Individuals who survive cancer before age 21 are nearly 5 times more likely to subsequently develop gastrointestinal (GI) cancers, researchers from the University of Chicago Medicine reported in the Annals of Internal Medicine.

Although there was some preliminary evidence that individuals who survive cancer during childhood are more likely to develop GI cancers at an earlier age, this study is the first to focus on a range of pediatric cancers with examination of detailed treatment information including radiation and chemotherapy exposures.
Tara Henderson, M.D, M.P.H, and team analyzed 14,358 survivors of soft tissue sarcoma, Hodgkin lymphoma, non-Hodgkin lymphoma, neuroblastoma, Wilms tumor or bone cancer. The researchers discovered that some participants were developing secondary GI cancers just 5.5 years after their primary cancer diagnosis.

Henderson explained:

“Due to advancements in therapies, we now have a burgeoning population of childhood cancer survivors. Sufferers of once nearly unequivocal deadly disease are thriving well into adulthood. Unfortunately, it appears that for some the impact of cancer therapy along with, in some cases, inherent genetic propensity may set the stage for a second cancer diagnosis.

It’s an important finding that will hopefully allow us to identify at-risk patients and implement better surveillance in clinical practice.”

According to the authors, 13.9 years was the mean age of study participants at their primary cancer diagnosis, and 33.5 years at diagnosis of secondary GI cancer. In the general population, the median age for colorectal cancers is 70. Henderson states that as this population ages, the incidence of secondary GI cancers will continue to rise.

The results coincide with earlier findings which indicated that radiation exposure significantly increases the risk of cancer survivors developing secondary cancers. Patients exposed to abdominal radiation were 11.2 times more likely develop secondary cancers than the general population.

However, the researchers found that patients were still at increased risk even if they did not receive radiation treatment for their primary cancer. Furthermore, exposure to high doses of procarbazine and cisplatin chemotherapies have also been associated to increased risk.
The investigators note that curing the primary childhood cancer remains a priority, and therefore current treatment protocols to reduce the long-term risk of GI cancers should not be modified.

Henderson said:

“However, pediatric oncologists continually strive to reduce or eliminate late toxicity without affecting the probability of cure. Therefore, the necessity of therapies such as radiation is under constant scrutiny.”

The authors say that childhood cancer survivors should be screened for GI cancers every 5 years, beginning 10 years after radiation treatment, or at age 35, particularly those with increased risk factors. They state that this would result in stronger survival rates with early detection of colorectal cancer where the current recommendation is to begin screening at age 50.

Henderson explained “We can’t yet predict which patients will face a subsequent cancer, but we can and should devise screening guidelines that take all the risk factors into account. Waiting until these patients are 50 is simply not enough.”

Written by Grace Rattue