Many cases of colorectal cancer in people between ages 40 and 49 could be detected earlier if physicians and patients followed screening guidelines that emphasize a family history of the disease according to new research. The study was published online April 20, 2020, in the journal Cancer.
Colorectal cancer is the third most common cancer diagnosed in the United States, following prostate cancer and lung cancer for men and breast cancer and lung cancer for women. Moreover, while colorectal cancer rates have fallen in people over 60 in the United States, they rose by about 2 percent per year in people ages 40 to 49 from 2012 to 2016, according to data from the American Cancer Society (ACS).
Colorectal cancer screening not only detects cancer, it can help prevent it because precancerous polyps found during colonoscopy can be removed before they become cancerous.
The startling rise in colorectal cancer incidence in younger adults has led some medical organizations to endorse earlier colorectal screening. In the past, most groups recommended starting screening at age 50 for people at average risk. However, the American Cancer Society now recommends people at average risk begin screening at age 45.
And The U.S. Preventive Services Task Force (USPSTF) recommends regular screening beginning at age 50 for people at average risk, and earlier if a close relative has had colorectal polyps or colorectal cancer.
The new study, however, suggests that guidelines emphasizing family history may be overlooked.
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Colorectal Cancer Screening: Family History Should Trigger Earlier Screening
In the new study, Samir Gupta, MD, of the VA San Diego Healthcare System and the University of California in San Diego, examined data on people ages 40 to 49 years old; 2,473 had been diagnosed with colorectal cancer and 772 did not have the disease.
He and his team used standard colorectal screening criteria to see who met the criteria for family history-based screening. The criteria state that people with a first-degree relatives with colorectal cancer start screening at age 40 or 10 years prior to the age at diagnosis of the youngest relatives with the disease.
The study showed that 25 percent of the colorectal cancer patients met the family history-based criteria for screening compared with 10 percent of those without cancer. Moreover, almost every patient with colorectal cancer — 98.4 percent of the group — who met family history–based criteria should have been screened at a younger age than when their cancer was diagnosed.
“In this scenario, 1 in 4 patients could have had the opportunity to have their cancer diagnosed at an earlier age,” says Dr. Gupta.
The study does not address why the patients with a family history of colorectal cancer were not screened earlier, Gupta says. It could be that patients don’t know their family history or don’t share it with their healthcare providers. Providers may not recommend screening or patients fail to follow through on a doctor’s recommendation.
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Colorectal Cancer: The Cost of Delayed Diagnosis
A delay in finding cancer can mean the disease is detected when it’s more advanced. A study published in March 2020 in the journal CA: A Cancer Journal for Clinicians found that colorectal cancer patients ages 40 to 49 are more likely to be misdiagnosed, leading to a delay in the correct diagnosis of cancer and the start of treatment.
The study also found that at least 63 percent of patients delayed going to a doctor after first experiencing symptoms because they didn’t suspect colorectal cancer. Two-thirds of the patients saw at least two doctors before receiving the correct diagnosis. A majority of the patients were diagnosed at a late stage.
Another study, published in July of 2019 in the journal Cancer, found a higher rate of patients under age 50 had more advanced cancer — stages 3 and 4 — compared with patients 50 and older (51.6 percent compared with 40 percent).
The new study findings lend support to the idea of starting screening for people considered a normal risk at age 45, Gupta says.
“We could consider screening people at an earlier age, such as 45. But the other option is to come up with better strategies to identify risk,” including information on gender, diet, exercise, and lifestyle factors, he says.
More research is also underway to identify additional genetic mutations that increase the risk of colorectal cancer, he says. Meanwhile, he says, it’s important to inquire among family members about family history, and share any relevant information with your doctor. “It could save your life or the life of one of your relatives,” he says.
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