SRS68 - The prognostic impact of imaging detected Tumour deposits: a meta-analysis

Abstract Background Tumour deposits (TDs) identified at pathology post rectal cancer resection, have been increasingly recognised as an adverse prognostic factor. Advances in magnetic resonance imaging (MRI) allow for the preoperative detection of TDs (mrTDs), raising the possibility that patients with mrTDs may benefit from tailored neoadjuvant treatment strategies or enhanced surveillance. This meta-analysis primarily aims to evaluate the prognostic significance of mrTDs and other high-risk features in rectal cancer patients. Methods A comprehensive literature search was conducted in MEDLINE, Embase and Scopus databases. PRISMA guidelines were followed. Primary prognostic end points included disease-free survival (DFS) and overall survival (OS). Pooled Hazard Ratios (HR) were calculated using R software. Results A total of 5813 and 5630 patients were included in the systematic review (13 studies) and meta-analysis (11 studies) respectively. The pooled HR for OS and DFS for mrTD was 2.1 (95% c.i.: 1.63–2.70; P < 0.0001) and 2.13 (95% c.i.: 1.68–2.71; P < 0.0001) respectively. The pooled HR for OS and DFS for extramural venous invasion (mrEMVI) and circumferential resection margin involvement (mrCRM) were also significantly increased (P < 0.01). The pooled HR for MRI predicted nodal disease (mrLNMs) for OS and DFS was insignificant (P > 0.05). Conclusions This meta-analysis confirms the prognostic significance of mrTDs on OS and DFS in rectal cancer. This was also observed for mrEMVI and mrCRM but not for mrLNMs. This further substantiates existing evidence that these features should be considered routinely in the pre-operative identification of patients at high risk of recurrence or death.