71848 - Microscopic vascular invasion is associated with non-radical resection of locally recurrent rectal cancer, and impaired disease-free survival

Introduction Negative resection margin (R0) is strongly associated with long term outcomes after surgical resection for locally recurrent rectal cancer (LRRC). The aim of this study was to evaluate the association of microscopic vascular invasion (V1) with probability of R0 resection and disease-free survival (DFS) when performing resection of LRRC with curative intent. Method Study design: Retrospective observational study. Participants: Patients operated with curative intent for LRRC at the Karolinska University Hospital from January 2003 until December 2017. Data were retrieved from medical records. Outcome measures were R status and DFS. Result Overall, 126 patients were operated for LRRC with curative intent. R0 resection was achieved in 96 patients (76%). The absence or presence of V1 was stated in the pathology report in 73 patients (58%). Of those 41 (56 %) were reported as V1 and 32 (44 %) as V0. The relative risk of R1 resection was 41 % when V1 was present and 0.0 % in the absence of V1 (P<0.001). Presence of V1 in the LRRC specimen was also associated with impaired DFS (P=0.05). Discussion Microscopic vascular invasion in LRRC is a significant risk factor for R1 resection and poor survival after resection with curative intent.