Treatment effect of neoadjuvant immunotherapy in melanoma correlates with tumor burden: meta-analysis of reported clinical trials

Neoadjuvant immune checkpoint inhibition (Neo-ICI) in melanoma is an emerging therapeutic strategy that induces pathologic responses with significant prognostic implications for survival. Tumor burden in nonresectable melanoma has a major impact on immunotherapy efficacy, yet little is known on its impact in the Neo-ICI setting. We evaluated the association between tumor burden, measured by the sum of diameters (SoD), and pathological response in melanoma patients treated with Neo-ICI. A meta-analysis of published trials in resectable stage III/IV melanoma was conducted, extracting data on patient characteristics, treatment regimens, pathological response, and survival outcomes. A total of 451 patients were included in the meta-analysis. The pooled pathological complete response (pCR) rate was 47% (95% confidence interval: 35-58%; P < 0.001). Meta-regression demonstrated a significant association between SoD and pCR (moderator = -0.36; P = 0.032), with greater tumor burden associated with lower pCR rates. No significant association was observed between SoD and recurrence-free survival (RFS). This study identifies higher tumor burden as a potential risk factor for lower pathologic response rates to neoadjuvant therapy, underscoring the need to incorporate tumor burden into future clinical research and potentially clinical decision-making.