Olfactory Rehabilitation in Total Laryngectomy Patients

Patients who undergo total laryngectomy often experience difficulties with their voice, olfaction, and taste due to the lack of airflow through nasal and oral cavities. While voice rehabilitation is more commonly performed, olfactory rehabilitation has gained importance in recent times with the use of various techniques. Previous studies have shown that incidence of hyposmia or anosmia (partial or total loss of smell) after total laryngectomy ranges from 25% to 100%. However, after olfactory rehabilitation, there has been notable improvement in olfaction, ranging from 46% to 88% of the patients. There are two main techniques for olfactory rehabilitation. The first involves creating airflow for smelling purposes by connecting the oral or nasal cavity to the tracheostoma using prosthetic laryngeal bypass devices. The second technique involves orofacial musculature training, which includes a nasal airflow-inducing maneuver known as the “polite yawning technique.” This maneuver creates negative pressure in the oropharynx, resulting in the induction of nasal airflow and potentially improving olfaction. Additionally, rehabilitation through biofeedback can facilitate airflow in the nasal cavity, further enhancing the sense of smell. In this review, we will introduce the principles, pathogenesis, and various techniques of olfactory rehabilitation, as well as summarize the outcomes of olfactory rehabilitation efforts.

Two Cases of Laryngomalacia With Congenital Vallecular Cyst Treated by Supraglottoplasty

Vallecular cyst consisted of a unilocular cystic mass of variable size arising from the lingual surface of the epiglottis and containing clear fluid is a rare occurrence in children. Although a cyst is benign, it may cause serious airway obstruction and even death if not treated appropriately. Also, laryngomalacia is the most common congenital anomaly that causes inspiratory stridor and airway obstruction in the newborn. Symptoms typically begin to appear at around 2 to 3 weeks of age and become worse between 4 and 8 months. With a review of literature, we report two cases of vallecular cyst with symptomatic laryngomalacia in a 1-month-old female and a 2-month-old male. Both patients experienced symptom relief after undergoing endoscopic supraglottoplasty.

Outcomes of Salvage Therapy for Oropharyngeal Cancer Recurrence Following Upfront Radiation Therapy and Prognostic Factors / Journal of the Korean Cancer Association, 대한암학회지

Purpose@#This study aimed to investigate the oncologic outcomes and prognostic factors of salvage treatments in patients with recurrent oropharyngeal squamous cell carcinoma (OPSCC) after radiotherapy (RT)-based treatment. @*Materials and Methods@#A cancer registry was used to retrieve the records of 337 patients treated with definitive RT or concurrent chemoradiotherapy (CRT) from 2008 to 2018 at a single institution. The poor-responder group (PRG) was defined as patients with residual or recurrent disease after primary treatment, and the oncologic outcomes for each salvage treatment method were analyzed. In addition, prognostic indicators of recurrence-free survival (RFS) and overall survival (OS) were identified in patients who underwent salvage treatment. @*Results@#After initial (C)RT, the PRG comprised 71 of the 337 patients (21.1%): 18 patients had residual disease, and 53 had recurrence after primary treatment (mean time to recurrence 19.5 months). Of these, 63 patients received salvage treatment (surgery 57.2%, re-(C)RT 23.8%, and chemotherapy 19.0%), and the salvage success rate was 47.6% at the last follow-up. The overall 2-year OS for salvage treatments was 56.4% (60.8% for the salvage surgery group and 46.2% for the salvage re-(C)RT). Salvage surgery patients with negative resection margins had better oncologic outcomes than those with close/positive resection margins. Using multivariate analyses, locoregional recurrence and residual disease after primary surgery were associated with poor outcome after salvage treatment. In Kaplan-Meier analyses, p16 status was significantly associated with OS in the initial treatment setting but not in the salvage setting. @*Conclusion@#In recurrent OPSCC after RT-based treatment, successful salvage was achieved in 56.4% patients who had undergone salvage surgery and radiation treatment. Salvage treatment methods should be selected carefully, given recurrence site as a prognostic factor for RFS.

