Aanalysis Of The Risk Factors Of Colorectal Polyp Malignant Transformation

Background and ObjectiveThe number of new cancer cases increases significantly in recent years.Among them, the cases of colorectal cancer increase seriously. According to the latest data published by Cancer in 2010, colorectal cancer is the third most common cancer in men(663,000 cases, 10.0% of the total) and the second in women(570,000 cases, 9.4% of the total) worldwide.About 608,000 deaths from colorectal cancer are estimated worldwide, accounting for 8% of all cancer deaths, making it the fourth most common cause of death from cancer[1]. Colorectal cancer(CRC) is harmful to human health and should be given extensive attention.Granted that a substantial body of evidence in support of the polyp-cancer sequence is already available(Morson & Bussey 1970) and Morson et al reported that CRC has a natural history of transition from precursor to malignant lesion that lasts an average of 10–15 yr[2,3]. Meanwhile, polypectomy has been shown to reduce the incidence and related death from CRC as it was demonstrated in the National Polyp Study that patients that are maintained “adenoma free” are generally kept “cancer free”. It can make the incidence of colorectal cancer reduce by 90% to disrupt the evolution process from adenoma to canceration by endoscopic treatment such as polypectomy[4]. Therefore, it is essential for us to investigate the risk factors of colorectal polyp malignant transformation and analyse the relationship between polyp malignant transformation and age of patients, gender of patients, location of polyps, size and histology type of polyps respectively. Analysis of the related risk factors can not only provide people reliable evidence to find colorectal polyp malignant transformation early but also be crucial for people to take effective intervention measures to reduce the incidence of colorectal cancer and improve the prognosis.Aim of the study is explore the related risk factors of colorectal polyp malignant transformation and provide reliable evidence for clinic diagnose and treatment.MethodsViewing the clinical materials of people who underwent colonoscopies in our hospital during the period from 2003 to 2012, 6334 patients with sporadic polyps confirmed by pathology were enrolled in this study. The statistics are required by analysis the canceration cases according to age, gender, size of polyps, location of polyps respectively. At last, the related risk factors of colorectal polyp malignant canceration are explored by analysis of the statistics with chi-square test.Results(1)During the period from 2003 to 2012, there were 6334 patients who underwent the colonoscopy and had sporadic polyps confirmed by pathology. All patients enrolled in the study were in the age of 2-93 years old, and means and standard errors of the age was 53.99±13.28. Specifically, there were 1564 subjects aged 2–44 yr, 2443 subjects aged 45–59 yr, 2037 subjects aged 60–74 yr, and 290 subjects aged 75–93 yr. The ratio of male to female was 1.48:1 and specifically there were 3776 men and 2558 women among them. 4011 cases of patients had single polyp and 2323 cases had multiple polyps. There were 1030 cases of patients with polyps located in the proximal, 4426 patients with polyps located in the distal, and 878 patients with polyps located in the whole intestine.Among the patients enrolled in the study, there were 3625 patients with polyp whose diameter was less than 1cm, 779 with polyp whose diameter was between 1cm and 2cm, and 1930 with polyp whose diameter was large than 2cm. Of the 2031 cases of inflammatory hyperplastic polyps, 1 case was with malignant transformation, while 934 cases with maligmant transformation in the 4303 cases of adenomatous polyps. Among the 4303 patients with adenomatous polyps enrolled,there are 2778 patients with tubular adenomas, 959 with tubulovillous adenoma, 543 with villous adenoma and 23 with serrated adenoma.(2)The number of patients whose polyps were located in the whole intestine increased with the growth of age.(3)The number of proximal and distal polyps in female were significantly higher than that in male(P= 0.000 and P=0.027 respectively), while the number of the whole intestine polyps in male were significantly higher than that in female(P= 0.000).(4)There were no significant differences in the grade of the intraepithelial neoplasia of polyp(P= 0.127) and the malignant transformation rate of polyp had statistically significant differences between different age groups( P= 0.000).At the same time, the malignant transformation rate of polyp increased obviously with the growth of age and the differences between any two age groups had statistically significance(P<0.00833).(5)There were no significant differences in the extent of intraepithelial neoplasia and the rate of malignant transformation of polyp between different gender(P= 0.211 and P= 0.411 respectively).(6)There were significant differences in the extent of intraepithelial neoplasia and the rate of malignant transformation of polyp distributing in different anatomic location of the intestine( P= 0.003 and P= 0.009 respectively).We further found that the intraepithelial neoplasia extent of polyp in the distal intestine was statistically more serious than that in the whole intestine( P< 0.0167). And the malignant transformation rate of polyp in the distal was statistically significant higher than that in the proximal intestine(P< 0.0167).(7)The grade of intraepithelial neoplasia and the rate of malignant transformation of polyp with different diameter had significant differences( P=0.000 and P= 0.000 respectively). The grade of intraepithelial neoplasia, as well as the rate of malignant transformation obviously increased and differences between any two size groups had statistically significance(P<0.0167) with the increase of the diameter of polyp.(8)There were statistically significant differences in the intraepithelial neoplasia and the rate of malignant transformation of polyp with different histology type(P= 0.000 and P= 0.000 respectively). Showed by comparison between groups, the detection rate of inflammatory hyperplastic polyp was statistically lower than any other histological types of polyps(P<0.005). The malignant transformation rate of polyp was obviously increased statistically with the increase of hair ingredients among tubular adenoma, tubular –villous and villous adenoma, and the differences between them had statistically significance(P<0.005).Conclusion(1)The patients of colorectal polyp were mainly in the age of 45-74 year, accounting for 70.73% and the male to female ratio was 1.48:1.(2)There were expansion in polyp distribution range with the increase of age.(3)Male was more susceptible to colorectal polyps which distributed in the whole intestine than female.(4)The malignant transformation rate of polyp increased obviously with the growth of age.(5)The gender was not the dangerous factor leading to colorectal polyp malignant transformation.(6)The malignant transformation rate of polyp in the distal was higher than that in the proximal intestine.(7)With the increase of the diameter of polyp, the rate of malignant transformation obviously increased.(8)The malignant transformation rate of polyp was obviously increased statistically with the increase of hair ingredients of polyps.(9)It was essential to take endoscopic treatment to prevent colorectal cancer for patients whose age was more than 45 year, with adenoma whose size was more than 1cm and located in left-side of the intestine.