<b><i>Introduction:</i></b> Glucose metabolism in cancer cells differs from noncancerous cells. The expression of transketolase-like protein 1 (TKTL1), a key enzyme in the glucose metabolism of cancer cells, predicts poor prognosis in several cancer types. We studied TKTL1 as a prognostic tool and whether TKTL1 expression correlates with 18F-FDG-PET-CT among patients with pancreatic ductal adenocarcinoma (PDAC). <b><i>Methods:</i></b> This retrospective study examined two PDAC patient cohorts: 168 patients operated on at Helsinki University Hospital between 2001 and 2011, and 20 patients with FDG-PET-CT results available from the Auria Biobank. We used immunohistochemistry for TKTL1 expression, combining results with clinicopathological data. <b><i>Results:</i></b> Five-year disease-specific survival (DSS) was slightly but not significantly better in patients with a high versus low TKTL1 expression, with DSS of 28.0 versus 17.3%, respectively (<i>p</i> = 0.123). TKTL1 served as a marker of a better prognosis in patients over 65 years old (<i>p</i> = 0.012) and among those with TNM class M1 (<i>p</i> = 0.018), stage IV disease (<i>p</i> = 0.027), or perivascular invasion (<i>p</i> = 0.008). <b><i>Conclusions:</i></b> Our study shows that TKTL1 cannot be used as a prognostic factor in PDAC with the exception of elderly patients and those with advanced disease. The correlation of TKTL1 with 18F-FDG-PET-CT requires further study in a larger patient cohort.
18F-FDG PET/CT versus Diagnostic Contrast-Enhanced CT for Follow-Up of Stage IV Melanoma Patients Treated by Immune Checkpoint Inhibitors: Frequency and Management of Discordances over a 3-Year Period in a University Hospital