Malignancies of the Upper Gastrointestinal Tract
Contrast-enhanced CT of chest and abdomen is the first-line procedure for staging of esophageal cancer. As CT is affected by a low accuracy in reliably detecting lymph node metastases, 18F-FDG PET/CT has a relevant additional contribution in this setting, although it cannot operate in distinguishing different T stages. Having been reported false-positive results in inflammatory/infective lesions, false-negative results, also at the level of lymph node metastases, may be related not only to little masses, but also to lesions showing a low FDG’s uptake . PET/CT plays an important implemental role in defining N stage, especially when analyzed together with endoscopic ultrasounds (EUS). Furthermore, also because of the complementary contribution of CT, 18F-FDG PET/CT is the best predictor of M stage, involving lungs and liver and, more rarely, pleura, muscles, and skeleton [2, 3]. For all the reasons above, 18F-FDG PET/CT may change the management in up of 38% of patients diagnosed with esophageal cancer , having the capability to upstage the disease in approximately 20% of the subjects with respect to CT/EUS, taken alone [2, 3]. Therefore, PET/CT may be considered mandatory in precluding highly destroying and expensive curative surgery, mainly in patients with a high probability of distant metastases, although negative at CT/EUS. From recent studies, the association of PET and EUS is emerging as more cost effective with respect to CT and EUS to decide the therapeutic strategy after diagnosis . More recently, a greater interest is growing on FDG’s capability to allow a “textural feature analysis,” based on the evaluation of intra-tumoral uptake’s heterogeneity. This information could define various patterns predicting a diverse response to chemoradiotherapy . Interesting results, mainly in the evaluation of T and locoregional disease, could also be achieved by PET/MRI; unfortunately, this new tool is negatively affected by high costs and scarce diffusion, creating difficulties in reaching a cost-effectiveness justifying its use in the clinical practice .
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