PET/CT and radiotherapy in gynecological cancer

Molecular imaging, in particular, positron emission tomography (PET), has brought an additional dimension to management of patients with cancer and to radiation therapy planning. The combination of PET and computed tomography (CT) in a single system (PET/CT) to form an inherently fused anatomical and functional dataset has provided an imaging modality which could be used as the prime tool in the delineation of tumour volumes and the preparation of patient treatment plans, especially when integrated with virtual simulation. PET imaging (typically using ¹⁸F-FDG) can provide data on metabolically active tumour volumes. These functional data have the potential to modify treatment volumes and to guide treatment delivery to cells with particular metabolic characteristics. Depending on its sensitivity and specificity, ¹⁸F-FDG PET has been shown to influence the selection of target volumes also in gynecological cancer. The potential of such data from PET was recognized at an early stage and was integrated into the radiotherapy treatment for some gynecological malignancies. In particular ¹⁸F-FDG PET has been demonstrated to be useful in patients with cervical cancer candidate to radiotherapy; preliminary data suggest a potential use also in patients with endometrial cancer, uterine sarcoma and ovarian cancer. This paper reviews the state of the art of the integration of PET and PET/CT applications in radiotherapy, and the use of ¹⁸F-FDG PET in disease staging, patient selection, treatment planning and treatment evaluation in gynaecological malignancies, in particular in patients with cervical cancer, endometrial cancer, uterine sarcoma and ovarian cancer.