Potential improvement of tumor control probability by induction chemotherapy for advanced nasopharyngeal carcinoma

Abstract

Purpose: To assess the reduction of tumor bulk and improvement of tumor control probability (TCP) by using induction chemotherapy for advanced nasopharyngeal carcinoma (NPC). Materials and methods: From February to December 2005, 20 patients with Stage III-IVB NPC were treated with induction-concurrent chemotherapy and intensity-modulated radiotherapy with accelerated fractionation. Combination of cisplatin and 5-fluorouracil was used in the induction phase and single agent Cisplatin in the concurrent phase. All patients were irradiated at 2 Gy per fraction, 6 daily fractions per week, to a total dose of 70 Gy. Results: Nineteen (95%) patients completed all 3 cycles of induction chemotherapy and 90% had ≥2 cycles of concurrent chemotherapy. Induction chemotherapy achieved significant down-staging of T-category in 35% of patients (p = 0.016) and reduction of gross tumor volume (GTV_P) from 55.6 to 22.9 cc (mean 61.4%, p < 0.001). Although the mean radiation dose did not show any substantial change, the volume within GTV_P that failed to reach 70 Gy was reduced from 10.2% to 3.8% (p = 0.017). The estimated local TCP increased from 0.83 to 0.89 (p = 0.002). Conclusions: Induction chemotherapy using cisplatin-5-fluorouracil could significantly reduce tumor bulk leading to potential improvement in tumor control. © 2008 Elsevier Ireland Ltd. All rights reserved.