Esophagectomy for esophageal cancer in patients with a history of total pharyngolaryngectomy: a Japanese nationwide retrospective cohort study.

BACKGROUND: Second primary esophageal cancer often develops in patients with head and neck cancer, and esophagectomy in patients with a history of total pharyngolaryngectomy (TPL) is challenging. However, the clinical outcomes of these patients have yet to be examined in a multicenter setting. METHODS: We evaluated the surgical outcomes of a nationwide cohort of 62 patients who underwent esophagectomy for esophageal cancer with a history of TPL. RESULTS: Ivor-Lewis and McKeown esophagectomies were performed in 32 (51.6%) and 30 (48.4%) patients, respectively. Postoperatively, 23 patients (37.1%) developed severe complications, and 7 patients (11.3%) required reoperation within 30 days. Pneumonia and anastomotic leakage occurred in 13 (21.0%) and 16 (25.8%) patients, respectively. Anastomotic leakage occurred more frequently in the McKeown group than in the Ivor-Lewis group (46.7% vs. 6.2%, P < 0.001). The adjusted odds ratio for anastomotic leakage in the McKeown group was 9.64 (95% confidence intervals (CI), 2.11-70.82, P = 0.008). Meanwhile, the 5-year overall survival rates were comparable between the groups (41.8% for Ivor-Lewis and 42.7% for McKeown), and the adjusted hazard ratio of overall survival was 1.44 (95% CI, 0.64-3.29; P = 0.381; Ivor-Lewis as the reference). CONCLUSIONS: In our cohort, anastomotic leakage occurred more frequently after McKeown than Ivor-Lewis esophagectomy, and almost half of patients in the McKeown group experienced leakage. Ivor-Lewis esophagectomy is preferred for decreasing anastomotic leakage when oncologically and technically feasible.

Clinical, genomic and immune microenvironmental determinants of nivolumab response in head and neck squamous cell carcinoma.

Background: In view of improving biomarkers predicting the efficacy of immunotherapy for head and neck squamous cell carcinoma (R/M HNSCC), this multicenter retrospective study aimed to identify clinical, tumor microenvironmental, and genomic factors that are related to therapeutic response to the anti- Programmed cell death protein 1 (PD-1) antibody, nivolumab, in patients with R/M HNSCC. Methods: The study compared 53 responders and 47 non-responders, analyzing formalin-fixed paraffin-embedded samples using 14-marker multiplex immunohistochemistry and targeted gene sequencing. Results: Of 100 patients included, responders had significantly lower smoking and alcohol index, higher incidence of immune related adverse events, and higher PD-1 ligand (PD-L1) expression in immune cells as well as PD-L1 combined positive score (CPS) than non-responders. The frequency of natural killer cells was associated with nivolumab response in patients with prior cetuximab use, but not in cetuximab-naïve status. Age-stratified analysis showed nivolumab response was linked to high CPS and lymphoid-inflamed profiles in patients aged ≥ 65. In contrast, lower NLR in peripheral blood counts was associated with response in patients aged < 65. Notably, TP53 mutation-positive group had lower CPS and T cell densities, suggesting an immune-excluded microenvironment. Patients with altered tumor suppressor gene pathways, including TP53, CDKN2A, and SMAD4 mutations, had lower CPS, higher smoking index, and were associated with poor responses. Conclusion: Nivolumab treatment efficacy in HNSCC is influenced by a combination of clinical factors, age, prior treatment, immune environmental characteristics, and gene mutation profiles.

Incidence and risk factors associated with the development of hypothyroidism after postoperative chemoradiotherapy for head and neck cancer patients with high-risk features: Supplementary analysis of JCOG1008.

