Diagnostic value of 18F-fluoro-2-deoxyglucose positron emission tomography/computed tomography imaging in acral melanoma-predominant Asian patients.

Abstract

Tumor staging is crucial for melanoma, of which acral melanoma is the predominant subtype in Asians. 18F-fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) and 18F-FDG-PET/computed tomography (18F-FDG-PET/CT) serve as non-invasive imaging tools for tumor staging. However, the literature is scarce on the diagnostic value of PET for acral melanoma. From January 1, 2006, to November 30, 2022, a total of 352 patients were diagnosed with melanoma at our hospital. Of them, 90 were diagnosed with cutaneous melanoma and underwent preoperative PET/CT for staging and sentinel lymph node biopsy or complete lymph node dissection. Staging of PET/CT was confirmed by histopathology or following imaging. The lymph node biopsy, distant metastasis status, and PET/CT imaging results were analyzed. Of all the 90 patients with cutaneous melanoma, 72 of them were diagnosed as acral melanoma(80.0%). Compared with the histopathologic results, the lymph nodes were true-positive, true-negative, false-positive, and false-negative in 12, 54, seven, and 17 cases, respectively. The sensitivity of PET/CT for local lymph nodes was 41.4% (95% confidence interval [CI], 23.5-61.1%), while its specificity was 88.5% (95% CI, 77.8-95.3%). As for the detection of distal metastasis, the PET results were true-positive, true-negative, false-positive, and false-negative in six, 65, 15, and four cases, respectively. The sensitivity of PET for distal metastasis detection was 60.0% (95% CI, 26.2-87.8%), while its specificity was 81.3% (95% CI, 71.0-89.1%). Although non-invasive, PET/CT has relatively low sensitivity in regional lymph node evaluations and fair sensitivity in distal metastasis detection in Asian patients with acral melanoma. Thus, PET/CT may be more useful in patients with clinically palpable nodes or more advanced disease stage.