TH3.6 Comparison Between Preoperative MRI and Postoperative Histopathological Staging in Rectal Cancer Surgery (RCS)

Abstract

Abstract Aim To evaluate diagnostic values of preoperative MRI imaging staging in comparison to postoperative histopathological staging (HPS) in rectal cancer surgery. Methods A retrospective chart auditing was performed on all RCS patients from 2019 till 2021. Data collected included patient demographic, preoperative MRI imaging and postoperative histopathological analysis. Results A total number of 83 rectal surgeries were performed during the given period, mean age was 67(±11) and 60% were males. 62.7% (52) of patients underwent anterior resection (low AR 27.7%). APR and Hartmann's procedure were performed in 27.7% and 6% of patients. Complete resection was achieved in 95.2% with average LN harvest of 20.5 (±5.8) nodes. The most common Tumour (T) burdens on preoperative MRI and postoperative HPS were T2 (45.6%) and T3 (44.5%) respectively with MRI diagnostic accuracy of 47%. Lymph nodes analysis showed diagnostic preoperative predictive values of 56.6%. Extramural vascular invasion (EMVI) was accounted in 68 Pre-MRI with diagnostic accuracy of 50.6%. Pre-MRI evaluated 69 CRM and accurately commented in 73.5%. Although Pre-MRI staging had tendency to over-stage tumour burden, lymph nodes analysis and EMVI in around 30% of reported cases. It showed accuracy in diagnostic values in CRM prediction with around 73%. Conclusion Preoperative MRI diagnostic values showed differences when compared with postoperative histopathological analysis. Pre-MRI showed a tendency to over-staging in tumour size, LNs and EMVI. However, Pre-MRI showed favourable values in accurately describing CRM which is the main factor affecting the outcome of surgery and the ongoing treatment.