BACKGROUND AND PURPOSE: Hypothyroidism is a recognized late adverse event following radiotherapy for head and neck cancer (HNC). In the JCOG1008 trial, we treated patients with high-risk HNC with postoperative chemoradiotherapy. We aimed to elucidate factors associated with hypothyroidism by analyzing the JCOG1008 data. MATERIALS AND METHODS: In 2012-2018, 261 patients from 28 institutions were enrolled in JCOG1008. Thyroid function tests were conducted to assess hypothyroidism, including free thyroxine (FT4) and thyroid-stimulating hormone assays. Hypothyroidism was defined as Grade 2 or higher in CTCAE v4.0. Various clinical and dosimetric parameters were analyzed. In radiotherapy, there were no dose constraints for the thyroid. Multivariable analysis was conducted on these variables to identify predictive factors for hypothyroidism. RESULTS: The analysis included 162 patients (57 with 3D-CRT and 105 with IMRT), with a median follow-up of 4.7 years (0.3-9.3 years). Among these, 27 (16.7 %) developed hypothyroidism within 2 years after radiotherapy. In a multivariable analysis, the weekly cisplatin [OR=7.700 (CI: 1.632-36.343, p = 0.010)] and baseline FT4 [OR=0.009 (CI: <0.001-0.313, p = 0.010)] were significantly associated with hypothyroidism in the IMRT group. Regarding dosimetric characteristics, V60Gy [OR=1.069 (CI: 0.999-1.143, p = 0.054)] was potentially associated with the development of hypothyroidism. CONCLUSION: The study revealed that the incidence of hypothyroidism within 2 years after postoperative chemoradiotherapy for high-risk HNC was 16.7 % based on analytical results from prospective clinical trials.

Clinical benefits of combining oral cytotoxic chemotherapeutic agents with radiotherapy in patients with T2N0 glottic squamous cell carcinoma based on the reports of the Head and Neck Cancer Registry of Japan.

BACKGROUND: T2N0 glottic squamous cell carcinoma (SCC) typically responds well to radiotherapy (RT); however, achieving local control remains challenging. In cases of RT failure, total laryngectomy may be necessary. Improved local control and preservation of the larynx directly enhances patients' quality of life. Our retrospective analysis using the Japan Head and Neck Cancer Registry (JHNCR) aimed to compare the clinical benefits of RT and chemoradiotherapy (CRT) in patients with T2N0 glottic SCC. METHODS: Using data from the JHNCR (2011-2015), we included 1,231 patients with T2N0 glottic SCC. Among them, 346 received curative RT and 425 underwent curative CRT. The CRT group was further divided into the oral CRT (Oral CRT, N=120) and intravenous CRT (DIV CRT, N=305) groups. This study assessed local control rate (LCR), progression-free survival (PFS), and overall survival (OS). A 1:1 propensity score-matching analysis was used to adjust for patient characteristics. RESULTS: After matching, 105 pairs compared RT with Oral CRT, and 224 pairs compared RT with DIV CRT. The variables were well-balanced in the matched populations. In the matched populations, the Oral CRT group had significantly better 5-year LCR and PFS than the RT group (LCR, 89.4 % vs. 80.6 %, P=0.043; and PFS, 85.5 % vs. 72.3 %, P=0.025, respectively), while the DIV RT group had significantly better 5-year PFS than the RT group (80.1 % vs. 68.6 %, P=0.026). CONCLUSIONS: The clinical benefits of better local and disease controls were observed when oral chemotherapy was added to RT in patients with T2N0 glottic SCC. Thus, the significance of adding oral chemotherapeutic agents to RT in the treatment of T2N0 glottic SCC requires further prospective investigation.

Factors related to the surgical outcomes of type I tympanoplasty for tympanic membrane perforation in children.

