Abstract
Randomized trials have shown that neoadjuvant immune checkpoint inhibitor (ICI) therapy improves outcomes compared with adjuvant therapy in patients with resectable stage III-IV melanoma. However, the generalizability of these findings to routine clinical practice is unclear. We conducted a nationwide, population-based cohort study including 279 consecutive patients with resectable stage III-IV cutaneous melanoma treated with neoadjuvant ICI in Sweden. Outcomes included pathological response, survival and adverse events. Among patients, 94% received PD-1 inhibitor monotherapy and 92% underwent surgery as planned. Major pathological response occurred in 43%, including 37% with complete response. After a median follow-up of 20 months, estimated 24-month EFS was 69%, DMFS 75%, and OS 87%. Pathological response was strongly associated with outcomes. Among 119 patients achieving major pathological response (MPR), withholding adjuvant therapy was associated with recurrence. Outcomes after neoadjuvant ICI were comparable to randomized trials. Withholding of adjuvant therapy after MPR warrants further study.