Tumor budding

Metastasis

Biology

Colorectal cancer

Adenocarcinoma

Cecum

Single Center

Rectum

Lymphovascular invasion

Mucinous carcinoma

Lymph node

Descending colon

Paleontology

Stage (stratigraphy)

Internal medicine

Pathological

Hepatology

Sigmoid colon

Medicine

Gastroenterology

Lymph node metastasis

Lymphatic system

Cancer

Pathology

International Journal of Colorectal Disease

Purpose Although some studies have reported differences in clinicopathological features between left- and right-sided advanced colorectal cancer (CRC), there are few reports regarding early-stage disease. In this study, we aimed to compare the clinicopathological features of left- and right-sided T1 CRC. Methods Subjects were 1142 cases with T1 CRC undergoing surgical or endoscopic resection between 2001 and 2018 at Showa University Northern Yokohama Hospital. Of these, 776 cases were left-sided (descending colon to rectum) and 366 cases were right-sided (cecum to transverse colon). We compared clinical (patients age, sex, tumor size, morphology, initial treatment) and pathological features (invasion depth, histological grade, lymphatic invasion, vascular invasion, tumor budding) including lymph node metastasis (LNM). Results Left-sided T1 CRC showed significantly higher rates of LNM (left-sided 12.0% vs. right-sided 5.4%, P &lt; 0.05) and lymphatic invasion (left-sided 32.7% vs. right-sided 23.2%, P &lt; 0.05). Especially, the sigmoid colon and rectum showed higher rates of LNM (12.4% and 12.1%, respectively) than other locations. Patients with left-sided T1 CRC were younger than those with right-sided T1 CRC (64.9 years ±11.5 years vs. 68.7 ± 11.6 years, P &lt; 0.05), as well as significantly lower rates of poorly differentiated carcinoma/mucinous carcinoma than right-sided T1 CRC (11.6% vs. 16.1%, P &lt; 0.05). Conclusion Left-sided T1 CRC, especially in the sigmoid colon and rectum, exhibited higher rates of LNM than right-sided T1 CRC, followed by higher rates of lymphatic invasion. These results suggest that tumor location should be considered in decisions regarding additional surgery after endoscopic resection. Trial registration This study was registered with the University Hospital Medical Network Clinical Trials Registry ( UMIN 000032733 ).

Left-sided location is a risk factor for lymph node metastasis of T1 colorectal cancer: a single-center retrospective study