More than four in 10 colorectal cancer (CRC) cases in the United States are now occurring among people below the age of 65, according to a March 2 peer-reviewed study published in an American Cancer Society journal.

CRC refers to cancers that start in the colon or the rectum. It is the third most commonly diagnosed cancer in men and women, and the second leading cause of cancer-related death in the United States. Researchers analyzed data of CRC cancer cases from a variety of sources to assess the current state of the illness in the United States.

“Nearly one half (45 percent) of new diagnoses are currently in individuals younger than 65 years, up from 27 percent in 1995,” the study says.

“There will be an estimated 158,850 new cases of CRC in the United States in 2026, including 108,860 colon tumors and 49,990 rectal tumors. In addition, an estimated 55,230 individuals will die from CRC in 2026, nearly one third of whom will be younger than 65 years.”

Between 1985 and 2022, CRC incidence among all age groups fell by 45 percent, which the researchers attributed to changing patterns in risk factors and protective factors, such as lower incidence of smoking, higher use of certain drugs, and the uptake of CRC screening among people aged 50 and above.

However, “longstanding declines in CRC overall are driven by the oldest adults, who have the highest rates, and mask trends in younger ages,” the study said.

Among individuals aged 20-49, CRC incidence has increased by 1–2 percent annually since the mid-1990s, accelerating to 3 percent per annum between 2013 and 2022.

“Incidence in adults younger than 50 years is increasing in every racial and ethnic group in the United States, ranging from 2 percent annually in Black individuals to 3 percent annually in AANHPI, AIAN, and White individuals and 4 percent annually in Hispanic individuals from 2013 to 2022,” the researchers wrote. AANHPI indicates Asian American, Native Hawaiian, and other Pacific Islander, while AIAN is American Indian and Alaska Native.

As for CRC deaths, the overall rate of mortality fell by roughly 2 percent per year between 2005 and 2020, and remained stable from 2020 to 2023.

Here as well, a difference in older and younger populations was identified. Among individuals aged 65 and above, the mortality rate continued to decline by 2.3 percent per year from 2012 to 2023. However, for individuals younger than 50 years, the mortality rate has risen by 1 percent per annum since 2004, according to the study.

Researchers warned that the CRC landscape in the United States was “changing rapidly,” with mortality and incidence rising in tandem among adults younger than 65 years of age.

This confirms an increase in the underlying risk of CRC among people born after 1950, the study said. As these generations age, researchers predict, the CRC burden from this group will “continue to swell like a tsunami moving through time.”

CRC screening rates were lower among younger populations. For people aged 45 and older, the screening rate was 65 percent in 2023. Within this group, the screening rate of 45- to 49-year-olds was 37 percent, while that for 50- to 54-year-olds was 55 percent, the study said.

In a March 2 statement published by the American Cancer Society, Rebecca Siegel, lead author of the report, said: “After decades of progress, the risk of dying from colorectal cancer is climbing in younger generations of men and women, confirming a real uptick in disease because of something we’re doing or some other exposure.

“We need to redouble research efforts to understand the cause but also circumvent deaths through earlier detection by educating clinicians and the general public about symptoms and increasing screening in people 45-54 years.”

The study authors declared no conflict of interest. All researchers were employed by the American Cancer Society, which receives grants from private and corporate foundations, including those linked to companies operating in the health sector.

CRC Risk Factors, Symptoms

According to a research letter published in the JAMA journal on Jan. 22, the death rate from colorectal cancer in Americans younger than 50 has risen by 1.1 percent per year since 2005. CRC has overtaken lung, breast, and other cancers to become the leading cause of cancer deaths among this demographic.

A Sept. 19 study published in the Nature Metabolism journal suggested that drinking sugary beverages containing glucose and fructose can worsen CRC in a person by enabling its spread throughout the body.

Researchers in the study exposed CRC cells to glucose and fructose. They found that the exposure enhanced “cellular motility and metastatic potential” of the CRC cells.

According to the American Cancer Society, risk factors of CRC include those that are changeable, such as lifestyle adaptations, and those that cannot be changed. Among changeable factors, key risks include excess body weight, smoking, alcohol use, and Type 2 diabetes.

CRC may not produce any symptoms in the initial stages, which typically appear only as the disease progresses further, the University of Texas MD Anderson Cancer Center said in a post.

Symptoms of colorectal cancer include diarrhea or constipation that does not go away, pain or discomfort during bowel movements, changes in appetite, rectal bleeding, blood in stool, abdominal pain when lowering the stomach, and losing weight without dieting.

There are several treatment options for colorectal cancer, which are dependent on the stage of the disease and other factors, according to the American Cancer Society.

Patients may be given local treatments, such as surgery or radiation therapy, to treat tumors without affecting other parts of the body.

Patients can also be subjected to systemic treatments, including the use of targeted therapy drugs and chemotherapy. Systemic means the treatments can reach cancer cells throughout almost all parts of the body.