Diagnostic value of neck node status using 18F-FDG PET for salivary duct carcinoma of the major salivary glands

Abstract

(18)F-FDG PET and PET/CT have shown clinical usefulness in the initial staging and follow-up of patients with salivary malignancy. Therefore, we evaluated the utility of (18)F-FDG PET in preoperative staging, determining the extent of neck node involvement, and surgical planning for patients with salivary duct carcinoma (SDC) of the major salivary gland.

Methods: We evaluated 18 patients with SDC who were assessed by (18)F-FDG PET and CT before surgery. The sensitivity, specificity, accuracy, and predictive values of CT and PET/CT for predicting the primary tumor site and determining the extent of neck node involvement at each dissected neck level were evaluated by comparing imaging findings with pathologic nodal stage.

Results: The median maximum standardized uptake value of the primary lesions and cervical nodes were 4.7 (range, 1.8-12.1) and 5.8 (range, 1.7-13.0), respectively. The sensitivities of (18)F-FDG PET and CT for predicting the primary tumor site were 100% (18/18) and 94.4% (17/18), respectively. In analyzing cervical lymph nodes at 73 dissected neck levels, (18)F-FDG PET had a sensitivity of 76.1%, a specificity of 96.3%, a positive predictive value of 97.2%, and a negative predictive value of 70.3%; the corresponding values for CT were 39.1%, 92.6%, 90.0%, and 47.2%, respectively. The sensitivity and negative predictive value were significantly higher for (18)F-FDG PET than for CT (P < 0.001 and P = 0.03, respectively).(18)F-FDG PET determination of the extent of neck node involvement changed the neck dissection regimen in 5 patients (27.8%).

Conclusion: SDC of the major salivary gland is a highly metabolic tumor with high (18)F-FDG uptake. (18)F-FDG PET is useful for evaluating neck node status and for determining surgical planning in patients with major salivary gland SDC.