Evaluating the Efficacy of Transoral Robotic Surgery (TORS) Versus Radiotherapy, Chemotherapy, and Open Surgery in Treating Oropharyngeal Squamous Cell Carcinoma (OPSCC): A Systematic Review of Reviews

Introduction

Traditional open surgical approaches have long been considered the gold standard in the field of head and neck surgery. While these methods provide extensive visibility into the surgical field, enabling the removal of tumours with adequate margins, they often result in surgical morbidity [1]. In recent years, there has been a shift towards alternative treatment modalities, such as primary irradiation and concurrent chemoradiation therapy (CCRT), for head and neck cancer [2,3]. CCRT combines radiation therapy and chemotherapy, and has shown efficacy in tumour reduction and reducing risk of recurrence. Treatment decisions for head and neck cancer depend on various factors, including the location and stage of the tumour, patient health, and preferences. Despite advancements in radiation therapy techniques, such as intensity-modulated radiotherapy (IMRT), CCRT still carries significant side effects. Patients undergoing CCRT often experience toxicities such as mucositis, xerostomia, and dysphagia, which adversely impact their quality of life [2,3]. To address these challenges, minimally invasive surgical approaches, such as transoral robotic surgery (TORS) and transoral laser microsurgery (TLM), have emerged as alternatives.

These approaches aim to reduce morbidity and improve patients' quality of life without compromising outcomes. While TLM is effective, it is associated with a restricted view of the surgical field and restricted tissue manipulation, both of which can affect surgical precision, particularly in areas outside the surgical field-of-view [3]. The development of robotic surgical systems, meanwhile, has revolutionised surgical approaches by overcoming certain limitations of traditional methods, such as limited visibility of the surgical site and the need for one-handed manipulation. The first TORS system was developed in 2005, and received approval in 2009 for the treatment of stage T1 and T2 oropharyngeal cancer. Since then, robotic-assisted maxillofacial surgery has gained popularity for its benefits, including a three- dimensional magnified view, accurate movement, bimanual operation with articulated arms, and tremor suppression, all of which enhance surgeons' physical skills [4,5]. Various systems have been designed specifically for TORS, aiming to overcome anatomical constraints and improve surgical exposure in the head and neck region [6,7]. However, the evidence supporting the use of TORS in treating oropharyngeal squamous cell carcinoma (OPSCC) is still emerging and requires further investigation, especially given the increasing prevalence of the disease [3]. The aim of this study, therefore, is to investigate the uses of TORS in the management of OPSCC, exploring its potential, limitations, and function.

Methods

This systematic review poses the research question: In patients with oropharyngeal squamous cell carcinoma, what is the impact of transoral robotic surgery (TORS) on overall survival and disease-free survival, compared with radiotherapy, chemotherapy and open surgery? Search strategy: The authors searched PubMed, Cochrane databases, and grey literature. Subject headings were also searched, as were the reference lists of the articles included in the study. The keywords used were “trans-oral robotic surgery” OR “TORS” AND

“oropharynx” OR “oropharyngeal cancer”. The search spanned articles from 2009 to January 2023. Selection criteria: Only systematic reviews were selected. The inclusion criteria were systematic reviews of human studies focusing on patients diagnosed with oropharyngeal squamous cell carcinoma. Studies were excluded if they were non-English articles that lacked translation, or did not meet the inclusion criteria. Data extraction, quality assessment, and qualitative synthesis: The studies’ eligibility for inclusion in this review was examined by the three authors independently. This review follows the Preferred Reporting Items for Review and Meta-analysis of Individual Participant Data [8]. Outcomes: The primary outcome was to measure the overall survival and disease-free survival of patients undergoing TORS for OPSCC, compared with those receiving other treatment modalities. The secondary outcome was to explore the rate of complications. TORS is a surgical procedure designed to treat OPSCC, and its effectiveness is primarily influenced by tumour characteristics, patient anatomy, and surgical expertise. In this research, we aimed to evaluate the overall effectiveness of TORS for OPSCC, focusing on the procedure's general efficacy without distinguishing between male and female patients.

