Gene Test Outperforms Standard Nomogram in Melanoma Biopsy Decisions

The study, which evaluated 912 patients, found that individuals classified as low risk by the i31-SLNB test exhibited a 2.6% observed positivity rate. This figure sits safely below the 5% threshold established by the National Comprehensive Cancer Network for considering the avoidance of sentinel lymph node biopsy. In contrast, the MIA nomogram failed to consistently identify this low-risk cohort, showing an observed positivity rate of 5.8% for patients it categorized as low risk.

Dr. Rohit Sharma, the study's lead author, noted that relying solely on clinicopathologic features often leaves clinicians with limited accuracy at lower risk thresholds. By integrating tumor biology into the assessment, the i31-SLNB result provides a clearer distinction for surgical decision-making. The data revealed a significant gap in performance: when the two methods disagreed, patients labeled high-risk by the i31-SLNB but low-risk by the MIA nomogram showed an actual positivity rate of 11.5%, highlighting the superior discriminative power of the genetic test.