Colorectal cancer is becoming a life threat 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 has 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.
Majority of the current international guidelines recommend onset age of colonoscopy screening as 50 years in persons with an average risk. This is based on the increase of CRC incidence about 50 years old. In 2009, the diagnosis of CRC was established in persons aged 50 years and over by 90% [18]. In a study by Chen et al., one colonoscopy screening in unscreened 50–65 years old population is 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 old [20].
In 2018, US Preventive Services Task Force (USPSTF) updated onset age of colonoscopy screening as 45 years old in average-risk patients [15]. In Saudi Arabia, onset age of colonoscopy screening is recommended as 45 years old, because the diagnosis of CRC is made in 55 years old in Saudi women and 60 years old 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 adult age group [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 an an earlier age [23].
In studies from various countries, the incidence of CRC in persons aged under 40 years has been reported. The incidence of CRC under 40 years old 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 persons aged under 40 years [28]. On the other hand, the incidence of CRC under 50 years old 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 the developed countries. We attribute this to more common colonoscopy screening programs 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 screening colonoscopy [32]. Similarly, in our study we found at least 1 polyp in 36.9% of the patients undergoing colonoscopy.
In our study, the most common indications of colonoscopy in < 45 yo patients were found as abdominal pain by 43%, changed bowel habits by 21%, rectal bleeding by 20%, and anemia by 10%. In a study by Mikaeel et al. investigating colorectal cancer in young adults, indications of colonoscopy in patients aged under 50 years were found as rectal bleeding by 51%, abdominal pain by 16%, anemia by 16%, and changed bowel habits by 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 be resulted from different sociocultural characteristics and lifestyle 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 ≥ 45 yo group compared to < 45 yo groups. However, colonoscopy was performed in 1078 patients < 45 yo (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 by 44%. The highest rate of pathologic findings were found in 41–50 years age group [34].
In our study, the most common localization of pathologic findings was rectum (19.6%) followed by sigmoid colon (11.5%). In the study by Peñaloza the most common localization was found as sigmoid colon [34]. Given that serrated adenomas are more common on the right side, the rate of pathologic findings detected in sigmoid colon was remarkable. In addition, 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.
In overall patients, no statistically significant difference was found between the patients with and without alarm symptoms (weight loss, anemia, etc.). This indicated that colonoscopy screening only in patients with alarm symptoms brought the possibility of missing polyps in the other patient groups. Therefore, we think that colonoscopy screening should be performed not only in patients with alarm symptoms, but also in all persons at a sufficiently early age and should be repeated with certain periods.
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 experience of the examiner and longer colonoscopy durations.
A ROC analysis was performed in order to determine age cut-off value that creates a risk for a high number of polyps. As a result of this analysis, 29.5 years old age cut-off value was found to create a risk for a high number of polyps by 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.
In conclusion; given the increasing incidence of early-onset CRC worldwide colonoscopy screening should be performed in young adults without alarm symptoms who present with abdominal pain. Better outcomes would be obtained with colonoscopy screening in young adults at an earlier age in terms of the prevention of cancer with detection and excision of colon polyps at a precancerous stage. In addition, colonoscopy should be performed by experienced gastroenterologists. In our study, the more experienced endoscopist detected more polyps than the others. Experience of the endoscopist, bowel cleaning and duration of withdrawing fom the cecum affects the number of detected polyps. Furthermore this screening should be performed in a longer duration in order to avoid missing of polyps. Based on our results, we believe that onset age of screening for colon polyps should be 45 years as recommended by updated guidelines.