Yield of Computed Tomography at Baseline Staging of Melanoma

Current guidelines call for baseline imaging only for very high-risk (T4b) primary cutaneous melanomas.

To estimate the frequency of computed tomography (CT) at baseline staging of primary cutaneous melanoma and the diagnostic yield of CT; and to describe the types and frequencies of incidentaloma findings.

Cross-sectional study of cutaneous melanoma cases (tumor classifications Tis to T4bN0M0) attended between 2008 and 2014 in a specialized melanoma unit. Reports of CT scans performed during baseline staging were reviewed to determine the frequency of positive scan results, incidentaloma findings, unit cost for detection of metastasis, and factors associated with the decision to order CT.

CT results were available for 310 of the 419 patients included (73.99%). The tumor classifications were as follows: Tis, 17; T1, 137; T2, 71; T3, 48; and T4, 37. The CT results were negative in 81.61%, and incidentalomas were found in 18.06%. Additional primary tumors were found in 2 patients (0.64%), and metastasis was identified in one patient (0.32%). The cost of finding the case of metastasis was €71,234.90. A T2 tumor classification (odds ratio [OR], 8.73) and age under 70 years (OR, 3.53) were associated with greater likelihood of CT being ordered. Excision of the primary tumor in the melanoma unit (OR, 0.08) was associated with less likelihood of ordering CT.

The results for this patient series support current recommendations restricting CT at baseline to cases where there is high risk of metastasis (stagesiiC-iii).