TUESDAY, Oct. 28, 2025 (HealthDay News) -- The combined clinicopathological factors and gene-expression profile (CP-GEP) test can identify which patients with primary cutaneous melanoma can safely forgo sentinel lymph node biopsy (SLNB), according to a study published online Oct. 22 in JAMA Surgery.

Tina J. Hieken, M.D., from the Mayo Clinic in Rochester, Minnesota, and colleagues established the predictive capability of the CP-GEP test to identify patients with primary cutaneous melanoma who can safely forgo SLNB. The study was conducted at nine academic medical centers and involved experienced melanoma surgeons. Patients with biopsy-proven invasive cutaneous melanoma with T1 to T3 tumors and clinically negative regional lymph nodes were included; using standard clinical criteria, all were deemed candidates for SLNB.

Overall, 1,761 patients underwent SLNB (17.6 percent SLN-positive) and had a successful CP-GEP test; in 97.7 percent of samples, GEP was successful. The researchers found that 651 patients (37.0 percent) were considered low risk by CP-GEP; of these, 7.1 percent were SLN-positive and the negative predictive value was 92.9 percent. The rate of SLN positivity was 23.8 percent among high-risk cases. With increasing T category, the percentage of cases with low-risk CP-GEP declined (68.2, 32.9, and 2.8 percent for T1, T2, and T3, respectively). Across primary sites, histological subtypes, and mitotic count categories, CP-GEP results were consistent for discriminating SLN positivity rates.

"Blinded prospective evaluations of GEP-based and other genomic predictive tests are essential to provide reliable estimations of their clinical utility, and ultimately cost-effectiveness, for selecting patients for SLNB," the authors write.

Several authors disclosed ties to the biopharmaceutical industry, including SkylineDx, which funded the study.

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