THE PREVALENCE OF THE TYPES OF POLYPS ON SCREENING COLONOSCOPY:
A FIVE YEAR CROSS-SECTIONAL STUDY
MMU Dujunco, MD, JANPangilinan, MD. St. Luke’s Medical Center, Quezon City
Significance: This is the first study in the Philippines to determine the prevalence of histologic types of polyps on screening colonoscopy. This data can guide physicians in colorectal cancer screening.
Methodology: This is a 5 year cross-sectional study of all completed screening colonoscopies done in a tertiary institution. Cases with polyps, with no histopathologic diagnosis were excluded. Prevalence of the type of polyp per location per sex was computed using SPSS. Comparison of the prevalence of the different histopathologic types of colonic polyps by colon localization was analyzed using the calculated 95% confidence interval by Epi Info. Level of significance was set at alpha = 0.05.
Results: In 3608 completed screening colonoscopies, 1253 of cases (34.7%) had polyps. The prevalence of polyps in male is higher (40.3% vs. 30.2%). Overall prevalence of hyperplastic polyps, tubular adenoma and tubulovillous adenoma are 17.7% (CI 16.4% – 19.0%), 20.1% (CI 18.8% - 21.5%) and 1.3% (1.0% - 1.78%), respectively. In all types of polyps, the prevalence was highest in the left colon as follows: hyperplastic 10.8% (CI 9.8% - 11.9%), tubular adenoma 13.1% (CI 12.1% - 14.3%), and tubulovillous adenoma 0.8% (CI 0.6% - 1.2%). Six cases of adenocarcinoma were likewise detected. The highest prevalence of polyps occurred in the group aged 50 to 75 years old.
Conclusion: Tubular adenomas are the predominant histologic type and majority are in the left colon, as in the West and in Southern Indian population. However, 11% of cases with polyps occurred in the right and transverse colon.