Colorectal cancer rates surge across all adults as scientists fear invisible environmental threat

Colorectal cancer rates are climbing in nearly every adult age group in the United States, not only among younger adults, a new analysis has found.Medical groups have been sounding the alarm about the recent rise of colorectal cancer among younger adults in the US.Data from the American Cancer Society show incidence among adults aged 20-49 rose by 3% annually between 2013 and 2022.A cancer patient holds the tubes that funnel chemotherapy drugs into his body at Cape Fear Valley Medical Center in Fayetteville, North Carolina (Getty Images)By 2026, the disease was the leading cause of cancer deaths in that age group.The new analysis of National Cancer Institute data looked at all ages up to 70.Researchers found incidence fell from 55.2 per 100,000 in 2000 to 36.7 in 2022, before rising to 38.3 in 2023.“This is the first time that we have seen an increase in the overall rate in more than 20 years,” study leader Caitlin Murphy of the University of Chicago said in a statement.“This is the first time that we have seen an increase in the overall rate in more than 20 years,” study leader Caitlin Murphy of the University of Chicago said in a statement (Getty)The steepest increase, 12.76% annually from 2019-2023, was seen in 45- to 49-year-olds.The researchers reported in NEJM Evidence that this was likely driven by more people undergoing colorectal cancer screening after US recommendations lowered the recommended age for the testing to 45 from 50.But the researchers said screening increases do not explain the overall rise in incidence or the rise in other age groups.That suggests unknown risk factors, including environmental ones, may be offsetting the gains made by screening.“That means that screening is doing as we intend it to do. It's catching cancer earlier,” Murphy said.“While we’re still at the beginning of understanding what these differences mean, our work gives researchers a new direction to pursue in tackling this urgent problem in human disease,” study co-author Ana Anderson of Harvard Medical School said in a statement (AP)A separate team of researchers has identified new clues to help explain why colorectal cancer is often more aggressive in younger patients.They analyzed 189 tumors from adults of all ages, looking for factors that changed gradually with age.Among tumors of the most common colorectal cancer subtype, younger patients' tumors had significantly more connective and supporting cells than cancer cells, the researchers reported in Nature Medicine.That finding has been linked to chemotherapy resistance in several types of solid cancer.Younger patients also had higher activity of long non-coding RNAs, molecules that can regulate genes without making proteins.Many are “dark” RNAs, whose functions remain largely unknown.A view of the Novartis booth and logo at the BIO International Convention 2026, a meeting of pharmaceutical and biotechnology leaders in San Diego (Reuters)The researchers also saw gene activity suggesting stronger signaling between cells that can help cancer cells move and invade nearby tissue in younger patients.“While we’re still at the beginning of understanding what these differences mean, our work gives researchers a new direction to pursue in tackling this urgent problem in human disease,” study co-author Ana Anderson of Harvard Medical School said in a statement.A combination of two targeted therapy drugs can dramatically improve survival for certain patients with newly diagnosed advanced kidney cancer, data from a midstage trial suggests.The trial testing the two drugs was launched before therapies known as immune-checkpoint inhibitors became the preferred treatment for such patients.Checkpoint inhibitors such as Merck's Keytruda and Bristol Myers Squibb's Opdivo cannot be used by patients with autoimmune diseases.Their cost can also be prohibitive, especially in low-resource settings.The 51 patients in the trial all had clear cell renal carcinoma that had spread throughout the body by the time it was first detected.They received Votrient (Novartis) and Roche's ROPC.S Avastin on an alternating basis.Both drugs block the action of a protein called vascular endothelial growth factor, or VEGF, which promotes the growth of new blood vessels that can supply the tumor with oxygen and nutrients.Votrient's effect on VEGF weakens over time, while Avastin actually removes VEGF from circulation.Patients survived a median of 63.2 months, researchers reported in The Lancet Oncology.That included 24.8 months during which their disease did not worsen.By comparison, when Votrient is given alone as the first-line treatment for patients with previously untreated metastatic clear cell renal cell carcinoma, overall survival ranges from 28.4 to 29.3 months.Median progression-free survival on Votrient alone is just 9.2 months.A particularly strong benefit was seen in the 33 trial participants who were considered “favorable-risk” based on their underlying health status.In this group, median progression-free survival, the time before the cancer began to worsen, reached 28.5 months, the researchers found.Overall survival was 76.9 months.In the favorable-risk patients, “the benefit from this novel regimen of (Votrient and Avastin) was comparable to or better than that of the contemporary immunotherapy combinations,” study leader Dr. Saby George of the Roswell Park Comprehensive Cancer Center in Buffalo, New York, said in a statement. “This is significant due to the lower cost of this regimen compared to the immunotherapy combinations.”