Transoral Robotic Surgery for Oropharyngeal Carcinoma: Update

Research Article

Austin J Otolaryngol. 2014;1(2): 6.

Transoral Robotic Surgery for Oropharyngeal Carcinoma: Update

Joshua Gurberg and Eitan Prisman*

Otolaryngology Head and Neck Surgery

*Corresponding author: Eitan Prisman MD, MA, FRCSC, Clinical Assistant Professor, Otolaryngology Head and Neck Surgery, University of British Columbia, Diamond Health Care Centre, 4th Floor, 2775 Laurel Street, Vancouver, B.C. Canada V5Z 1M9

Received: June 22, 2014; Accepted: September 24, 2014; Published: September 27, 2014


Background: Oropharyngeal squamous cell carcinoma is increasing in incidence and its epidemiology is evolving to affect more young, HPV+, non-smokers. There have been multiple paradigm shifts in the treatment of this disease. Open surgery has been largely replaced by chemo radiation; however, recently, trans-oral robotic surgery (TORS) is emerging as a new minimally invasive therapeutic modality.

Objectives: Update the evidence evaluating TORS in the treatment of or pharyngeal squamous cell carcinoma.

Methods: Descriptive review of the literature.

Results: Integrating TORS into the multidisciplinary treatment of or pharyngeal squamous cell carcinoma allows carefully selected patients to return home early with intact airway and swallowing function in the majority of cases, without sacrificing oncologic control or survival. These findings compare favorably to open surgery and chemo radiation.

Conclusions: TORS appears to be a safe, feasible, and efficacious surgical modality for the treatment of a subset of carefully selected patients with oropharyngeal squamous cell carcinoma. HPV positive non-smokers appear to particularly benefit.


Oropharyngeal cancer

According to the American Cancer Society, there will be an estimated 42,440 new cases of cancer of the oral cavity and pharynx in 2014 leading to 8,390 deaths (Cancer facts and figures 2014). The oropharynx is the area of the pharynx extending from the soft palate to the epiglottis and is composed of the tongue base, soft palate, tonsils, and posterior pharyngeal wall [1]. Malignancies of this region are primarily squamous cell carcinoma and, as a result of rich oropharyngeal lymphatics, are characterized by early nodal spread with resultant high stage disease at diagnosis [1]. The overall 5-year survival rate of Oropharyngeal squamous cell cancer (OPSCC) has been relatively stable at 60% over the past decade [1].

While the incidence of oral, hypopharyngeal, and laryngeal squamous cell carcinoma (SCC) has been decreasing, OPSCC is actually on the rise [2]. With the increase in incidence of OPSCC, there has also been a shift in the epidemiology of the disease [2]. What was once a demographic dominated by elderly male smokers with concurrent alcohol consumption is now one characterized by younger patients with limited exposure to these carcinogens [2]. Mounting evidence suggests that these findings are associated with oncogenic HPV infection (HPV types 16 and 18) [3,4]. Weinberger et al. analyzed a sample of 79 OPSCC pathologic specimens using real time PCR and tissue microarrays, determining that 61% of cases were HPV positive and that those with p16 over-expression had improved overall and disease free survival as well as lower 5 year local recurrence rates than their HPV/p16 negative counterparts [4]. Furthermore, in 2010, Ang and colleagues retrospectively analyzed the association between tumor HPV status and survival among patients with stage III or IV OPSCC who were previously enrolled in a randomized control trial comparing accelerated to standard fractionation radiotherapy [3]. With 4.8 years of follow up, patients with HPV positive tumors had improved 3-year overall survival and 58% reduction in the risk of death [3]. HPV-positive tumors appear to maintain normal protein sequences, and as such, when subjected to radiotherapy and chemotherapy, are more susceptible to apoptosis and immune surveillance mechanisms [2]. This has led to changing treatment patterns with a focus on de-intensification therapy [2].

Multiple paradigm shifts

The history of the treatment of OPSCC has been characterized by multiple paradigm shifts. Prior to the Veterans Affairs study in 1991, most institutions were treating head and neck squamous cell carcinoma with surgery and adjuvant radiotherapy [5]. For OPSCC, surgery often consisted of the historically so-called “commando procedure”: en bloc resection of the tumor via lip split mandibulotomy, pharyngotomy, orolingual release often accompanied by ipsilateral or bilateral neck dissection [6,7]. These procedures, while offering acceptable rates of locoregional disease control, often resulted in significant disruption of native tissues requiring insensate, adynamic flap reconstruction leading to compromised speech, swallow, and airway function [6,7].

