Nasopharyngeal carcinoma is by far the most common malignant tumor of the nasopharynx. It is uncommon in the United States but very common in southern region of China accouting for over 18% of all cancers. It is also common in Taiwan. the new molecular imaging biomarker 68Ga-DOTA-NOC may potentially provide earlier and better management of undifferentiated Nasopharyngeal carcinoma.
Head Neck. 2015 Aug 14.
Khor LK1, Loi HY1, Sinha AK1, Tong KT2, Goh BC3, Loh KS4, Lu SJ5.[expand title=”Show Affiliations”]
1Department of Diagnostic Imaging, National University Hospital, Singapore.
2Department of Nuclear Medicine and PET, Singapore General Hospital, Singapore.
3Department of Hematology and Oncology, National University Hospital, Singapore.
4Department of Otolaryngology, National University Hospital, Singapore.
5Nuclear Medicine and PET Centre, Mount Elizabeth Hospital, Singapore.[/expand]
Increased somatostatin receptor (SSTR) expression in patients with undifferentiated nasopharyngeal carcinoma (NPC) has been demonstrated with receptor autoradiography, 111 In-Octreotide scintigraphy, and 68 Ga-DOTA-TOC positron emission tomography (PET)/CT imaging. We sought to compare and correlate the uptake of fluorodeoxyglucose (FDG) and DOTA-NOC in undifferentiated NPC to ascertain the possible role of 68 Ga-DOTA-NOC PET/CT as a new imaging biomarker and to assess whether targeted peptide receptor radionuclide therapy is a feasible treatment option.
After obtaining approval from our institutional review board, 4 patients with biopsy proven nonkeratinizing undifferentiated NPC who had just undergone routine staging/restaging 18 F-FDG PET/CT imaging were prospectively and consecutively recruited for 68 Ga-DOTA-NOC PET/CT imaging. Of these 4 patients, 3 were newly diagnosed with untreated NPC, whereas 1 patient was diagnosed with a case of recurrent NPC with previous treatment. These patients subsequently underwent 68 Ga-DOTA-NOC PET/CT within 10 days from the 18 F-FDG PET/CT to ensure lesion comparability. Tracer uptake in tumor lesions were assessed visually and semiquantitatively by measuring maximum standardized uptake values (SUVmax).
There were 12 FDG-avid lesions of which 7 showed avid uptake of DOTA-NOC greater than liver uptake, whereas 5 showed low uptake of DOTA-NOC less than liver uptake. Subset analysis of the FDG-avid lesions at the primary and recurrent sites showed that all the FDG-avid primary tumors in the nasopharynx showed avid uptake of DOTA-NOC. On the contrary, the case of recurrent NPC showed avid FDG uptake but low DOTA-NOC uptake. Subset analysis of the suspicious FDG-avid cervical lymph nodes showed that 50% of them demonstrated avid DOTA-NOC uptake greater than liver uptake, whereas the remaining demonstrated low-grade DOTA-NOC uptake less than liver uptake. The 2 subcentimeter cervical lymph nodes that showed low-grade uptake of FDG lower than mediastinal blood pool activity were deemed to be reactive/inflammatory and showed low-grade uptake of DOTA-NOC.
This study highlights the potential of 68 Ga-DOTA-peptide PET/CT as a new molecular biomarker for newly diagnosed undifferentiated NPC, and less so for recurrent NPC and metastatic nodes. This potentially opens up new diagnostic and therapeutic options in the management of undifferentiated NPC. © 2015 Wiley Periodicals, Inc. Head Neck, 2015.
© 2015 Wiley Periodicals, Inc.
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