Urinary dysfunction after rectal cancer surgery: Results from a randomized trial comparing mesorectal excision with and without lateral lymph node dissection for clinical stage II or III lower rectal cancer (Japan Clinical Oncology Group Study, JCOG0212).

BACKGROUND: Postoperative urinary dysfunction is a major complication of rectal cancer surgery. A randomized controlled trial (JCOG0212) concluded that the noninferiority of mesorectal excision alone to mesorectal excision with lateral lymph node dissection was not confirmed in terms of relapse-free survival.

METHODS: Eligibility criteria included histologically proven clinical stage II/III rectal cancer, a main lesion located in the rectum with the lower margin below the peritoneal reflection, and the absence of lateral lymph node enlargement. After confirming R0 resection by mesorectal excision, patients were randomized intraoperatively. The residual urine volume was measured three times. Urinary dysfunction was defined as ≥50 mL residual urine occurring at least once or no measurement of residual urinary volume. This trial was registered with the UMIN Clinical Trials Registry, number C000000034.

RESULTS: In the mesorectal excision alone and the mesorectal excision with lateral lymph node dissection groups, the incidence of early urinary dysfunction were 58% and 59%, respectively. A tumor location in the lower rectum (vs. upper rectum) and a blood loss of ≥500 mL (vs. <500 mL) were associated with an increased risk of early urinary dysfunction. However, only blood loss was independently predictive of early urinary dysfunction (relative risk, 1.25 [95% CI: 1.10-1.55], p = .04).

CONCLUSIONS: Mesorectal excision with lateral lymph node dissection is not associated with a significant increase in the incidence of urinary dysfunction. Urinary dysfunction is associated with tumor location and blood loss.