This study reveals that obese individuals are 1.28 times more likely to develop right-sided colon cancer and highlights factors like age, sex, and race that influence this risk.
Colorectal cancer (CRC) is among the most common cancer types in the United States and globally. There are two distinct types of CRC: right-sided colon cancer (RsCC) and left-sided colon cancer (LsCC). Between the two, RsCC is associated with higher mortality. Furthermore, CRC disproportionately affects racial minorities, and CRC risk is higher among obese individuals. Existing studies confirm that RsCC disproportionately affects Blacks.
However, the relationship between obesity and the sidedness of CRC is unclear. This cross-sectional study, published in the Journal of Surgical Oncology, explored the relationship between obesity and CRC sidedness. Additionally, it explored how race, age, and sex affect mortality among obese people.
Obesity and Colorectal Cancer Outcomes
For the study, researchers used the National Inpatient Sample (NIS) database. The NIS covers approximately 20% of all those discharged from community hospitals in the United States. The investigation included all those older than 18 years diagnosed with CRC and discharged between January 1, 2016 and December 31, 2019.
The study included data from more than four million patients. Out of them, 24,549 patients met the study’s criteria. The race distribution of the dataset was representative of the general U.S. population. As expected, the study found that the incidence of CRC was much higher in older adults. However, the study also found that LsCC was more likely to be diagnosed in young patients. It also found that RsCC was more common in females compared to LsCC (54% vs. 45.8%, respectively), coinciding with earlier findings.
The study found that obese people were 1.28 times more likely to develop RsCC compared to normal-weight individuals. Female sex was associated with a 1.29-times higher risk of RsCC. Further, for every year of increase in age, the risk of RsCC diagnosis increased by 3.3%. Crohn’s disease increased the risk of RsCC by 1.67 times. Further, Black obese individuals had a 1.23-times higher risk of RsCC compared to normal-weight White individuals.
The Bottom Line
The authors concluded that there is strong evidence of increased risk of RsCC in obese people. This is one of the first studies to confirm the association between RsCC and obesity. However, investigators could not fully understand the cause of such disparities, hypothesizing that the increased risk could be due to multiple reasons, including genetic, hormonal, and environmental factors, metabolic dysfunction, systemic inflammation, and microbial dysbiosis.
The higher risk of RsCC in females is relatively easy to explain, and it may be due to estrogen. Racial disparities were challenging to explain, and researchers think that this may be due to multiple reasons like socioeconomic factors, differences in epigenetic aging, and healthcare inequalities.
Source:
Ulanja, M. B., Ntafam, C., Beutler, B. D., Antwi‐Amoabeng, D., Rahman, G. A., Ulanja, R. N., Mabrouk, T., Governor, S., Djankpa, F. T., & Alese, O. B. (2022). Race, age, and sex differences on the influence of obesity on colorectal cancer sidedness and mortality: A national cross‐sectional study. Journal of Surgical Oncology, 127(1), 109–118. https://doi.org/10.1002/jso.27096
