Over 18,000 childhood cancer survivors followed for three decades have revealed a truth that reframes the conversation around long-term health after cancer treatment: the lifestyle choices they make as adults may matter just as much as the intensive therapies that saved their lives.
Two landmark studies, published in Nature Communications and JACC: CardioOncology, show that childhood cancer survivors face a paradox. The radiation and chemotherapy treatments that cured them also increased their risk of cardiovascular disease and other chronic health problems decades later. Yet remarkably, this elevated risk is not inevitable. Researchers led by Aron Onerup at the University of Gothenburg and St. Jude Children's Research Hospital in Memphis have discovered that physical inactivity, obesity, smoking, and high alcohol intake together account for a burden of disease in survivors that is comparable to what the cancer treatments themselves account for.
This discovery matters because, unlike past medical treatment, lifestyle can be changed. "This reveals that lifestyle plays a much bigger role than previously thought. Unlike the treatments already given, the lifestyle can actually be changed," Onerup explains in the Nature Communications study.
The findings are particularly striking when examined through the lens of specific cancers. The second study focused on more than 2,300 survivors of Hodgkin's lymphoma, a cancer that emerges in the lymph nodes. The results show that survivors who lack regular exercise have a 1.4 times higher incidence of cardiovascular disease compared to the general population. More striking still: the excess cardiovascular disease burden in inactive survivors is twelve times greater than can be explained by insufficient exercise alone in the general population. This suggests that childhood cancer survivors' bodies respond to inactivity in ways that are qualitatively different—and more dangerous—than in people without a cancer history.
What makes this finding hopeful is what it implies: if inactivity poses such a disproportionate risk, then physical activity becomes a uniquely powerful intervention for this vulnerable group. "Physical activity can make a big difference in reducing the extra risk that emerges after cancer treatment and modify the negative effects from cancer treatments," Onerup notes.
The research suggests an emerging standard of care. Both studies underscore that healthy lifestyles—particularly physical activity and maintaining a healthy weight—should become an integral part of long-term follow-up after childhood cancer, not an afterthought. Sweden has already begun to integrate these insights into its national health care program for long-term follow-up, with an emphasis on mapping lifestyle habits early.
But mapping habits is only the beginning. Onerup and his colleagues are now developing and testing practical interventions to help survivors adopt and sustain healthy lifestyles across childhood, adolescence, and adulthood. The goal is not simply to tell survivors what they should do, but to provide structured support that makes lasting change possible.
For the thousands of children diagnosed with cancer each year, these studies offer a hopeful message: the future is not predetermined by past treatment. With the right support and sustained effort, survivors can actively shape their long-term health outcomes in ways that were previously underestimated.