We read the meta-analysis by Hassan and colleagues with great interest.[1] The authors reported that the detection rate of advanced neoplasia was higher with colonoscopy (relative risk = 3.56; 95% CI = 1.79–7.09) than that with faecal tests.

In our cross-sectional study in Taiwan, six subjects (0.14%) were found to have rectosigmoid adenocarcinomas among 4413 subjects undergoing flexible sigmoidoscopy during self-referred health examinations between 2001 and 2004.[2] A population-based study using the Taiwan cancer registry database has shown that 25% of total colorectal cancers were located in the right side of the colon.[3]

Therefore, flexible sigmoidoscopy cannot detect all colorectal cancers. Based on Hassan et al.'s and our findings, colonoscopy should be superior to sigmoidoscopy and faecal tests for detection of colorectal cancer in a screening setting.


  1. Top of page
  2. Acknowledgement
  3. References

Declaration of personal and funding interests: None.


  1. Top of page
  2. Acknowledgement
  3. References
  • 1
    Hassan C, Giorgi Rossi P, Camilloni L, et al. Meta-analysis: adherence to colorectal cancer screening and the detection rate for advanced neoplasia, according to the type of screening test. Aliment Pharmacol Ther 2012; 36: 92940.
  • 2
    Liao KF, Lai HC, Lai SW, Cheng KC, Lin CH. Association between rectosigmoid adenomas and cardiovascular risk factors: a hospital-based, cross-sectional study. Ann Acad Med Singapore 2009; 38: 6306.
  • 3
    Chen TA, Kang HY, Chang HC, Lin WC, Chao TM, Horng JT. Gender differences in colorectal cancer during the past 20 years in Taiwan. Int J Colorectal Dis 2012; 27: 34553