Addition of intracavitary brachytherapy to external beam radiation therapy for T1–T2 nasopharyngeal carcinoma

Abstract

We compared efficacy and toxicity outcomes of patients with T1-T2 nasopharyngeal carcinoma (NPC) treated with external beam radiation therapy (EBRT) in combination with intracavitary brachytherapy (BT) vs. a historical cohort treated with EBRT alone. Of the 348 NPC patients diagnosed with T1-2N0-3M0 disease, 175 received EBRT+BT and 173 received EBRT alone. For the EBRT+BT group, median dose of EBRT was 58 Gy and median dose of BT was 20 Gy; for the EBRT group, median dose was 72 Gy (range, 60-82.4 Gy). Measured outcomes included 5- and 10-year local control (LC), regional failure-free survival, distant metastasis-free survival, disease-free survival, overall survival (OS), and late toxicity. Median followup duration was 120 months (range, 5-190). Ten-year OS and LC rates for the EBRT+BT and EBRT-alone groups were 71.7% vs. 49.9% and 94.0% vs. 85.2%, respectively (χ(2)=21.273, p= 0.000 for OS and χ(2)=4.684, p= 0.030 for LC). Late complication rates for EBRT+BT were generally lower compared with the EBRT-alone group except for nasopharyngeal ulceration or necrosis, where the rate was higher but not statistically significant. Both stage of disease at diagnosis and treatment techniques (i.e., the use of BT) were significant predictive factors for OS and LC. Intracavitary BT in combination with EBRT may improve the therapeutic ratio for T1-T2 NPC.