Early-onset colorectal cancer is unlikely to be a different disease from average-onset colorectal cancer, according to a paper, ‘A comprehensive comparison of early-onset and average-onset colorectal cancers’, published in the Journal of the National Cancer Institute.
Colorectal cancer incidence in people under 50 has increased by 1%-2% annually since the mid-1990s. By 2030, 10.9% of all colon cancers and 22.9% of all rectal cancers will affect patients younger than 50 (compared with 4.8% and 9.5%, respectively, in 2010).
Researchers have observed a similar increase in many other places around the world. Some evidence suggests westernized diets, high-fructose corn syrup, synthetic dyes, growth hormones used in food supply chains, obesity, and stress may lead to early-onset colorectal cancer. While earlier research suggested that early-onset colorectal cancer was inherently more aggressive, additional treatment for patients with such a disease has not improved survival.
Using an institutional database collected from patients at Memorial Sloan Kettering Cancer Center between 2014 and 2019, researchers here compared tumour biology in 759 patients with early-onset colorectal cancer compared with 687 patients diagnosed later. They investigated the location of the tumour, symptoms at diagnosis, patients' risks for hereditary colorectal cancer, and other tumour molecular features.
Patients with early-onset colorectal cancer were more likely to have tumours on the left side of their bodies. They were also more likely to experience rectal bleeding and abdominal pain. Patients with early-onset colorectal cancer also had a higher risk of inherited genetic predisposition for the disease.
However, with regard to the genetic make up of the tumours and response to treatment in advanced disease, the two types of patients were otherwise indistinguishable. This suggests that early-onset colorectal cancer is not biologically distinct from average-onset colorectal cancer and more aggressive treatment for early-onset colorectal cancer is neither necessary nor effective.
"The study noted no specific findings to differentiate early-onset colorectal cancer patients from average-onset colorectal cancer patients," said Dr Cathy Eng of Vanderbilt-Ingram Cancer Center, who wrote an editorial to accompany the study. "I am hopeful with increased awareness and education, other investigators will collect additional data inclusive of a diverse patient population to determine if the findings from this study apply to the general public impacted by early-onset colorectal cancer."