Figure 4.

Margin clearance in treatment-naïve PDAC (A) and in PDAC following neoadjuvant therapy (B). A treatment-naïve tumour with clearance ≤ 1 mm is considered R1. However, following neoadjuvant therapy, a clearance of >1 mm does not preclude the presence of residual cancer in the surgical bed (R1) because, due to partial tumour regression, the distance between residual cancer cells may become considerably larger (blue dots: cancer cells, green line: resection margin, grey interrupted line: 1 mm clearance).