APOA1 and nasopharyngeal carcinoma: In summary, we observed that elevated serum ApoB/ApoA1 ratio is positively correlated with RN volume and negatively correlated with QOL, which indicated serum ApoB/ApoA1 ratio as an independent risk factor for RN volume and QOL in RN patients after radiotherapy for NPC, suggesting a bright intervention target in RN treatment.