BACKGROUND: Factors related to surgical outcomes of type I tympanoplasty for tympanic membrane (TM) perforation in children are controversial. OBJECTIVES: To investigate factors related to anatomical results of type I tympanoplasty for TM perforation 1 year after surgery. MATERIAL AND METHODS: We examined 68 ears. Anatomical results were determined based on the presence or absence of re-perforation, atelectasis, and otitis media with effusion. We retrospectively analyzed factors based on age (≤8 and >8 years), cause and size of TM perforation (<50% and ≥50%), history of asthma and cleft palate, and size of mastoid air cell system in bilateral ears before tympanoplasty. Audiological prognosis was evaluated in ears with anatomical success 1 year after surgery. RESULTS: Anatomical success was achieved in 80.9% (55/68) of the ears. No significant differences were observed between these factors and anatomical results. All children with cleft palate had anatomical success. Mean pure-tone average (0.5-4 kHz) was 16.25 dB HL for ears with both TM perforations <50% and ≥50%. CONCLUSION AND SIGNIFICANCE: We observed no significant relationship between factors considered and surgical outcomes. However, audiological prognosis was favorable for anatomical success regardless of TM perforation size. Accordingly, type I tympanoplasty is considered useful for TM perforation in children.

Human papillomavirus-driven head and neck cancers in Japan during 2008-2009 and 2018-2019: The BROADEN study.

There is limited understanding of epidemiology and time trends of human papilloma virus (HPV)-driven head and neck cancers (HNC) in Japan, especially outside of the oropharynx. To assess HPV-driven HNC, a non-interventional study (BROADEN) of HNC patients diagnosed in 2008-2009 and 2018-2019 was conducted in Japan. Adult patients with oropharyngeal, nasopharyngeal, laryngeal, hypopharyngeal or oral cavity cancers were included in this study. HPV was centrally tested using p16INK4a immunohistochemistry, HPV-DNA PCR and HPV E6*I mRNA. HPV attributability required positivity in at least two tests (p16INK4a immunohistochemistry, HPV-DNA PCR, HPV E6*I mRNA) in the oropharynx, and HPV-DNA and HPV E6*I mRNA positivity for non-oropharynx sites. Nineteen hospitals included a total of 1108 patients, of whom 981 had valid samples. Men accounted for 82% of HNC diagnoses. Patients in the earlier cohort were younger and included a higher percentage of smokers. There was an increasing trend of HPV-driven oropharyngeal cancer over the last decade, from 44.2% to 51.7%. HPV attribution in nasopharyngeal cancers was 3.2% in 2008-2009 and 7.5% in 2018-2019; and 4.4% and 0% for larynx respectively. In total, 95.2% of HPV-driven HNC were attributed to HPV genotypes included in the 9-valent HPV vaccine being HPV16 the most prominent genotype. These results suggest that an epidemiologic shift is happening in Japan, with a decrease in smoking and alcohol use and an increase in HPV-driven HNC. The increasing trend of HPV-driven HNC in Japan highlights the need for preventive strategies to mitigate the rise of HPV-driven HNC.

Transoral robotic surgery (TORS) in Japan: procedures, advantages and current status.

Transoral robotic surgery (TORS), introduced by Weinstein et al. in 2005, has been widely adopted as a minimally invasive procedure, particularly for the treatment of patients with early stage oropharyngeal cancer. TORS is typically performed using the da Vinci Surgical System, similar to robot-assisted surgeries for other malignancies. The main difference between TORS and these other robot-assisted surgeries is that it is performed through the natural orifice of the mouth, which limits the surgical working space, and that it progresses from the lumen of the pharynx to the deeper tissues. The advantages of TORS are mainly due to the benefits of using the da Vinci Surgical System, such as three-dimensional high-definition images, magnification, multiple forceps articulation, tremor-stabilization function and motion scale function. To date, many big data and meta-analyses have shown that TORS is superior to conventional surgeries, such as open surgery, in terms of oncological outcomes, post-operative functionality and quality of life. In Japan, TORS is expected to spread across the country, as it has been covered by health insurance since April 2022. This review highlights the procedures of TORS, its unique aspects, its unparalleled advantages as a minimally invasive surgery for treating laryngeal and pharyngeal cancers, and its current status in Japan.

Risk factors of secondary cancer in laryngeal, oropharyngeal, or hypopharyngeal cancer after definitive therapy.

