Efficacy of IFN-alpha-2b as adjuvant treatment for acral melanoma: A retrospective analysis of 113 cases in China.

Abstract

e21558 Background: High-dose interferon-alpha-2b (HD-IFN) has an important place in the adjuvant treatment of acral melanoma (AM). However, studies on the adjuvant treatment of AM with HD-IFN remain limited. This retrospective study aimed to evaluate the relationships between the dosing regimen during the HD-IFN intensification phase, the duration of treatment, and the interval between surgery and the first dose of HD-IFN with postoperative recurrence and survival in AM patients. Methods: A total of 113 patients with AM were included in this study, including 2 patients with stage 0, 7 patients with stage IA, and 5 patients with unknown stage. The remaining patients were stratified according to the risk of recurrence into low-risk (stage IB-IIA, n=42), high-risk (stage IIB-IIIA, n=42), and very high-risk (stage IIIB-IIID, n=15). Dosing regimen during intensification phase：the intravenous infusion and subcutaneous injection were recorded as groups A1 and A2. The duration of treatment：patients completing 18-20MIU d1-5/w ·4 w were classified as group B1, those completing 18-20MIU d1-5/w ·4 w and 9-10MIU d1-3/w ·48w <180 days and ≥180 days were recorded as groups B2 and B3, respectively. The interval from surgery to the first dose of HD-IFN：T≤30 days (group C1) and T≥31 days and T≤142 days (group C2). The endpoints of this study were recurrence-free survival (PFS) and overall survival (OS). Results: The median follow-up time was 75.37m, the median RFS was 38.40m, and the 5-year OS rate was 71.60%. In total population (n = 100), patients with different dosing regimen during intensification phase (group A1, n = 68; group A2, n = 32) had a 5-year OS rate of 77.90% vs. 51.90% (P = 0.033). Stratified analysis showed a 5-year OS rate (95.80% vs 46.00%, P=0.004) for dosing regimen during intensification phase in the low-risk group (group A1 n=27 vs group A2 n=11). Stratified analyses of treatment duration showed a median RFS (23.50m vs 52.90m, P=0.032) in the high-risk group (Group B2 n=18 vs Group B3 n=18). In the very high-risk group (group B2, n = 8; group B3, n = 7) had a 3-year RFS rate of 12.50% vs. 57.10% (P = 0.005), and a 5-year OS rate of 25.00% vs. 85.70% (P = 0.018).Stratified analysis of the interval between surgery and the first dose of HD-IFN showed a 5-year OS rate (55.00% vs. 82.50%, P = 0.034) in the high-risk group (group C1 n=22 vs. group C2 n=19). Conclusions: This study found that in the total population and the low-risk group, the OS benefit of the HD-IFN intravenous infusion group was superior to that of the subcutaneous injection group. Among high- and very high-risk groups, those in the HD-IFN treatment duration of ≥ 180 days group had greater RFS benefits than those in the < 180 days group. In the high-risk group, patients with an interval between surgery and the first dose of HD-IFN of ≤ 30 days demonstrated superior OS benefits compared to those with the interval between 31 and 142 days.