Yoon Woo Koh

Oncologic Outcomes After Transoral Robotic Surgery : A Multi-institutional Study

IMPORTANCE Large patient cohorts are necessary to validate the efficacy of transoral robotic surgery (TORS) in the management of head and neck cancer. OBJECTIVES To review oncologic outcomes of TORS from a large multi-institutional collaboration and to identify predictors of disease recurrence and disease-specific mortality. DESIGN, SETTING, AND PARTICIPANTS A retrospective review of records from 410 patients undergoing TORS for laryngeal and pharyngeal cancers from January 1, 2007, through December 31, 2012, was performed. Pertinent data were obtained from 11 participating medical institutions. INTERVENTIONS Select patients received radiation therapy and/or chemotherapy before or after TORS. MAIN OUTCOMES AND MEASURES Locoregional control, disease-specific survival, and overall survival were calculated. We used Kaplan-Meier survival analysis with log-rank testing to evaluate individual variable association with these outcomes, followed by multivariate analysis with Cox proportional hazards regression modeling to identify independent predictors. RESULTS Of the 410 patients treated with TORS in this study, 364 (88.8%) had oropharyngeal cancer. Of these 364 patients, information about post-operative adjuvant therapy was known about 338: 106 (31.3) received radiation therapy alone, and 72 (21.3%) received radiation therapy with concurrent chemotherapy. Neck dissection was performed in 323 patients (78.8%). Mean follow-up time was 20 months. Local, regional, and distant recurrence occurred in 18 (4.4%), 15 (3.7%), and 10 (2.4%) of 410 patients, respectively. Seventeen (4.1%) died of disease, and 13 (3.2%) died of other causes. The 2-year locoregional control rate was 91.8% (95% CI, 87.6%-94.7%), disease-specific survival 94.5% (95% CI, 90.6%-96.8%), and overall survival 91% (95% CI, 86.5%-94.0%). Multivariate analysis identified improved survival among women (P = .05) and for patients with tumors arising in tonsil (P = .01). Smoking was associated with worse overall all-cause mortality (P = .01). Although advanced age and tobacco use were associated with locoregional recurrence and disease-specific survival, they, as well as tumor stage and other adverse histopathologic features, did not remain significant on multivariate analysis. CONCLUSIONS AND RELEVANCE This large, multi-institutional study supports the role of TORS within the multidisciplinary treatment paradigm for the treatment of head and neck cancer, especially for patients with oropharyngeal cancer. Favorable oncologic outcomes have been found across institutions. Ongoing comparative clinical trials funded by the National Cancer Institute will further evaluate the role of robotic surgery for patients with head and neck cancers.

Is lack of placement of drains after thyroidectomy with central neck dissection safe? A prospective, randomized study

Objective: Selective use of drains after thyroidectomy has been suggested in the literature. Although the safety of thyroidectomy without drains has been reviewed, there is little specific data available to identify the safety of thyroidectomy combined with central neck dissection (CND) without drains. This study aims to determine the feasibility and safety of thyroidectomy without drains, especially in cases of combined CND.

The harmonic scalpel technique without supplementary ligation in total thyroidectomy with central neck dissection: a prospective randomized study.

Objective:To investigate the safety and efficacy of the no-tie (NT) technique using the harmonic scalpel (HS) in terms of the operating time and complications in total thyroidectomy with central neck dissection (CND). Summary Background Data:Recently, the HS has been used as an alternative to conventional hand-tied ligation for hemostasis in thyroid surgery, which is a time-consuming procedure. Limited data have been published on the evidence of its safety in total thyroidectomy accompanied by CND without supplementary hand-tied ligation. Methods:Sixty-five consecutive thyroidectomized patients were enrolled in this study. The final pathology in all the patients was thyroid papillary carcinoma. All patients underwent total thyroidectomy with CND. The NT technique using HS group consisted of 31 patients. The conventional hand-tied ligation technique group comprised 34 patients. The following variables were examined: operating time, intraoperative bleeding, incidence of perioperative complications (hemorrhage, hematoma, seroma, recurrent laryngeal nerve palsy, hypoparathyroidism, and injury to the adjacent structures including the trachea and esophagus), the number of pathologically proven lymph nodes, total amount of drainage, duration of drain placement, and time of hospital discharge. Results:The use of the HS reduced the operating time of total thyroidectomy with CND by an average of 43.12 minutes (P < 0.001). The number of pathologically proven lymph nodes was 7.32 ± 1.66 in the NT group and 6.85 ± 1.76 in the CT group (P = 0.274). No significant difference was observed in the overall perioperative complications, such as postoperative bleeding, temporary recurrent laryngeal nerve palsy, and temporary hypoparathyroidism, between the 2 groups. No permanent recurrent laryngeal nerve palsy and hypoparathyroidism occurred in either group. Conclusions:The NT technique with the HS is a relatively safe and effective method in total thyroidectomy combined with CND. Moreover, the HS significantly reduced the operating time.

