Trending Clinical Topic: Right-sided Colon Cancer

Ryan Syrek


January 22, 2021

Each week, we identify one top search term, speculate about what caused its popularity, and provide an infographic on a related condition. If you have thoughts about what's trending and why, share them with us on Twitter or Facebook.

News about the incidence and mortality of colon cancer resulted in this week's top trending clinical topic. Results of a recent biopsy study showed that the right colon appears to age faster in Black people than in White people (see Infographic below). Researchers analyzed specimens from 128 individuals who had undergone routine colorectal screening. They compared DNA methylation levels in right and left colon samples from the same patient and assigned epigenetic ages to the samples using the Horvath clock. Results showed that the epigenetic age of the right colon among Black patients was 1.51 years ahead of the left colon. Among White patients, the right colon was epigenetically 1.93 years younger than the left colon. Experts believe that these findings could help explain racial differences in the location of colorectal cancers (CRCs).

The death of actor Chadwick Boseman at age 43 helped bring attention to disparities in the screening and prevention of CRC between Black and White communities. Clarissa G. Clinkscales, BSN, RN, who knew Boseman and is an advocate on the issue, recently spoke out on the subject. She pointed to initiatives to increase CRC screening rates, especially among Black men, and called for healthcare professionals to do more in order to reach those who may be unaware of their degree of risk.

Incidence of CRC in adults younger than 55 years has been increasing in many countries across Europe as well as in Australia, New Zealand, Canada, and the United States. A new study identified geographic hot spots for early-onset CRC associated with worse survival among men in the United States. Those locations include counties in the lower Mississippi Delta, west-central Appalachia, and eastern Virginia/North Carolina. According to the findings, young adult non-Hispanic Black men were specifically at risk and were more likely to die compared with persons of other racial groups.

The risk for CRC among all young adults has prompted changes to several guidelines, with some lowering the age at which routine screening should begin to 45. However, a recent study found that the CRC risk among young adults is actually lower than has been estimated, as previous studies did not differentiate between colorectal adenocarcinoma and the histologically different carcinoid tumors. The study found that 4%-20% of lesions previously described as CRC were actually carcinoid tumors, which are typically indolent and have a better prognosis than most other cancer types. Experts suggest that these carcinoid tumors represent incidental findings with "little health benefit from detection." The fear is that they may add to "the burden and harms of screening without the balance of additional benefit."

In terms of mortality, the COVID-19 pandemic has meant delays in cancer screening, diagnosis, and treatment for many patients. A new study found that this delay can be particularly deadly in colon and early-stage lung cancer. For example, for stage III colon cancer, 5- and 10-year predicted mortality was 38.9% and 54%, respectively, with a time-to-treatment initiation (TTI) of 61-120 days, and increased to 47.8% and 63.8%, respectively, with a TTI of 181-365 days. Each additional 60-day delay was associated with a 3.2%-6% increase in 5-year mortality for stage III colon cancer and a 0.9%-4.6% increase for stage I colon cancer.

From insights into incidence rates to data that confirm the urgency of treatment, varied news about colon cancer helped make the condition this week's top trending clinical topic.

Read more clinical information about colon cancer.


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