Risk of advanced proximal adenoma and cancer according to rectosigmoid findings in the Korean population

Colorectal cancer is one of the leading causes of cancer death in the United States and Europe. Recently, the incidence of colorectal cancer has been increasing remarkably in Korea. To reduce the high incidence, screening of colorectal cancer in asymptomatic individuals has been advocated. Sigmoidoscopy is simpler, faster, and better tolerable than total colonoscopy, but the scope cannot reach the proximal colon segment and, therefore, may miss proximal colon cancer. In the present study, we intended to investigate the prevalence of proximal adenoma and cancer according to the findings in rectosigmoid colon and to find their risk factors. Data were collected retrospectively from 1541 consecutive patients who underwent total colonoscopy at the Department of Gastroenterology, Hanyang University, between October 2003 and December 2004. Neoplasms were classified as diminutive adenoma (< or =5 mm), small adenoma (6-9 mm), advanced adenoma (> or =10 mm, with villous component or high-grade dysplasia), and cancer. The sites of neoplasms were defined as rectosigmoid (rectum and sigmoid colon) and proximal (from cecum to descending colon) colon. The prevalence of advanced proximal adenoma was associated with severe rectosigmoid findings. On the other hand, the prevalence of proximal colon cancer did not show such a tendency. Among the 131 patients with proximal advanced adenoma, 66% had no neoplasm in the rectosigmoid colon. Moreover, among the 27 patients with proximal cancer, 52% had no neoplasm in the rectosigmoid colon. Multivariate logistic regression analysis revealed that age, gender, and advanced rectosigmoid adenoma were the risk factors of advanced proximal adenoma, but nothing was associated with the risk for proximal colon cancer. Advanced rectosigmoid adenoma may be the predictor of advanced proximal adenoma, especially in old males. However, nothing is related to the risk for proximal colon cancer. Therefore, colonoscopy may be more adequate for colorectal cancer screening than sigmoidoscopy in the Korean population.

Colorectal cancer in Asians: a demographic and anatomic survey in Malaysian patients undergoing colonoscopy

BACKGROUND

Colorectal cancer is one of the most common forms of gastrointestinal cancer in the world today. In the Asia-Pacific area, it is the fastest emerging gastrointestinal cancer.

AIM

To determine the basic demographic features of patients with colorectal cancer and the anatomic distribution and characteristics of the tumour in a local Asian population.

METHODS

We conducted a review of consecutive patients who had undergone colonoscopy from 1999 to 2003 at the University of Malaya Medical Center, Kuala Lumpur, Malaysia.

RESULTS

Analysis was carried out on 3404 patients who underwent colonoscopy. A total of 228 patients (7%) were diagnosed with carcinoma. The mean age of diagnosis (+/-s.d.) was 64.4 +/- 13.1 years. The male to female ratio was 1.15. Polyps were noted in 470 patients (14%). Polyps detected concomitantly with a colorectal cancer were noted in 55 patients (2%). Four patients (0.1%) were diagnosed to have familial adenomatous polyposis coli. Of the 228 patients 209 (92%) had tumours at only one site whereas 19 (8%) had synchronous lesions. Tumours were mainly left sided [198 of 248 patients (80%)] with the majority located in the recto-sigmoid region. Detailed records of treatment were available only in 176 patients. A total of 147 of 176 patients (84%) underwent surgery and 50 (28%) also received adjuvant or palliative chemotherapy (28%). Seven of 154 patients (5%) were diagnosed to have stage A cancers, 64 (42%), stage B, 23 (15%), stage C and 60 (39%), stage D. Multivariate analysis using multiple logistic regression analysis showed that age > or =65 years (OR = 1.78; 95% CI: 1.35- 2.36) and Malay (OR = 2.09; 95% CI: 1.30-3.35) and Chinese (OR = 1.77; 95% CI: 1.77-2.69) race were significant independent predictive factors for colorectal cancer.

CONCLUSIONS

The demography of colorectal cancer is different from western patients. Tumours were mainly left sided in our patients. However, no differences in anatomic location were found between races, men and women and younger and older age groups. Colorectal cancer presented in an advanced stage in the majority of patients.