Increased rectal wall stiffness after prostate radiotherapy: relation with fecal urgency

Area of Science:

• Oncology
• Gastroenterology
• Radiation Medicine

Background:

• Late anorectal toxicity is a common side effect of external beam radiotherapy (EBRT) for prostate cancer.
• The exact cause of this toxicity is unknown, but impaired rectal distensibility due to fibrosis is suspected.
• This study aimed to investigate the impact of EBRT on rectal distensibility and its relation to anorectal function.

Purpose of the Study:

• To determine if external beam radiotherapy (EBRT) alters rectal distensibility.
• To explore the relationship between anorectal complaints and specific changes in anorectal function after EBRT.
• To assess the impact of EBRT on rectal capacity, compliance, and sensory thresholds.

Main Methods:

• Thirty-two men with localized prostate carcinoma underwent barostat measurements and anorectal manometry before and one year after EBRT.
• Rectal distensibility was measured using stepwise isobaric distensions.
• Patients also completed a questionnaire on anorectal complaints, and sensory thresholds and anal pressures were assessed.

Main Results:

• EBRT significantly reduced maximal rectal capacity and the area under the pressure-volume curve (P < 0.001 and P < 0.005, respectively).
• Rectal compliance showed a non-significant trend towards reduction (P = 0.12).
• Fifty percent of patients reported anorectal complaints; those with urgency experienced reduced anal squeeze and maximum pressures, indicating impaired external anal sphincter function.

Conclusions:

• Prostate cancer irradiation leads to decreased rectal distensibility.
• Urgency symptoms in patients treated with EBRT are associated with impaired anal sphincter function.
• These findings suggest a link between reduced rectal distensibility and anorectal dysfunction following radiation therapy.