Favorable Response to Intensity-Modulated Proton Therapy for Nasopharyngeal Non-Intestinal-Type Adenocarcinoma: A Case Report.

Sanda, Naoya; Sawabe, Michi; Yamashita, Yoriko; Iwata, Hiromitsu; Kawakita, Daisuke; Iwasaki, Shinichi · Head Neck · 2026

case_report · Level V

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Abstract

Nasopharyngeal non-intestinal-type adenocarcinoma (non-ITAC) is a rare malignancy of the nasopharynx. Here, we report a case of nasopharyngeal non-ITAC that showed a favorable response to intensity-modulated proton therapy (IMPT). A 56-year-old man presented with otitis media with effusion. Nasopharyngoscopy revealed a mass in the left nasopharyngeal wall, and biopsy confirmed low-grade non-ITAC. Imaging examinations showed no evidence of invasion or metastasis, and the tumor was staged as cT1N0M0. Given the risk of an insufficient deep margin with surgery, the patient underwent IMPT (64 GyRBE in 16 fractions). The patient developed acute treatment-related mucositis but successfully completed the planned treatment. Imaging confirmed complete remission of the tumor, and he remains disease-free after 2 years of follow-up. This case demonstrates successful management of nasopharyngeal non-ITAC treated with IMPT, suggesting it to be a promising option for inoperable tumors.