INTENSITY MODULATE RADIOTHERAPY OR OLDER RADIATION TECHNIQUES FOR NASOPHARYNGEAL CANCER: DOES THE OUTCOMES DEPEND ON WHERE PATIENTS ARE LIVING?

Purpose: To compare the efficacy in terms of local control (LC) and survival (OS) of intensity modulate radiotherapy (IMRT) with conventional (2D) or conformational (3D) radiotherapy for nasopharyngeal cancer from endemic or non-endemic area. Materials and Methods: Records of patients from our institutional database were retrospectively assessed. A paired comparison analysis was used to evaluate the oncological outcomes between patients treated with IMRT or 2D3D RT (control). The endpoints were LC, and OS. A systematic review of the literature and meta-analysis was also performed to evaluate LC, and OS. Results: Our cohort included 57 patients, 29 IMRT and 28 3DRT in each Group. The median followup time was 48 months. IMRT produced better local control rate (85 vs. 60 %, p = 0.01) with no impact on OS (52 vs. 58 %, p = 0.92). The meta-analysis included 8 retrospective studies (12771 patients), 6 from endemic and 2 from non-endemic areas revealed that IMRT had a higher LC (OR=2; CI=1.7-2.3, p=0.004) independently of subgroup area. However, the IMRT had better OS only for NPC from endemic areas (OR=1.46; CI=1.3-1.6, p=0.0001). Conclusions: IMRT is the better technique to treated locally advanced NPC in patients from endemic or non-endemic area. The survival benefit from IMRT treatment for NPC detected in the meta-analysis was restricted only to patients from the endemic area and can be related to differences of histological subtypes.