Analysis of clinical and pathological factors in patients undergoing surgery for rectal cancer: a single-centre experience with 692 patients in China
Authors: Xu Liping , Zhang Chi , Zhang Zhaoyue , Tang Xinyu , Qin Qin , Sun Xinchen 
Published: March 2020

Abstract
Background: The management of rectal carcinoma has substantially evolved over the past two decades, so as AJCC staging and NCCN guidelines. The inherent relationships of pathologic factors warrant further study. The present study aimed to assess the associations of clinical and pathological factors in rectal cancer patients undergoing radical surgery.Methods: From October 2015 to February 2019, all rectal cancer patients treated with radical surgery without neoadjuvant therapy were identified. The analysis was performed with data obtained from the prospectively collected database. Predictive factors for lymph node metastasis were analysed.Results: In total, 692 patients with a median age of 61.64 years (range: 22-89) were included. There was no significant difference in onset age between male and female patients (61.75±11.10 vs 61.43±11.92, P=0.723).Tumour location (P=0.004), perineural invasion (PNI) (P=0.000), lymphovascular invasion (LVI) (P=0.000), tumour deposit (TD) (P=0.000), and differentiation grade (P=0.000) were significantly related to pathologic T stage in univariate analysis, while sex was not (p=0.192).Compared to patients with T1 disease, there was a significantly higher proportion of positive LVI in patients with stage T3 disease (P=0.011, OR=3.404, 95% CI: 1.319-8.787) but not in those with T2 (P=0.686, OR=0.804, 95% CI: 0.280-2.310) and T4 (P=0.063, OR=3.200, 95% CI: 0.941-10.886) disease. Compared to patients with T2 disease, there was a significantly higher proportion of perineural invasion in patients with stage T3 (P=0.000, OR=6.2376, 95% CI: 3.371-11.685) but not T4 (P=0.172, OR=2.309, 95% CI: 0.694-7.676) disease. Compared to patients with T1 disease, a significantly higher proportion of TDs occurred in patients with stage T3 (P=0.013, OR=6.106, 95% CI: 1.455-25.631) and stage T4 (P=0.019, OR=7.146, 95% CI: 1.378-37.044) but not stage T2 (P=0.435, OR=0.503, 95% CI: 0.089-2.824) disease. The overall incidence of lymph node metastasis was 44.9% (19.6% for T1, 23.6% for T2, 56.7% for T3, and 67.8% for T4). Patient age, sex, and tumour location did not significantly affect lymph node metastasis (LNM). The presence of LVI (OR=3.882, 95% CI=2.338-6.440, P=0.000), TD (OR=27.645, 95% CI=9.805-77.947, P=0.000), higher T stage (OR=1.969, 95% CI=1.471-2.635, P=0.000), and poorly differentiated histology (OR=2.255, 95% CI=1.544-3.293, P=0.000) were associated with a higher incidence of LNM on multivariate analysis. Perineural invasion (P=0.000) significantly affected LNM in univariate but not multivariate analysis (OR=1.213, 95% CI=0.734-2.003, P=0.452).Conclusion: There was no significant difference between male and female patients in onset age. Tumour location, PNI, LVI, TD, and differentiation grade were significantly related to pathologic T stage. Patients with the presence of LVI and TD, higher T stage, and poorly differentiated histology have a significantly higher chance of LNM.