Long-term anorectal dysfunction after postoperative radiotherapy for rectal cancer

Dis Colon Rectum. 2005 Jul;48(7):1343-9; discussion 1349-52; author reply 1352. doi: 10.1007/s10350-005-0049-1.


Purpose: Adjuvant radiotherapy in the treatment of rectal cancer has been shown to increase long-term morbidity causing severe anorectal dysfunction with physiologic changes whose interaction remains poorly understood. This study examines long-term anorectal morbidity from adjuvant postoperative radiotherapy.

Methods: In a prospective study, patients with Dukes B or C rectal carcinoma were randomized to postoperative radiotherapy or no adjuvant treatment after anterior resection. The long-term effect of radiotherapy on anorectal function in a subset of surviving patients was assessed from a questionnaire on subjective symptoms and from physiology laboratory evaluation and flexible sigmoidoscopy.

Results: Twelve of 15 patients (80 percent) treated with radiotherapy had increased bowel frequency compared with 3 of the 13 patients (23 percent) who did not have radiation therapy (P = 0.003). The former group had loose or liquid stool more often (60 vs. 23 percent, P = 0.05), had fecal incontinence more often (60 vs. 8 percent, P = 0.004), and wore pad more often (47 vs. 0 percent, P = 0.004). They also 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. Anorectal physiology showed a reduced rectal capacity (146 vs. 215 ml, P = 0.03) and maximum squeeze pressure (59 vs. 93 cm H2O, P = 0.003) in the radiotherapy group. Impedance planimetry demonstrated a reduced rectal distensibility in these patients (P < 0.0001).

Conclusions: Adjuvant postoperative radiotherapy after anterior resection causes severe long-term anorectal dysfunction, which is mainly the result of a weakened, less sensitive anal sphincter and an undistensible rectum with reduced capacity.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Aged, 80 and over
  • Analysis of Variance
  • Anastomosis, Surgical
  • Combined Modality Therapy
  • Endoscopy, Gastrointestinal
  • Endosonography
  • Fecal Incontinence / diagnostic imaging
  • Fecal Incontinence / etiology*
  • Fecal Incontinence / physiopathology
  • Female
  • Gastrointestinal Transit / physiology
  • Humans
  • Male
  • Manometry
  • Middle Aged
  • Prospective Studies
  • Radiotherapy, Adjuvant / adverse effects*
  • Rectal Neoplasms / diagnostic imaging
  • Rectal Neoplasms / radiotherapy*
  • Rectal Neoplasms / surgery*
  • Retrospective Studies
  • Sigmoidoscopy
  • Statistics, Nonparametric
  • Surveys and Questionnaires
  • Treatment Outcome