Nasopharyngeal carcinoma with intracranial extension in the era of intensity-modulated radiotherapy: case–control study using propensity score matching method

The objective of the study was to evaluate long-term survival outcomes and toxicity of T4 classification nasopharyngeal carcinoma (NPC) with intracranial extension (IE group) or without intracranial extension (non-IE group) after intensity-modulated radiotherapy (IMRT) using the propensity score matching method. After generating propensity scores given the covariates of age, sex, N classification, and concurrent chemotherapy, 132 patients in each group were matched. The 5-year local failure-free survival rate and the 5-year overall survival rate in the IE group were lower than the patients in the non-IE group (74.6 vs. 88.9 %, p = .008; 51.1 vs. 71.9 %, p = .005). Grade 2 hypothyroidism was more common in the IE group (13.2 vs. 3.4 %, p = .029). For patients with T4 classification NPC after IMRT, patients with intracranial extension need more attention to the thyroid gland function and are more likely to experience local failure and death than patients without intracranial extension.