What’s Behind the Enormous Increase in Early-Onset Gastrointestinal Cancers?

A new paper published in the journal BJS indicates that early-onset gastrointestinal cancer rates are rising dramatically across the globe.

In the United States, the age-standardized rate of colorectal cancer decreased from 66.2 cases per 100,000 people in 1985 to 35.7 cases per 100,000 people in 2018. In contrast, early-onset colorectal cancer has shown a marked increase in both men and women in the United States since the mid-1990s, with the age-adjusted incidence rising from 5.9 cases per 100,000 in 2000 to 8.4 cases per 100,000 in 2017. Compared with adults born in 1950, those born in 1990 have twice the risk of developing colon cancer and four times the risk of developing rectal cancer.

The incidence of early-onset colorectal cancer, the most common type of gastrointestinal cancer, is also increasing globally, particularly in high-income countries. A study of 20 European countries revealed significant increases in early-onset colorectal cancer from 2004 to 2016, with increases of 7.9 percent, 4.9 percent, and 1.6 percent for individuals aged 20–29, 30–39, and 40–49 years, respectively. A recent Centers for Disease Control analysis revealed 185 percent increase among people between 20 and 24 and a 333 percent increase in incidence of colorectal cancer among people between 15 and 19.

With these rising rates, early-onset colorectal cancer has become the leading cause of cancer-related death for men under 50 and the second-leading cause for women under 50 in the United States. The disease affects Black, Hispanic, Indigenous, and Asian people disproportionately. A National Cancer Institute analysis from 1973 through 2009 demonstrated that doctors diagnosed 16.5 percent of American Indians/Alaska Natives, 15.4 percent of Hispanics, 12 percent of Asians/Pacific Islanders, and 11.9 percent of Black patients with colorectal cancer before age 50, compared to only 6.7 percent of non-Hispanic White patients.

The researchers in this study explain that patients with early-onset colorectal cancers often experience delays in diagnosis because neither physicians nor patients suspect cancer. Consequently, doctors are more likely to diagnosis such patients when they are at advanced stages of the disease.

Though official guidelines for early-onset and average-onset cancers are the same, researchers here emphasize that younger patients are more likely to receive aggressive treatment, often without a survival advantage. Young patients with gastrointestinal cancers also have unique and often unmet needs as they navigate cancer care. Often in their peak earning years, younger patients are more likely to experience financial hardship because of their cancer diagnosis. They may find it particularly difficult to explain such diagnosis with young children. They also may be thinking of growing or starting their families at the time.

Though the American Society of Clinical Oncology recommends oncologists discuss treatment-related fertility concerns with patients of reproductive age, a recent study found that 50 percent of patients reported that their doctors did not talk to them about the impact of their disease or treatment on having future children.

Survivors of early-onset colorectal cancer are also more likely to report problems with anxiety, body image, and sexual dysfunction compared to advanced onset survivors, and are also more likely to report worse social functioning and physical quality of life. Male patients with early-onset colorectal cancers are more likely to suffer depression than those diagnosed with average-onset colorectal cancers.

The researchers note that risk factors associated with increased risk of early-onset gastrointestinal cancers include obesity, a Western-style diet, non-alcoholic fatty liver disease, smoking, and alcohol use. Obesity, particularly in childhood and adolescence, is increasing in the United States, and is a leading theory for the rising rates of several early-onset gastrointestinal cancers. In a 2019 study of 85,256 women in the United States, those with a BMI over 30 had close to double the risk of developing early-onset colorectal cancer compared women with lower BMIs.

“The incidence of GI cancers in adults younger than age 50 is rising globally,” said the paper’s lead author, Sara Char. “Ongoing research efforts investigating the biology of early-onset GI cancers are critical to developing more effective screening, prevention, and treatment strategies.”