Role of Magnetic Resonance Imaging in Preoperative Staging of Rectal Cancer

Aim of the Study: Evaluation of the accuracy of MRI in preoperative staging of rectal carcinoma in comparison with postoperative histopathology. Background: Accurate staging of rectal carcinoma is an important issue in preoperative planning for the management. Patients and Methods: Twenty seven patients, 17 males and 10 females were included in the study their ages ranging between 25 to 65 years. These patients were diagnosed by PR, colonoscopy and histopathology to have rectal carcinoma. Preoperative MRI was done. Rectal wall invasion (T stag), lymph node status (N stag), relation of the tumour to the anal sphincter complex and Circumferential Resection Margin (CRM) were assessed by MRI. The imaging results were compared with the histopathology regarded as the gold standard of the local staging. Results: Constipation was the mean complaint in 11 cases, bleeding in 10 cases. Low anterior resection was done in 16 cases; abdominoperineal resection was done in 9 cases. Neo-adjuvant was taken in 13 cases for down staging. Comparison between MRI and histopathology in rectal wall invasion is statistically insignificant (p-value=0.999) in contrary to the lymph node status p-value is 0.005. Conclusion: MRI rectum and anal canal is accurate for proper preoperative local staging of rectal cancer.