EADV 2026: DecisionDx-Melanoma Data Support Risk-Based SLNB Decisions in Cutaneous Melanoma

New prospective data presented at the European Academy of Dermatology and Venereology (EADV) Congress 2026 suggest that gene expression profiling may help clinicians refine sentinel lymph node biopsy (SLNB) decisions and identify patients with cutaneous melanoma whose recurrence risk may not be fully captured by conventional staging.

Results from a prospective, multicenter study of 2,799 patients across 29 US centers showed that the ingetegrated 31-gene expression profile (i31-SLNB) identified a group of patients with a less than 5% predicted risk of sentinel lymph node (SLN) positivity. Among SLNB-eligible patients with low-risk results who did not undergo the procedure, 5-year recurrence-free survival (RFS) was 99.6%.

The late-breaking findings were presented in abstract LB-339, “The integrated 31-gene expression profile (i31-SLNB) identifies patients with a low risk of sentinel lymph node positivity and 31-GEP identifies patients with high 5-year recurrence risk: The largest prospective, multicenter study of GEP for cutaneous melanoma.”

Refining SLNB Risk

Among 676 patients who underwent SLNB and had an i31-SLNB result, patients categorized as having a low predicted risk of SLN positivity—defined as less than 5%—had an observed positivity rate of 4.4%. In comparison, patients with a predicted risk greater than 10% had an observed SLN positivity rate of 22.8%.

Investigators also evaluated 565 SLNB-eligible patients with low-risk i31-SLNB results who did not undergo SLNB. Five-year RFS in this population reached 99.6%, providing prospective outcome data for patients in whom the procedure was avoided.

Together, the findings suggest the molecular risk assessment could provide additional information when clinicians and patients are considering whether the potential value of SLNB warrants undergoing the procedure.

“Staging is an essential starting point, but understanding a patient's tumor biology can help us make more informed recommendations about sentinel lymph node biopsy and follow-up care,” Joseph Gadzia, MD, study author and board-certified dermatologist and Mohs micrographic surgeon at Kansas Medical Center in Topeka, Kansas, said in a news release.

Gadzia added that the favorable outcomes observed among patients with low-risk i31-SLNB results who did not undergo biopsy may provide clinicians with greater confidence when incorporating the test into shared decision-making.

Identifying Recurrence Risk Beyond Stage

The study also evaluated the ability of the DecisionDx-Melanoma 31-gene expression profile (31-GEP) Class result to stratify 5-year recurrence risk.

The analysis found significant differences in recurrence risk according to molecular classification, including among patients with early-stage disease. Patients with stage I to IIA melanoma who received a high-risk Class 2B result had RFS comparable with that of patients with stage IIB disease.

According to the investigators, these findings suggest that molecular risk information could help identify patients whose risk may be underestimated by traditional staging and who may warrant closer surveillance or consideration of additional management strategies.

Gene Expression Profiling in Transected Melanoma

Separate EADV 2026 data explored whether the 31-GEP test could provide additional risk information for patients with transected melanoma, a setting in which incomplete tumor thickness measurements can complicate staging.

The multicenter analysis included 687 patients with transected melanomas. Five-year RFS was 93.2% among patients with low-risk Class 1A results compared with 64.1% among those with high-risk Class 2B results (P < .001).

Among patients with stage I to IIA disease, those with Class 2B results had a 5-year RFS of 73.7%, similar to the recurrence risk reported among patients with stage IIB melanoma.

The findings may be particularly relevant when transection creates uncertainty around conventional staging. According to the study authors, low-risk results may support less intensive follow-up, whereas high-risk results could identify patients who may benefit from closer surveillance or consideration of imaging not typically recommended on the basis of stage alone.

DecisionDx-Melanoma analyzes tumor gene expression alongside select clinicopathologic features to provide individualized estimates of SLN positivity and recurrence or metastatic risk. The test is intended to supplement, rather than replace, conventional clinicopathologic staging when informing decisions around SLNB, surveillance, imaging, and referrals.

The EADV findings add prospective evidence supporting the potential role of tumor biology in risk-aligned melanoma management, particularly when clinicians are weighing SLNB in patients with low predicted nodal risk or determining surveillance strategies for patients whose molecular risk appears higher than their conventional stage suggests.

References

1. Castle Biosciences. Late-breaking EADV 2026 data support use of DecisionDx-Melanoma in SLNB decision-making and risk-aligned post-surgical management. Published September 30, 2026. Accessed October 12, 2026. Castle Biosciences
2. Beard T, Guenther JM, Leong SP, et al. The integrated 31-gene expression profile test identifies low-risk patients with cutaneous melanoma who can forego the SLNB procedure: results from a prospective, multicenter trial. Future Oncol. 2026;22(8):933-938. doi:10.1080/14796694.2026.2640227. PubMedPubMed