Prevalence of Otolaryngologic Diseases in South Korea: Data from the Korea National Health and Nutrition Examination Survey 2008

Objectives The aims of this study were to evaluate the prevalence of otolaryngologic diseases in Korea. Methods We obtained data from the 2008 Korea National Health and Nutrition Examination Surveys (KNHANES), which were cross-sectional surveys of the civilian, non-institutionalized population of South Korea (n=4,930). A field survey team that included an otolaryngologist, nurses, and interviewers moved with a mobile examination unit and performed otolaryngologic interviews and physical examinations. Results The prevalence of subjective hearing loss, tinnitus, preauricular fistua, tympanic membrane perforation, and cholesteatoma were 11.97%, 20.27%, 2.08%, 1.60%, and 1.18%, respectively. Dizziness and vestibular dysfunction were common among Korean adults, since 23.33% of the participants reported symptoms of dizziness or imbalance, and the prevalence of vestibular dysfunction was 3.86%. The prevalence of nasal diseases was relatively high, as the prevalence of allergic rhinitis, chronic rhinosinusitis, and a deviated nasal septum were 28.01%, 7.12%, and 42.94%, respectively. Subjective dysphonia was found in 6.60% of the participants, and the prevalence of subjective dysphonia increased with age. Conclusion This is the first nation-wide epidemiologic study to assess the prevalence of otolaryngologic diseases by both the Korean Otolaryngologic Society and the Ministry of Health and Welfare. Considering the high prevalence of otolaryngologic diseases in Korea, the results call for additional studies to better prevent and manage otolaryngologic diseases.

Feasibility of Robot-Assisted Neck Dissections via a Transaxillary and Retroauricular (“TARA”) Approach in Head and Neck Cancer: Preliminary Results

BackgroundRecently, robot-assisted neck dissection in thyroid cancer patients with lateral neck node metastasis has been demonstrated to be feasible. We realized the necessity of technical modification in order to apply robotic system to comprehensive neck dissection for head and neck squamous cell carcinoma. This study examined the feasibility and safety of transaxillary and retroauricular (“TARA”) approach for robotic neck dissection in patients with head and neck squamous cell cancer.MethodsFour human cadaveric dissections were followed by robotic neck dissections in seven patients with oral cavity or laryngopharyngeal cancer through TARA incision.ResultsIn all cases, vital structures including major vessels and nerves were preserved. The numbers of retrieved lymph nodes in robotic neck dissections were comparable with those in conventional neck dissections.ConclusionsRobotic neck dissection via TARA approach is a feasible and useful method with excellent cosmetic results for treating nodal metastasis in selected cases of head and neck squamous cell cancer.

Voice Outcomes of Polyacrylamide Hydrogel Injection Laryngoplasty

Objectives: Polyacrylamide hydrogel (PAAG, Aquamid) is widely used as permanent facial tissue filler during facial plastic surgery. In this study, we examined the long‐term effects and safety aspects of PAAG as a vocal fold augmentation material for patients with permanent unilateral vocal cord paralysis.

PD-L1 expression on immune cells, but not on tumor cells, is a favorable prognostic factor for head and neck cancer patients

To investigate the expression of programmed death-ligand 1 (PD-L1) and immune checkpoints and their prognostic value for resected head and neck squamous cell cancer (HNSCC). PD-L1 expression on tumor cells (TC) and tumor-infiltrating immune cells (IC), abundance of tumor-infiltrating lymphocytes (TILs), and expression of the immune checkpoints were investigated in 402 HNSCC patients. PD-L1 expression on TC and IC was categorized into four groups according to the percentage of PD-L1-positive cells. PD-L1 positivity was defined as ≥5% of cells based on immunohistochemistry. High PD-L1 expression on IC, but not TC, was an independent favorable prognostic factor for RFS and OS adjusted for age, gender, smoking, stage, and HPV. High frequencies of CD3+ or CD8+ TILs, Foxp3+ Tregs, and PD-1+ TILs were strongly associated with favorable prognosis. PD-L1 was exclusively expressed on either TC or IC. Transcriptome analysis demonstrated that IC3 expressed higher levels of the effector T cell markers than TC3, suggesting that PD-L1 expression is regulated via an adaptive IFNγ-mediated mechanism. High PD-L1 expression on IC, but not TC, and high abundance of PD-1+ T cells and Foxp3+ Tregs are favorable prognostic factors for resected HNSCC. This study highlights the importance of comprehensive assessment of both TC and IC.

