Background: Colorectal cancer (CRC) is the third most prevalent cancer in the world and is the second cause of cancer death. Positron emission tomography/computed tomography (PET/CT) using 18F-FDG is used for its staging and follow up.
Aim: To assess the occurrence of synchronous colonic and extracolonic tumors detected with contrast-enhanced F18-FDG PET/CT (PET/CTc) in patients with a recently diagnosed CRC.
Material and methods: PET/CTc of 210patients aged 16-91, years (63% men) with a recently diagnosed CRC were reviewed. PET/CTc with incidental findings, not expected to be due to CRC, were followed (laboratory, imaging and pathology) searching for synchronous tumors.
Results: Ten patients (4,7%) had a second synchronous CRC. Only 70% of synchronous CRC were accessible to colonoscopy, due mainly to incomplete procedures for stenotic tumors. Extracolonic synchronous neoplasms were detected in 12 patients (5,7%), namely lung cancer in three, renal cell carcinoma in two, non-Hodgkin lymphoma in two, pancreatic cancer in one, breast cancer in one, hepatocellular carcinoma in one, bladder cancer in one and thyroid cancer in one.
Conclusions: Ten percent of patients with a recently diagnosed CRC had a synchronic neoplasm detected at staging using PET/CTc.