Recent research shows that chemotherapy can leave behind changes in healthy cells that may affect a person’s health years after treatment.
A 3-year-old cancer patient’s blood cells showed the genetic wear of an 80-year-old after chemotherapy, highlighting new evidence that life-saving drugs leave lasting damage in healthy cells—a change that can persist for a lifetime.
Chemotherapy can permanently damage the DNA of healthy blood cells, causing them to age prematurely and potentially increasing patients’ risk of developing secondary cancers decades later, recent research shows.
“The damage to DNA lasts a lifetime,” said Dr. Daniel Landau, an oncologist and hematologist with The Mesothelioma Center at Asbestos.com, who was not involved in the study. “Probably the biggest concern is the increased risk of other cancers developing as a result of exposure to prior chemotherapy.”
A Child’s Blood Cells Aged Decades in Months
The study, recently published in Nature Genetics, examined how chemotherapy affects healthy blood cells at the genetic level.
Researchers compared blood samples from 23 people, ages 3 to 80 years, who had received chemotherapy, with samples from nine people who had never been diagnosed with cancer. The chemo group had received an average of 21 different treatments, including platinum and alkylating agents—drugs that kill cancer cells by damaging their DNA.
In one case, the team found that a 3-year-old boy who had undergone chemotherapy showed 10 times more mutations in his blood than healthy peers his age. His blood cells appeared genetically older than those of an 80-year-old who had never received chemotherapy.
“While traditional chemotherapy can be effective at reducing tumor burden, it also carries a significant risk of collateral damage to healthy tissue, along with an increased risk of mutational changes and resistance in cancer cells,” said John Oertle, chief medical officer at Envita Medical Centers, who was not involved in the study.
Genetic Signs of Treatment
The study found that cancer-fighting drugs leave distinct genetic traces in normal blood cells that persist long after treatment ends, fundamentally altering how these cells function and age.
Using advanced DNA sequencing and mathematical modeling, researchers isolated blood stem cells and mature blood cells to examine their entire genomes. They identified four specific DNA damage patterns called mutational signatures—genetic markers that reveal what caused cellular damage.
Eleven signatures were found only in the blood of those who had received chemotherapy, including four that had never been documented before. These signatures are like permanent genetic “scars” left by cancer treatment.
The findings may help explain why cancer survivors often face higher risks of heart disease, diabetes, stroke, and dementia later in life. “Damaged stem cells never fully recover and can develop into other problems much later in life,” Landau said.