Results

Out of 14,675 articles, 68 were identified as eligible, as illustrated in the PRISMA chart (Figure 1). After applying the inclusion and exclusion criteria, a total of 10 studies were included in our systematic review, with a total of 16,917 patients. Oropharyngeal SCC was seen in 13,791 of these patients. The characteristics of the included studies were summarised in Tables 1-3. Overall survival and disease-free survival: Six articles reported an overall survival rate ranging from 74―100% and disease-free survival for oropharyngeal cancer treated with TORS [3,9,11,12,13,17].

gure 1. PRISMA 2009 Flow Diagram

Number of papers

Sample

Tumour

Follow-up Results

included

size

staging

Number of papers included

Sample size Tumour staging

Follow up Results

LRC: Locoregional Control, TORS: Transoral Robotic Surgery, IMRT: Intensity-Modulated Radiation Therapy, OPSCC: Oropharyngeal Squamous Cell Carcinoma, CCRT: Concurrent Chemoradiation Therapy, TAL: Transcervical Arterial Ligation, DSS: Disease-Specific Survival, OS: Overall Survival, DFS: Disease-Free Survival, TLM: Transoral Laser Microsurgery

Discussion

To our knowledge, this is the first systematic review of systematic reviews examining the effect of

transoral robotic surgery on overall survival and disease-free survival compared with intensity- modulated radiation therapy. However, it may be limited by unfavourable patient anatomy and is most

suitable for T1-T2 and select T3-T4 tumours. Comparing TORS with IMRT is challenging due to varying applications and limited availability of robotic systems. IMRT: The results showed that primary TORS can obtain similar, but also better oncological outcomes when compared with primary IMRT. TORS is able to achieve oncological and functional outcomes that are at least comparable to primary radiotherapy. As we see in the results, the ratio is highly proportional between them, but the TORS results remain better in OS and DFS for T1, T2, and selected T3 tumours.

CRT: Chemoradiotherapy can be a good option for patients whose disease is incurable or hard to access due to location, patients whose disease is severe and who cannot tolerate surgery, and those who refuse surgery [11]. The combination of chemotherapy and radiotherapy improved oncological outcomes but increased complications, toxicity was more common after chemoradiotherapy than after radiotherapy alone (56% vs. 30%), the adverse effects of chemoradiotherapy were more silent, and toxicities such as osteonecrosis, stenosis, and fibrosis appeared late and were difficult to treat [20]. Open surgery: Primary TORS has several notable advantages, including improved disease-free survival rates. It does come with limitations, however, such as high costs and bulky equipment [13]. Additionally, individual patient factors like obesity, a short neck, or a small jaw can pose challenges during the procedure, potentially leading to discomfort or dental injuries. Nonetheless, TORS proves to be a cost-effective

Conclusion

A systematic review of 10 studies found that transoral robotic surgery (TORS) is a safe and effective treatment for oropharyngeal squamous cell carcinoma (OPSCC). TORS was found to have similar overall survival and disease-free survival rates to intensity-modulated radiation therapy

option for early stage oropharyngeal cancer treatment [13]. Haemorhage: Haemorrhage is a common complication after TORS; it is also an effective and influential element in surgical and functional outcomes [10], with larger tumours and anticoagulant therapy increasing the risk. For example, larger tumours are more likely to require removal deeper into the parapharyngeal region or the base of the tongue. Anatomically, this places the incision nearer to the major branches of the lingual, upper pharyngeal, and facial arteries [21]. While intraoperative bleeding occurs less with TORS than with open surgery, postoperative bleeding poses a significant risk and may even lead to death [13]. While TORS offers enhanced visualisation and instrumentation, it can be less than ideal with regard to postoperative complications, and haemorrhage in particular.

Limitations

The studies included in this review varied in terms of their designs and procedures, sample sizes, and follow-up durations (which ranged from 1―54 months), making them inadequate for sufficient oncological analysis and meta-analysis. Due to potential selection bias (most patients were pre-screened for TORS suitability), ‘surgeon bias’ (surgeons conducting the studies may have an inherent bias toward demonstrating surgical success), and financial bias (all studies required large investments of time, money, and resources from the performing institutions, which may have influenced the desire for successful outcomes), all of the studies may be considered flawed. This review may be further limited by factors such as not exploring the effect of gender difference on the results, and the fact that only articles in English were included. Publication bias may also present.

(IMRT) and concurrent chemoradiotherapy (CRT), and better overall survival and disease-free survival rates than open surgery. TORS was also associated with less postoperative bleeding than open surgery. Overall, based on the evidence presented in this systematic review, transoral robotic surgery (TORS) emerges as a promising treatment option for

oropharyngeal squamous cell carcinoma (OPSCC). It offers comparable oncological outcomes to traditional methods such as radiotherapy and open surgery, while demonstrating advantages in terms of reduced postoperative bleeding and improved functional outcomes. While TORS may not be suitable for all patients due to anatomical constraints or tumour stage, it represents a valuable minimally invasive approach that can enhance patient quality of life. Future research should focus on expanding the evidence base, particularly for advanced-stage tumours, and investigating the long-term outcomes of TORS compared with other treatment modalities. CONFLICT OF INTEREST None. ACKNOWLEDGEMENTS None. FUNDING None.