FDG-PET in gynaecological cancers: recent observations

Hypermetabolic Calcified Lymph Nodes on 18Fludeoxyglucose-Positron Emission Tomography/Computed Tomography in a Case of Treated Ovarian Cancer Recurrence: Residual Disease or Benign Formation?

The contribution of positron emission tomography/computed tomography (PET/CT) with 18F-fludeoxyglucose (FDG) in evaluating ovarian cancer recurrence even after a prolonged disease-free interval, and in therapy response is well-described. Calcifications observed in CT, although usually attributed to benign conditions, may actually represent active disease. Such an example of calcified formations is psammoma bodies. We present a case of 56-y. o. patient with ovarian cancer relapse at the supraclavicular area 18 years after complete response and disease-free interval. The patient received chemotherapy and underwent 18F-FDG-PET/CT for the evaluation of treatment response. Both CT corrected and uncorrected PET images showed hypermetabolism in the massively calcified lymph nodes in the neck, mediastinum, axilla and abdomen, indicative of active residual disease.

Clinical evidence on PET-CT for radiation therapy planning in cervix and endometrial cancers

PET-CT plays an increasing role in the diagnosis and treatment of gynaecological cancers. In cervix cancer, whilst MRI remains the best imaging technique for initial primary tumor staging, PET-CT has been showed to be a highly sensitive method to determine lymph node status, except in patients with early-stage cervical cancer where PET-CT cannot replace surgical exploration of pelvic lymph nodes. In patients with advanced cervical cancer, PET-CT has the potential of showing lymph node metastasis not only within the pelvis, but also outside the pelvis, more particularly in the para-aortic area. PET-CT has also been described as a useful tool in 3-D-based adaptative brachytherapy. In endometrial cancer, the issues are different, as the recent decade has seen a therapeutic decrease in early-stage disease, especially in postoperative radiation therapy, whilst more advanced disease have been approached with more aggressive treatments, integrating chemotherapy and external beam radiotherapy. Lymph node status is also an important issue and PET-Scan may replace lymph node surgical procedure particularly in obese patients.

Positron emission tomography in ovarian cancer: 18F-deoxy-glucose and 16alpha-18F-fluoro-17beta-estradiol PET

The most frequently used molecular imaging technique is currently 18F-deoxy-glucose (FDG) positron emission tomography (PET). FDG-PET holds promise in the evaluation of recurrent or residual ovarian cancer when CA125 levels are rising and conventional imaging, such as ultrasound, CT, or MRI, is inconclusive or negative. Recently, integrated PET/CT, in which a full-ring-detector clinical PET scanner and a multidetector helical CT scanner are combined, has enabled the acquisition of both metabolic and anatomic imaging data using one device in a single diagnostic session. This can also provide precise anatomic localization of suspicious areas of increased FDG uptake and rule out false-positive PET findings. FDG-PET/CT is an accurate modality for assessing primary and recurrent ovarian cancer and may affect management. FDG-PET/CT may provide benefits for detection of recurrent of ovarian cancer and improve surgical planning. And FDG-PET has been shown to predict response to neoadjuvant chemotherapy and survival in advanced ovarian cancer. This review focuses on the role of FDG-PET and FDG-PET/CT in the management of patients with ovarian cancer. Recently, we have evaluated 16α-18F-fluoro-17β-estradiol (FES)-PET, which detects estrogen receptors. In a preliminary study we reported that FES-PET provides information useful for assessing ER status in advanced ovarian cancer. This new information may expand treatment choice for such patients.