As the prevalence of colorectal cancer in young adults continues to rise at an alarming rate in the U.S., the American Cancer Society (ACS) has implemented new guidelines, recommending that patients with average risk begin screening at age 45. While research continues to seek an explanation for the increased rate, clinicians must take action to address the needs of a unique patient population.
Research recently published in The Journal of Medical Screening found that, for people in their 40s, colon cancer incidence has increased by 1.3 percent per year since the mid-1990s, while rectal cancer increased by 2.3 percent each year (2019; doi: 10.1177/0969141319859608). Those patterns are in contrast to people aged 55 and over who have seen declining rates of colon cancer since the mid-1980s and fewer cases of rectal cancer since the mid-1970s, with accelerated declines in the early 2000s, in part due to increased colonoscopy utilization. Current screening guidelines for average-risk adults recommend sigmoidoscopy every 5 years, stool testing annually, and/or colonoscopy every 10 years beginning at age 50, though the ACS updated that age to 45 in 2018.
Screening for colorectal cancer escalated in the early-to-mid 2000s after Medicare began covering colonoscopy for average risk beneficiaries in 2001, and nationwide colonoscopy rates over the last 10 years rose from approximately 20 percent in 2000 to 47 percent in 2008; in 2015, it increased to 59 percent among adults aged 50-75, the research noted. Though the increased screening prevalence may have spilled over to younger ages, including those under age 50, the research noted the debate remains as to whether the rise in colorectal rates among younger adults reflects increased disease occurrence or detection as a result of more colonoscopies being performed.
In 2017, the ACS found that adults born around 1990 have twice the risk of colon cancer and four times the risk of rectal cancer compared to those born around 1950, a statistic both Pankaj Vashi, MD, AGAF, FASPEN, Chair of the Department of Medicine and Medical Director of Gastroenterology/Nutrition & Metabolic Support at Cancer Treatment Centers of America Chicago, and Rebecca Siegel, MPH, Scientific Director of Surveillance Research at ACS, attribute to changing lifestyle factors, including diet, physical activity, and alcohol consumption.
“Most of what we know about colorectal cancer is based on information from cancer occurring in older adults,” Siegel said. “But while we really know very little about cancer specifically for young adults, most of the information applies. For example, obesity is associated with an increased colorectal cancer risk of about 20 percent, and excess red and processed meat consumption, alcohol consumption, and physical inactivity are additional risk factors.”
Vashi noted that, while the risk factors for colorectal cancer are the same regardless of age, it's important to distinguish that increased rates of the cancer are happening more in younger people now compared to 2-3 decades ago.
“Childhood obesity has a major role to play in the young adult population today, because if a person is overweight at a younger age, the risk of cancer becomes higher compared to gaining weight in your 40s or 50s,” he said. “The increased risk is directly related to the diet that patients have followed throughout their lives—many of which are low in fiber, high in fat, and combined with a sedentary lifestyle.”
Vashi added that, although genetic factors do play a role, genetically inherited colorectal cancer makes up less than 5 percent of all colorectal cancer cases. “For 95 percent of patients, the environmental and lifestyle factors explain why we are seeing more cancer in young patients than we did 20 years ago,” he said. “As a result, the best way to tackle the issue is to stress a more active lifestyle and better diet.”
When working with the young adult patient population, awareness is key. Siegel noted that many signs of colorectal cancer are also common gastrointestinal symptoms, and often young adults attribute them to other causes or feel uncomfortable speaking to a physician about changes.
“The most common symptoms of colorectal cancer would be blood in the stool, constipation, bloating, rectal bleeding, and diarrhea,” she said. “It is also important to pay attention to the shape of the stool, such as a narrower stool, which does tend to change with colorectal cancer.” Vashi added that additional key red flag symptoms include unexplainable abdominal pain that lasts more than 2 weeks, weight loss, and chronic fatigue.
Siegel urged clinicians to speak with patients about these symptoms, especially when they persist over a week. “In light of the increasing trend of colorectal cancer in young adults, it's important to encourage follow-up on the patient side,” she said. “Cancer just isn't on the radar of a physician who is examining a patient in their 20s and 30s. Increasing awareness is very important because young patients are being diagnosed at a later stage much more often than older patients.”
With those symptoms and statistics in mind, Siegel noted the importance of screening—and the associated risks. “There is a large population of people under 50 who should be screened early for colorectal cancer, even aside from the new ACS guidelines,” she said. “Anyone with a family history or history of adenomas in parents should be screened, and patients whose parents had polyps should begin screening at age 40.”
When recommending screenings, Siegel said emphasis should be placed on whether the benefits outweigh the potential risks associated to colonoscopy. “It's important to realize that screening guidelines are determined based on patient populations and where the risk increases when looking at age-specific rates,” she said. “We are looking for high rates in a certain group, when in fact if those patients were screened a decade earlier, the risk for cancer would be eliminated or reduced.”
However, she noted, “That is tricky to think about for colorectal cancer specifically. For example, breast cancer screening doesn't remove the cancer—it just detects it. For colorectal screenings, we want to remove lesions before they develop into malignancy, but there are also harms to that screening and we don't want to screen a population that has a very low risk because the harm could outweigh the benefit.” Such risks include proliferation of the colon or complications with anesthesia, Siegel said. “Most of the risks are not life-threatening, but it is important to be aware of the balance between harm and benefit.”
Vashi added that the need for early screening is especially critical in patients with a family history of colorectal cancer. “If there is a genetic abundance or strong family history of cancer, such as first-generation relatives who have colorectal or endometrial cancer, patients should be screened for genetic disorders such as Lynch syndrome, which increases a patient's risk for colorectal cancer as much as 80 percent,” he said.
To combat the risks associated with colonoscopies, Vashi recommended alternative screenings such as stool tests, which can scan DNA and test for polyps. “There are tests that will combat the challenges patients face with colonoscopies,” he said. “That is an invasive procedure, compared to other screenings, such as Pap smears or breast exams. We need to find more noninvasive tests to offer larger populations that can be given to younger patients who are high risk.”
Vashi stressed that, ultimately, the physician community should focus on spreading awareness in the younger patient population—especially those with a family history—to get checked and encourage their families to be screened as well.
“We can do a better job of doing thorough family history evaluations and screening at multiple levels,” he noted. “For the younger population, we must identify high-risk patients and be aware that the rates of colorectal cancer are increasing. Awareness, detection, and early treatment are key.”
Kelly Wolfgang is a contributing writer.
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