Prospective longitudinal study of patient-reported dysphagia in nasopharyngeal carcinoma treated with intensity-modulated proton therapy.

Abstract

Purpose: To evaluate longitudinal changes in patient-reported dysphagia and identify its predictors in nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated proton therapy (IMPT).

Methods: Newly diagnosed, non-metastatic NPC patients were prospectively enrolled. The MD Anderson Dysphagia Inventory (MDADI) was administered at seven time points from baseline to 12 months post-IMPT. Primary endpoints included: (1) clinically significant decline (CSD), defined as a ≥10-point decrease in MDADI composite score from baseline to end of IMPT, and (2) no recovery to baseline (NRB) at 12 months. Clinical, sociodemographic, and dosimetric variables were analyzed.

Results: Of 58 patients, 49 completed MDADI assessments at all time-points. CSD occurred in 69 %, and NRB in 34 %. Patients with CSD had significantly higher mean doses to the oral cavity and superior pharyngeal constrictor muscle (S-PCM) (p < 0.05), while those with NRB had higher doses to the oral cavity, S-PCM, and middle PCM (M-PCM) (p < 0.01). After adjustment clinical and sociodemographic variables, independent predictors of CSD were mean dose to oral cavity (OR = 1.210) and S-PCM (OR = 1.249). Predictors of NRB included mean dose to oral cavity (OR = 1.268), S-PCM (OR = 1.211), and M-PCM (OR = 1.166). Limiting mean doses below 12.2Gy[RBE] (oral cavity) and 55.4Gy[RBE] (S-PCM) reduced CSD risk to <0.6 and NRB risk to <0.2, respectively; a dose below 36.1 Gy[RBE] (M-PCM) reduced NRB risk to <0.2.

Conclusion: Minimizing mean doses to the oral cavity, S-PCM, and M-PCM is crucial for reducing patient-reported dysphagia following IMPT in NPC patients.