'Children Are Not Small Adults': Why It Matters in Cancer

Fran Lowry

September 14, 2016

A new report by the American Cancer Society and the Alliance for Childhood Cancer underscores the difficulties in doing pediatric cancer research and highlights the serious health problems that childhood cancer survivors face.

Cancer is the leading disease-related cause of death for children aged 1 to 19 years, according to the report, and the disease takes a huge toll because it occurs so early in life and survivors face extremely high rates of late effects that can last a lifetime.

In addition, the American Cancer Society predicts that in 2016, there will be 10,380 new childhood cancer cases and 1250 cancer deaths among children aged 0 to 14 years, and an estimated 4280 new cancer diagnoses and 600 cancer deaths in adolescents aged 15 to 19 years.

The report is titled "Translating Discovery Into Cures for Children With Cancer: Childhood Cancer Research Landscape Report" and can be viewed at www.cancer.org/childrensreport.

"There is a lot of conversation around the progress that has been made in childhood cancers, but we also know that this progress is pretty uneven," Katharine Sharpe, senior vice president for patient and caregiver support at the American Cancer Society, told Medscape Medical News.

Katharine Sharpe

"Some of the cancer types have a much better prognosis, but we still have so many that unfortunately do not have very good outcomes," Sharpe said.

According to the report, the 5-year survival rate for all cancers combined rose from 64% among children diagnosed from 1975 to 1979 to 84% for children diagnosed from 2005 to 2011. For neuroblastoma, 5-year survival is currently 78%, but for high-risk neuroblastoma, 5-year survival is only 40% to 50%. The 5-year survival rate for some cancers, such as diffuse intrinsic pontine glioma, is still essentially zero.

"As the report shows, there are still areas of research where progress is urgently needed," Sharpe said.

Developing drugs for childhood cancers is a big challenge, the report notes.

"One of the key findings from the report, and one that I am particularly fond of, is that children are not small adults," she said.

"Many aspects of childhood cancer drug developments are shared with adult drug developments, but there are some pretty significant differences. So, even though some cancers share the same name in adults and children, the childhood versions are quite different biologically. This makes a difference in how you look at this from a research perspective and how you ultimately treat the disease," Sharpe said.

The childhood versions are quite different biologically. Katharine Sharpe

Importantly, children who survive their initial cancers remain at risk for developing other cancers. Side effects from treatment have significant health impacts on children because their treatments occur when they are very young, during vulnerable periods of development.

"About 20% of those children who survive their cancer will die later of either a cancer recurrence or a new cancer, or they are often at such high risk for developing another disease as a result of the toxicities of their treatments. Some drugs damage the heart, some cause sterility, so the price these kids pay is pretty high," Sharpe said.

The report also highlights the fact that society has afforded special protective status for children involved in research, which changes the type of research generally considered to be ethical for children and also changes the process for approving such research.

In addition, the fact that childhood cancers are so rare makes drug companies unenthusiastic about developing and marketing drugs for this population.

"There are a relatively low number of children diagnosed with cancer, so how do you get the appropriate number within any clinical study, and how do you create an environment in which investment in this type of research is not something that you're looking at in terms of the market to justify large research expenditures for a smaller number of patients," Sharpe said.

Coping with the challenges represented by pediatric cancer is daunting, she added.

"It requires a cooperation among researchers, advocacy groups, regulatory communities, and all of us who share the goal of finding cures for pediatric cancers to recognize and address the barriers and challenges that are described in this report. We have to look at how we can work together as a collective to understand these problems and then push in the appropriate areas to work together to resolve some of these issues. Essentially, this report is a call to action," Sharpe said.

Ms Sharpe is an employee of the American Cancer Society.

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