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Multiple R1 margins are associated with shorter overall survival: national register-based study on pancreatic cancer
Patrik Larsson1, Carlos Fernández Moro2,3, Melroy D'Souza1
1Division of Surgery and Oncology, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
Background:
Resection status is associated with overall survival among patients operated on for pancreatic ductal adenocarcinoma (PDAC). This study investigated whether the number of R1 margins is associated with shorter survival.
Methods:
Adult patients who underwent pancreatoduodenectomy for primary resectable PDAC between 2017 and 2024 recorded in the Swedish National Pancreatic Registry were included. Overall survival was analysed according to overall R status and the number of R1 margins. Overall survival was analysed using Kaplan-Meier estimates, Cox regression analysis for estimated adjusted survival time, and Laplace regression for analysis of percentile distribution.
Results:
Overall, 1043 patients were included, 398 patients (38.2%) with R0 and 645 patients (61.8%) with R1 margins. The adjusted median survival was 8.2 (95% confidence interval (c.i.) -12.0 to -4.3) months shorter for patients with R1 versus R0 margins, with a progressively shorter survival with a higher number of R1 margins. Specifically, compared with R0 margins, the adjusted median survival for one, two and three or more R1 margins was 4.6 (95% c.i. -10.2 to 1.0), 6.7 (95% c.i. -11.9 to -1.5), and 12.4 (95% c.i. -16.5 to -8.3) months shorter, respectively.
Conclusions:
Patients with R1 margins had an adjusted median survival that was 8 months shorter than patients with R0 margins. An increased number of R1 margins was associated with shorter survival. These results suggest that the current practice of reporting binary R status is insufficient, and future guidelines should consider revising this routine and adopt a standardized, detailed margin assessment protocol.
