2017 Section 7 Green Book

Review Clinical Review & Education

Use of FDG-PET/CT in Oropharyngeal Squamous Cell Carcinoma

Figure 2. Value of Positron Emission Tomography/Computed Tomography (PET/CT) in Detecting Distant Metastasis and Second Primary Cancer in Patients With Oropharyngeal Squamous Cell Carcinoma

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B

A and B, Axial fused PET/CT) images of initial scan of a man in his 60s with a diagnosis of poorly differentiated squamous cell carcinoma of the oropharynx. A, The PET/CT scan demonstrated an intensely fludeoxyglucose (FDG)-avid primary lesion (standard uptake value [SUV], 36.5) (blue arrowhead); fludeoxyglucose-avid metastasis to regional neck nodes (SUV, 11.8) (red arrowhead). B, Fludeoxyglucose-avid lung metastasis (SUV, 4.4) (arrowhead). C and D, Axial fused PET/CT image of initial PET/CT scan of a man in his 60s who presented with a mass in the right tonsil; PET/CT scan was performed for staging and evaluation for metastatic disease. C, The FDG PET/CT scan demonstrated an intensely FDG-avid lesion within the region of the right palatine tonsil (SUV, 9.3) (arrowhead). D, In addition, it revealed another moderately FDG-avid lung lesion (SUV, 7.45) (arrowhead) in the right upper lobe

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compatible with synchronous primary lung carcinoma, which biopsy proved to be an adenocarcinoma of the lung.

A population-based cohort study of 75 087 patients with head and neck SCC reported that the rate of developing second primary cancer in patients with OPSCC has decreased to the lowest levels of any subtype and claimed that this is because of the increasing rate of HPV-related OPSCC. 26 Gan et al 27 reported that smoking status (former, current, or nonsmoker) was an important factor in devel- oping a second primary cancer in patients with OPSCC, and Rodri- guez-Bruno et al 28 recommended not performing routine panen- doscopyfordetectionofsecondprimarytumorinpatientswhonever have smoked. In general, it seems that because of the increasing in- cidence of HPV-related OPSCC and the low rate of a second pri- mary cancer in this subgroup of patients, future studies are needed toprovide a guideline for secondprimary cancer screening inOPSCC according to HPV and smoking status (Figure 2C and D). Value of Contrast-Enhanced Head and Neck PET/CT in Staging The TNMstaging of OPSCC is an essential factor for determining sur- gical and radiation treatment strategies. Aside fromanatomic evalu- ation of the tumor with CT and MRI, assessment of metabolic fea- tures seems to be important for accurate staging of head and neck cancers. As noted, PET scan provides advantages over anatomic imaging in the assessment of the primary tumor and cervical me- tastasis; in addition, PET is capable of detecting distant metastasis or a second primary tumor, if present. Altogether, PET increases the accuracy of pretreatment staging of OPSCC. 4

It is known that PET alone or PET/CTwithout contrast does not provide sufficient anatomic detail for surgical planning. Krabbe et al 4 reported that performing a single PET/CT with contrast instead of a separate PET/CTwithout contrast and neck CTwith contrast in initial staging of OPSCC has several advantages, such as providing fully optimized head and neck CT, reduced radiation dose, de- creased false-positive results, and increased confidence for stag- ing. Other advantages are improved lesion conspicuity, precise tu- mor delineation, evaluation of resectability of primary lesions, and detection of distant metastasis such as liver metastases. These ad- vantages of PET/CT with contrast have been shown to change ini- tial oncological management compared with PET/CT without contrast. 29 In addition, it is less efficient to prepare 2 images sepa- rately andwrite 2 separate reports, and if 2 different radiologists re- port separately, the other physicians may see conflicting interpre- tations that could lead to treatment delay. 29 It has been shown that baseline contrast-enhancedPET/CTdecreases theneed for a supple- mentary contrast CT scan and can provide both high-quality ana- tomic and functional information in a single study. Today, it is rec- ommended that a single contrast-enhanced PET/CT study be performed for initial assessment and staging of patients with OPSCC. 29

Value of PET/CT in Therapy Planning for OPSCC Radiotherapy with or without chemotherapy is the mainstay of therapy for advancedOPSCC. To decrease the adverse effects of ra-

(Reprinted) JAMA Otolaryngology–Head & Neck Surgery January 2016 Volume 142, Number 1

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