Post-irradiation Sinus Mucosa Disease in Nasopharyngeal Carcinoma Patients Treated With Proton Therapy

Objective: Post-irradiation sinonasal mucosa disease (SMD) is observed in patients with nasopharyngeal carcinoma (NPC) treated with radiotherapy (RT), leading to a detrimental impact on quality of life. This study aimed to assess the incidence, severity, and regression of the post-irradiation SMD among patients with NPC treated with proton therapy.

Methods: NPC patients treated with proton therapy were retrospectively enrolled. The incidence of SMD was detected using scheduled follow-up magnetic resonance images. The severity of SMD was evaluated using the Lund-Mackay (L-M) staging system. Localized inflammation of the nasopharynx was measured with the endoscopy score.

Results: A total of 161 NPC patients were recruited. The incidence of SMD significantly increased from the third month to the first year after RT. The severity of SMD gradually decreased over time. Regression analyses showed that patients with pre-treatment SMD (OR = 1.75; p = 0.005) and lower serum total protein (OR = 0.16; p = 0.01) were associated with persistence of SMD at 2 years post-RT. Correlations were observed between post-RT L-M and endoscopy scores (r_s = 0.239, p < 0.001). A high endoscopy score (cut-off value, 1.5 [sensitivity, 87.5%; specificity, 49.2%]) predicted the persistence of SMD.

Conclusions: Proton therapy in patients with NPC induces SMD, which peaked at 3 months post-RT, decreased gradually with time, and became insignificant at 2 years post-RT. Pre-existence of SMD and lower serum total protein levels were factors associated with the persistence of post-irradiation SMDs.

Level of evidence: 4 Laryngoscope, 2024.