Diagnostic Accuracy of Image-guided Biopsies for Diagnosis of Metastatic Melanoma in a Real-life Setting

Early detection of melanoma metastasis is essential in order to initiate treatment and improve patient prognosis. The aim of this study was to determine the diagnostic accuracy of different image-guided biopsy techniques in patients with melanoma. A cohort study of patients diagnosed with melanoma who had undergone image-guided biopsies (ultrasound-guided fine-needle aspiration cytology, ultrasound-guided core-needle biopsy, computerized tomography-guided fine-needle aspiration cytology and computerized tomography-guided core-needle biopsy) to detect melanoma metastasis between 2004 and 2021 was conducted. The reference standard was histological confirmation and/or clinical-radiological follow-up. Sensitivity, specificity, positive and negative predictive values were calculated. A total of 600 image-guided biopsies performed on 460 patients were included for analysis. Locoregional lesions represented 459 (76.5%) biopsies, and 141 (23.5%) were distant lesions. Of the included biopsies, 49 (8.2%) were insufficient for diagnosis. Overall, sensitivity and specificity were 92% (95% confidence interval 89–94) and 96% (95% confidence interval 91–99), respectively. Sensitivity sub-analyses revealed lower diagnostic accuracy values in the lung, inguinal lymph nodes, and computerized tomography-guided lesions under 1 cm. Limitations include spontaneous metastasis regression and arbitrary minimum follow-up period. Image-guided biopsies in patients with melanoma have high sensitivity and specificity for detection of regional or distant metastasis. Tissue type, location and tumour burden may influence the diagnostic accuracy of the test.