Local Triamcinolone Injection and Oral Steroid in the Patients with Thyrohyoid Syndrome / 대한이비인후과학회지

Background and Objectives@#Thyrohyoid syndrome is rare disease characterized by unilateral chronic neck pain on hyoid bone area. Currently, local triamcinolone injection was widely used, but oral steroid treatment was rarely tried. We compared the oral steroid and triamcinolone injection for the thyrohyoid syndrome. Subjects and Method Patients who had unilateral pain and tenderness at thyrohyoid membrane were enrolled while excluding those with other diseases, such as gastroesophageal reflux, by physical exam and history taking. Patients were treated with oral steroid (n=15) and local triamcinolone injection (n=11); pain scores based on the pretreatment and post-treatment numeric rating scale (NRS)-11 were compared between the groups. @*Results@#Patients with thyrohyoid syndrome were comorbid with globus (42.3%), sore throat (19.2%), and radiating pain (15.4%). In the oral steroid group, posttreatment pain scores (4.0± 2.2) significantly improved (p=0.001) more than pretreatment pain scores (7.7±1.2). In the triamcinolone injection group, posttreatment pain scores (2.3±1.7) also significantly improved (p=0.003) more than pretreatment scores (7.5±1.4). None of the patients revealed treatment related complications. Pretreatment scores were not significantly different, but post-treatment scores wre significantly better in the triamcinolone injection group than in the oral steroid group (p=0.047). @*Conclusion@#Oral steroid treatment could be easily performed and have significant effects for patients with thyrohyoid syndrome. Local triamcinolone injection was more effective than oral steroid treatment.

Analysis of Failure Causes of Open Airway Reconstruction in Children With Combined Subglottic and Posterior Glottic Stenosis / 대한이비인후과학회지

Background and Objectives@#Airway reconstruction surgery in children is still challenging, especially in cases of combined subglottic and posterior glottic stenosis (PGS). The aim of this study was to review the underlying reasons of failure in open airway reconstruction surgeries performed for children with combined subglottic and PGS.Subjects and Method We reviewed medical records of seven children who received more than two open airway reconstruction surgeries to finally achieve and maintain decannulation status for more than one year. Twenty-two reconstructive surgeries were performed and they consisted of 19 laryngotracheal reconstruction (LTR), 2 cricotracheal resection with end-toend anastomosis (CTR) and one extended CTR. For each patient, the following potential causes of failure were evaluated; preoperative evaluation (PE), type of reconstruction (TR), single vs. double staging (SDS), type of stent (TS), and perioperative optimization (PO). @*Results@#The median age of patients at the time of surgery was 32 months (range, 4-64 months). Successful decannulation was achieved after the median open surgery of three (range, 2-5 times for each patient). Recognized causes of failure were as follows: 8 insufficient PE, 10 inadequate TR, 3 improper SDS, 8 ill-chosen TS, and 2 inappropriate PO. @*Conclusion@#PE of dynamic airway is important, especially vocal fold mobility and tracheomalacia. Types of reconstruction should be carefully decided after full consideration of potential causes of failure, and adequate laryngotracheal stent is essential.

Sublingual Gland Excision and Sclerotherapy for Plunging Ranula and Management of Recurrence / 대한이비인후과학회지

Background and Objectives@#For plunging ranula, excision of the sublingual gland has been the major treatment option, with sclerotherapy being widely used as minimal invasive treatment. We compared the outcomes of these two methods as an initial treatment for ranula and investigated the outcomes of salvage procedure in recurred patients.Subjects and Method Patients were classified into the excision group (n=35) and the sclerotherapy group (n=39) according to the type of their initial treatment. The outcomes of the initial and salvage treatment were determined as recurrence or non-recurrence at 3 months after treatment, and statistically compared between the excision and the sclerotherapy groups. @*Results@#Recurrence in the sclerothearpy group (n=20, 51.3%) showed a significantly higher rate (p<0.001) than in the excision group (n=3, 8.6%). Recurring patients who received treatment different from the initial treatment (n=7) were cured, while those who had same procedure as the initial treatment (n=11) showed recurrence of 72.7% (n=8). There was no procedure related complication among the patients. @*Conclusion@#Sublingual gland excision was more effective than ethanol sclerotherapy for the treatment of plunging ranula. In addition, sublingual gland excision was effective even after the failure of ethanol sclerotherapy.

A Case of a 16-Year-Old Patient With Chronic Invasive Aspergillosis in the Trachea Treated With Segmental Tracheal Resection and Cricotracheal Anastomosis

Chronic invasive aspergillosis is a life-threatening disease, especially in immunocompromised patients. The diagnosis and treatment of tracheal aspergillosis (TA) are challenging because of its rarity and nonspecific clinical presentations. The treatment standard of TA has been medical treatment like other forms of invasive aspergillosis, but patients with medically resistant TA require surgical intervention. We demonstrated a successful surgical outcome of chronic invasive TA in a 16-year-old patient with immunocompromised status related to acute myelocytic leukemia.