BACKGROUND: Our previous research showed that a high rate of secondary carcinogenesis is observed during follow-up after transoral surgery in patients with early-stage laryngeal, oropharyngeal, and hypopharyngeal cancers. We speculate that the contributing factors are alcohol drinking, smoking, and aging; however, we could not provide clear evidence. In this study, we aimed to identify the risk factors for secondary carcinogenesis in patients with these cancers, particularly factors associated with drinking and/or smoking. METHODS: The medical records of all-stage laryngeal, oropharyngeal, and hypopharyngeal cancer patients who had undergone definitive treatment were retrospectively analyzed. Assessments included visual and endoscopic observations of the primary site, enhanced cervical CT or US of the primary site and regional lymph nodes, PET-CT, and enhanced whole-body CT. Clinical characteristics were compared in patients with and without secondary carcinogenesis and in patients with hypopharyngeal cancer and patients with other cancers. RESULTS: Hypopharyngeal cancer was an independent risk factor for secondary cancer. The 5-year incidence rate of secondary cancer was 25.5%, 28.6%, and 41.2% in laryngeal, oropharyngeal, and hypopharyngeal cancers, respectively. Radiotherapy was defined as an independent risk factor in hypopharyngeal cancer patients with secondary cancers. No direct correlation was found between secondary carcinogenesis and alcohol consumption, smoking, or aging. CONCLUSIONS: Patients with hypopharyngeal cancer require close follow-up as they are at high risk of developing secondary cancer, possibly because out-of-field radiation exposure may induce systemic secondary carcinogenesis in hypopharyngeal cancer patients with genetic abnormality induced by alcohol consumption.

Pre-treatment Tumor Size and Tumor Growth Rate as Prognostic Predictors for Patients With Recurrent/Metastatic Squamous Cell Carcinoma of the Head and Neck Treated With Nivolumab.

BACKGROUND/AIM: The prognosis of recurrent/metastatic squamous cell carcinoma of the head and neck (R/M SCCHN) is poor, although immune checkpoint inhibitors (ICIs), such as nivolumab, have been shown to prolong survival. We investigated the factors that predict the efficacy of nivolumab when selecting an appropriate treatment strategy for patients with R/M SCCHN. PATIENTS AND METHODS: Forty-four Japanese patients with R/M SCCHN treated with nivolumab between May 2017 and October 2021 were analyzed. The primary endpoint of the study was overall survival (OS). We defined pre-treatment tumor size (PTS) as the sum of the size of all measurable lesions, and tumor growth rate (TGR) as the total growth rate of the largest tumor diameter on CT scans taken to determine treatment response, divided by the interval between CT scans. Receiver operating characteristic (ROC) curves were used to identify the cutoff points of PTS and TGR for OS. Cox proportional hazards regression analysis was performed to examine the relationships between various factors, including patient characteristics, PTS, and TGR, as well as treatment outcomes. RESULTS: In multivariate analysis, Eastern Cooperative Oncology Group (ECOG) performance status (PS) score ≥1, progressive disease (PD) as best overall response (BOR), and TGR >0.60%/day were independent risk factors for poor OS in patients with R/M-SCCHN. CONCLUSION: Higher TGR, poor PS, and PD as BOR may be prognostic factors in patients with R/M SCCHN.

Impact of lymph node ratio and number of lymph node metastases on survival and recurrence in laryngeal squamous cell carcinoma.

INTRODUCTION: The aim of this study is to assess the impact of lymph node ratio (LNR) and number of positive lymph nodes (NPLN) on mortality and recurrence rates in patients with laryngeal squamous cell carcinoma. MATERIALS AND METHODS: We conducted a retrospective multicenter international study involving 24 Otorhinolaryngology-Head and Neck Surgery divisions. Disease-specific survival (DSS) and disease-free survival (DFS) were evaluated as the main outcomes. The curves for DSS and DFS according to NPLN and LNR were analyzed to identify significant variations and establish specific cut-off values. RESULTS: 2507 patients met the inclusion criteria. DSS and DFS were significantly different in the groups of patients stratified according to LNR and NPLN. The 5-year DSS and DFS based on LNR and NPLN demonstrated an improved ability to stratify patients when compared to pN staging. CONCLUSION: Our data demonstrate the potential prognostic value of NPLN and LNR in laryngeal squamous cell carcinoma.