Radiotherapy Deteriorates Postoperative Functional Outcome After Partial Glossectomy With Free Flap Reconstruction

PURPOSE Most patients with tongue cancer require surgical resection of the tongue to varying degrees. As a result, quality of life, which is strongly related to speech, chewing, and swallowing, can deteriorate severely from extensive surgical treatment of tongue cancer. In addition to surgery, adjuvant therapy may affect the severity of functional impairment. Therefore, the influence of postoperative radiotherapy on functional outcome after partial glossectomy with free flap reconstruction was evaluated in patients with early oral tongue cancer. PATIENTS AND METHODS Functional outcome was measured and charts of 31 patients with oral tongue cancer who were surgically treated at Yonsei Head and Neck Cancer Clinic from 2003 through 2008 were reviewed. Only patients who underwent partial glossectomy and reconstruction with radial forearm free flap and did not develop recurrence were included. Speech integrity was evaluated with diadochokinetic testing by a professional speech therapist. Tongue mobility was checked by measurements of upward distance, protrusion distance, and lateral deviation distance. Swallowing capacity was evaluated with the M.D. Anderson Dysphagia Inventory. RESULTS Diadochokinetic rates of the surgery-only and postoperative radiotherapy groups were 27.8 and 23.9, respectively, which was statistically different. Swallowing capacity was significantly superior in the surgery-only group. Tongue mobility was not statistically different between the 2 groups. CONCLUSIONS Functional outcome of speech and swallowing is negatively influenced by postoperative radiotherapy.

Robot-Assisted Selective Neck Dissection via Modified Face-lift Approach for Early Oral Tongue Cancer: A Video Demonstration

Recently, early-stage oral cavity cancers are successfully resected via a transoral approach. Nodal metastasis is a crucial factor in determining the survival of oral cavity cancer patients. However, elective neck dissection in earlystage oral cavity cancers is a still controversial procedure. In recent period, in an attempt to hide the cervical scars, robotic modified neck dissection via a transaxillary approach has been introduced by Kang et al. in thyroid cancer with neck metastasis. However, there are limitations to dissect the upper neck level including level I via transaxillary approach. Therefore, we demonstrate our novel technique for robot-assisted neck dissection (RAND) for level I, II, and III via modified face-lift approach (MFLA) and show the pitfalls of the operation, as well as tips for its successful completion.

Green tea (−)-epigallocatechin-3-gallate inhibits HGF-induced progression in oral cavity cancer through suppression of HGF/c-Met☆

Hepatocyte growth factor (HGF) and c-Met have recently attracted a great deal of attention as prognostic indicators of patient outcome, and they are important in the control of tumor growth and invasion. Epigallocatechin-3-gallate (EGCG) has been shown to modulate multiple signal pathways in a manner that controls the unwanted proliferation and invasion of cells, thereby imparting cancer chemopreventive and therapeutic effects. In this study, we investigated the effects of EGCG in inhibiting HGF-induced tumor growth and invasion of oral cancer in vitro and in vivo. We examined the effects of EGCG on HGF-induced cell proliferation, migration, invasion, induction of apoptosis and modulation of HGF/c-Met signaling pathway in the KB oral cancer cell line. We investigated the antitumor effect and inhibition of c-Met expression by EGCG in a syngeneic mouse model (C3H/HeJ mice, SCC VII/SF cell line). HGF promoted cell proliferation, migration, invasion and induction of MMP (matrix metalloproteinase)-2 and MMP-9 in KB cells. EGCG significantly inhibited HGF-induced phosphorylation of Met and cell growth, invasion and expression of MMP-2 and MMP-9. EGCG blocked HGF-induced phosphorylation of c-Met and that of the downstream kinases AKT and ERK, and inhibition of p-AKT and p-ERK by EGCG was associated with marked increases in the phosphorylation of p38, JNK, cleaved caspase-3 and poly-ADP-ribose polymerase. In C3H/HeJ syngeneic mice, as an in vivo model, tumor growth was suppressed and apoptosis was increased by EGCG. Our results suggest that EGCG may be a potential therapeutic agent to inhibit HGF-induced tumor growth and invasion in oral cancer.