Imaging in Cutaneous Melanoma: Which Test to Order and When?

by Vishal Patel, MD, Brooke M. Su-Velez, MD, MPH, Kyle Hannabass, MD, and Maie A. St. John, MD, PhD •

TRIO Best PracticeTRIO Best Practice articles are brief, structured reviews designed to provide the busy clinician with a handy outline and reference for day-to-day clinical decision making. The ENTtoday summaries below include the Background and Best Practice sections of the original article. To view the complete Laryngoscope article, visit Laryngoscope.

Background

Cutaneous melanoma has a propensity for locoregional and distant metastatic spread and carries a high risk of recurrence, even when treated at early stages (J Natl Cancer Inst. 2011;103:129-142, Melanoma Res. 2003;13:183-188). About a quarter of all melanoma occurs in the head and neck. Sentinel lymph node biopsy for pathology is acknowledged to be the gold standard for staging, but the role of imaging is less clear (J Natl Cancer Inst. 2011;103:129-142). Imaging studies can help detect clinically occult disease and identify the presence of metastases and can thus play a critical role in staging and treatment decisions. Imaging can also help determine treatment response and can be an important asset in routine surveillance; however, the costs of routine imaging and choice of modalities remain controversial (J Natl Cancer Inst. 2011;103:129-142; Melanoma Res. 2019;29:53-58).

The National Comprehensive Cancer Network (NCCN) currently recommends no imaging for asymptomatic Stages I and II patients, the consideration of imaging for Stage IIIA, and further imaging only for clinically node-positive Stages IIIB and IIIC, with no specific recommended modalities, although options include ultrasound (US), computer tomography (CT), positron-emission tomography(PET)/CT, and magnetic resonance imaging, particularly for brain metastases (NCCN. Cutaneous Melanoma [version 2.2019]). No consensus currently exists regarding the use of imaging in surveillance. Here, we examine the literature to evaluate the proper indications for and best modalities of imaging for cutaneous melanoma.

BEST PRACTICE

Regarding staging for cutaneous melanoma, there is no evidence to suggest that imaging for distant metastasis should be performed for Stages I and II patients in the absence of localizing symptoms, consistent with current NCCN guidelines. Whole body imaging with PET/CT should be performed in Stages IIIB and IIIC patients with clinically positive nodes or positive sentinel nodes, also in line with NCCN recommendations. US has been demonstrated to be highly sensitive compared to physical examination of lymph nodes and can be considered a low-cost, low-risk part of primary imaging to assess for locoregional spread. In surveillance, US has been shown to be the most sensitive modality in detecting locoregional recurrence compared to other means and should be considered a low-risk adjunct tool in follow-up. It is important to note that US sensitivity can be variable depending on the experience of the US technician and the interpreting radiologist (Melanoma Res. 2003;13:183-188). CT and PET/CT seemed to be most effective in detection of distant recurrence; however, additional higher-level investigation is needed to see if survival benefits from early detection can offset the low positive predictive values and healthcare burden of the routine implementation of whole body studies.