An examination of cancer survivors from the 1970s to the 1990s shows that the rate of severe health problems occurring five or more years after diagnosis has declined over time.

The study— presented at the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting—analyzed 23,600 childhood cancer survivors in the Childhood Cancer Survivor Study (CCSS) and found that the rate of severe health problems dropped from 12.7 percent for those diagnosed in the 1970s to 10.1 percent in the 1980s, to 8.8 percent for survivors diagnosed in the 1990s.

The rate of survivors of Wilms’ tumor—a rare kidney cancer—dropped from 13 percent in the 1970s to 5 percent in 1990s. Over the course of the survey the rate of survivors of Hodgkin lymphoma decreased from 18 percent to 11 percent, the rate for survivors of astrocytoma fell from 15 percent to 9 percent, from 10 percent to 6 percent among survivors of non-Hodgkin lymphoma and from 9 percent to 7 percent among survivors of acute lymphoblastic leukemia.

According to the study, advances in treatment and supportive care have improved the five-year survival rate after childhood cancer diagnosis from 58 percent in the 1970’s to 84 percent today. Previous research showed that changes in treatment over the last three decades lowered the chance of dying from late effects of therapy among childhood cancer survivors by 6.4 percent.

“Our analysis marks the first comprehensive assessment of changes in the rates of chronic health complications over time in a large group of cancer survivors,” lead study author Todd Gibson, Ph.D., an assistant member at St. Jude Children’s Research Hospital in Memphis, said in a statement. “From our findings, it is clear that survivors diagnosed and treated in more modern treatment eras are doing better.

“Not only are more children being cured, but they also have lower risk for developing serious health problems due to cancer treatment later in life,” he added.

The CCSS used periodic surveys to explore long-term outcomes in survivors of childhood cancer diagnosed between 1970 and 1999 that survived at least five years after diagnosis, focusing on severe, disabling, life-threatening or fatal health problems occurring within 15 years of the diagnosis.

While the researchers saw a decrease in health issues for survivors of several forms of cancer, they did not see a reduction among survivors of other types of cancer including neuroblastoma, acute myeloid leukemia, soft-tissue sarcoma and osteosarcoma.

They did however see great reductions in the incidence of endocrine conditions, which went from 4 percent in the 1970s to 1.6 percent in the 1990s and second cancers, which fell from 2.4 percent in the 1970s to 1.6 percent in the 1990s. There was also a significant reduction in gastrointestinal conditions and neurological conditions over the course of the survey, while the rate of heart or lung conditions did not change.

“We were a little surprised that the incidence of severe cardiovascular disease did not decrease, knowing that deaths from cardiovascular disease dropped among survivors in recent decades,” Gibson said. “This is a reminder that survivors continue to have an increased risk for serious health problems compared to the general population and need to be followed closely.”

The researchers now plan to study specific health conditions further and would also like to follow survivors beyond 15 years after diagnosis and study how late treatment effects intersect with aging.

The abstract can be viewed here.