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The majority of adults who have survived childhood cancer are not up to date with potentially life-saving surveillance screening tests to check for delayed effects of their initial treatment, Canadian research suggests.

The study, which included data for 3241 individuals diagnosed with cancer at one of Ontario’s five pediatric cancer centers between 1986 and 2014, showed that by 2020 just 6% were adherent to recommended screening for colorectal cancer, 13% were adherent to breast cancer screening, and 53% were adherent to screening for cardiomyopathy.

The findings highlight a need for “a centralized system to identify survivors and provide them and their family physicians with personalized information about recommended surveillance,” first author Jennifer Shuldiner, from the Women’s College Hospital Institute for Health System Solutions and Virtual Care in Toronto, told Inside Precision Medicine.

“We envision a system where survivors are asked if they want to know about their screening recommendations and are then provided with the necessary information. This system should also have reminders to keep survivors on track and send information to the primary care provider if they have one,” she said.

As many as 80% of childhood cancer survivors will develop a serious or life-threatening effect, such as cardiomyopathy and colorectal and breast cancer, resulting from their treatment by age 45 years. The risk for colorectal cancer is two to three times higher than that for the general population, while the risk of breast cancer in females who underwent chest radiation is similar to that of people with a BRCA mutation.

Screening tests for these conditions, through echocardiograms, breast MRIs and mammograms, and colonoscopies can reduce the impact of disease, but previous research has shown that “staying up to date with screening recommendations is a struggle for childhood cancer survivors,” said Shuldiner.

The current analysis, published in CMAJ, shows that, during a median 7.8 years of follow-up, the 234 survivors at risk for breast cancer were adherent to breast cancer screening recommendations just 10% of the time. The proportion of time spent adherent was 14% among the 327 survivors at elevated risk for colorectal cancer, and 43% for the 3205 at risk for cardiomyopathy.

“In Ontario, there is a network of survivor clinics that childhood cancer survivors can attend; however, by the time survivors reach their 30s, 40s, or 50s, most do not attend,” Shuldiner explained.

“The reality is that the onus falls on the patient and their family doctor (if they have one) to be aware of their specific screening requirements. Guidelines are complex, dependent on the treatment children received many years ago, and change frequently. It is hard to expect primary care providers to know the most up to date information, necessitating the development and implementation of new tools to communicate these needs.”

The researchers also found that the proportion of patients adherent to screening for colorectal cancer and cardiomyopathy increased with time, whereas breast cancer screening adherence decreased over time.

Shuldiner suggested that this could be because breast cancer screening recommendations have changed to include MRI rather than just a mammogram. MRIs “are not always easy to get, and this complexity may have reduced overall screening rates,” she remarked.

She also noted that the screening adherence rates for cardiomyopathy were likely higher than those for cancer because echocardiograms are more readily available and easier to complete than mammograms, breast MRIs, or colonoscopies.

Across the surveillance tests, higher levels of comorbidity were associated with better adherence, which may indicate that survivors with more medical problems and their physicians are more motivated to conduct investigations.

In addition, individuals who were older at diagnosis were more likely to follow breast and colorectal cancer screening guidelines, whereas younger age at diagnosis was associated with higher likelihood of following screening guidance for cardiomyopathy.

There are several potential reasons why keeping up with screening in this population is difficult, said Shuldiner. “Firstly, childhood cancer survivors received treatment when they were young, they might not know what treatment they received or even what type of cancer they had. Without this information, it is impossible to know what screening they should receive; Secondly, guidelines are complex and are also changing as we learn more about the effects of treatments survivors have received; Thirdly, primary care providers often do not have access to which treatments the survivor has received, and are not aware that screening is recommended; Fourthly, right now, the burden is on the survivor to know about their screening and inform their primary care provider. This can be tough, these survivors need support to stay healthy.”

Shuldiner and colleagues now plan to carry out a trial to investigate whether a centralized system that provides to survivors and their family physicians with recommended screening test surveillance details could work in Ontario.

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