Analysis for Risk Factors and Effect of Vocal Hygiene Education in Patients of Vocal Polyp

Background and Objectives@#Vocal polyp is one of the most common benign diseases of vocal fold caused by overuse of voice. Laryngeal microsurgery is the first treatment of choice for vocal polyp. However, surgery has many risks such as side effects of general anesthesia, injury of tooth and psychological burden. And we often experience reduction of vocal polyps without surgical procedure. The purpose of study is to evaluate the effect of non-surgical treatment such as vocal hygiene education and proton pump inhibitor (PPI) in patients with vocal polyp.Materials and Method We performed retrospective study for seventy-three patients of vocal polyp who treated with non-surgical modalities such as vocal hygiene education and PPI over three months. Treatment outcomes and risk factors such as age, sex, polyp size, position, symptom duration, presence of laryngopharyngeal reflux (LPR) symptoms, smoking history, voice abuse history and vocal hygiene education were evaluated by comparison between polyp size improved group and non-improved group. @*Results@#5.5% of enrolled patients showed complete response and 23.3% showed partial response without surgery. Polyp size improved group significantly carried out more practice of vocal hygiene education treatment than the non-improved group (p=0.040). And the presence of LPR symptoms [hazard ratio (HR) 3.368, confidence interval (CI) 1.055–10.754, p=0.040] and not performing of vocal hygiene education (HR 3.664, 95% CI 1.078–12.468, p=0.038). @*Conclusion@#Vocal hygiene education can be a useful treatment option when making a decision to treat with vocal polyp.

Analysis for Risk Factors and Effect of Vocal Hygiene Education in Patients of Vocal Polyp

Background and Objectives@#Vocal polyp is one of the most common benign diseases of vocal fold caused by overuse of voice. Laryngeal microsurgery is the first treatment of choice for vocal polyp. However, surgery has many risks such as side effects of general anesthesia, injury of tooth and psychological burden. And we often experience reduction of vocal polyps without surgical procedure. The purpose of study is to evaluate the effect of non-surgical treatment such as vocal hygiene education and proton pump inhibitor (PPI) in patients with vocal polyp.Materials and Method We performed retrospective study for seventy-three patients of vocal polyp who treated with non-surgical modalities such as vocal hygiene education and PPI over three months. Treatment outcomes and risk factors such as age, sex, polyp size, position, symptom duration, presence of laryngopharyngeal reflux (LPR) symptoms, smoking history, voice abuse history and vocal hygiene education were evaluated by comparison between polyp size improved group and non-improved group. @*Results@#5.5% of enrolled patients showed complete response and 23.3% showed partial response without surgery. Polyp size improved group significantly carried out more practice of vocal hygiene education treatment than the non-improved group (p=0.040). And the presence of LPR symptoms [hazard ratio (HR) 3.368, confidence interval (CI) 1.055–10.754, p=0.040] and not performing of vocal hygiene education (HR 3.664, 95% CI 1.078–12.468, p=0.038). @*Conclusion@#Vocal hygiene education can be a useful treatment option when making a decision to treat with vocal polyp.

Endonasal Septal Perforation Repair: Free Mucosal Graft With Lyoplant® Bioscaffold

Nasal septal perforation (NSP) is a common complication of nasal surgery and can cause nasal obstruction, crust, and epistaxis. Many surgical methods have been introduced for repair of NSP, among which mucosal flap and artificial dermis have been widely used. However, mucosal graft can shrink and migrate and is difficult to fix at the perforation site. Mucosal advancement flap requires a wide extent of septal mucosa dissection, and artificial dermis can cause nasal obstruction because of its bulkiness and lower biocompatibility than autologous mucosa. To overcome these problems, we reported successful outcomes in 4 cases of small NSP by free mucosal graft with bioscaffold.

