Conventional 2D (2DRT) and 3D conformal radiotherapy (3DCRT) versus intensity-modulated radiotherapy (IMRT) for nasopharyngeal cancer treatment

Nasopharyngeal carcinoma represents a distinct entity as compared to other head and neck tumours. Radio-chemotherapy is the treatment of first choice in non-metastatic disease. Intensity-modulated radiation therapy (IMRT) allows the sparing of parotid glands, improving the toxicity profile. The aim of this study was to compare the results obtained with IMRT with those obtained with conventional 2D (2DRT) and 3D conformal radiation therapy (3DCRT) in terms of tumour control, survival, acute and late toxicity. We reviewed the clinical records of 52 patients with histologically proven carcinoma of the nasopharynx (stage I-IVB according to the 2002 American Joint Committee on Cancer staging system) treated with curative intent between January 2003 and August 2011: 26 patients were treated with 2D or 3D technique (arm A) and 26 with IMRT technique (arm B) with simultaneous integrated boost. Fifty patients (96 %) received chemotherapy. Local control (LC), locoregional control (LRC), disease-free survival (DFS), overall survival (OS), acute and late toxicity were retrospectively evaluated. After a median follow-up of 37.6 months (69 months in arm A and 23 months in arm B), 69 % of patients were alive and disease-free, 10 % were alive with disease and 21 % died of disease, with an OS of 81 % at 2 years and 79 % at 5 years, a LC rate of 88 % at 2 years and 78 % at 5 years, a LRC rate of 80 % at 2 years and 73 % at 5 years and a DFS of 74 % at 2 years and 65 % at 5 years, with no statistically significant differences between IMRT and 2DRT/3DCRT. In multivariate analysis, the TNM stage and the volume treated at high dose correlated with DFS. No factor was found to be related to OS. Chronic toxicity was not statistically different in the two study groups and in particular a parts per thousand yenG2 xerostomia rates were 67 and 41 % in arm A and B, respectively (p = 0.10). The findings of this study confirm that IMRT associated with chemotherapy, even with moderately hypofractionated regimens, allows good disease control with better results in terms of late xerostomia, although without statistically significant differences compared to 2DRT and 3DCRT. The hypothesis of an impact of IMRT on survival has yet to be confirmed.