Abstract:
Objective To investigate the regression of regional lymph nodes after administering neoadjuvant short-course chemoradiotherapy combined with immunotherapy in patients with locally advanced rectal cancer (LARC).
Methods This retrospective study analyzed the clinical data of 40 patients with LARC admitted to Zhongshan Hospital Affiliated to Xiamen University (32 cases) and the Union Hospital, Tongji Medical College, Huazhong University of Science and Technology (8 cases) between January 2021 and December 2022. The control and experimental groups consisted of 20 patients who underwent direct laparoscopic surgery and neoadjuvant short-course chemoradiotherapy combined with immunotherapy prior to the laparoscopic surgery, respectively. The detection of the postoperative lymph node was compared between the two groups. In addition, the pathologic complete response (pCR) rate of the primary tumor and regional lymph nodes in the experimental group was assessed.
Results The number of patients with N downstaging (18 vs. 7, P<0.001) significantly increased, whereas the positive lymph node metastasis rate (1.4% vs. 19.1%, P<0.001) and number of patients with positive lymph nodes (4 vs. 16, P<0.001) significantly decreased in the experimental group compared to those in the control group. Although the number of detected lymph nodes in the experimental group was slightly lower compared to that in the control group (18.3±8.7 vs. 20.4±6.5, P=0.392), it was not statistically different. Furthermore, the pCR rate of the regional lymph nodes was significantly higher than that of the primary tumor in the experimental group (80% vs. 30%, P=0.001).
Conclusions Neoadjuvant short-course chemoradiotherapy combined with immunotherapy caused significant pathological remission of positive lymph nodes in patients with LARC. This study hypothesizes that a “spatial effect” contributes to the pathological remission of regional lymph nodes in rectal tumors.