[Comparison of short-term efficacy and perioperative safety between neoadjuvant therapy and total neoadjuvant therapy in patients with locally advanced rectal cancer]

Abstract

Objective: To compare the short-term efficacy and perioperative safety of neoadjuvant chemoradiotherapy (nCRT) with total neoadjuvant treatment (TNT) in patients with locally advanced rectal cancer (LARC). Methods: A retrospective cohort analysis was carried out. Inclusion criteria: (1) rectal adenocarcinoma confirmed by pathology with a distance from tumor inferior border to anal verge within 12 cm; (2) clinical stage cT3-4N0 or cT1-4N1-2 diagnosed by magnetic resonance imaging (MRI) or endorectal ultrasonography; (3) a single rectal tumor confirmed by colonoscopy; (4) patients suitable for chemoradiotherapy; (5) no previous history of other tumors. Exclusion criteria: (1)patients with previous rectal cancer surgery and local recurrence; (2) those who did not complete nCRT course; (3) those with distant metastases; (4) those with defective clinicopathological data. According to the above criteria, a total of 134 LARC patients at the Department of General Surgery of Beijing Chaoyang Hospital from January 2016 to January 2019 were enrolled, including 82 males and 52 females, with a male-female ratio of 1.58∶1.00 and mean age of (59.6±11.2) (26-81) years. Based on neoadjuvant regimen, patients were divided into nCRT group (n=55) and TNT group (n=79). There were no statistically significant differences in baseline data, such as age, sex, distance from tumor to anal verge, Eastern Cooperative Oncology Group (ECOG) performance status and clinical TNM stage, between the two groups (all P>0.05). All the patients received pelvic intensity-modulated radiotherapy (IMRT) with a total dose of 50.4 Gy in 28 fractions. Patients in nCRT group received oral capecitabine chemotherapy during radiotherapy and underwent surgery 6-8 weeks after chemoradiation. Patients in TNT group received one cycle of induction CapeOX (oxaliplatin and capecitabine) and concurrent chemoradiotherapy, then underwent a radical surgery two weeks after completion of consolidation chemotherapy. The efficacy of neoadjuvant therapy, adverse events of chemoradiotherapy and perioperative safety were compared between the two groups. Results: Patients of two groups completed the course of neoadjuvant therapy. There were no statistically significant differences between nCRT group and TNT group in the incidence of adverse events in neutropenia [7.3% (4/55) vs. 10.1% (8/79)], anemia [3.6% (2/55) vs. 3.8% (3/79)], thrombocytopenia [5.5% (3/55) vs. 7.6% (6/79)], gastrointestinal dysfunction [3.6% (2/55) vs. 6.3% (5/79)] and radiation enteritis [9.1% (5/55) vs. 8.9% (7/79)] (all P>0.05). One hundred and thirty patients completed TME surgery, including 54 patients in nCRT group and 76 patients in the TNT group. Compared with the nCRT group, the proportion of abdominoperineal resection (APR) was higher in the TNT group [31.6% (25/76) vs. 13.0% (7/54), χ(2)=9.382, P=0.009]. No statistically significant differences in morbidity of postoperative complication, operation time, intraoperative blood loss and postoperative hospital stay between the two groups were found (all P>0.05). The distal and circumferential margins were negative in all the patients. Seventeen patients in the TNT group 22.4% (17/76) got pathologic complete response (pCR), which was significantly higher than 7.4% (4/54) in nCRT group (χ(2)=5.217, P=0.022). There were no statistically significant differences in ypTNM classification, perineural invasion and venous invasion between the two groups (all P>0.05). Conclusion: The pCR of TNT is higher than that of nCRT without increasing the incidence of toxicity and complications of radiotherapy and chemotherapy for patients with locally advanced rectal cancer.

Keywords: Neoadjuvant chemoradiotherapy; Rectal neoplasms, locally advanced; Total neoadjuvant treatment.