Is Ultrasound-Based Imaging Essential for Melanoma Active Surveillance?

BACKGROUND

Two landmark trials demonstrated that active surveillance with nodal ultrasound (US) yields equivalent oncologic outcomes to completion lymph node dissection (CLND) in sentinel lymph node (SLN)-positive melanoma. Yet, real-world adherence to US surveillance remains inconsistent, and its role alongside modern cross-sectional imaging is inadequately defined.

METHODS

In a retrospective cohort of SLN-positive adults diagnosed from 2017 to 2023 at an NCI-designated integrated health network, adherence to guideline-concordant surveillance was assessed for 2 years following definitive resection. We evaluated recurrence detection patterns and the diagnostic yield of biopsies prompted by each surveillance modality. Multivariable logistic regression identified predictors of surveillance adherence.

RESULTS

Among 240 patients, 223 (92.9%) were planned for active surveillance, while 17 (7.1%) underwent immediate CLND. Of surveillance patients, 55.3% and 88.0% underwent guideline-concordant US and cross-sectional imaging, respectively. Later diagnosis (2021-2023) predicted US adherence, while older age and head and neck tumors predicted lower use. During a median follow-up of 36.4 months, 77 patients (32.1%) developed recurrence, most commonly distant (n=29) or in the draining nodal basin (n=26), with fewer local (n=11) and in transit (n=11) recurrences. Cross-sectional imaging detected 50 recurrences (64.9%), including 27 distant and 17 nodal recurrences. US detected 6 (7.8%) and prompted more negative biopsies (n=11) than true positives (n=6).

CONCLUSIONS

Cross-sectional imaging was more consistently performed and diagnostically effective than nodal basin US. These findings highlight an opportunity to modernize surveillance programs, minimize excessive testing, and reexamine the strict application of MSLT-II trial protocols in contemporary practice.