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.