Analysis of retrograde infection of prophylactic pelvic drains in rectal cancer surgery: a retrospective cohort study

The role of prophylactic pelvic drains in rectal surgery remains controversial. This study aimed to clarify the clinical impact of one major concern: retrograde drain infection. The subjects of this retrospective study were 852 consecutive patients who underwent rectal cancer resection with bowel anastomosis and drain placement at a single referral hospital in Japan. Retrograde drain infections were categorized based on infection depth, as superficial/deep or organ/space. Patients with anastomotic leakage (n = 10) were excluded from the analysis. Outcomes included infection frequency, characteristics, risk factors, and oncological effects. Retrograde drain infection developed in 5.5% of the patients, with the vast majority (84.8%) diagnosed on or after postoperative day (POD) 7. Male sex was a significant risk factor (7.0% vs. 3.3%, P = 0.025). Patients with a retrograde drain infection had longer hospital stays (median 22 vs. 16 days, P < 0.001). Organ/space infections were associated with poorer recurrence-free survival for patients with Stage I–III disease. Drain placement helped early detection in 6 of 10 patients with anastomotic leakage, avoiding stoma creation in 2 patients. Retrograde drain infection occurs more frequently in male patients and prolongs the hospital stay. While prophylactic drains may aid early leakage detection, removal within 7 days is recommended to reduce infection risk.