The efficacy and predictive value of 99mTc-rituximab for sentinel lymph node biopsy in acral melanoma patients.

BACKGROUND: We sought to evaluate the efficacy and predictive value of 99mTc-rituximab as a tracer for sentinel lymph node biopsy (SLNB) in acral melanoma (AM) patients.

METHODS: We retrospectively analyzed data from 663 melanoma patients who underwent SLNB in our center between February 2009 and March 2019. Participants enrolled in the study included 374 AM and 128 cutaneous melanoma (CM) patients, who received 99mTc-rituximab during the SLNB procedure. The SLNB success rate, SLNB-positivity rate, prognosis and influencing factors were compared between the two groups using SPSS 25.0 software with P < 0.05 considered to be statistically significant.

RESULTS: SLNs were successfully imaged using SPECT-CT and harvested from all 374 AM and 128 CM patients. Of these study participants, 19 AM and 9 CM patients were diagnosed as false negative (FN) SLN corresponding to a FN rate of 17.9% and 20.5%, respectively. The rate of positive SLN was 23.3% and 27.3% (P = 0.353) in AM and CM, respectively. No predictive factors were discovered for FN. The T stage was found to be a potential risk factor for SLNB-positive (OR: 1.311; 95% CI: 1.051-1.635; P = 0.016) cases in AM patients, whereas no significant differences were observed in CM patients (P > 0.05). Cox-regression multiple factor analysis revealed that SLNB positivity was an independent risk factor for DFS and OS in AM patients.

CONCLUSION: 99mTc-rituximab is an effective tracer for SLNB of AM and is essential for determining patient prognosis. In addition, we show that T stage may be a risk factor for SLNB-positive cases in AM.