Developmental Outcome of Very-Low-Birth-Weight Infants without Major Brain Injuries Based on Data from the Korean Neonatal Network: A Nationwide Cohort Study

Purpose@#As preterm infants have shown advances in survival rate, many very-lowbirth-weight (VLBW) infants have shown developmental delay even without a major brain injury. Thus, the incidence of and risk factors associated with poor neurodevelopmental outcome should be evaluated. @*Methods@#A multicenter nationwide prospective longitudinal cohort study of VLBW infants born in South Korea between 2013 and 2015 was conducted. Poor neurodevelopmental outcome was diagnosed if the Bayley Scales of Infant and Toddler Development (BSID)-III composite score was ≤85 (cognition, language, motor). We analyzed the associations of baseline neonatal characteristics, environmental characteristics and neonatal morbidities with poor neurodevelopmental outcome. @*Results@#The study included 285 infants, of whom 34 (11.9%) exhibited cognition delay; 59 (20.7%), showed language delay and 32 (11.2%) showed motor delay. The mean gestational age and birth weight were 29 weeks and 1,130 g, respectively. Moderate and severe bronchopulmonary dysplasia (P=0.056) and intraventricular hemorrhage grade I (P=0.079) were marginally associated with cognition delay. Higher paternal educational level (P<0.05) was significantly associated with the language outcome. Birth weight (P<0.05) and head circumference at discharge (P<0.05) were the major predictors of motor delay. @*Conclusion@#The population-based nationwide cohort study shows that approximately 20% of VLBW infants without major brain injury have developmental delay. Several factors that are not directly associated with major brain injury were significantly associated with poor neurodevelopmental outcome.

Developmental Outcome of Very-Low-Birth-Weight Infants without Major Brain Injuries Based on Data from the Korean Neonatal Network: A Nationwide Cohort Study

Purpose@#As preterm infants have shown advances in survival rate, many very-lowbirth-weight (VLBW) infants have shown developmental delay even without a major brain injury. Thus, the incidence of and risk factors associated with poor neurodevelopmental outcome should be evaluated. @*Methods@#A multicenter nationwide prospective longitudinal cohort study of VLBW infants born in South Korea between 2013 and 2015 was conducted. Poor neurodevelopmental outcome was diagnosed if the Bayley Scales of Infant and Toddler Development (BSID)-III composite score was ≤85 (cognition, language, motor). We analyzed the associations of baseline neonatal characteristics, environmental characteristics and neonatal morbidities with poor neurodevelopmental outcome. @*Results@#The study included 285 infants, of whom 34 (11.9%) exhibited cognition delay; 59 (20.7%), showed language delay and 32 (11.2%) showed motor delay. The mean gestational age and birth weight were 29 weeks and 1,130 g, respectively. Moderate and severe bronchopulmonary dysplasia (P=0.056) and intraventricular hemorrhage grade I (P=0.079) were marginally associated with cognition delay. Higher paternal educational level (P<0.05) was significantly associated with the language outcome. Birth weight (P<0.05) and head circumference at discharge (P<0.05) were the major predictors of motor delay. @*Conclusion@#The population-based nationwide cohort study shows that approximately 20% of VLBW infants without major brain injury have developmental delay. Several factors that are not directly associated with major brain injury were significantly associated with poor neurodevelopmental outcome.

Risk Factor Analysis of Endoscopic Dilation Procedure for the Management of Subglottic Stenosis in Pediatric Patients

Background@#and Objective Endoscopic airway dilation is the primary treatment for pediatric subglottic stenosis (SGS) due to its feasibility and non-invasiveness. The aim of this study is to evaluate the risk factors for the failure of endoscopic airway dilation in pediatric patients with SGS. @*Materials and Methods@#This study reviewed medical records of 38 pediatric patients had endoscopic dilation from a single and tertiary referral center, retrospectively. The success of the endoscopic dilation procedure was defined as no dyspneic symptom without tracheostomy or laryngotracheal reconstruction. Demographic profiles, underlying disease, and Myer-Cotton SGS severity grade were recorded. Success rates and risk factors for the failure of treatment were analyzed. @*Results@#The SGS patients with severity grade I was most common. After mean 1.8 numbers of procedures, there were 23 patients (60.5%) in the success group and 15 patients (39.5%) in the failure group. Age, sex, underlying diseases, and SGS severity grade were not significantly different between two groups. In patients who had multiple endoscopic procedures, the failure group showed SGS deteriorated after procedures in 66.7%, compared to 11.1% of the success group. In multivariable analysis, a long-term intubation (≥1 month) was identified as an independent risk factor for failure of endoscopic dilation procedure. @*Conclusion@#Although endoscopic dilation procedure is safe and effective for the management, repetitive endoscopic dilation may not give clinical benefit in patient with long-term intubation. Other airway procedures must be considered in those group of patients.

