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Updated: Jan 12, 2026
Elastic Staining on Paraffin-embedded Slides of pT3N0M0 Gastric Cancer Tissue
Published on: May 1, 2019
Relationship between fibrosis induced by preoperative chemoradiotherapy and real-time tissue elastography of internal
Akira Sakamoto1, Kazuhito Sasaki2, Hiroyuki Abe3
1Department of Surgical Oncology, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
Background:
It has been suggested that chemoradiotherapy may cause fibrosis of the internal anal sphincter, resulting in sclerosis. However, no report has quantitatively investigated this relationship by using real-time tissue elastography.
Objective:
To clarify the relationship between fibrosis and elasticity of the internal anal sphincter in patients undergoing surgery for lower rectal cancer with or without preoperative chemoradiotherapy from a histological perspective.
Design:
A single-center, prospective cohort study.
Settings:
The surgical and pathological departments in a tertiary referral university hospital.
Patients:
Eighteen patients with rectal cancer who underwent abdominoperineal resection between May 2019 and May 2022 were included in the study.
Main Outcome Measures:
Real-time tissue elastography was performed before surgery to measure internal anal sphincter hardness as "elasticity" (hardest (0) to softest (255); decreased elasticity indicated sclerotic changes). Internal anal sphincter fibrosis was evaluated using Masson's trichrome and Elastica van Gieson staining. We evaluated internal anal sphincter elasticity after preoperative chemoradiotherapy and preoperatively in patients who did not undergo preoperative chemoradiotherapy and analyzed the correlation with the percentage of internal anal sphincter fibrosis in the resected specimens.
Results:
Of the 18 patients, 10 underwent preoperative chemoradiotherapy. A significantly higher percentage of internal anal sphincter fibrosis was observed in the chemoradiotherapy group. Post-chemoradiotherapy elasticity was significantly lower in patients undergoing chemoradiotherapy compared to pre-chemoradiotherapy elasticity and that in patients not undergoing chemoradiotherapy. The analysis of the correlation between internal anal sphincter elasticity and fibrosis showed that elasticity decreased as the percentage of fibrosis increased.
Limitations:
This study was conducted at a single institution, and the number of cases was small. The radiation dose to the anal canal may have differed depending on the location of the tumor, which may have affected internal anal sphincter elasticity.
Conclusions:
Internal anal sphincter elasticity may reflect tissue sclerosis associated with fibrosis caused by chemoradiotherapy.
