Meta-analysis of predictive clinicopathologic factors for lymph node metastasis in patients with early colorectal carcinoma

Abstract

The objective of this study was to conduct a meta-analysis to determine risk factors that may facilitate patient selection for radical resections or additional resections after a polypectomy. Eligible articles were identified by searches of PUBMED, Cochrane Library and Korean Medical Database using the terms (early colorectal carcinoma [ECC], lymph node metastasis [LNM], colectomy, endoscopic resection). Thirteen cohort studies of 7,066 ECC patients who only underwent radical surgery have been analysed. There was a significant risk of LNM when they had submucosal invasion (≥ SM2 or ≥ 1,000 µm) (odds Ratio [OR], 3.00; 95% confidence interval [CI], 1.36-6.62, P = 0.007). Moreover, it has been found that vascular invasion (OR, 2.70; 95% CI, 1.95-3.74; P < 0.001), lymphatic invasion (OR, 6.91; 95% CI, 5.40-8.85; P < 0.001), poorly differentiated carcinomas (OR, 8.27; 95% CI, 4.67-14.66; P < 0.001) and tumor budding (OR, 4.59; 95% CI, 3.44-6.13; P < 0.001) were significantly associated with LNM. Furthermore, another analysis was carried out on eight cohort studies of 310 patients who underwent additional surgeries after an endoscopic resection. The major factors identified in these studies include lymphovascular invasion on polypectomy specimens (OR, 5.47; 95% CI, 2.46-12.17; P < 0.001) and poorly or moderately differentiated carcinomas (OR, 4.07; 95% CI, 1.08-15.33; P = 0.04). For ECC patients with ≥ SM2 or ≥ 1,000 µm submucosal invasion, vascular invasion, lymphatic invasion, poorly differentiated carcinomas or tumor budding, it is deemed that a more extensive resection accompanied by a lymph node dissection is necessary. Even if the lesion is completely removed by an endoscopic resection, an additional surgical resection should be considered in patients with poorly or moderately differentiated carcinomas or lymphovascular invasion.

Keywords: Colectomy; Colorectal Neoplasms; Endoscopy; Lymph Nodes.

Fig. 1. Flowchart of patient selection. (A) Patients with radical surgery. (B) Patients with additional surgeries after an endoscopic resection.

Fig. 2. Forest plots for lymph node metastasis in early colorectal carcinoma patients who underwent radical surgery. Categorized by (A) grossly depressed carcinoma vs. elevated carcinoma, (B) poorly or moderately differentiation vs. well differentiation, (C) lymphatic invasion vs. absence of lymphatic invasion, (D) vascular invasion vs. absence of vascular invasion. (E) SM2 or ≥ 1,000 µm vs. SM1 or < 1,000 µm, and (F) tumor budding vs. absence of tumor budding.

Fig. 3. Forest plots for lymph node metastasis in early colorectal carcinoma patients who underwent additional surgeries after an endoscopic resection. Categorized by (A) lymphovascular invasion vs. absence of lymphovascular invasion, (B) positive margin vs. clear margin at the time of endoscopic resection, and (C) poorly or moderately differentiation vs. well differentiation.