A Novel Adenomatous Polyposis Coli Gene Mutation of Cribriform-Morular Variant Papillary Thyroid Carcinoma: A Case Report / 대한이비인후과학회지

Cribriform-morular variant papillary thyroid carcinoma (CMV-PTC) is a rare cancer that may arise in patients with familial adenomatous polyposis (FAP). Adenomatous polyposis coli (APC) gene mutation is associated with FAP, which is known as a premalignant lesion of colon cancer. In this report, we report a 16 years old patient of CMV-PTC comorbid with FAP, which was related with a new type of APC gene mutation.

Early Injection Laryngoplasty With a Long-Lasting Material in Patients With Potentially Recoverable Unilateral Vocal Fold Paralysis

OBJECTIVES: Injection laryngoplasty (IL) is one of the major options for treatment of unilateral vocal fold paralysis (UVFP). Early IL in patients with abrupt-onset UVFP can reduce hoarseness and aspiration-related discomfort and complications. Temporary or short-lasting materials are recommended for the early IL since permanent or long-lasting materials may negatively affect the voice quality when vocal fold motion is spontaneously recovered. METHODS: Patients who received IL with a long-lasting material (ArteSense) within 1 month following development of postoperative UVFP were enrolled for this study. They were categorized into a spontaneously recovered group (n=30) and unrecovered group (n=276) from UVFP. The subjective and objective voice parameters were collected before and 6 months after IL. Patients' demographics and collected voice parameters were compared between the two groups. RESULTS: Age and sex distributions were not different between the two groups. Aspiration symptom, maximum phonation time (MPT), jitter, shimmer, noise to harmonic ratio (NHR), overall grade (G) and breathiness (B) of GRBAS (grade of dysphonia, roughness, breathiness, asthenia, strain) scale score, and voice handicap index (VHI) were significantly improved after IL in both groups. The amounts of improvement in MPT, jitter, shimmer, NHR and VHI were significantly greater in the recovered group. There was no IL-related complication including granuloma formation, hypersensitivity to injection material, or worsening of hoarseness. CONCLUSION: Early IL with a long-lasting material can be safely performed to improve voice quality and to reduce aspiration episode for the patients with postoperative UVFP, regardless of recovery from the paralysis. The amounts of improvement in the subjective and objective voice parameters were significantly greater in patients who showed spontaneous recovery from UVFP when compared with those in patients who did not.

A Novel Adenomatous Polyposis Coli Gene Mutation of Cribriform-Morular Variant Papillary Thyroid Carcinoma: A Case Report / 대한이비인후과학회지

Cribriform-morular variant papillary thyroid carcinoma (CMV-PTC) is a rare cancer that may arise in patients with familial adenomatous polyposis (FAP). Adenomatous polyposis coli (APC) gene mutation is associated with FAP, which is known as a premalignant lesion of colon cancer. In this report, we report a 16 years old patient of CMV-PTC comorbid with FAP, which was related with a new type of APC gene mutation.

Various Clinical Presentation of Post-Transplant Lymphoproliferative Disorder in Head and Neck: A Case Series of 3 Patients / 대한이비인후과학회지

The outcome of solid organ and bone marrow transplantation has been dramatically improved with the development of immunosuppressive agent. However, the use of immunosuppressive agents could increase the risk of malignancies such as post-transplant lymphoproliferative disorder (PTLD). PTLD is regarded as the lymphoid malignancy of patients using immunosuppressive agents, and it could present diverse and non-specific symptoms. It involves various organs including the tonsil, adenoid, lymph node, and the brain. Because of its poor prognosis, an early suspicion of pathologic diagnosis is crucial for the treatment of PTLD. In this report, we demonstrate the case of three pediatric patients who had been treated for PTLD of various clinical presentations by early suspicion and pathologic diagnosis.

Comparison of Voice Outcomes between Medialization Thyroplasty and Arytenoid Adduction with or without Injection Laryngoplasty in Unilateral Vocal Fold Paralysis Patients

