Impact of Preoperative Radiotherapy on Anastomotic Leakage and Stenosis After Rectal Cancer Resection: Post Hoc Analysis of a Randomized Controlled Trial.

BACKGROUND

Evidence regarding the effect of preoperative radiotherapy on anastomotic integrity remains conflicting in rectal cancer surgery. Prospective comparisons with appropriate controls are needed.

OBJECTIVE

This study aimed to assess the impact of preoperative radiotherapy on anastomotic leakage and stenosis after rectal cancer resection.

DESIGN

This was a post hoc analysis of a randomized controlled trial (NCT01211210).

SETTINGS

Data were retrieved from the leading center of the trial, which is a tertiary hospital.

PATIENTS

The full analysis population of 318 patients was included.

INTERVENTIONS

Patients were randomly assigned to receive preoperative radiation (50 Gy per 25 fractions) and 5-fluorouracil infusion, alone (arm A) or combined with oxaliplatin (arm B), or preoperative chemotherapy with 5-fluorouracil and oxaliplatin without radiation (arm C).

MAIN OUTCOME MEASURES

The rates of anastomotic leakage and stenosis were calculated for each treatment arm. Multivariate analysis was used to verify the effect of preoperative radiotherapy.

RESULTS

The treatment arms were comparable in terms of most baseline characteristics, but more diversions were used in the chemoradiotherapy arms. Anastomotic leakage occurred in 20.2% of patients in arm A, 23.6% of patients in arm B, and 8.5% of patients in arm C (p = 0.007). The corresponding rates of stenosis were 17.0%, 18.9%, and 6.8% (p = 0.02). Multivariate analysis confirmed the correlation between preoperative radiotherapy and clinical leakage (p = 0.02), which was associated with delayed stenosis (p < 0.001). For patients undergoing chemoradiotherapy, radiation proctitis was identified as an independent risk factor for clinical leakage (p = 0.01) and stenosis (p < 0.001).

LIMITATIONS

The main limitations were discrepancies in stoma creation and chemotherapy regimen among the treatment arms.

CONCLUSIONS

Preoperative radiotherapy increases the risk of anastomotic leakage and stenosis after rectal cancer resection. Clinical leakage independently contributes to the development of stenosis.