P4HA1 Promotes Cell Migration and Colonization in Hypopharyngeal Squamous Cell Carcinoma.

BACKGROUND/AIM: This study aimed to identify key molecules associated with the survival of patients with hypopharyngeal squamous cell carcinoma (HpSCC) by combining in silico and in vitro analyses. MATERIALS AND METHODS: Differentially expressed genes (DEGs) were screened using the Gene Expression Omnibus database. For DEGs, we performed functional enrichment and protein-protein interaction network analyses to identify potential biological functions and hub genes. Functional analysis of HpSCC cell lines verified the critical roles of the hub genes. RESULTS: DEGs were associated with the extracellular matrix. Among the hub genes, high expression of prolyl 4-hydroxylase subunit alpha 1 (P4HA1) was significantly associated with shorter survival. In addition, P4HA1 knockdown inhibited cell migration and colonization. Suppression of cell proliferation was demonstrated using P4HA1-selective inhibitors. CONCLUSION: P4HA1 may be a useful therapeutic target for the treatment of HpSCC.

Effects of Pembrolizumab in Recurrent/Metastatic Squamous Cell Head and Neck Carcinoma: A Multicenter Retrospective Study.

BACKGROUND/AIM: Pembrolizumab exhibits anticancer efficacy in platinum-sensitive or platinum-unfit patients with recurrent/metastatic squamous cell carcinoma of the head and neck (R/M SCCHN). However, no large-scale retrospective real-world data are available. This retrospective study aimed to examine the efficacy and safety of pembrolizumab in multiple facilities. PATIENTS AND METHODS: Data of 167 patients with R/M SCCHN treated with pembrolizumab between December 2019 and February 2022 were analyzed. The endpoint was overall survival (OS), progression-free survival (PFS), and immune-related adverse events (irAEs). OS and PFS were analyzed comparatively with and without irAEs, and complete response (CR) or partial response (PR), and stable disease (SD) or progressive disease (PD) were compared. RESULTS: One hundred thirty-five patients received pembrolizumab alone, whereas the others received pembrolizumab with chemotherapy. For the pembrolizumab only group, the median OS and PFS were 22.7 and 5.1 months, respectively. There were significant differences in OS and PFS between CR or PR and SD or PD (p<0.01, p<0.01, respectively). For pembrolizumab with chemotherapy, the OS was not reached and median PFS was 7.0 months. There was a significant difference in PFS between CR or PR and SD or PD (p<0.01). There was a significant difference in PFS between patients with and without irAEs (p=0.02). CONCLUSION: The real-world therapeutic effect of pembrolizumab for R/M SCCHN was comparable to that observed in the KEYNOTE048 trial. In addition, irAEs and best overall response were considered as prognostic factors.

Effect of HER2-targeted therapy on PDX and PDX-derived organoids generated from HER2-positive salivary duct carcinoma.

BACKGROUND: We previously established a patient-derived xenograft (PDX) model, patient-derived organoids (PDOs), and PDX-derived organoids (PDXOs) for salivary duct carcinoma (SDC). Using these models, this study examined the therapeutic effect of human epidermal growth factor receptor 2 (HER2) blockade on HER2-positive SDC. METHODS: The therapeutic effect of lapatinib was assessed in SDC PDXOs with regards to cell growth, receptor/downstream signaling molecule expression, phosphorylation levels, and apoptosis. Effect of lapatinib treatment was evaluated in vivo in SDC PDX mice. RESULTS: The siRNA knockdown of HER2 and lapatinib suppressed cell proliferation in SDC PDXOs. Lapatinib inhibited the phosphorylation of HER2 and its downstream targets, and induced apoptosis in SDC PDXOs. Lapatinib also significantly reduced tumor volumes compared with that of the control in SDC PDX mice. CONCLUSION: For the first time, we demonstrated the efficacy of anti-HER2 therapy in HER2-positive SDC using preclinical models of SDC PDX and PDXO.

