Clinical outcomes and prognostic factors of 582 nasopharyngeal carcinoma patients treated with intensity-modulated radiotherapy.

Abstract

5597 Background: To evaluate the 5-yrs clinical outcomes and prognostic factors of 582 nasopharyngeal carcinoma (NPC) patients treated with intensity modulated radiotherapy (IMRT). Methods: 582 NPC patients primarily treated with IMRT in Sichuan Cancer Hospital from Jan.2001 to Dec.2004 were analyzed retrospectively, including 460 males and 122 females. The prescription dose was delivered as follows: gross target volume (GTVnx) 67-76Gy in 30-33 fractions, positive neck lymph nodes (GTVln-R/L) 60-70Gy in 30-33 fractions, The lower neck and the supraclavicular fossae were irradiated with the conventional 2D technique using an anterior field. The Kaplan-Meier method was used to calculate the local-regional control rate (LRC) and overall survival rate (OS). Acute and late toxicities were graded according to the Radiation Therapy Oncology Group (RTOG) radiation morbidity scoring criteria, meanwhile analyze the prognostic factors. Results: The median follow-up interval was 66.4 months. The 5-year local control, regional control, distant metastasis-free survival, disease free survival, disease specific survival and overall survival rate was 89.8%, 95.2%, 74.1%, 69.6%, 83.2% and 77.1%. 133 patients died during the follow-up. The 5-year DMFS of IMRT and IMRT combined with chemotherapy was 62.1% and 70.9%, the OS of them was 75.9% and 79.1%. The incidence of grade 3 acute and late toxicity was 38.3% and 4.2% respectively.Univariate analysis revealed that gender, T/N stage, clinical stage, radiotherapy interruption, anemia and weight loss was the significant prognostic factor for the OS. Multivariate analysis showed that N stage, radiotherapy interruption, chemotherapy, the volume of GTVnx, age, anemia and weight loss was the independent prognostic factors for the OS. Conclusions: The 5-year local control and overall survival rate of NPC treating with IMRT was 89.8% and 77.1%. The clinical stage, N stage , volume of GTVnx and chemotherapy was the main prognostic factor for the OS. The acute and late toxicities were mainly grade I and II. Distant metastasis was the main pattern of failure.