Abstract
Cancer surveillance after 1980 has revealed that the incidence of second primary cancers (SPC) is 1.53-8.5% in patients with known malignant lesions and is being increased because of increasing population of elder patients and prolonged survival rate resultant from advanced effective treatment. Detection of SPC is important, since these cancers highly impact treatment algorithms. 2- [18F] fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) /CT scan enables systemic survey of malignant tumors and has been expected to be a powerful tool for detecting SPC. The present study analyzed SPC detected by FDG PET/CT scan in 3374 patients who underwent this scan to evaluate known or suspected first primary cancers at our institution. A total of 18 SPC in 17 patients, including 10 synchronous and 8 metachronous cancers in other organs, were detected by FDG PET/CT scan. These cancers were most frequently found in patients with head and neck cancers, and in the lung and stomach. 6 (35.2%) of these cancers were not identified prior to FDG PET/CT scan. 7 (41.1%) of these SPC were operable. FDG PET/CT scan can play an important role for non-invasively detecting SPC in various organs. The knowledge of primary cancers and organs which have a relative high incidence of SPC is important for interpretation of this examination.
