Subgroups of parotid gland infiltrating ductal carcinoma benefit from postoperative radiotherapy: a population-based study

Aim: To analyze the prognostic factors and the impact of postoperative radiotherapy (PORT) in parotid gland infiltrating ductal carcinoma (IDC). Materials & methods: 252 patients diagnosed with parotid gland IDC were identified from the SEER database. Kaplan-Meier and Cox regression analysis was performed to evaluate the prognostic factors. Propensity score matching was applied then. Results: Multivariate analysis showed old age and chemotherapy were independent risk factors in parotid gland IDC. Subgroup analysis demonstrated that overall survival (OS) rate of the PORT group was significantly superior to that of the no radiotherapy group in the T3-4 subgroup (p=0.049), N1 subgroup (p=0.019) and Tumor, Node, Metastasis (TNM) III subgroup (p=0.025). Conclusion: PORT improved survival of parotid gland IDC patients within T3-4, N1 and TNM III subgroups.