Determining the False-Negative Rate Using Fluorescence Image-Assisted Sentinel Lymph Node Biopsy in Cutaneous...

Despite the advances in cutaneous melanoma management, the false-negative rates (FNRs) of sentinel lymph node biopsy (SLNB) are still high. These rates are dependent not only on the technique but also on definitional terms and percentage of head/neck melanoma (highest false-negative SLNB). Fluorescence imaging technology is well acquainted in plastic surgery and other specialties. Having demonstrated that fluorescence-assisted SLNB is effective in melanoma, we are interested in determining its FNR.

We obtained institutional review board approval to follow up prospectively all patients with cutaneous melanoma who underwent radioisotope/fluorescence-assisted SLNB with the intent to capture 100 negative SLNB patients. Inclusion criteria were as follows: (1) National Comprehensive Cancer Network criteria; (2) an SLNB report; (3) at least 24 months of follow-up in the negative SLNB group. The outcome variables were FNR and adjusted FNR of SLNB, considering the criterion standard of assessing the accuracy of SNLB. The FNR was defined as the proportion of patients with false-negative SLNB to patients with true-positive and false-negative SLNB [false negative/(false negative + true positive)]. Adjusted FNR refers to the previously described false-negative SLNB, but in the absence of local/in-transit recurrence or distant metastases. Furthermore, false-negative incidence (false-negative/negative SLNB patients) was also calculated. Length of follow-up was date of surgery to the date of last follow-up/death.

A total of 125 participants, with 52.0% being male and 48.0% being female, were included. One hundred patients had an SLNB negative for metastases, whereas the rest had positive SLNB results. Median follow-up time of the cohort and that of the negative SLNB group were 36.7 (2.6-58.5) and 37.9 (24.0-58.5) months, respectively. A relatively high number (24.8%) of head/neck melanoma were included. We identified 2 cases of false-negative SLNB, with one having in-transit metastases. Thus, the FNR and adjusted FNR were 7.4% and 3.7%, respectively. The false-negative incidence and adjusted false-negative incidence were 2.0% and 1.0%, respectively.

This is the first prospective study examining the FNR of fluorescence-assisted SLNB for patients with cutaneous melanoma. Our study reveals that this technique has one of the lowest FNRs published, especially considering the large percentage of participants with head/neck melanoma involved.