Research by the American Cancer Society published in 2017 found that people born in the 1990s (I.E., Millennials) are developing colon and rectal cancers at increasing rates. According to the study, Millennials born around 1990 are two times more likely to develop colon cancer and four times more likely to develop rectal cancer compared to young adults in the 1950s, a period of time when risk was the lowest.

The research, which was published in the Journal of the National Cancer Institute, found that rates of colon and rectal cancers (often lumped together with the phrase “colorectal cancer”) have been steadily increasing among adults younger than 50 since the mid-1980s. In addition to Millennials – those aged 22 to 38 – the generation preceding them, Gen X, was also found to be at higher risk of developing colorectal cancers. Conversely, incidences of colorectal cancers have dropped among the nation’s older citizens.

So, why are Millennials at a higher risk for colorectal cancer, a disease that the Centers for Disease Control and Prevention recommends first screening for at age 50? According to oncologist Dr. Milan Sheth, who is affiliated with MemorialCare Long Beach Medical Center, the answer could lie in significant lifestyle and cultural shifts that took place over the course of the last century.

“We used to be a culture that was very much active in lifestyle. We were eating freshly made foods that were grown on organic farms, or even just homegrown foods,” Sheth said. “All that changed in the latter part of the last century where they became sort of the couch potato generation: watching TV, not as active anymore, dependent on our cars for transportation, and eating more processed foods and fast foods.”

Sheth believes the shift to a more sedentary existence has contributed to what he considers another major factor in increasing colorectal cancer rates among young adults: the obesity epidemic.

According to an annual report on obesity rates compiled by the Trust for America’s Health and the Robert Wood Johnson Foundation, in 2000, 13.9% of children aged two to 19 were obese, while 18.5% of adults were obese. In 2016, those rates jumped to 30.5% and 39.6%, respectively. According to the report, there are significant ethnic disparities in obesity rates, with Black and Latino Americans having higher rates of obesity than Whites and Asians.

“Certainly smoking, obesity and sedentary lifestyle in general has been shown to be a causative factor in colon cancer. But to what severity, to what magnitude, none of that has really been elucidated,” Sheth said.

The American Cancer Society’s research found that young adults diagnosed with colorectal cancer were more likely than older adults to be diagnosed with a late stage of the disease. According to Sheth, this is in part due to a perception that younger adults are not likely to develop the disease.

“These are patients who are just not tuned in to the fact that they could have colon cancer. . . and therefore they do not get the attention that they need from a patient perspective,” Sheth said. “Similarly, from a physician standpoint, if a younger patient comes to the office and says, ‘I have X, Y and Z symptoms,’ they too may not think [it’s] colon cancer because they are also not primed into thinking that these younger patients are at risk of getting colon cancer,” he explained. As a result, he said, by the time such patients are screened for colorectal cancer, years could have gone by as the disease progressed unchecked.

Individuals with a family history of colorectal cancer are at higher risk of developing it themselves, according to Sheth.

Signs and symptoms of the disease include: bleeding from the gastrointestinal tract, “typically manifested by either having dark colored stools or stools with bright red blood,” Sheth said; unintentional weight loss; nausea or vomiting; abdominal bloating; and changes in bowel habits. Of the latter, Sheth explained, “Patients may have several days of feeling really constipated and that will alternate with several days of having diarrhea.”

The good news is that colorectal cancer is “extremely treatable,” according to Sheth. In the early stage of colorectal cancer, when it is localized to the colon or rectum, the five-year survival rate is 90%, according to the American Cancer Society. That rate decreases to 71% if the cancer has spread to nearby structures or lymph nodes, and drops precipitously to 14% if the cancer has spread to distant parts of the body such as the liver or lungs – illustrating why it’s crucial to catch the cancer early.

Most people equate screening for colon cancer with a colonoscopy, a procedure in which a flexible tube containing a tiny video camera is inserted via the rectum to inspect the colon for abnormalities. Preparation for the procedure involves switching to a liquid diet the day prior, and can also include taking a laxative or an enema. During the procedure, a physician may also use instruments to remove small abnormalities such as polyps – tiny growths that may be precancerous.

Young individuals who may not think they are at risk for the disease may avoid this screening procedure due to its discomfort, Sheth said. But there are other ways to screen for colon cancer, including testing fecal matter for blood or cancer cells, he emphasized.

“Once a patient is found to have colon cancer, the first step then is to understand how advanced the disease may or may not be,” Sheth said. “That is done by obtaining a CAT scan to see what the status of the liver, lungs and bones look like. . . . As long as there is no evidence of distant disease, that patient would then be taken to surgery to have the cancer removed.” If the cancer has spread, treatment would likely include chemotherapy and removing tumors or nodules, he noted.

Sheth estimated that 10-15% of his patients with colorectal cancer are young adults. While the American Cancer Society has recommended beginning colorectal cancer screenings at age 45 due to its research, Sheth recommends beginning at age 40 if there is a family history of the disease, and as early as 20 if there is evidence of a related genetic syndrome. He believes there needs to be a widespread campaign on multiple platforms to inform the public about the risk for colorectal cancer.

“Also, I think that people need to really understand and realize that this is happening because of these culturally related risk factors,” Sheth emphasized. “Trying to adopt a less sedentary lifestyle, trying to practice healthier habits with better foods and less smoking and less alcohol and things like that is also something that the public needs to be made aware of.”