Limitations of PET and PET/CT in detecting upper gastrointestinal synchronous cancer in patients with head and neck carcinoma.

The aim of this study was to verify the effectiveness of PET (positron emission tomography) or PET/CT (fusion images of PET with computed tomography) in detecting synchronous cancer in patients with head and neck carcinoma. We reviewed 682 patients with carcinoma of the head and neck between January 2001 and December 2010. In 98 patients, 111 synchronous cancers were diagnosed. Of these 98 patients, the index cancer was predominantly located in the hypopharynx (47 cases), followed by the larynx (23 cases), oropharynx (12 cases) and the oral cavity (6 cases). Esophageal cancer was diagnosed as the most synchronous cancer (57 lesions), followed by gastric cancer (20 lesions), lung cancer (9 lesions) and head and neck cancer (8 lesions). Among these 98 patients, PET or PET/CT was performed in 82 patients. Of these 82 patients, PET or PET/CT detected 34 out of 94 (36.2 %) synchronous cancers. No significant difference was observed between PET and PET/CT in terms of lesion detectability (p = 0.21). Regarding synchronous T1 and Tis upper gastrointestinal (UGI) cancer, PET or PET/CT detected 4 out of 43 (9.3 %) of the cancers. No statistical difference in detectability was observed in patients who underwent PET or PET/CT scanning before or after histological examination of synchronous UGI cancer. In conclusion, synchronous cancer was most frequently observed in the UGI, especially in the esophagus in patients with head and neck carcinoma. PET and PET/CT have limitations in the detection of these lesions.