Acral melanomas are a unique subset of melanomas occurring on the palms, soles, and nails. There is poor prognosis with surgery alone and no specific guidelines for the treatment of metastatic acral melanoma. This meta-analysis explored the systemic therapy outcomes for metastatic acral melanoma. Medline, Pubmed, EMBASE, and the grey literature were searched from 2010 to August 2020 for studies specifying the treatment outcome of metastatic acral melanoma. Studies were assessed by two investigators. A random-effects meta-analysis was performed and pooled Kaplan-Meier curves for progression-free survival and overall survival were created. Critical appraisal was performed using the Newcastle-Ottawa Scale. Nineteen nonrandomized studies were included, comprising 646 patients with acral melanomas and 1609 patients with nonacral melanomas treated with systemic therapy including chemotherapy, KIT-targeted drugs, as well as anti-CTLA-4 and anti-PD-1 checkpoint inhibitor therapy. Thirteen studies included Kaplan-Meier curves for progression-free survival or overall survival and 11 studies reported treatment responses. Patients with acral melanomas had worse prognosis than nonacral cutaneous melanoma (acral overall survival: median 15 months, 95% CI, 13.7-16.3 months; nonacral cutaneous: median 24 months, 95% CI, 22.6-25.4 months, P < 0.001). Acral melanoma patients treated with anti-PD-1 monotherapy had higher overall survival at 12 months (53%) compared with anti-CTLA-4 monotherapy (34%; P < 0.001). This study provides estimates of treatment response for metastatic acral melanoma, demonstrating low activity across a breadth of approved drug therapies, including anti-PD-1, the most active therapy in melanoma to date. Further research into treatments for metastatic acral melanoma is needed.

中文翻译：

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转移性肢端黑色素瘤治疗结果：系统评价和荟萃分析。

肢端黑色素瘤是发生在手掌、脚底和指甲上的黑色素瘤的一个独特亚型。单纯手术预后较差，并且没有治疗转移性肢端黑色素瘤的具体指南。这项荟萃分析探讨了转移性肢端黑色素瘤的全身治疗结果。检索了 2010 年至 2020 年 8 月的 Medline、Pubmed、EMBASE 和灰色文献，以查找明确转移性肢端黑色素瘤治疗结果的研究。研究由两名研究人员进行评估。进行了随机效应荟萃分析，并创建了无进展生存期和总生存期的汇总 Kaplan-Meier 曲线。使用纽卡斯尔-渥太华量表进行严格评估。纳入 19 项非随机研究，包括 646 名肢端黑色素瘤患者和 1609 名非肢端黑色素瘤患者，接受全身治疗，包括化疗、KIT 靶向药物以及抗 CTLA-4 和抗 PD-1 检查点抑制剂治疗。13 项研究包括无进展生存期或总生存期的 Kaplan-Meier 曲线，11 项研究报告了治疗反应。肢端黑色素瘤患者的预后比非肢端皮肤黑色素瘤差（肢端总生存期：中位 15 个月，95% CI，13.7-16.3 个月；非肢端皮肤：中位 24 个月，95% CI，22.6-25.4 个月，P < 0.001）。与抗 CTLA-4 单一疗法（34%；P < 0.001）相比，接受抗 PD-1 单一疗法治疗的肢端黑色素瘤患者 12 个月总生存率 (53%) 更高。这项研究提供了转移性肢端黑色素瘤治疗反应的估计，证明了多种已批准药物疗法的活性较低，其中包括迄今为止治疗黑色素瘤最有效的抗 PD-1 药物。需要进一步研究转移性肢端黑色素瘤的治疗方法。