Fibrinogen-to-lymphocyte Ratio Predicts the Outcomes of Hypopharyngeal Squamous Cell Carcinoma Treated With Definitive Radiotherapy.

BACKGROUND/AIM: Previous studies have identified several inflammatory biomarkers that are useful as prognostic biomarkers for various cancer types. However, the fibrinogen-to-lymphocyte ratio (FLR) has not been addressed in head and neck squamous cell carcinoma. Here, we aimed to examine the value of pretreatment FLR as a prognostic marker in patients who received definitive radiotherapy for hypopharyngeal squamous cell carcinoma (HpSCC). PATIENTS AND METHODS: This retrospective study included 95 patients treated with definitive radiotherapy for HpSCC between 2013 and 2020. The prognostic factors for progression-free (PFS) and overall (OS) survival were identified. RESULTS: The optimal cut-off value of pretreatment FLR for discriminating PFS was 2.46. Based on this value, 57 and 38 patients were classified into groups with high and low FLR, respectively. A high FLR was significantly associated with advanced local disease and overall stage, and with the development of synchronous second primary cancer compared with a low FLR. The high FLR group had significantly lower PFS and OS rates than the low FLR group. Multivariate analysis showed that having a high pretreatment FLR was an independent prognostic factor for poorer PFS and OS [PFS: hazard ratio (HR)=2.14, 95% confidence interval (CI)=1.09-4.19, p=0.026; OS: HR=2.86, 95% CI=1.14-7.20, p=0.024]. CONCLUSION: The FLR has a clinical effect on PFS and OS in patients with HpSCC, suggesting that it has potential application as a prognostic factor for patients with HpSCC.

Establishment of experimental salivary gland cancer models using organoid culture and patient-derived xenografting.

PURPOSE: Depending on its histological subtype, salivary gland carcinoma (SGC) may have a poor prognosis. Due to the scarcity of preclinical experimental models, its molecular biology has so far remained largely unknown, hampering the development of new treatment modalities for patients with these malignancies. The aim of this study was to generate experimental human SGC models of multiple histological subtypes using patient-derived xenograft (PDX) and organoid culture techniques. METHODS: Tumor specimens from surgically resected SGCs were processed for the preparation of PDXs and patient-derived organoids (PDOs). Specimens from SGC PDXs were also processed for PDX-derived organoid (PDXO) generation. In vivo tumorigenicity was assessed using orthotopic transplantation of SGC organoids. The pathological characteristics of each model were compared to those of the original tumors using immunohistochemistry. RNA-seq was used to analyze the genetic traits of our models. RESULTS: Three series of PDOs, PDXs and PDXOs of salivary duct carcinomas, one series of PDOs, PDXs and PDXOs of mucoepidermoid carcinomas and PDXs of myoepithelial carcinomas were successfully generated. We found that PDXs and orthotopic transplants from PDOs/PDXOs showed similar histological features as the original tumors. Our models also retained their genetic traits, i.e., transcription profiles, genomic variants and fusion genes of the corresponding histological subtypes. CONCLUSION: We report the generation of SGC PDOs, PDXs and PDXOs of multiple histological subtypes, recapitulating the histological and genetical characteristics of the original tumors. These experimental SGC models may serve as a useful resource for the development of novel therapeutic strategies and for investigating the molecular mechanisms underlying the development of these malignancies.

Narrow-field supracricoid partial laryngectomy: Procedure development and initial clinical experiences.

