**10. Outcomes**

#### **10.1 Oncological outcome**

A recent report by Tomifuji et al. demonstrated excellent outcomes of TOVS for both new and salvage cases [5]. In 83 new hypopharyngeal cancer cases, the 2-year overall survival (OS), disease-specific survival (DSS), local control rate (LCR), laryngeal preservation rate (LPR), and disease-free survival (DFS) were 90.6%, 97.4%, 96.3%, 96.9%, and 80.40%, respectively, and the 5-year OS, DSS, LCR, LPR, and DFS were 83.2%, 94.3%, 94.7%, 94.6%, and 73.0%, respectively. In 12 salvage cases of hypopharyngeal and supraglottic cancer after RT or CRT, the 2-year OS, DSS, LCR, LPR, and DFS were 100%, 100%, 75%, 91.7%, and 75%, respectively, and the 5-year OS, DSS, LCR, LPR, and DFS were 87.5%, 87.5%, 75%, 82.5%, and 75%, respectively. Regarding T classification, advanced T stage showed worse OS and DSS outcomes than early stage. Regarding N classification, patients with N3 neck disease showed a significantly worse prognosis in terms of OS and DSS.

Among 115 cases of hypopharyngeal and supraglottic cancer, 20.8% of patients had a previous history of RT or CRT in the neck, 28.7% of patients were performed postoperative RT or CRT. As the result, 50.4% of patients could be spared RT or CRT [5].

#### **10.2 Functional outcome**

Regarding swallowing functional outcomes, most patients maintain good oral food intake. Among 115 patients more than 6 months after TOVS, the functional outcome swallowing scale (FOSS) score, which divides the swallowing function

*Transoral Videolaryngoscopic Surgery (TOVS) DOI: http://dx.doi.org/10.5772/intechopen.97473*

into six stages, was 0 in 65% patients, 1 in 20% patients, 2 in 4.3% patients, 3 in 7.0% patients, and 4 in 3.5% patients (0–2, stable status; 3, unstable status requiring occasional follow-up of swallowing function; and 4–5, life-threatening status requiring tube feeding or surgical intervention). In 3.4% of patients, oral food intake could not be achieved within 6 months of surgery and required tube feeding, total pharyngolaryngectomy due to severe pharyngeal stenosis, or laryngotracheal separation surgery. Another 1.7% of patients had deteriorated swallowing function after 4.5 years and 7 years of TOVS and underwent laryngotracheal separation surgery to prevent aspiration pneumonia. Therefore, 5.2% of patients could not maintain oral intake during the long-term follow-up [5]. The risk factors associated with postoperative severe dysphagia include patient age (particularly >80 years), large resection area, arytenoid and/or pyriform sinus resection, pulmonary dysfunction, and tracheostomy [10].

Postoperative voice impairment was found in 29.1% of hypopharyngeal and supraglottic cancer cases 6–12 months after TOVS. Scar contracture after wound healing was the mechanism described in Section 8.2. Large resection area including the medial and lateral pyriform sinuses was the risk factor [11]. Surgeons should inform the patients regarding the risk of postoperative voice impairment during pre-operative counseling.

#### **10.3 Complications**

In 115 cases of hypopharyngeal and supraglottic cancer, the major complications related to TOVS were neck emphysema (7.8%, conservative observation: 100%), airway edema (6.9%, steroid treatment: 88%, tracheostomy: 12%), bleeding (2.6%, tracheostomy: 67%, reoperation: 33%), partial laryngopharyngeal necrosis due to postoperative RT and CRT (1.7%), perforation of the neck (0.86%), and laryngeal chondritis (0.86%) [5].

The proportion of patients avoiding endotracheal tube extubation immediately after surgery and maintain intubation for 1 day due to long operation time or poor oxygenation was 1.7%. Tracheostomy was performed in 9.5% of patients—in 4.3% of patients, prophylactic tracheostomy was performed; in 3.4% of patients, emergency tracheostomy was performed; and in 1.7% of patients, preoperative tracheostomy was performed due to dyspnea or difficulty of intubation. Tracheostomy could not be closed due to persistent laryngeal stenosis and persistent dysphagia in 3.4% of all patients undergoing TOVS [5].

#### **11. Future directions**

#### **11.1 Development of devices**

In the early phase of TOVS establishment, a major problem in the surgical procedure was the conflict of instruments in the narrow laryngopharyngeal cavity due to the straight shape of the endoscope and forceps. In recent years, endoscopes, forceps, CO2 lasers, and electrocautery with flexibility have been commercially available (**Figure 1d**).

The currently available endoscopes are designed for two-dimensional imaging. Therefore, TORS, which uses three-dimensional (3D) imaging, is considered superior to TOVS. However, the newly developed 3D endoscopes that can be used for TOVS will be commercially available soon. TOVS has the advantage of having tactile sense; hence, it can be a more suitable surgery for hypopharyngeal lesions using a 3D endoscope than TORS.

In addition, new curved blades for the FK-WO retractor have been developed (**Figure 3**). In a trial conducted in our department, new curved blades enabled appropriate exposure of surgical fields in the pyriform sinus apex and esophageal inlet in five cases with poor surgical field exposure using conventional blades, and surgical procedures could be accomplished in all cases. While using curved blades, the surgical maneuver is occasionally difficult with straight devices; however, malleable devices fit well [5].

