Adjuvant radiotherapy in the treatment of rectal cancer has been shown to increase long-term morbidity.
Ajuvant radiotherapy for rectal cancer causes severe anorectal dysfunction with physiologic changes whose interaction remains poorly understood.
Dr Lilli Lundby and colleagues from Denmark examined long-term anorectal morbidity from adjuvant postoperative radiotherapy.
|60% of those receiving radiotherapy had liquid stool vs 23% who had no radiotherapy|
|Diseases of the Colon & Rectum|
The researchers conducted a prospective study assessing the long-term effect of radiotherapy on anorectal function in a subset of surviving patients.
The patients had Dukes B or C rectal carcinoma and were randomized to postoperative radiotherapy or no adjuvant treatment after anterior resection.
The team assessed long-term effects of radiotherapy using a questionnaire on subjective symptoms.
Physiology laboratory evaluation and flexible sigmoidoscopy was also used to assess the long-term effects of radiotherapy after anterior resection.
The researchers found that 80% of patients treated with radiotherapy had increased bowel frequency compared with 23% who had no radiation therapy .
The team observed that the 60% group treated with radiotherapy had loose or liquid stool versus 23% of those who were not treated with radiotherapy.
The patients treated with radiotherapy also had fecal incontinence more often, and wore pads more often.
The team noted that patients treated with radiotherapy experienced fecal urgency and were unable to differentiate stool from gas more often.
Endoscopy revealed a pale and atrophied mucosa and telangiectasias in the irradiated patients.
The team reported that anorectal physiology showed a reduced rectal capacity and maximum squeeze pressure in the radiotherapy group.
In addition, impedance planimetry demonstrated a reduced rectal distensibility in these patients.
Dr Lundby's team concludes, “Adjuvant postoperative radiotherapy after anterior resection causes severe long-term anorectal dysfunction.
“This is mainly the result of a weakened, less sensitive anal sphincter and an undistensible rectum with reduced capacity.”