CORRELATION BETWEEN DIGITAL RECTAL EXAMINATION AND MAGNETIC RESONANCE IMAGING IN ASSESSING THE DISTANCE OF RECTAL TUMORS FROM THE ANAL MARGIN IN PATIENTS FROM A UNIVERSITY HOSPITAL

Introduction The evaluation of distal rectal cancer (RC) includes digital rectal examination (DRE), endoscopic examination, and staging by magnetic resonance imaging (MRI). In clinical practice, specialists use DRE to assess the tumor's distance from the anal margin. MRI is employed for staging to indicate the degree of invasion in the mesorectal fascia layers, the presence of lymph nodes, and the tumor's distance from the sphincter complex and anal margin.

Objective To evaluate whether the distance of rectal tumors from the anal margin measured by DRE correlates with the distance measured by MRI.

Method We reviewed 65 patient records with rectal tumors who underwent DRE and MRI to measure the tumor's distance from the anal margin between 2019 and 2024 at a university hospital. Forty-one records were selected for evaluation based on the inclusion criterion of explicitly stating the tumor's distance from the anal margin in both DRE and MRI exams. The respective measurements were assessed using Pearson's correlation coefficient (r) and Intraclass Correlation Coefficient (ICC), as well as paired T-tests.

Results The mean distance of tumors from the anal margin measured by DRE and MRI were 5.3 cm and 6.9 cm, respectively, with standard deviations of 2.45 and 2.67. The analysis revealed a moderately strong positive correlation between the measurements of both exams (r = 0.673), suggesting that tumor size can be measured similarly by DRE and MRI. The Intraclass Correlation Coefficient (ICC(3k)) for the agreement between the two exams was calculated to be 0.80 (95% CI: 0.67-0.88), showing substantial agreement between them, indicating robust consistency in the measurements and ensuring reliable clinical evaluations. The comparison of the measured distances showed a statistically significant difference between DRE and MRI (Paired t-test: t(40) = 3.0348, p < 0.005), with an approximate mean difference of 0.985 (95% CI: 0.33-1.64), suggesting that although the distances are not identical, the magnitude of the difference should be interpreted in the clinical context.

Conclusion Based on the data obtained in this study, it can be concluded that the measurement of the rectal tumor's distance from the anal margin by DRE has a good correlation with the measurement by magnetic resonance imaging, although there is significant variability.

Publication History

Article published online:
25 April 2025