Rectal Cancer in Asian vs. Western Countries: Why the Variation in Incidence?
- 614 Downloads
Colorectal cancer (CRC) is the third most common cancer worldwide. CRC has been thought to be less common in Asia compared to Western countries. However, the incidence rates of CRC in Asia are high and there is an increasing trend in the Asian population. Furthermore, colorectal cancer accounts for the greatest number of all incidences of CRC in Asia. The increasing adoption of a Western lifestyle, particularly in dietary habits, is likely the most important factor contributing to the rapid increase in colon cancer incidence; it is noteworthy that trends for rectal cancer were flat. The etiology of colon and rectal cancer is a bit different. The risks of distal colon and rectal cancers are more likely to be related to environmental factors, such as polluted surface water sources, alcohol consumption, and habitual smoking. The lack of great change in the incidence of rectal cancer might be due to weaker associations with such lifestyle factors. Therefore, it has been hypothesized that proximal and distal sections of the colon and rectum are two different organs in terms of function and genetic background. It may mean differences in differential sensitivities and exposures to carcinogens. However, despite the decrease in whole incidence, the CRC incidence in young adults in Western countries are reversely increasing, especially in rectal cancer, due to reasons largely unknown. Although the treatment algorithm is different between Asia and western countries, globally, the survival rate for patients with rectal cancer has risen during the past 10 years. Screening contributes a great deal to reducing the incidence and improving survival. Most countries in Asia, such as China, need nationwide registration and screening systems to provide better data.
KeywordsRectal cancer Asia incidence Incidence trend Risk factors Etiology difference Treatment algorithm
Compliance with Ethical Standards
Conflict of Interest
Yanhong Deng declares that she has no conflict of interest.
Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
References and Recommended Reading
Papers of particular interest, published recently, have been highlighted as: •Of importance, ••Of major importance
- 14.•• Robsahm TE, Aagnes B, Hjartåker A, Langseth H, Bray FI, et al. Body mass index, physical activity, and colorectal cancer by anatomical subsites: a systematic review and meta-analysis of cohort studies. Eur J Cancer Prev. 2013;22:492–505. Provide the fundamental reasons for why the difference of incidence change of rectal and colon cancer occurred.CrossRefPubMedGoogle Scholar
- 29.Oyesanmi O, Snyder D, Sullivan N, Reston J, Treadwell J, et al. Alcohol consumption and cancer risk: understanding possible causal mechanisms for breast and colorectal cancers. Evid Rep Technol Assess (Full Rep). 2010;197:1–151.Google Scholar
- 33.Tawadros PS, Paquette IM, Hanly AM, Mellgren AF, Rothenberger DA, Madoff RD. Adenocarcinoma of the rectum in patients under age 40 is increasing: impact of signet-ring cell histology. Dis Colon rectum. 2015;58:474–8.Google Scholar
- 42.• Deng Y, Chi P, Lan P, Wang L, Chen W, et al. Modified FOLFOX6 with or without radiation versus fluorouracil and leucovorin with radiation in neoadjuvant treatment of locally advanced rectal cancer: initial results of the Chinese FOWARC multicenter, open-label, randomized three-arm phase III trial. JCO. 2016;34:3300–7. Provide the treatment algorithm in China. Physicians are more cautious about preoperative radiation being routinely done in locally advanced rectal cancer.CrossRefGoogle Scholar
- 44.Petrelli F, Tomasello G, Borgonovo K, Ghidini M, Turati L, et al. Prognostic survival associated with left-sided vs right-sided colon cancer: a systematic review and meta-analysis. JAMA Oncol. 2016; doi: 10.1001/jamaoncol.2016.4227.
- 45.Tejpar S, Stintzing S, Ciardiello F, Tabernero J, Van Cutsem E. Prognostic and predictive relevance of primary tumor location in patients with RAS wild-type metastatic colorectal cancer: retrospective analyses of the CRYSTAL and FIRE-3 trials. JAMA Oncol. 2016; doi: 10.1001/jamaoncol.2016.3797.