Dose volume effects of re-irradiation for locally recurrent nasopharyngeal carcinoma.

BACKGROUND: This study analyzed the dose volume effects of re-irradiation for locally recurrent nasopharyngeal carcinoma (NPC) and attempts to determine the optimal dose for the best survival. METHODS: Ninety-one patients were studied. The local control, fatal complication, and overall survival were analyzed against the dose (in Equivalent Dose at 2 Gy/fractions) and recurrent gross tumor volume (GTV). RESULTS: The local control and fatal complication rate appear to increase with prescribed dose. The overall survival peaks at around 60 Gy10 . Local control decreases significantly with increasing GTV (P < .001) while overall survival shows similar trend (P = .06). No correlation was observed between the fatal complication rate and GTV volume. The dose response of local control appears to be stronger for smaller tumors. CONCLUSION: GTV volume plays a significant role in local control. A 60 Gy10 appears to be optimal for the best survival outcome; higher doses might be considered for small tumors.