The research, published in the Journal of the American Medical Association, presents a dismal picture of life after cancer.
Conducted by St. Jude Children's Research Hospital, it provides a glimpse into St. Jude's LIFE program, a two- to three-day initiative that brings long-term childhood cancer survivors back to the hospital for regular check-ups throughout their adult lives.
The goal is to monitor adult survivors to better understand the mechanisms that promote survival. The former patients undergo various checks and screenings including basic health exams, blood tests and X-rays.
The authors report that by age 45, 80% of survivors have a life-threatening, disabling or serious health condition. Sixty-five percent of the survivor participants who were at risk for lung problems after their treatment had abnormal lung functions, and 61% of former patients at risk for neurocognitive issues had endocrine problems in areas of the brain like the hypothalamus. Another 56% of survivors had heart abnormalities, and 48% had memory difficulties.
"It is not surprising, but it helps quantify what our fears were in this population," says study author Dr. Melissa Hudson, the director of the St. Jude Division of Cancer Survivorship. "We have known for many years that adults who were treated for cancer in childhood have a higher risk for health problems, and these health problems appear to increase as they age."
The study population is one of the oldest groups of survivors to be studied. Participants ranged from 18 to 60 years old, though the average age was 33. Their average time from cancer diagnosis was 26 years, with a range from 11 to 48 years from diagnosis.
Previous studies looking at cancer survivors' health have typically relied on surveys instead of actual check-ups in the doctor's office.
"We know we are underestimating the amount of disease," says Hudson. "This comprehensive study allows us to get down to what are the undiagnosed conditions that are hopefully in early stages so intervention will benefit them."
The researchers say their findings support tailoring treatments to patients so that exposure to radiation from chemotherapy is kept to a minimum. Patients should have regular check-ups throughout their lives and maintain a healthy lifestyle in order to not exacerbate their risk.
"Physicians and health care providers should be advocating for healthier lifestyle practices for anyone they see in their practice, but it is particularly important for childhood cancer survivors because they have already had treatments when their organs were more vulnerable that put them at risk for types of diseases we see in aging populations like high blood pressure, osteoporosis, high cholesterol, etc.," says Hudson.
Screening programs like the one at St. Jude's not only identify health issues early in these at-risk patients, but also help doctors identify which screening processes are most helpful and aid in characterizing what patient profiles are at a higher risk for certain diseases.
"Our greatest findings were that these patients had diseases that were not identified," says Hudson. "This type of care really understands their risk for disease in the context of their previous cancer history."
This story was initially published on TIME.com.