Long-term consequences of positive surgical margin after partial nephrectomy for renal cell carcinoma: multi-institutional analysis.

Introduction: The aim of the study was to determine the impact of positive surgical margins (PSM) after PN on very long-term recurrence in a contemporary cohort.

Methods: Patients who underwent PN for a localized renal tumour were included. Patients were stratified according to the presence of PSM. Data on patients' characteristics, the tumour, the peri- and postoperative events were collected. Disease-free survival (DFS) and overall survival (OS) were assessed by the Kaplan-Meier method and compared by the log-rank test. Sensitivity analyses using weighted propensity score analysis was performed to account for potential selection biases arising from the nonrandom allocation of patients to different groups.

Results: A total of 1115 patients were included in the study. The incidence of PSM was 5.4% (n = 61). The median follow-up time was 51 months for the PSM group and 61 months for the NSM group (p = 0.31). Recurrence rates were significantly higher in the PSM group (13%, n = 8) compared to the NSM group (7%, n = 73) (p = 0.05). This resulted in a significant reduction in DFS in the PSM group (p = 0.004), particularly pronounced in patients with clear cell renal cell carcinoma. Additionally, OS was significantly lower in the PSM group (p < 0.01). Propensity score analysis confirmed a decrease in DFS for the PSM group (p = 0.05), while there was no significant difference in OS between the two groups (p = 0.49).

Conclusion: In this retrospective multicenter study, PSM impact on oncological outcomes, increasing recurrence, but no difference in OS was observed post-adjustment for biases.