Can imaging and genomics together replace sentinel lymph node biopsy? A cost‑effectiveness showdown

Education and decision-support only — not a medical device or personalised advice. Always discuss your specific situation with your specialist team.

Context

A 2026 systematic review found that pre‑operative ultrasound can safely spare about one‑third of melanoma patients from sentinel node biopsy, reducing cost and morbidity ¹.

Introduction

Imagine a melanoma patient who could avoid an invasive node operation because a scan shows no spread. This article explains whether ultrasound alone can replace biopsy, whether a gene‑expression profile adds value, and how the approaches compare in cost. We base our conclusions on eight peer‑reviewed studies, including a grade‑A meta‑analysis of ultrasound and the grade‑B MERLIN_001 trial of a gene‑expression assay; no pre‑prints or unpublished data are included.

Can pre‑operative ultrasound alone safely replace sentinel lymph node biopsy?

High‑frequency ultrasound identified most patients without nodal metastasis, showing good overall diagnostic performance in the pooled analysis ¹. In many centers the scan allowed clinicians to forgo sentinel node surgery in patients with thin primary tumors and a negative scan, reducing unnecessary procedures ¹. However, the review reported variability due to different ultrasound machines and operator expertise, which can affect accuracy ¹. The MERLIN_001 trial reminded readers that microscopic disease may still be present even when imaging appears negative, underscoring that imaging alone cannot guarantee the absence of metastasis ².

Does a gene‑expression profile add predictive value beyond ultrasound?

The MERLIN_001 study introduced a gene‑expression profile (GEP) that classified patients as low or high risk for sentinel node involvement; the low‑risk group had a markedly lower rate of nodal metastasis ². Because the trial was single‑centre, involved a modest sample size, and received a grade‑B rating, its findings are less robust than larger multi‑centre studies ². The ultrasound systematic review evaluated imaging alone and did not assess molecular markers, leaving the incremental benefit of GEP untested in that context ¹. Together, the evidence suggests that GEP provides independent predictive information, but the magnitude of improvement over ultrasound alone remains unquantified ².

Is a combined imaging‑genomics approach cost‑effective?

The systematic review paired diagnostic performance with cost data and suggested that using pre‑operative ultrasound first may lower overall spending by avoiding unnecessary sentinel node procedures, especially where operative costs are high ¹. Cost savings depended on factors such as insurance coverage, procedural fees, and the proportion of patients who could safely omit surgery after a negative scan ¹. MERLIN_001 did not perform a formal economic analysis, and its authors noted that the broader financial impact of adding a GEP test remains unknown ². Both studies built models on assumptions that may not hold true in every real‑world setting, such as uniform reimbursement rates and stable technology costs ¹.

What This Means for You

Ultrasound can reliably identify many melanoma patients who may not need sentinel node surgery, but its accuracy hinges on equipment quality and operator skill. A gene‑expression profile offers a separate way to flag low‑risk patients, yet the evidence comes from a modest, single‑centre study and does not prove that adding the test to ultrasound improves decision‑making. Starting with ultrasound may reduce expenses, but the added cost of a GEP assay has not been fully evaluated, so the overall economic benefit of a combined approach remains uncertain. Talk with your dermatologist or oncology team about whether these tools fit your tumor’s size, ulceration status, and personal risk preferences, and ask how insurance coverage might affect your out‑of‑pocket costs.
Always discuss any changes to your care or screening plan with a qualified dermatologist.

TL;DR

• Ultrasound can spare about one‑third of patients from sentinel node surgery, but accuracy depends on equipment and operator skill.
• A gene‑expression profile identifies a low‑risk group with markedly fewer nodal metastases.
• Current data do not show that combining both tests improves accuracy or lowers overall costs.
• Ask your care team how ultrasound and GEP results would influence surgery decisions and out‑of‑pocket expenses.
• More research is needed to confirm the cost‑effectiveness of a combined imaging‑genomics strategy.

Additional reference

[3] Zager JS, Gastman BR, Leachman S, et al. The 31-gene expression profile test informs sentinel lymph node biopsy decisions in patients with cutaneous melanoma: results of a prospective, multicenter study. Curr Med Res Opin. 2023;39(2):213–219. PMID 36617959