A prospective study shows the test more accurately identifies patients who may safely avoid biopsy compared to the Melanoma Institute Australia nomogram.
Castle Biosciences announced the publication of a prospective, multicenter study showing that its DecisionDx-Melanoma integrated sentinel lymph node biopsy (i31-SLNB) test result more accurately identifies patients at risk of sentinel lymph node positivity than a traditional clinicopathologic tool.
The study, published in Dermatology and Therapy, compared the i31-SLNB test with the Melanoma Institute Australia (MIA) nomogram. The i31-SLNB test integrates a 31-gene expression profile score with clinicopathologic factors, while the MIA nomogram estimates risk using clinicopathologic factors alone.
According to the study, patients classified as low risk by the i31-SLNB result had a 2.6% observed sentinel lymph node positivity rate. This falls below the 5% threshold established by the National Comprehensive Cancer Network for considering the avoidance of a sentinel lymph node biopsy. In contrast, the MIA nomogram yielded a 5.8% observed positivity rate for patients it classified as low risk, failing to identify patients below the 5% threshold.
“Many clinicians are familiar with nomograms that estimate risk of sentinel lymph node positivity using clinicopathologic features alone, yet current guidelines acknowledge limitations in their performance at lower risk thresholds,” says Rohit Sharma, MD, FACS, lead author of the study and surgical oncologist at Marshfield Clinic Health System, in a release. “The study findings demonstrate that incorporating tumor biology through DecisionDx-Melanoma’s i31-SLNB test result can improve risk assessment, helping clinicians better distinguish which patients with melanoma may safely avoid SLNB and which should consider having the surgery.”
The research also analyzed cases where the two methods provided conflicting risk classifications. Patients classified as low risk by i31-SLNB but higher risk by the MIA nomogram had an actual positivity rate of 2.8%. For patients classified as low risk by the MIA nomogram but high risk by the i31-SLNB, the actual positivity rate was 11.5%. Overall, the i31-SLNB result demonstrated higher discriminative performance with an area under the curve of 0.74 compared to 0.61 for the MIA nomogram.
Sentinel lymph node biopsy is used in melanoma staging to determine if the cancer has spread to nearby lymph nodes, but up to 88% of these procedures are negative and roughly 15% of patients experience complications from the surgery, according to the study. Current National Comprehensive Cancer Network guidelines recommend avoiding the procedure when the likelihood of positivity is less than 5%, considering it when risk is between 5% and 10%, and offering it when risk exceeds 10%.
The prospective cohort analysis evaluated 912 patients considering the biopsy procedure who were enrolled in the multicenter DECIDE study. This is the second multicenter study to show the i31-SLNB result outperforms the MIA nomogram, according to Castle Biosciences.
ID 7616697 © Convit | Dreamstime.com
