a lower 3-year overall survival (93.8%) compared to the open surgery group (99%). Similarly, Melamed et al. compared the survival rates associated with early-stage cervical cancer patients who underwent minimally invasive surgery vs. laparotomy [9]. They reported a 4-year mortality rate of 9.1% for the subjects who underwent minimally invasive surgery and a 5.3% mortality rate for the patients treated with open surgery.

In cancer surgery, obtaining negative postoperative margins is imperative in attenuating disease recurrence rates [11]. While decreased survival was observed with the cervical cancer patients who underwent minimally invasive surgery, this effect was not reported in endometrial and ovarian cancer [12,13]. Perhaps, the decreased survival associated with endoscopic surgery is exclusive to cervical cancer [9]. In the Melamed et al. study, there were no significant group differences regarding positive margins, but nevertheless, margin extent following laparoscopic surgery may have adversely impacted survival outcomes [14].

An endoscopic nipple-sparing mastectomy was initially utilized to preserve cosmesis and successfully achieve negative surgical margin status in the treatment of breast cancer [15]. Thereafter, robotic-assisted surgery has garnered significant acclaim, primarily based upon the improved resolution, enhanced magnification, and visualization over traditional laparoscopy [16]; additionally, the results from case series elucidating the safety, technical feasibility, and initial oncologic outcomes were encouraging [17]. However, few breast cancer studies have compared the efficacy and safety outcomes of robot-assisted surgery to traditional endoscopy or an open procedure [18]. Accordingly, in 2019, the US Food and Drug Administration (FDA) issued a warning against the use of robotic surgery for the treatment of breast and cervical cancers [19].

The FDA, coinciding with the ACOG committee opinion, disputed the putative safety and efficacy associated with robotic-assisted mastectomy; in particular, the FDA was concerned with the absence of randomized clinical trial data, and expressed their concern with the persistent use of a robotic-assisted mastectomy for the prevention and treatment of breast cancer [17]. The FDA further remarked that until substantive clinical trials have evaluated the safety and relevant cancer-related surrogate markers (e.g., overall survival, disease recurrence, and disease-free survival) in comparison to traditional surgical endeavors, the formal indications and authorization for robotic surgery will not be approved.

Conclusions
Robotic surgery overcomes limitations inherent to traditional laparoscopic surgery, namely, enhanced mobility, increased visibility and facilitated haptic precision [20]. However, one may conjecture that the outcome of any operation is directly impacted by the surgeon’s proficiency, and the discrete benefits from using robotic surgery are immaterial. Perhaps, an overreliance on tactile and visual perception may detract from a surgeon’s independent experience in making sophisticated intraoperative decisions [4].

In open surgery, larger incisions facilitate greater surgical access compared to what may be availed upon with minimally invasive surgery [21,22]. Moreover, since gynecologic oncology fellowships primarily emphasize robotic surgery platforms compared to open surgery [23], perhaps there is a predilection for many contemporary surgeons to perform robotic-assisted surgery when prima facie, an open surgery should be otherwise indicated.

Currently, robotic-assisted surgery is steadily increasing and in 2017, more than 600,000 procedures were conducted in the United States [24]. Nevertheless, the FDA’s safety concerns with robotic surgery and the rising cost of this procedure, which is 25% higher compared to laparoscopic surgery, should be a significant consideration prior to universally accepting this endoscopic approach [25].

While the reported oncologic efficacy and safety evidence associated with robotic surgery remain scant [26], we may ultimately ascertain that robotic surgery is neither as safe nor efficacious than traditional laparoscopy and open surgery [9,10]. Consequently, the FDA and the Centers for Medicare & Medicaid Services should remain vigilant regarding the ongoing presence of robotic surgery and ensure that until the clinical results are borne out (i.e., there is an incontrovertible clinical benefit derived from robotic surgery), this approach should not be readily integrated into the various surgical disciplines and needlessly considered standard of care practice [27].