Rectosigmoid tumours: should we continue sitting on the fence?

Area of Science:

• Gastroenterology
• Surgical Oncology
• Anatomical Pathology

Background:

• Current definition of rectal cancers (tumors below 15 cm from the anal verge via rigid sigmoidoscopy) lacks anatomical reproducibility.
• Variability in the peritoneal reflection's distance from the anal canal complicates accurate tumor localization.
• Distinguishing between rectal and sigmoid colon cancers is critical for treatment, particularly neoadjuvant chemoradiotherapy eligibility.

Purpose of the Study:

• To propose a more reliable and reproducible anatomical landmark for defining the upper limit of the rectum.
• To investigate the sacral promontory as a fixed bony landmark for demarcating the rectosigmoid junction.

Main Methods:

• Review of current definitions and clinical trial criteria for rectal cancer.
• Analysis of anatomical variability in the rectosigmoid region.
• Postulation of the sacral promontory as a fixed anatomical reference point, leveraging preoperative MRI assessments.

Main Results:

• The 15 cm criterion is subject to significant inter-individual anatomical variation.
• A fixed bony landmark, such as the sacral promontory, offers superior reproducibility.
• Preoperative MRI facilitates the identification and utilization of bony landmarks.

Conclusions:

• The sacral promontory is a more reliable landmark for defining the upper rectal border than the current 15 cm measurement.
• Adopting the sacral promontory can enhance diagnostic accuracy and standardize patient selection for neoadjuvant therapies in rectal cancer management.