Related Experiment Video
Updated: Feb 1, 2026

Dissection of the Auditory Bulla in Postnatal Mice: Isolation of the Middle Ear Bones and Histological Analysis
Published on: January 4, 2017
A retrospective multicenter study of carbon-ion radiotherapy for external auditory canal and middle ear carcinomas
Kazuhiko Hayashi1, Masashi Koto1, Yusuke Demizu2
1Hospital of the National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Sciences and Technology, Chiba, Japan.
Background:
We conducted a retrospective multicenter study to assess the clinical outcomes of carbon-ion radiotherapy (CIRT) for head and neck malignancies (Japan Carbon-Ion Radiation Oncology Study Group [J-CROS] study: 1402 HN). We aimed to evaluate the safety and efficacy of CIRT in patients with external auditory canal (EAC) and middle ear (ME) carcinomas.
Methods:
Thirty-one patients treated with CIRT at four Japanese institutions were analyzed. Fourteen patients (45.2%) had squamous cell carcinomas, 13 (41.9%) had adenoid cystic carcinomas, and four (12.9%) had other types. Nineteen (61.3%), six (19.4%), three (9.7%), and three (9.7%) patients had T4, T3, T2, and T1 disease, respectively. All patients had N0M0 status. The median radiation dose was 64 Gy (relative biological effectiveness) in 16 fractions. The median gross tumor volume was 33.3 mL.
Results:
The median follow-up period was 18.4 months (range, 5.1-85.6). The 1- and 3-year local control and overall survival rates were 75.0% and 55.0% and 79.3% and 58.7%, respectively. Regarding grade 3 or higher toxicities, three patients (9.7%) had grade 3 dermatitis, one (3.2%) had grade 3 mucositis, and two (6.5%) had grade 3 central nervous necrosis (ie, radiation-induced brain necrosis). No grade 4 or worse reactions were observed.
Conclusion:
CIRT was effective for EAC and ME carcinomas.
Related Concept Videos
The Carbon Cycle
Common Ion Effect
Hearing
Work Done on a System by External Force
In the presence of a non-conservative opposing force, like friction, some part of the work done...
Carbon Skeletons
Precipitation of Ions
The equation that describes the equilibrium between solid calcium carbonate and its solvated ions is:

