IMRT vs. 2D-radiotherapy or 3D-conformal radiotherapy of nasopharyngeal carcinoma : Survival outcome in a Korean multi-institutional retrospective study (KROG 11-06)

Abstract

OBJECTIVE: We compared treatment outcomes of two-dimensional radiotherapy (2D-RT), three-dimensional conformal radiotherapy (3D-CRT), and intensity-modulated radiotherapy (IMRT) in patients with nasopharyngeal carcinoma (NPC).

PATIENTS AND METHODS: In total, 1237 patients with cT1-4N0-3M0 NPC were retrospectively analyzed. Of these, 350, 390, and 497 were treated with 2D-RT, 3D-CRT, and IMRT, respectively.

RESULTS: 3D-CRT and IMRT showed better 5-year overall survival (OS) rates (73.6 and 76.7?%, respectively) than did 2D-RT (5-year OS of 59.7?%, all p?<?0.001). In T3-4 subgroup, IMRT was associated with a significantly better 5-year OS than was 2D-RT (70.7 vs. 50.4?%, respectively; p?≤?0.001) and 3D-CRT (70.7 vs. 57.8?%, respectively; p?=?0.011); however, the difference between the 2D-RT and 3D-CRT groups did not reach statistical significance (p?=?0.063). In multivariate analyses of all patients, IMRT was a predictive factor for OS when compared with 2D-RT or 3D-CRT, as was 3D-CRT when compared with 2D-RT.

CONCLUSION: Our study showed that 3D-CRT and IMRT were associated with a better local progression-free survival and OS than was 2D-RT in NPC. IMRT was significantly superior in terms of OS for advanced primary tumors (T3-4).