3D-CT implanted interstitial brachytherapy for T2b nasopharyngeal carcinoma

BACKGROUND To compare the results of external beam radiotherapy in combination with 3D- computed tomography (CT)-implanted interstitial high dose rate brachytherapy (ERT/3D-HDR-BT) versus conventional external beam radiotherapy (ERT) for the treatment of stage T2b nasopharyngeal carcinoma (NPC). METHODS Forty NPC patients diagnosed with stage T2b NPC were treated with ERT/3D-HDR-BT under local anesthesia. These patients received a mean dose of 60 Gy, followed by 12-20 Gy administered by 3D-HDR-BT. Another 101 patients diagnosed with non-metastatic T2b NPC received a mean dose of 68 Gy by ERT alone during the same period. RESULTS Patients treated with ERT/3D-HDR-BT versus ERT alone exhibited an improvement in their 5-y local failure-free survival rate (97.5% vs. 80.2%, P = 0.012) and disease-free survival rate (92.5% vs. 73.3%, P = 0.014). Using multivariate analysis, administration of 3D-HDR-BT was found to be favorable for local control (P = 0.046) and was statistically significant for disease-free survival (P = 0.021). The incidence rate of acute and chronic complications between the two groups was also compared. CONCLUSIONS It is possible that the treatment modality enhances local control due to improved conformal dose distributions and the escalated radiation dose applied.