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We assessed the sensitivity of positron emission tomography (PET) for detecting synchronous multiple primary cancers, particularly synchronous esophageal cancers in head and neck cancer patients. We retrospectively reviewed 230 head and neck cancer patients. All the patients routinely underwent the following examinations: urinalysis, occult blood, tumor marker detection [squamous cell carcinoma (SCC), cytokeratin fragment (CYFRA), and carcinoembryonic antigen (CEA)], esophagogastroduodenoscopy, colonoscopy (when CEA was high or occult blood was positive), abdominal ultrasonography, plain chest computed tomography (CT), and PET. Bronchoscopy was performed when CT revealed lung shadow of central region. Synchronous multiple primary cancers were detected in 42 (18.2%) patients. The diagnostic sensitivity of PET for synchronous primary cancers was as follows: esophagus, 7.6% (1/13); stomach, 25.0% (2/8); lung, 66.7% (4/6); head and neck, 75.0% (3/4); colon, 0% (0/1); kidney, 0% (0/1); and subcutaneous, 100% (1/1). The sensitivity of PET for detecting synchronous esophageal cancers is low because these are early-stage cancers (almost stage 0-I). Therefore, it is necessary to perform esophagogastroduodenoscopy for detecting synchronous esophageal cancers. PET is an important additional tool for detecting synchronous multiple primary cancers because the diagnostic sensitivity of PET in synchronous head and neck cancer and lung cancer is high. But PET has the limitation of sensitivity for synchronous multiple primary cancers because the diagnostic sensitivity of PET in synchronous esophageal cancer is very low. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The aim of this study was to verify the effectiveness of positron emission tomography (PET) in detecting primary sites in carcinoma of unknown primary (CUP) patients. In this study, CUP represented a group of heterogeneous tumors that shared the clinical manifestation of metastatic carcinoma with no obvious primary site at the time of first diagnosis, which included clinical investigations, computed tomography, magnetic resonance imaging and panendoscopy. We reviewed the records of 24 patients with CUP between January 1995 and December 2009. The patients who demonstrated additional tracer uptake sites other than previously known metastatic lesions by PET scan were done direct biopsies for the sites of accumulation. Patients who had a negative PET scan or for whom the primary site could not be identified by direct biopsies underwent examination under anesthesia of the at-risk occult tumor sites. PET scan demonstrated focal accumulation suspicious for primary tumor in 12 (50.0%) of 24 patients: tonsil 5, nasopharynx 3, hypopharynx 1, tongue 1, larynx 1, and maxillary sinus 1. A subsequent biopsy of these sites revealed primary cancer in 9 (37.5%) of 24 patients: tonsil 5, nasopharynx 1, hypopharynx 1, tongue 1, and maxillary sinus 1. In the remaining three patients, no malignant cells were found by the biopsy of the accumulated area: nasopharynx 2, larynx 1. PET scans increase the yield of primary tumor by 37.5%. The sensitivity, specificity for PET scan were 80.8, 76.9%, respectively. PET scanning is useful in detecting primary cancer of CUP patients. [ABSTRACT FROM AUTHOR]