The morbidity of classical surgery, and advancements in chemotherapeutics and radiotherapy led to several large studies that changed the face of Head and Neck oncology, including OPSCC therapy. Randomized control trials such as the Veteran’s affairs [8] and RTOG [9] studies in the late 80s and early 90s, which compared chemoradiation therapy to surgery and adjuvant radiation, demonstrated equivalent survival but improved functional status in the non-surgical group leading most specialized centers to treat OPSCC non-operatively [10]. While the Veteran’s affairs trial showed equivalent overall survival between the surgical and the chemoradiation cohorts with two thirds of patients in the latter cohort maintaining a larynx, this trial was restricted to patients with laryngeal cancer alone [8]. In the RTOG trial, 70 patients with advanced stage OPSCC were randomized to receive pre-operative, post-operative, or definitive radiation therapy (RT) alone. The small number of patients in each of these groups did not show any significant difference in overall survival, (30%, 36%, and 33% respectively) or locoregional recurrence (43%, 52% and 38 % respectively) [9]. Nevertheless, these results have influenced most centers to treat OPSCC using non-surgical modalities.

Over 10 years ago, Parsons and colleagues undertook the largest retrospective review of operative vs. non-operative treatments restricted to OPSCC. When comparing surgery (with or without adjuvant RT) to primary external beam RT performed in a patient population primarily characterized by male smokers and drinkers, the cumulative 5-year survival was 47% for patients undergoing surgery and 43% for RT with or without neck dissection [11]. The severe complication rate was 23% in the primary surgery group and 6% in the primary RT group [11]. While this review was retrospective in nature, it highlighted that this cohort of OPSCC patients have a poor survival independent of treatment choice, albeit with a decreased rate of complication with a non-surgical treatment.

The poor overall survival of this patient population combined with the shift to treat OPSCC primarily with RT led to several centers to investigate the effect of increasing doses of radiation and altered fractionation regimens. However, these interventions have been associated with serious concerns relating to both early and late toxicity, significant functional deficits and diminished quality of life [7,12]. During the course of advancing radiation technology and studying the effect of these techniques on the treatment of OPSCC, there has been a marked change in the epidemiology of OPSCC to a younger demographic with less comorbidities and an improved response to therapy. This has led to ye t another paradigm shift to de-intensify therapy. This has been accompanied by a re-emergence of the potential application of surgical treatments and in particular minimally invasive surgery such as transoral robotic surgery (TORS) [2,12].


Minimally invasive transoral surgery began with the practice of transoral laser microsurgery (TLMS) [6]. TLMS uses an operating microscope, laryngoscope, microlaryngeal instruments, and a CO2 laser to resect lesions through the open mouth [6]. In 2003 Steiner and colleagues popularized TLMS as a method of resecting OPSCC lesions without large cervical incisions, a technique which gained popularity in few specialized centers with impressive results [6]. However, this technique has not been universally incorporated and can be challenging with issues related to line of site. TLMS is mentioned here as it initially brought forth the idea of transoral resection, but is otherwise outside of the scope of this review. For more information please see the work of Li and colleagues [6].

Because of the challenges of TLMS, transoral robotic surgery (TORS) has quickly become the most commonly utilized minimally invasive transoral approach for the removal of squamous cell carcinoma of the tonsil and base of tongue [6]. TORS uses the da Vinci surgical robot to resect lesions via the open mouth [7]. TORS has been used for OPSCC since it was granted FDA approval for transoral otolaryngology surgical procedures restricted to T1 and T2 benign and malignant lesions in 2009 [6].

The da Vinci surgical robot is made up of a surgeon console, where the surgeon is immersed in a 3D magnified image of the operative field and remotely operates the robot using hand controls and foot pedals which are transmitted via a master-slave interface that eliminates tremor and scales down movements 5:1 [7]. The robotic cart is docked at a 30-degree angle to the operating table and is equipped with either a 0 or 30 degree binocular endoscope and 2 EndoWrist instruments [7]. These EndoWrist instruments provide 7 degrees of freedom (much like the human arm and wrist) and 90 degrees of articulation [7]. The vision cart is the final component, and allows support staff and the surgical assistant providing suction and retraction to visualize the operative field [7]. A typical TORS set up can be seen in Figure 1.