Subsite- and histology-specific epidemiology of head and neck cancers in Japan from 2016 to 2019 - an application of a new classification of rare cancers

Sep 22, 2026

Head and neck cancers include diverse anatomical sites and histologies, but prior epidemiology often aggregated distinct entities or omitted rare cases, while cancer definitions changed with advances in pathology. Using the National Cancer Registry of Japan, this study builds a comprehensive list of head and neck epithelial tumors and sarcomas (excluding lymphoid diseases) for 2016–2019. Results estimate roughly 30,000 annual cases, identify common sites, and confirm most entities as rare. Incidence trends are interpreted alongside evolving classification systems.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages7

Reading Time18 min

AccessFree to download

Abstract

Introduction

Definitions and challenges

Japanese National Cancer Registry and prior classification

Patients and methods

Data sources and study population

Results

Conclusion

International Journal of Clinical Oncology (2026) 31:940–946 [https://doi.org/10.1007/s10147-025-02952-6](https://doi.org/10.1007/s10147-025-02952-6) Subsite‑ and histology‑specific epidemiology of head and neck cancers in Japan from 2016 to 2019: an application of a new classification of rare cancers Ryoko Rikitake1 · Yu Mizushima1 · Yoko Yamamoto1 · Takahiro Higashi1 · Toshihiko Sakai2 · Akira Kawai3 · Takahiro Asakage4 Received: 19 September 2025 / Accepted: 17 December 2025 / Published online: 10 April 2026 © The Author(s) 2026 Abstract Background Head and neck cancers comprise multiple anatomical sites. Due to their rarity, previous studies have often aggregated anatomically or histologically distinct cancers or excluded rare entities altogether. Moreover, the list of head and neck cancer entities has evolved along with the adoption of new pathological insights. Methods In our previous study, we proposed a new classification of rare cancers, based on the International Classification of Diseases for Oncology 3.2 coding system, using data from cancer patients at all sites recorded in the National Cancer Registry of Japan. In this study, we created a comprehensive list of head and neck cancers to improve the accuracy of epidemiological reporting using population-based data from 2016 to 2019. Lymphoid diseases were excluded, and only epithelial tumors and sarcomas were included in the analysis. Results In Japan, head and neck cancer accounts for approximately 30,000 cases annually, accounting for 2.9% of all cancer cases. The incidence of squamous cell carcinoma arising from the oral cavity and lip was 7.5 cases per 100,000 per year, which does not meet the criterion for a rare cancer. Other head and neck cancers were rare. The most frequent sites were the oral cavity and lip, followed by the larynx, hypopharynx, and oropharynx. The annual number of cases increased during the study period. Conclusion Most head and neck cancers were rare during the study period. This result highlights the importance of continued efforts to track incidence trends in parallel with evolving pathological definitions. Keywords Cancer statistics · Head and neck cancer · National cancer registry · Rare cancer · Oral cavity cancer * Takahiro Asakage[tasakage@gmail.com](tasakage@gmail.com) 1 Department of Public Health and Health Policy, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan 2 Department of Head and Neck Surgery, National Cancer Center Hospital, Tokyo, Japan 3 Rare Cancer Center, National Cancer Center Hospital, Tokyo, Japan 4 Department of the Head and Neck Surgery, Institute of Science Tokyo (Formerly Tokyo Medical and Dental University), 1-5-45 Yushima, Bunkyo-Ku, Tokyo 113-8519, Japan Introduction Head and neck cancers (HNCs) comprise a heterogeneous group of malignancies and collectively rank as the seventh most common cancer worldwide [1] . These cancers typically include malignancies of the oral cavity and lip, pharynx (nasopharynx, oropharynx, and hypopharynx), larynx, major salivary glands, nasal and sinuses, and middle ear, excluding thyroid cancer. Although squamous cell carcinoma of the oral cavity is relatively common, most HNCs are classified as rare due to their low incidence rates when assessed at individual anatomical sites with specific histologies. The anatomical and pathological diversity of HNCs has historically impeded unified epidemiological reporting, particularly the generation of detailed, subsite-specific data. Previous studies have often aggregated anatomically or histologically distinct cancers or excluded rare entities altogether, leading to inconsistent definitions and incomplete epidemiological interpretation [2] . A rare cancer is typically defined as one with an incidence of fewer than six cases per 100,000 persons per year, according to the project Surveillance of Rare Cancers in Europe (RARECARE) [3, 4] . However, the classification of HNC entities co

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What were the main findings about incidence and rarity from 2016 to 2019?

The study reports about 30,000 annual head and neck cancer cases (2.9% of all cancers). Most entities were rare, while the oral cavity and lip sites were the most frequent and some common squamous cell carcinoma did not meet rare-cancer criteria.

Sep 22, 2026

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