Correlation Analysis Between Prognostic Nutritional Index Trajectory Categories and Radiotherapy-induced Severe Oral Mucositis in Head and Neck Cancer Patients Undergoing Radiotherapy.

Purpose: To establish the potential prognostic nutritional index (PNI) trajectory categories and examine the association between these PNI trajectory categories and severe radiotherapy-induced oral mucositis (RIOM).

Materials and methods: This was a longitudinal retrospective observational study on 470 head and neck cancer inpatients who were to undergo radiotherapy from a grade-A tertiary hospital in Hunan Province between July 2022 and October 2023. The latent class growth model and growth mixed model were used to identify PNI trajectory categories. Logistic regression analysis was used to examine the correlation between PNI trajectory categories and severe RIOM.

Results: Three PNI trajectory categories were identified: 'PNI high-level group' (20.9%), 'PNI medium-level group' (61.3%) and 'PNI low-level group' (17.9%). The risk of severe RIOM was statistically significantly higher in the 'PNI medium-level group' and 'PNI low-level group' with OR 2.174 (95%CI 0.980-4.822) and OR 3.45 (95%CI 1.212-9.815), respectively. PNI trajectory categories and cancer type were independent risk factors for severe RIOM.

Conclusion: PNI can be used as a biomarker to predict severe RIOM. Patients with head and neck cancer who have a lower PNI are at higher risk of severe RIOM.