Understanding early-onset colorectal cancer: why are cases on the rise?

Chadwick Boseman’s death from colorectal cancer (CRC) at age 43 was a shock to many, but it has helped to bring the difficult issue of early-onset CRC to the forefront of public attention. According to the most recent CRC statistics, the incidence of new CRC cases among adults below the age of 50 continues to increase by about 2% per year. In comparison, new CRC cases were on the decline for people aged 50-64, though since 2016 the rates have been increasing by 1% per year.

About 1 in 5 younger patients with CRC have a genetic predisposition to the disease, though only about half of them have a family history of the disease that actually exhibits the genetic mutation. This highlights the importance of genetic testing among all young patients to help to protect their families. Other factors such as obesity, changes in the gut bacteria from antibiotic use, diets rich in sugar, fat, red meat and alcohol, and decreased physical activity and exercise have all been hypothesized as potential drivers of CRC incidence in young adults.

In young adults diagnosed with CRC, cancer tends to be located closer to the rectum, resulting in rectal bleeding. However, younger patients may sometimes go much longer before being diagnosed because they either ignore their symptoms or, if they do talk about their symptom with their doctor, CRC is not even considered as a possible cause. Both patients and doctors need to be educated about this growing concern so that no signs or symptoms are missed.

Another issue that was brought to the surface with Chadwick Boseman’s death was the question of why Black populations experience greater CRC incidence and mortality rates compared to other racial groups. Disparities in health, such as differential access to quality healthcare including cancer treatment, screening, follow-ups and referrals to cancer specialists, as well as diet, obesity and socioeconomic factors are likely to have a significant role in how CRC impacts Black populations. A recent retrospective study published in JAMA Network Open examined data from 16,382 adult patients from the California Cancer Registry and found that Black patients were the least likely to receive chemotherapy or surgery to remove CRC liver metastases, and had a 17% higher chance of death compared to White patients. The researchers found that among patients who underwent liver resection for metastases, there was no difference in survival between Black and White patients. This suggests that if Black patients were able to access life-saving therapies such as liver resection at the right time, they would not experience the increased number of unnecessary deaths due to the disease.

Colorectal cancer is highly treatable when it is caught early, which depends on screening when you are healthy and well. Once symptoms such as rectal bleeding, change in bowel habits or abdominal pain begin to emerge, evaluation by a healthcare professional is necessary. The American Cancer Society recently changed their CRC screening guidelines to take into account the rising incidence of early-onset disease and recommends that all people at normal risk begin screening at 45 years instead of 50. Screening is typically performed with a routine colonoscopy or through fecal immunochemical testing. Each test has its advantages and disadvantages, and the hope is that every individual will adhere to at least one form of screening.