With the continuous development of devices and by combining devices such as 3D endoscopes, malleable devices, and new curved blades, TOVS will be an easier procedure with a broad indication of the entire laryngopharynx and will be a more accomplished surgery with better oncological outcomes and safety.

#### **11.2 Management of lymph node metastasis**

Cervical lymph node metastasis is one of the most important prognostic factors in head and neck squamous cell carcinoma. Although many cases of transoral surgery are in the early stage with a clinically node-negative (cN0) status, the rate of positive lymph node metastasis in patients with cN0 laryngopharyngeal cancer is approximate 20–30%. Therefore, it is debatable whether neck dissection should be performed immediately in cN0 cases.

Tomifuji et al. reported the relationship between the histological parameters of resected primary lesions of TOVS and lymph node metastasis in supraglottic and hypopharyngeal cancers. Tumor depth and venous invasion were the most useful parameters for predicting lymph node metastases. They recommended that elective ND should be considered when the tumor depth is >1 mm and/or there is a presence of venous invasion. Moreover, careful observation when the tumor depth is between 0.5 and 1 mm, and, regular clinical follow-up when <0.5 mm, are recommended, respectively [12].

Another promising strategy for the management of lymph node metastasis is sentinel node navigation surgery (SNNS). It enables a personalized evaluation for neck dissection in cN0 cases individually, thereby eliminating unnecessary ND. Araki et al. reported a multicenter feasibility study of the combination of transoral surgery with SNNS for laryngopharyngeal cancer using an intraoperative injection of indocyanine green. In 22 patients with cN0 hypopharynx, oropharynx, or supraglottic cancer, the accuracy, sensitivity, and specificity of the combination strategy were 95.5%, 75%, and 100%, respectively. The 5-year DSS rate was 100%, and OS was 72.3% [13]. This combination strategy holds promise as a feasible tool for personalized and minimally invasive treatment options for both primary lesions and lymph node metastasis with favorable oncological outcomes.

#### **11.3 Conversion surgery with neoadjuvant chemotherapy (NAC)**

While the major indications for TOVS are early-stage up to T2, TOVS can be performed in selected cases with advanced lesions when NAC is effective for shrinking the lesions. Tomifuji et al. reported good results of conversion surgery with NAC. In the cases of T3 and T4 hypopharyngeal cancer treated by NAC (cisplatin +5FU or docetaxel + cisplatin +5FU) followed by TOVS, the 5-year OS, DSS, LCR, LPR, and DFS were 75.0%, 82.5%, 91.7%, 100%, and 66.7%, respectively [5].

Although this strategy of conversion surgery seems to be effective, it also has an issue. When lesions shrink by NAC, the remaining lesion may be a single mass *Transoral Videolaryngoscopic Surgery (TOVS) DOI: http://dx.doi.org/10.5772/intechopen.97473*

in some cases or multiple scattered lesions in other cases. When the resection area is limited to shrunk lesions, some of the scattered lesions outside the resection area might be missed despite the negative resection margin. The resection areas after NAC should be determined according to the initial lesions, and it is technically difficult to completely resect the entire area of the original advanced lesions. Hence, the indication of TOVS as a conversion surgery for advanced lesions should be limited to highly selected cases, and research on an appropriate and effective strategy for conversion surgery with NAC is necessary for the future.

#### **11.4 Other than laryngopharyngeal cancer surgery**

TOVS can be applied to any other surgery in addition to that for primary laryngopharyngeal cancer. Parapharyngeal and retropharyngeal metastatic lesions can be treated by TOVS in combination with a navigation system [14]. Less invasiveness surgery is needed for benign diseases in the laryngopharyngeal region compared to that for malignant diseases. The technique of TOVS has great benefits as a minimally invasive surgery for benign diseases including cysts, papilloma, benign

#### **Figure 9.**

*56-year-old male, recurrent laryngeal pleomorphic adenoma. The orginal lesion was resected 1 year ago at another hospital. The recurrent lesion was located right arytenoid to aryepiglottic fold. a. Pre-operative endoscopic view, b. pre-operative view of surgical field, c. resection from inter arytenoid to right arytenoid, d. resection of right aryepiglottic fold, e. view after resection: Whole right arytenoid to aryepiglottic fold was resected and fibring grue is sprayed. f. Post-operative endoscopic view (9 months after TOVS).*

#### **Figure 10.**

*19-year-old female, Neurofibromatosis type2. The lesion was located left arytenoid. a. Preoperative view of surgical field, b. resection of the lesion.*

#### **Figure 11.**

*30-year-old female, pyriform sinus fistula. a. Pre-operative view of surgical field, b. resection of the duct as far as possible, c. suture closure of mucosa, e. view after mucosal closure.*

tumors (**Figures 9, 10**), pyriform sinus fistula [15] (**Figure 11**), foreign bodies, injection laryngoplasty for unilateral vocal cord palsy, cricopharyngeal myotomy for dysphagia, laryngopharyngeal dilatation surgery for stenosis and so on.

### **12. Conclusions**

TOVS is a minimally invasive organ preservation surgery for laryngopharyngeal cancer with good oncological and functional outcomes. The procedure of this surgery has some advantage in maneuver and less invasiveness when compared to TLM and TORS, especially for hypopharyngeal cancer. It is expected that transoral surgery including TOVS will become increasingly popular as one of the standard treatments with the development of devices and establishing the evidence by accumulating cases.