OBJECTIVES: To evaluate the feasibility of narrow-field supracricoid partial laryngectomy with cricohyoidoepiglottopexy (NF-SCPL-CHEP). METHODS: Between 2019 and 2020, five patients with glottic cancers underwent NF-SCPL-CHEP. The mean durations of surgical drains, tracheostomy canula, and nasogastric tube use were evaluated. Length of stay following NF-SCPL-CHEP was compared with that of our open SCPL historical controls. A case summary is provided for the first patients, with detailed information about postoperative management and function. RESULTS: All five patients achieved uneventful postoperative recoveries without major complications. The average time for surgical drains, tracheostomy canula, and nasogastric tube use were 2, 15, and 46 days, respectively. The mean overall hospitalization period was 36 days for NF-SCPL-CHEP patients. The mean period of hospitalization based on our early experiences between 1997 and 2005 with classical open SCPL was 72 days. All patients were fully functional and local recurrences or distant metastases were not encountered during a mean observation period of 39 months. CONCLUSIONS: NF-SCPL-CHEP with 6 cm cervical access appeared technically feasible and oncologically sound in this initial clinical experience. An extra 2 cm incision, which enabled lateral neck dissection, was not felt to detract from the overall minimally invasive basis of NF-SCPL-CHEP. The clinical results were encouraging with limited complications and predictable postoperative recovery. The length of stay for patients undergoing NF-SCPL was half that of open SCPL historical controls. Less damages to local circulation may associate with the positive influences. Further study with a large patient sample across multiple institutions are needed to carefully evaluate long-term functional and oncological outcomes.

Head and neck small-cell carcinoma: A multicenter study of 39 cases from 10 institutions.

Objective: Basal information of head and neck small-cell carcinoma (HNSmCC) including epidemiology, primary site, treatment, and prognosis remains sparse due to its rarity. We report here a multicenter retrospective study on the diagnosis, treatment, and outcomes of patients with HNSmCC. Materials and methods: This study involved 47 patients with HNSmCC from 10 participating institutions. Eight patients were excluded for whom no pathological specimens were available (n = 2) and for discrepant central pathological judgements (n = 6). The remaining 39 patients were processed for data analysis. Results: As pretreatment examinations, computed tomography (CT) was performed for the brain (n = 8), neck (n = 39), and chest (n = 32), magnetic resonance imaging (MRI) for the brain (n = 4) and neck (n = 23), positron emission tomography-CT (PET-CT) in 23 patients, bone scintigraphy in 4, neck ultrasonography in 9, and tumor markers in 25. Primary sites were oral cavity (n = 1), nasal cavity/paranasal sinuses (n = 16), nasopharynx (n = 2), oropharynx (n = 4), hypopharynx (n = 2), larynx (n = 6), salivary gland (n = 3), thyroid (n = 2), and others (n = 3). Stages were II/III/IV-A/IV-B/IV-C/Not determined = 3/5/16/6/5/4; stage IV comprised 69%. No patient had brain metastases. First-line treatments were divided into 3 groups: the chemoradiotherapy (CRT) group (n = 27), non-CRT group (n = 8), and best supportive care group (n = 4). The CRT group included concurrent CRT (CCRT) (n = 17), chemotherapy (Chemo) followed by radiotherapy (RT) (n = 5), and surgery (Surg) followed by CCRT (n = 5). The non-CRT group included Surg followed by RT (n = 2), Surg followed by Chemo (n = 1), RT alone (n = 2), and Chemo alone (n = 3). The 1-year/2-year overall survival (OS) of all 39 patients was 65.3/53.3%. The 1-year OS of the CRT group (77.6%) was significantly better compared with the non-CRT group (31.3%). There were no significant differences in adverse events between the CCRT group (n = 22) and the Chemo without concurrent RT group (n = 9). Conclusion: Neck and chest CT, neck MRI, and PET-CT would be necessary and sufficient examinations in the diagnostic set up for HNSmCC. CCRT may be recommended as the first-line treatment. The 1-year/2-year OS was 65.3%/53.3%. This study would provide basal data for a proposing the diagnostic and treatment algorithms for HNSmCC.