Introduction
The incidence of early-onset colorectal cancer has been increasing worldwide, and action is urgently needed to address this problem. Although we have previously reported age-related changes with respect to molecular pathology, the vast majority remains unknown regarding the clinicopathologic characteristics of early-onset colorectal cancers and adenomas, especially those resected by endoscopic approaches. In this study, we defined early-onset colorectal tumors as adenoma and carcinoma diagnosed age at 40 or under. The aim of this study was to examine the clinicopathologic characteristics of endoscopically resected early-onset colorectal tumors compared with later-onset colorectal tumors diagnosed at age 40 or older.
Aims & Methods
We examined the clinicopathological characteristics of endoscopically resected colorectal adenomas and carcinomas in 1,005 patients with 2,367 lesions including early-onset colorectal carcinoma/adenoma (159 lesions in 96 consecutive cases from January 2010 to December 2020), late-onset colorectal carcinoma (183 lesions in 90 cases from January 2010 to December 2020), and late-onset adenoma (2,025 lesions in 819 consecutive cases from January 2020 to July 2020) endoscopically resected at the Nippon Medical School Hospital. The chi-square test was used to compare categorical variables, and the Mann-Whitney U test was used to compare continuous variables.
Results
Median age (quartiles) and sex (female/male) of cases were 37 (34-38), 34 (35%) / 62 (65%) in the early-onset tumor group; and 55 (46-72), 277 (30%) / 632 (70%) in the late-onset tumor group, respectively. The distribution rate of tumor location was 49 cases (31%) for proximal colon, 97 (61%) for distal colon, 13 (8.2%) for rectum in the early-onset group; and 1085 (49%), 899 (41%), 83 (10%) in the later-onset group, respectively. Macroscopic types were classified into Ip for 46 cases (29%), Is and Isp for 100 (63%), II for 13 (8.2%) in the early-onset group; and 278 (13%), 1574 (71%), 356 (16%) in the late-onset group, respectively. Histological types were classified into tubular adenocarcinoma or papillary carcinoma for 14 cases (8.8%), high-grade tubular adenoma (TA) for 36 (23%), low-grade TA for 97 (61%), sessile serrated lesion or traditional serrated adenoma for 12 (7.5%) in the early-onset tumor group; and 183 (8.3%), 281 (13%), 1655 (75%), 89(4%), respectively. Compared with the later-onset colorectal tumors, a higher rate of left-sided tumor location and macroscopic type Ip was observed in the early-onset colorectal tumor (p <0.001, respectively). When limited to adenoma lesions, the rate of high-grade was significantly higher in the early-onset colorectal adenomas than those in the later-onset colorectal adenomas.
Conclusion
Regarding tumor location and macroscopic type, unique clinicopathological features were observed in early-onset colorectal tumors compared with later-onset colorectal tumors. Further studies are needed to investigate the association between early-onset colorectal cancer and adenomas stratified by the method by tumor resection.