Colon cancer becomes leading cause of US cancer deaths for those under 50

Cancer-related deaths among U.S. adults under age 50 have decreased for every leading malignancy except colorectal cancer, which is now the most common cause of cancer death, up from the fifth place in the early 1990s, according to a new data analysis.

Colorectal cancer achieved its first-place position sooner than expected, researchers from the American Cancer Society said, noting that it had originally been predicted to become the lead cause of cancer deaths in the under-50 age group by 2040.

From 1990 through 2023 – the latest year for which data is available – nearly 1.3 million people died of cancer in the U.S. before age 50, the analysis reported in JAMA found.

During that period, and after accounting for age, the cancer death rate decreased by 44%, from 25.5 per 100,000 adults to 14.2.

On average, death rates from 2014 through 2023 declined by 0.3% per year for brain cancer, 1.4% for breast cancer, 2.3% for leukemia, and 5.7% for lung cancer.

Bucking the trend, colorectal cancer mortality rose by 1.1% annually from 2005 through 2023.

“These findings are consistent with reports of increased colorectal mortality among adults younger than 50 years overall and in most racial and ethnic groups,” researchers said.

Given that most colorectal cancer patients diagnosed before age 50 already have advanced disease, researchers advised education about unique red-flag symptoms, including bright red blood in stool and abdominal pain. They also called for screening beginning at age 45.

Wildfire smoke in third trimester linked with autism risk

Exposure to wildfire smoke during the final months of pregnancy may raise the risk of an autism diagnosis in the child, a California analysis found.

Researchers looked at more than 200,000 births in Southern California from 2006 to 2014, including 3,356 in which children were diagnosed with autism by age 5. They found that expectant mothers exposed to one to five days of any wildfire smoke particles during the third trimester had children with an elevated risk of autism compared to those not exposed.

During wildfires, burning vegetation and buildings release toxic metals and other pollutants that can be inhaled, the researchers noted in a report published in Environmental Science & Technology.

The strongest association was in mothers exposed to more than 10 days of wildfire smoke during the final trimester, they found.

In that group, children had a 23% higher risk of autism diagnoses compared to those whose mothers were never exposed to wildfire smoke while pregnant.

Risk factors for mothers of children diagnosed with autism included that they were older, in their first pregnancy, or had pre-pregnancy diabetes or obesity.

The researchers say their study cannot prove that prenatal wildfire exposure causes autism, but it adds to growing evidence of the adverse impact of air pollutants on development of the fetal brain.

“As climate change increases the frequency and intensity of wildfires in many parts of the world, understanding their relationship with autism is important to being able to develop preventive policy and interventions that will protect pregnant women and their children,” study leader Mostafijur Rahman of Tulane University said in a statement. — Reuters