Role of PET/CT in Treatment Planning for Head and Neck Cancer Patients Undergoing Definitive Radiotherapy

Background: In this study, we aimed to investigate the benefits of 18F-deoxyglucose positron emissiontomography/computed tomography (FGD-PET/CT) imaging for staging and radiotherapy planning in patientswith head and neck cancer undergoing definitive radiotherapy. Materials and
Methods: Thirty-seven headand neck cancer patients who had undergone definitive radiotherapy and PET/CT at the Uludag UniversityMedical Faculty Department of Radiation Oncology were investigated in order to determine the role of PET/CTin staging and radiotherapy planning.
Results: The median age of this patient group of 32 males and 5 femaleswas 57 years (13-84years). The stage remained the same in 18 cases, decreased in 5 cases and increased in 14cases with PET/CT imaging. Total gross tumor volume (GTV) determined by CT (GTVCT-Total) was increasedin 32 cases (86.5%) when compared to total GTV determined by PET/CT (GTVPET/CT-Total). The GTV of theprimary tumor determined by PET/CT (GTVPET/CT) was larger in 3 cases and smaller in 34 cases comparedto that determined by CT (GTVCT). The GTV of lymph nodes determined by PET/CT (GTVLNPET/CT) waslarger in 20 cases (54%) and smaller in 12 cases (32.5%) when compared to GTV values determined by CT(GTVLNCT). No pathological lymph nodes were observed in the remaining five cases with both CT and PET/CT.
Conclusions: We can conclude that PET/CT can significantly affect both pretreatment staging and assessedtarget tumor volume in patients with head and neck cancer. We therefore recommend examining such cases withPEC/CT before treatment.