Among childhood cancer survivors in Ontario, Canada, who faced an elevated risk due to chemotherapy or radiation treatments, 53% followed screening recommendations for cardiomyopathy, 13% met colorectal cancer screening guidelines, and 6% adhered to breast cancer screening guidelines.
“Although over 80% of children newly diagnosed with cancer will become long-term survivors, as many as four out of five of these survivors will develop a serious or life-threatening late effect of their cancer therapy by age 45,” lead author Jennifer Shuldiner, PhD, MPH, a scientist at Women’s College Hospital Institute for Health Systems Solutions and Virtual Care in Toronto, told this news organization.
For instance, the risk for colorectal cancer in childhood cancer survivors is two to three times higher than it is among the general population, and the risk for breast cancer is similar between those who underwent chest radiation and those with a BRCA mutation. As many as 50% of those who received anthracycline chemotherapy or radiation involving the heart later develop cardiotoxicity.
The North American Children’s Oncology Group has published long-term follow-up guidelines for survivors of childhood cancer, yet many survivors don’t follow them because of lack of awareness or other barriers, said Dr. Shuldiner.
“Prior research has shown that many survivors do not complete these recommended tests,” she said. “With better knowledge of this at-risk population, we can design, test, and implement appropriate interventions and supports to tackle the issues.”
The study was published online on March 11 in CMAJ.
Changes in Adherence
The researchers conducted a retrospective population-based cohort study analyzing Ontario healthcare administrative data for adult survivors of childhood cancer diagnosed between 1986 and 2014 who faced an elevated risk for therapy-related colorectal cancer, breast cancer, or cardiomyopathy. The research team then assessed long-term adherence to the North American Children’s Oncology Group guidelines and predictors of adherence.
Among 3241 survivors, 3205 (99%) were at elevated risk for cardiomyopathy, 327 (10%) were at elevated risk for colorectal cancer, and 234 (7%) were at elevated risk for breast cancer. In addition, 2806 (87%) were at risk for one late effect, 345 (11%) were at risk for two late effects, and 90 (3%) were at risk for three late effects.
Overall, 53%, 13%, and 6% were adherent to their recommended surveillance for cardiomyopathy, colorectal cancer, and breast cancer, respectively. Over time, adherence increased for colorectal cancer and cardiomyopathy but decreased for breast cancer.
In addition, patients who were older at diagnosis were more likely to follow screening guidelines for colorectal and breast cancers, whereas those who were younger at diagnosis were more likely to follow screening guidelines for cardiomyopathy.
During a median follow-up of 7.8 years, the proportion of time spent adherent was 43% for cardiomyopathy, 14% for colorectal cancer, and 10% for breast cancer.
Survivors who attended a long-term follow-up clinic in the previous year had low adherence rates as well, though they were higher than in the rest of the cohort. In this group, the proportion of time that was spent adherent was 71% for cardiomyopathy, 27% for colorectal cancer, and 15% for breast cancer.
Shuldiner and colleagues are launching a research trial to determine whether a provincial support system can help childhood cancer survivors receive the recommended surveillance. The support system provides information about screening recommendations to survivors as well as reminders and sends key information to their family doctors.
“We now understand that childhood cancer survivors need help to complete the recommended tests,” said Dr. Shuldiner. “If the trial is successful, we hope it will be implemented in Ontario.”