Hematochezia is also one of the most common presentations of colorectal cancer [1]. Colonoscopy is considered as the most effective modality to evaluate patients with suspected colorectal cancer. Generally, colonoscopy is indicated in patients presenting with hematochezia aged >50 years. On the other hand, most cases of hematochezia are related to benign anorectal diseases in patients aged less than 40 years. Therefore, sigmoidoscopy is usually performed to evaluate these patients. Although several recent studies have shown the efficacy of colonoscopy in patients aged <50 years [2-4], its role in patients aged <40 years is debatable. So far, few studies have evaluated the necessity of colonoscopy, or the sufficiency of sigmoidoscopy in patients with hematochezia aged under 40 years [4-8].

Tang et al. report an analysis on colonoscopies performed in patients aged <40 years [9]. This single-center retrospective study included rectal bleeding in 115 and 338 patients aged <30 and 30–39 years, respectively. The major cause of bleeding was hemorrhoids. Another result of the study was that 67 colonic polyps were detected in 63 patients. The polyps were hyperplastic polyps (n=35), tubuloadenomas with low-grade dysplasia (n=30), advanced adenoma (n=1), and malignant polyp (n=1). Excluding hyperplastic polyps, the overall incidence of polyps was 6.5%. The incidence of polyps in the group aged 3,039 was significantly higher than that in the group aged <30 years (7.4% vs. 1.7%, p=0.026). While the majority of the polyps in both groups were detected in the distal colon, approximately a quarter of was proximally located in the group of aged 30–39 years.

The result of this study differed from that of previous studies, which concluded that colonoscopy in patients under 40 years of age was unnecessary due to relatively low rates of polyp detection. In this study, colonic polyps are more prevalent in patients aged 30–39 years than in those aged <30 years. Compared with the incidence of colonic neoplastic lesions in patients aged 40–50 years in previous studies (9.9%–17.9%) [2-4], the occurrence rate of neoplastic lesions in patients aged 30–39 years (7.4%), in our study, is noteworthy. Also, a quarter of the polyps in patients aged 30–39 years were located in the proximal colon which was contrary to a previous study that reported that sigmoidoscopy was sufficient because most polyps were mainly found in the distal colon [8]. It suggests that sigmoidoscopy may be insufficient for young patients aged 30–39 years according to this study’s result.

This study had some limitations. First, it was a single-center, retrospective study and the sample size was relatively small. Second, in this study, most colonic polyps were asymptomatic and usually detected during screening tests. Colonic polyps that were incidentally detected during colonoscopy were unrelated to hematochezia. Therefore, recommending colonoscopy in young patients with hematochezia to detect polyp is not based on the study result because we observed no direct relationship between colonic polyps and hematochezia. In addition, there was a case of a patient who suffered from colonic perforation. The colonoscopic-related complications such as perforation could be fatal. Considering the benefits and risks of colonoscopy in patients with hematochezia, it might be better to conduct sigmoidoscopy rather than colonoscopy to determine the cause of rectal bleeding in young patients.

A recently published study suggested that the incidence of colorectal cancer in young patients is increasing, and their characteristics tend to present with a higher pathologic grade, a greater incidence of recurrence, and metastatic disease [10]. Therefore in developed countries such as Singapore and South Korea where hospitals that can offer colonoscopy to younger patients with hematochezia are easily accessible, the necessity of colonoscopy in patients aged of <40 years having hematochezia should be considered. The detection and removal of polyps which are precursors to colorectal neoplasia is also meaningful in that group of patients.