Incidence and Multiplicities of Adenomatous Polyps in TNM Stage I Colorectal Cancer in Korea.

Purpose: In recent years, the incidence of early-stage colorectal cancer (CRC) has markedly increased in the population within the Republic of Korea. The aim of this study was to evaluate the clinicopathologic features of adenomatous polyps in TNM stage I CRC patients and in the general population.

Methods: Between March 2003 and September 2009, 168 patients with stage I CRC were enrolled in this study. In addition, the records of 4,315 members of the general population without CRC, as determined by colonoscopy during a health check-up, were reviewed.

Results: Of the 168 patients with stage I CRC, 68 (40.5%) had coexisting colorectal adenomatous polyps and of the 4,315 members of the general population, 1,112 (26.0%) had coexisting adenomatous polyps (P = 0.006). The prevalences of adenomatous polyp multiplicity in early CRC and in the general population were 32% and 15%, respectively (P = 0.023). Patients with coexisting adenomatous polyps had a higher frequency of tubulovillous or villous adenomas than members of the general population with polyps (7.5% vs. 2.0%, P = 0.037). Furthermore, a subgroup analysis showed that the occurrence (44% vs. 34%, P = 0.006) and the multiplicity (32% vs. 15%, P = 0.023) of adenomatous polyps were greater for T2 than T1 cancer.

Conclusion: The prevalence and the multiplicity of adenomatous polyps in TNM stage I CRC is higher than it is in the general population. The findings of this study suggest that depth of invasion of early stage CRC affects the prevalence and the number of adenomatous polyps in the remaining colon and rectum.