engleski

THE UNSPECIFIC LYMPH NODE UPTAKE OF F-18-CHOLINE IN PATIENTS WITH PROSTATE CANCER

BACKGROUND: Prostate cancer is the most common malignancy in men in Europe and the US. F-18- choline PET/CT is considered as a particularly useful mechanism in several stages of patient care, but with the added information gained from revealing multiple pathophysiological processes, other sites of tracer uptake have been observed, especially in lymph nodes out of the pelvis. AIM: The aim of this study was to recognize, describe and evaluate the unspecific uptake of F-18- choline in patients with prostate cancer. METHODS: 39 patients (median age 73 y ; range 50-86) with prostate cancer (Tx-T3N2M1) were included in this study. They underwent F-18-choline PET/CT for staging or restaging of prostate cancer. Whole-body PET/CT was acquired 20 minutes after the F-choline administration (Siemens Biograph PET/CT ; mean activity administered 180 MBq, 3 minutes per bed position). The mean follow up period was 8 months. RESULTS: Unspecific accumulation of F-18-choline in lymph nodes was found in 17 patients (43.6%). Most of these findings (N=12, 30.7%) are nonspecific accumulation of the tracer in mediastinal lymph nodes. Other sites of unspecific tracer uptake were pulmonary hili (N=6, 15.5%), axillary lymph nodes (N=4, 10.3%) and inguinal lymph nodes (N=4, 10.3%). Mean SUV values for mediastinal lymph nodes, pulmonary hili, axillary and inguinal lymph nodes were 5.1, 5.3, 3.4 and 3.8, respectively. Mean SUV values were considerably lower than tracer uptake values measured in confirmed metastases sites (bone metastases mean SUV max value 12.9, metastatic lymph nodes mean SUV max value 9.1).CONCLUSION: F-18-choline PET/CT is a valuable and an established functional diagnostic imaging method for staging and restaging prostate cancer. However, uptake of the tracer can often be seen in lymph nodes not related to primary disease. Patient history, clinical examination, laboratory tests and correlation with other imaging methods, must be taken into consideration when interpreting F-18-choline PET/CT findings.

F-18-choline; prostate cancer; false positive uptake; pitfalls

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