[Influence of neoadjuvant chemoradiotherapy on peritoneal wound healing after abdominoperineal resection]

Objective: To study the influence of neoadjuvant chemoradiotherapy on peritoneal wound recovery after abdominoperineal resection (APR). Methods: This was a retrospective cohort study of data of 219 patients who had been pathologically diagnosed with low rectal cancer and undergone APR in the Union Hospital of Tongji Medical College of Huazhong University of Science and Technology between January 2018 and December 2021. Of these patients, 158 had undergone surgery without any pre-surgical treatment (surgery group), 35 had undergone surgery after neoadjuvant chemotherapy (neoadjuvant chemotherapy group), and 26 had undergone surgery after neoadjuvant chemoradiotherapy (neoadjuvant chemoradiotherapy group). The primary outcome was perineal wound complications occurring within 30 days. The status of wound healing was classified into the following three levels: Level A: abnormal wound seepage that improved after wound discharge; Level B: wound infection and dehiscence; and Level C: Level B plus fever. The patients' general condition, tumor status, perianal wound healing level, and intra- and post-operative recovery were recorded. Results: None of the study patients had any complications during surgery. The duration of surgery was 240.0 (180.0-300.0) minutes, 240.0 (225.0-270.0) minutes and 270.0 (240.0-356.2) minutes in the surgery, neoadjuvant chemotherapy, and neoadjuvant chemoradiotherapy groups, respectively (H=6.508, P=0.039). The rates of perineal wound complications were 34.6% (9/26) and (22.9%, 8/35)in the neoadjuvant chemoradiotherapy group and the neoadjuvant chemotherapy group, being significantly higher than that in the surgery group (10.1%, 16/158). After adjusting for patient age and sex using a logistic regression model, the risk of complications was still higher in the neoadjuvant chemoradiotherapy than in the surgery group (OR=4.6, 95%CI: 1.7-12.7; OR=2.6, 95%CI: 1.0-6.8), these differences being statistically significant (both P<0.05). The duration of hospital stay was 9.5 (7.0-12.0) days, 10.0 (8.0-17.0) days and 11.5 (9.0-19.5) days for patients in the surgery, neoadjuvant chemotherapy, and neoadjuvant chemoradiotherapy groups, respectively (H=0.569, P=0.752). However, after adjusting for patient age and sex by using a generalized linear model, hospital stay was longer in the neoadjuvant chemoradiotherapy than in the surgery group (β [95% CI]: 4.4 [0.5-8.4], P=0.028). After surgery, 155 of 219 patients required further adjuvant chemotherapy. A higher proportion of patients with than without wound complications did not attend for follow-up (32.2% [10/31] vs. 16.1% [20/124]); this difference is statistically significant (χ²=4.133, P=0.023). Conclusions: In patients with low rectal cancer, neoadjuvant radiotherapy may be associated with an increased risk of perineal wound infection and non-healing.