Most survivors of childhood cancer don’t meet surveillance guidelines that recommend screening for adult cancers or other long-term adverse effects of treatment, according to a new study.

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.

photo of Jennifer Shuldiner
Jennifer Shuldiner, PhD, MPH

“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 Medscape Medical News.

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 much 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 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 Shuldiner. “If the trial is successful, we hope it will be implemented in Ontario.” 

Survivorship Care Plans 

Low screening rates may result from a lack of awareness about screening recommendations and the negative long-term effects of cancer treatments, the study authors wrote. Cancer survivors, caregivers, family physicians, specialists, and survivor support groups can share the responsibility of spreading awareness and adhering to guidelines, they noted. In some cases, a survivorship care plan (SCP) may help.

photo of Adam Yan
Adam Yan, MD

“SCPs are intended to improve adherence by providing follow-up information and facilitating the transition from cancer treatment to survivorship and from pediatric to adult care,” Adam Yan, MD, a staff oncologist and oncology informatics lead at the Hospital for Sick Children in Toronto, told Medscape Medical News.

Yan, who wasn’t involved with this study, has researched surveillance adherence for secondary cancers and cardiac dysfunction among childhood cancer survivors. He and his colleagues found that screening rates were typically low among survivors who faced high risks for cardiac dysfunction and breast, colorectal, or skin cancers.

However, having a survivorship care plan seemed to help, and survivors treated after 1990 were more likely to have an SCP.

“SCP possession by high-risk survivors was associated with increased breast, skin, and cardiac surveillance,” he said. “It is uncertain whether SCP possession leads to adherence or whether SCP possession is a marker of survivors who are focused on their health and thus likely to adhere to preventive health practices, including surveillance.”

The study was funded by the Canadian Institutes of Health Research and ICES, which receives support from the Ontario Ministry of Health and the Ministry of Long-Term Care. Shuldiner received a Canadian Institutes of Health Research Health System Impact Postdoctoral Fellowship in support of the work. Yan disclosed no relevant financial relationships. 

Carolyn Crist is a health and medical journalist who reports on the latest studies for Medscape, MDedge, and WebMD. 

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