A study published in the Journal of the National Cancer Institute made headlines last year for its startling and mysterious conclusion: The incidence of colorectal cancer in young adults has increased sharply in generations born after 1950. Individuals born in the 1990s (currently age 20 to 29) are twice as likely to develop colon cancer and four times as likely to develop rectal cancer than individuals born in the 1950s were at those ages.
Unfortunately, no one has discovered why is this type of cancer is suddenly on the rise in younger adults. Cancer researchers suspect contributing factors may include changes in diet, more sedentary lifestyles, and obesity. Another theory is that cancers are simply being detected much earlier than in past decades.
Cancer researchers from Johns Hopkins have concluded that some patients may develop colon cancer due to two specific digestive bacteria that form a film on the colon. According to the study paper, which was published December 2015 inScience magazine, these two types of bacteria invade the protective mucous layer of the colon and create a small ecosystem, including nutrients the bacteria need to survive, causing chronic inflammation and subsequent DNA damage that supports tumor formation. These findings also seem to add to the growing evidence that gut bacteria is more influential on our immune system than we may realize.
The two bacteria the doctors found are known as Bacteroides fragilis and Escherichia coli (or E. coli). The B. fragilis strain, called ETBF, appears to cause inflammation in the colon, while the E. coli strain causes DNA mutations.
Also, the bacteria was linked to patients without a family history of colon cancer. Cancers such as these--where there is no genetic tie--are known as sporadic cancers. Only 5-10% of cancers are considered heredity, meaning the remaining 90-95% are considered sporadic.
Many of you may have heard that the American Cancer Society (ACS) changed the age of colorectal screening for individuals at an average risk to age 45 at the end of May. But why? While the number of diagnoses for colorectal cancer for adults aged 55 and over has declined over the last 20 years, a disturbing increase of 51% in colorectal diagnoses has been noted for adults under the age of 50 since 1994 (American Cancer Society, 2018). Furthermore, death rates from colorectal cancer in the younger age group are also rising. Based on these statistics, the ACS funded a modeling study that used the age 45 to begin screening rather than at the age of 50. The ACS found that it is more likely that adults will have more favorable outcomes at the lowered age.
I recently turned 50 which meant it was time for my first colonoscopy. Colon cancer is the third leading cause of cancer deaths and generally when caught early, has a good cancer prognosis. Yet, 30% of adults age 50 and older have not had a colonoscopy to screen for colon cancer! However, getting your first colonoscopy doesn’t have to be scary, and you can prep to make the procedure go as smoothly as possible.
As a kid, the only time I wondered about a colon was whether I used it correctly when writing a paper. As I neared the age of 50, I worried if the 5 feet of my colon was healthy. More people need to worry about their colon too. Colorectal cancer is the 3rd most common cancer diagnosed in both men and women in the United States and is the 3rd leading cause of deaths caused by cancer.1 Colorectal cancer is most often diagnosed in adults over the age of 50 though over the last few decades there has been an increase in the diagnosis of colorectal cancers in adults younger than 50.