The emperor has no clothes-the need for standardized anatomical segment definitions in the management of colon cancer

There is no standardized classification system for defining segments of colon carcinoma within cancer registries. We aimed to conduct a systematic literature review on studies that specifically address colon cancer and provide definitions for each segment.

Five authors conducted an independent systematic literature search of studies on colon cancer between 01/1992 and 11/2023. Only English-language original articles including cohort studies, case series, previous reviews, meta-analyses, and randomized clinical trials were considered for inclusion. Exclusion criteria were case reports, editorials, and letters. After identifying the relevant studies, those describing particular colon cancer segments were assessed. Whether or not oncologic outcomes were assessed, whether any definitions for particular colon cancer segments were used, were reviewed and extracted.

A total of 9059 articles were screened, and 1143 of them were identified and included in the current study. Out of 1143 included articles, 130 defined the specific colon cancer segment. Distribution of included articles with definition ratios for each segment was as follows: Cecum (n = 2; 2.35%), ascending colon (n = 2; 1.94%), hepatic flexure (n = 2; 33.3%), transverse colon (n = 33; 42.85%), splenic flexure (n = 38; 58.46%), descending colon (n = 16; 8.04%), sigmoid colon (n = 34; 4.99%), and rectosigmoid colon (n = 16; 15.23%). A total of 397 articles reported long-term oncologic outcomes.

Our study unveils discrepancies in the published literature, revealing that nearly 10% of the studies focusing on colon cancer provide various definitions for each colonic segment. Standardizing the definitions of colon cancer segments is essential to prevent the use of arbitrary definitions, which can result in inconsistency and hinder accurate outcome assessments.