Colorectal cancer is becoming a life-threatening disease for young adults, because it is often diagnosed in an advanced stage. In this study, we investigated whether colonoscopy screening for colonic polyps should be made at an earlier age than reported in the current guidelines. Especially since neoplastic colon polyps have malignant potential, it is important to detect these polyps in a sufficiently early stage, when removal of these polyps with a simple procedure can prevent the development of colorectal cancer.
Most current international guidelines recommend the onset age of colonoscopy screening as 50 years of age in people with moderate risk. This is based on the increase of CRC incidence around 50 years of age. In 2009, the diagnosis of CRC was established in people aged 50 years and over by 90% [18]. In a study by Chen et al., one colonoscopy screening in unscreened 50-65 year-old population was expected to prevent mortality from CRC by 49% [19]. In the Canadian Task Force on Preventive Health Care (CTFPEC) guidelines (Canada), colonoscopy screening onset age is recommended as 50 years, allowing postponing of screening until 60 years of age [20].
In 2018, US Preventive Services Task Force (USPSTF) updated the onset age of colonoscopy screening as 45 years in patients with moderate risk [15]. In Saudi Arabia, the onset age of colonoscopy screening is recommended as 45 years, because the diagnosis of CRC is made in 55 years of age in Saudi women and 60 years of age in Saudi men [21]. Studies in the literature have reported that the incidence of CRC is increasing in parallel with the increasing incidences of sedentary lifestyle, obesity, and diabetes mellitus in young adults [22]. In 2013, 50310 people died from CRC in the USA and it has been reported that thousands of these people could be potentially saved with colonoscopy screening at an earlier age [23].
Studies from various countries have reported the incidence of CRC in people aged under 40 years. The incidence of CRC under 40 years of age was reported as 52% in a study from Pakistan [24], 39% in a study from India [25], 36% in a study from Iran [26], and 22% in a study from Korea [27]. In a study from Turkey, the incidence of early-onset CRC was reported as 20% in people aged under 40 years [28]. On the other hand, the incidence of CRC under 50 years of age was reported as 10% in a study from the USA [29], while this rate was reported as 5% in a study from the UK [30]. It is seen that the incidence of CRC in young adults is higher in developing countries compared to developed countries. We attribute this to colonoscopy screening programs being more common in developed countries.
The European Society of Gastrointestinal Endoscopy (ESGE) recommend to evaluate bowel cleanness during colonoscopy and appropriate or good cleanliness should be reported in at least 90% of screenings [31]. In our study, bowel cleanliness, which is among the factors affecting the quality of colonoscopy, was near 100% in all patients.
In a recent study, it was reported that at least 1 polyp was detected in 34.3% of patients undergoing colonoscopy screening [32]. Similarly, in our study, we found at least 1 polyp in 36.9% of patients undergoing colonoscopy.
In our study, the most common indications of colonoscopy in <45 yo patients were found as abdominal pain in 43%, changed bowel habits in 21%, rectal bleeding in 20%, and anemia in 10%. In a study by Mikaeel et al. on colorectal cancer in young adults, indications of colonoscopy in patients aged under 50 years were found as rectal bleeding in 51%, abdominal pain in 16%, anemia in 16%, and changes in bowel habits in 13% [33]. We believe that although the indications in our study were similar to those of the mentioned study, the differences between the rates might have resulted from different sociocultural characteristics and lifestyles between the countries.
Based on the updated recommendations in recent guidelines for performing colonoscopy at an earlier age, we divided our patients into two groups as ≥45 yo and <45 yo and evaluated the data again between these two groups. The presence of polyps and neoplastic polyps was statistically significantly higher in the ≥45 yo group compared to the <45 yo group. However, colonoscopy was performed in 1078 patients in the <45 yo group (52.3%) and pathologic findings were detected in 55.3% of these patients. In a study by Peñaloza et al. in 2017, a total of 411 colonoscopies were analyzed and pathologic findings were observed in 44% of cases. The highest rate of pathologic findings was found in the 41-50-year-old age group [34].
In our study, the most common localization of pathologic findings was rectum (19.6%), followed by sigmoid colon (11.5%). In study of Peñaloza et al., the most common localization was found as sigmoid colon as well [34]. Given that serrated adenomas are more common on the right side, the rate of pathologic findings detected in sigmoid colon was remarkable. Also, recent studies have shown that hyperplastic polyps at the right side of the intestines may have malignant potential and should be closely followed up [5]. In our study, more than 5% of the hyperplastic polyps were localized in the cecum, ascending colon, and transverse colon at the right side.
Overall, no statistically significant difference was found between patients with and without alarm symptoms (weight loss, anemia, etc.). This indicates that performing colonoscopy screening only in patients with alarm symptoms brought the possibility of missing polyps in other patient groups. Therefore, we think that colonoscopy screening should be performed not only in patients with alarm symptoms, but in all patients presenting with lower gastrointestinal complaints.
In our study, there was a significant difference between the numbers of polyps detected by the three examiners. Accordingly, the first examiner found a higher number of polyps than the other examiners. We believe this was resulted from longer colonoscopy durations.
A ROC analysis was performed to determine the cut-off value for the age that creates a risk for a high number of polyps. As a result of this analysis, a cut-off value of 29.5 years was found to create a risk for a high number of polyps with a sensitivity of 98.6% and a specificity of 91.4%. We think that this result suggests the importance of colonoscopy screening at an earlier age.