BACKGROUND AND OBJECTIVES: In unilateral vocal fold paralysis (VFP), medialization thyroplasty (MT), arytenoid adduction (AA) and injection layrngoplasty (IL) are the most common procedures to correct phonatory problems. There is no consensus that which procedure is superior to the other for correcting the glottal insufficiency. The purpose of this study was to compare the phonatory parameters between MT, AA and AA with IL (AA+IL) in patients with unilateral VFP. MATERIALS AND METHODS: This retrospective study enrolled patients from 2005 to 2016. Total 72 patients (49 male, 23 female, mean age 54.5 years) were classified into three groups ; MT (n=28), AA (n=12), and AA+IL (n=32). GRBAS scales, maximum phonation time (MPT), jitter, shimmer, noise to harmonic ratio (NHR), and voice handicap index (VHI)-10 and VHI-30 were preoperatively and postoperatively collected and compared between the three groups. RESULTS: Age, gender and cause of VFP were not significantly different between the three groups. In MT and AA groups, MPT, VHI, G (overall grade) and B (breathiness) were significantly improved. In AA+IL group, jitter, shimmer, NHR, MPT, VHI, G and B were significantly improved. In analysis of differences (pre-postoperative values), Δ jitter (p < 0.001), Δ shimmer (p=0.031), and Δ NHR (p=0.002) were significantly different and AA+IL group showed the greatest improvement. CONCLUSION: Analysis of voice parameters showed that all the three procedures for patients with unilateral VFP are effective in the improvement of voice ; especially in MPT, VHI-10, G and B scales. Compared to the others, AA+IL provided the better acoustic values including jitter, shimmer and NHR.

Comparison of Endoscopic Tympanoplasty to Microscopic Tympanoplasty

OBJECTIVES: This study aimed to compare the outcome of endoscopic and microscopic tympanoplasty. METHODS: This was a retrospective comparative study of 73 patients (35 males and 38 females) who underwent type I tympanoplasty at Samsung Medical Center from April to December 2014. The subjects were classified into two groups; endoscopic tympanoplasty (ET, n=25), microscopic tympanoplasty (MT, n=48). Demographic data, perforation size of tympanic membrane at preoperative state, pure tone audiometric results preoperatively and 3 months postoperatively, operation time, sequential postoperative pain scale (NRS-11), and graft success rate were evaluated. RESULTS: The perforation size of the tympanic membrane in ET and MT group was 25.3%±11.7% and 20.1%±11.9%, respectively (P=0.074). Mean operation time of MT (88.9±28.5 minutes) was longer than that of the ET (68.2±22.1 minutes) with a statistical significance (P=0.002). External auditory canal (EAC) width was shorter in the ET group than in the MT group (P=0.011). However, EAC widening was not necessary in the ET group and was performed in 33.3% of patients in the MT group. Graft success rate in the ET and MT group were 100% and 95.8%, respectively; the values were not significantly different (P=0.304). Pre- and postoperative audiometric results including bone and air conduction thresholds and air-bone gap were not significantly different between the groups. In all groups, the postoperative air-bone gap was significantly improved compared to the preoperative air-bone gap. Immediate postoperative pain was similar between the groups. However, pain of 1 day after surgery was significantly less in the ET group. CONCLUSION: With endoscopic system, minimal invasive tympanoplasty can be possible with similar graft success rate and less pain.

Prediction of Lymph Node Metastasis by Tumor Dimension Versus Tumor Biological Properties in Head and Neck Squamous Cell Carcinomas / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Lymph node metastasis (LNM) is a strong prognostic factor in many solid cancers, including head and neck squamous cell carcinomas (HNSCC), and LNM can be dependent upon primary tumor biology, as well as tumor dimension. Here, we investigate the relative risk of LNM in accordance to tumor dimension and biology in HNSCC subsites. MATERIALS AND METHODS: Medical data of 295 HNSCC patients who had undergone the initial curative surgery (oral tongue 174, oropharynx 75, hypopharynx 46) were analyzed to identify the significant predictive factor for LNM. Tumor volume and thickness were set as tumor dimensional variables, and biological variables included lymphovascular, perineural invasion, and tumor differentiation. Statistical analyses were conducted to assess the predictability of LNM from variables, and subgroup analyses according to the tumor subsites. In addition, we evaluated the impacts of tumor dimension and biological variables on the treatment outcomes and survival in HNSCC subsites. RESULTS: The overall tumor dimension and biological variables had a similar impact on the prediction of LNM in HNSCC (area under the curve, 0.7682 and 0.7717). The prediction sensitivity of LNM in oral tongue cancer was mainly dependent on tumor dimension, while LNM in oroand hypo-pharynx cancers was more influenced by biological factors. Survival analyses also confirmed that biological factor was more powerful in estimating disease-free survival of hypopharyngeal cancer patients, while tumor dimension was more significant in that of oral cancer patients. CONCLUSION: Tumor dimension and biology have a significant, tumor subsite-dependent impact on the occurrence of LNM and disease-free survival in HNSCC.