Abstract
PurposeAlthough 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.MethodsSubjects 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).ResultsLeft-sided T1 CRC showed significantly higher rates of LNM (left-sided 12.0% vs. right-sided 5.4%, P < 0.05) and lymphatic invasion (left-sided 32.7% vs. right-sided 23.2%, P < 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 < 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 < 0.05).ConclusionLeft-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 registrationThis study was registered with the University Hospital Medical Network Clinical Trials Registry (UMIN 000032733).
Highlights
Colorectal cancer (CRC) is one of the most common cancers worldwide
We compared the clinicopathological features of left-sided T1 CRC with right-sided CRC
More careful management would be required for leftsided T1 CRC when determining the need for additional surgery after endoscopic resection
Summary
Colorectal cancer (CRC) is one of the most common cancers worldwide. In Japan, the incidence and mortality of CRC have increased during the last several decades. Compared with right-sided CRC, left-sided advanced (T2– T4) CRC has the following features: longer overall survival; Int J Colorectal Dis (2020) 35:1911–1919 younger patients; higher number of male patients; less mucinous or poorly differentiated histology; less associated with BRAF and APC mutations, microsatellite instability (MSI), and CpG island methylator phenotype (CIMP); and better response to anti-epidermal growth factor receptor (EGFR) therapies. Many studies have investigated the differences in epidemiology, pathogenesis, genetic alterations, and molecular pathways between left- and right-sided advanced CRC, as well as those that divided the location of CRC into the colon and rectum [14,15,16]. Few articles have focused on the differences in early-(T1) stage disease and divided the tumor location into the left- and right-sided colon. The present study was designed to evaluate the clinicopathological characteristics between left- and right-sided T1 CRC
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