The impact of positive surgical margins after cystectomy on oncological outcomes: a nationwide study from the Prospective Bladder Cancer Infrastructure (ProBCI)

This nationwide cohort study evaluated if surgical margin status alongside existing postoperative risk indicators improves identification of bladder cancer patients who may benefit from adjuvant therapy following radical cystectomy (RC). Adults with cT2–4aN0/xM0 disease (November 2017–December 2020) who underwent RC were selected from the Netherlands Cancer Registry. Overall survival (OS) and progression-free survival (PFS) were assessed using the Kaplan-Meier method. Multivariable Cox regression analysis was performed to assess the independent prognostic effect of positive surgical margins (carcinoma in situ [CIS] only or invasive carcinoma) on PFS and OS. Among 1,445 patients (53% open, 47% robot-assisted), 9.3% had positive margins. In the entire cohort, OS was 79% at 12 and 60% at 48 months after RC. Multivariable Cox regression showed worse OS (HR 2.02, 95%-CI 1.58–2.58) in patients with surgical margins with invasive carcinoma versus patients with negative margins. Patients with only CIS in the margins showed no difference for OS versus negative margins (HR 1.30, 95%-CI 0.80–2.12). Invasive positive margins should be considered a ‘high-risk feature’ due to impaired survival, warranting investigation of the potential efficacy of adjuvant therapy (i.e., radiotherapy or systemic therapy).