EP625 - Comparative Efficacy of MRI vs. Rigid Recto sigmoidoscopy in Rectal Tumor Assessment

Monday, May 12, 2025

8:10 AM – 8:15 AM PT

Location: Monitor 4, Sails Pavilion, Upper Level

Author(s)

SN

Stephany t. Nin, n/a

PGY-5
HOSPITAL GENERAL DE MEXICO "DR. EDUARDO LICEAGA"
mexico city, Distrito Federal, Mexico

Disclosure information not submitted.

ePoster Presenter(s)

Jeziel Karina Ordonez Juarez (she/her/hers)

Resident
Hospital general de México
Universidad Nacional Autónoma de México
Mexico, Mexico

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.

Senior Author(s)

JV

JUAN ANTONIO VILLANUEVA HERRERO, Sr., n/a

Program director
Hospital General de Mexico
Mexico, Distrito Federal, Mexico

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.

Author(s)

JD

Jorge Luis De leon Rendon, 7948396

Coordinator and Founder, Inflammatory Bowel Disease Clinic
Hospital General de México “Dr. Eduardo Liceaga”. Inflammatory Bowel Disease Clinic. Coloproctology Service.
PUEBLA, Distrito Federal, Mexico

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.
SP

Sergio Ulises Perez-Escobedo, M.D.

Colon & Rectum Surgeon
Hospital General de México
Ciudad de México, Distrito Federal, Mexico

All of the relevant financial relationships listed below have been mitigated.
This individual has no financial relationships with ineligible companies.
LA

Lisbeth Alarcón Bernes, n/a

FELLOW PELVIC FLOOR
NONE
mexico city, Distrito Federal, Mexico

Disclosure information not submitted.
BJ

Billy Jimenez Bobadilla, n/a

Doctor
Hospital General de Mexico
Ciudad de Mexico, Distrito Federal, Mexico

Disclosure information not submitted.

All of the relevant financial relationships listed below have been mitigated.

Jeziel Karina Ordonez Juarez: This individual has no financial relationships with ineligible companies.

JUAN ANTONIO VILLANUEVA HERRERO, n/a, Sr.: This individual has no financial relationships with ineligible companies.

Jorge Luis De leon Rendon, 7948396: This individual has no financial relationships with ineligible companies.

Sergio Ulises Perez-Escobedo, M.D.: This individual has no financial relationships with ineligible companies.

Image or Table (Do Not add text here):

Purpose/Background: This study aimed to determine the correlation between RSCR and MRI measurements of the lower margin in middle and lower rectal tumors. Additionally, we aimed to evaluate whether MRI could be used as an alternative to RSCR for guiding surgical procedures when RSCR cannot be performed.

Methods/Interventions: This retrospective study included 22 patients diagnosed with rectal cancer at the Coloproctology Unit of the General Hospital of Mexico. All patients underwent rigid rectosigmoidoscopy (RSCR), MRI, and computed tomography (CT) as part of the staging protocol. Measurements were obtained to determine the distance from the lower tumor margin to the anal verge. Patients with incomplete records or those who required emergency surgery due to tumor perforation or obstruction were excluded. Pearson correlation coefficients were calculated to determine the degree of agreement between RSCR and MRI measurements. MRI evaluations were conducted by both a colorectal surgeon and a specialist radiologist.

Results/Outcomes: A total of 22 patients (9 women and 13 men) were included in the study. The mean age was 56 years (range: 41-71 years). The average distance from the lower tumor margin to the anal verge as measured by RSCR was 5.7 cm (standard deviation: ±2.29 cm). The correlation coefficient between RSCR and MRI measurements evaluated by a colorectal surgeon was 0.653 (p < 0.05), indicating a moderate correlation. When the measurements were evaluated by an MRI specialist, the correlation coefficient was slightly higher at 0.709 (p < 0.05), suggesting a stronger but still moderate agreement. In nine patients (41%), RSCR could not be performed due to tumor-related luminal obstruction. MRI showed lymph node involvement in 72.7% of patients, but only 54.5% were confirmed by pathology, resulting in a poor correlation for lymph node detection (r = 0.189, p = 0.626). This poor correlation may be due to MRI's tendency to overestimate lymph node involvement based on size, as many benign lymph nodes may also appear enlarged.

Conclusion/Discussion: The findings of this study demonstrate that MRI can be used as a reliable alternative to RSCR for determining the distance from the lower tumor margin to the anal verge in patients with middle and lower rectal cancer, particularly in situations where RSCR cannot be performed due to tumor obstruction or patient discomfort. MRI is valuable for tumor staging, but it may overestimate lymph node involvement, potentially leading to over-staging. Therefore, careful interpretation of MRI findings is necessary, and a multidisciplinary approach should be used to ensure optimal patient management and treatment planning.