8/10/2010 - Childhood Cancer: Progress, But Need for Targeted Therapies

First, the good news: better treatments saved the lives of about 38,000 childhood cancer patients between 1975 and 2006, with overall survival rates now at about 80%, according to a report published online yesterday in the Journal of Clinical Oncology. Now, the bad: while progress against leukemias and lymphomas continues, five-year survival rates for almost all solid tumors in kids and teens haven’t budged over the past 10-20 years.

To find out why, the Health Blog talked to Eugenie Kleinerman, professor and head of pediatrics at M.D. Anderson Cancer Center.

Why has progress against solid tumors in kids stalled?

We’ve come as far as we have due to chemo [and other conventional treatments like surgery and radiation]. But to make progress in solid tumors like sarcomas and brain tumors we really need to understand the biology of the tumors. We need to know if the [molecular] pathways, for example, are the same as in adults.

Why are these diseases so hard to study?

Childhood cancer in general counts as a rare disease, and solid tumors are even rarer. They’re ultra-orphan diseases if you look at them individually. So you can’t say, “Let’s just study pediatric solid tumors.” You have to say “Let’s study Ewing’s sarcoma” or “Let’s study osteosarcoma.” And you have to do it in a cooperative group setting, since the diseases are so rare, which means you have to get [a consensus] from everyone in the group [on what to study].

Might targeted therapies approved for adults work in kids?

That’s a possibility. We need basic research to see if some of these molecular targets are also overexpressed in pediatric tumors. Things like [Roche's] Avastin, which targets the vascular system, may overlap across many tumors. But for a long time we couldn’t get our hands on Avastin [to study in kids] because there was this feeling that it stunted growth in mice. We were ten years behind our adult cancer colleagues in understanding how to use this.

What about other approved therapies?

[Genentech's] Herceptin is a possibility, but we’ve been very slow in getting a consensus to use it. We’ve shown that the Her-2 protein is overexpressed in several forms of sarcoma, but not in the same pattern as in breast cancer. In adults the Her-2 protein is overexpressed on the cell surface membrane. In sarcomas, it’s overexpressed in the cell cytoplasm.

So what’s the top priority?

Funding is the number one issue. We can’t open up the door on how to move forward until we understand tumor biology. The NCI’s budget is $4.8 billion, and the total for grants that have anything to do with pediatric cancer is $173 million.