Clinical outcomes of IMRT planned with or without PET/CT simulation for patients with pharyngeal cancers

Clinical results of computed tomography (CT) simulations and [¹⁸F]-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET)/CT simulations were compared retrospectively.

Between 2006 and 2011, [¹⁸F]-FDG PET/CT simulation was performed on 68 consecutive patients with pharyngeal cancers (PET/CT group). As an historical control, conventional CT simulation was performed on 56 consecutive patients with pharyngeal cancer between 2000 and 2006 (CT group). In the PET/CT group, the primary sites were nasopharynx (NPC), oropharynx (OPC), and hypopharynx (HPC) in 35, 20, and 13 patients, respectively; in the CT group, the primary sites were NPC, OPC, and HPC in 21, 17, and 18 patients, respectively. All but five patients in the PET/CT group were treated with intensity modulated radiation therapy (IMRT).

In the PET/CT group, TNM and clinical stages changed in 11 (16 %) and eight (12 %) patients, respectively. Although the 5-year overall survival (OS) rates for the PET/CT and the CT groups were 80 and 64 %, respectively (p = 0.0420), this result may be attributable to the background difference between the two groups. Similarly, the 5-year locoregional control rates of the two groups were 82 and 70 %, respectively (p = 0.0501). Notably, marginal recurrences around the planning target volume (PTV) were only noted in four CT group patients.

PET/CT simulation was useful for delineating an accurate clinical target volume (CTV) of pharyngeal cancer, and its clinical results were satisfactory.