Difference Between Pediatric and Adult Cancer

Thank you to Chalice Chick, who has afforded me the opportunity to write about the difference between pediatric and adult cancers. It’s certainly an area I knew nothing about, a year and a half ago. I will state up front that if someone else could state something better than I, I just pasted their words in. This ain’t no term paper.

CC asked: “… how does childhood cancer differ from regular cancer?

If a child and an adult both have lung cancer, don't they have the same disease? If I give money for lung cancer research and it is done on adults, doesn't that ultimately help both of them, and if not them, then a child and adult in a similar situation 20 years from now."

Childhood cancer is very different from adult cancer, which is why pediatric oncology is its own field. Here are some of the major differences:

Type
Childhood cancers are biologically different from the cancers that affect adults and tend to occur at different sites from those common in adults. Among the most common childhood cancers are leukemias, lymphomas, brain tumors, and bone cancer. Each of these cancers also occurs in adults, but adult cancers tend more commonly to strike the lung, colon, breast, prostate, and pancreas.

There are some childhood cancers that almost never occur in adults (such as what LW has – Wilms’ Tumor) and some cancers that affect adults but virtually never occur in children. With very rare exceptions, there are some malignant diseases that do affect teenagers and younger adults, but by and large most of the diseases that pediatric oncologists deal with are fundamentally different diseases and thus are treated much differently than adult cancers are.

Growth
At the time of diagnosis, cancer is usually much more advanced in children than in adults. Only 20% of adults, versus 80% of children, have cancer that has spread to other parts of the body at the time of diagnosis. Childhood cancers tend to be more aggressive. Childhood tumors, perhaps because they are a primitive cell, tend to spread more easily than adult cancers. For this reason, pediatric oncologists are more likely to use chemotherapy, even in cancers that are localized at the time that they are diagnosed.

On top of that, kids are pumping out a lot of growth hormones which can increase the growth rate of cancer thus requiring faster working chemo.

Effect of Chemo
I didn’t know until LW began treatment, that the way chemotherapy works is to attack the fastest dividing cells. (Which is why your hair normally falls out.)

Kids, because they’re growing, just happen to be chock-full of fast dividing cells, and so they suffer more bodily damage from the chemos - many chemos developed for use in adults are completely unusable in children because of this damage.

In addition to chemo, the helper drugs – such as anti-nausea medications – have extremely different toxicity profiles when you compare children to adults.

Research
A lot of adult cancers are 'acquired' cancers, caused by environmental damage, smoking, obesity, etc. Because of this, a lot of the money given for adult cancer research is based on how to prevent these diseases developing and educating people not to do the things that cause them.

Other than in areas of massive environmental damage – Chernobyl, for example – there have been no definitive links between environment/behavior and childhood cancer. Many of the cancers that affect children are embryomas. An embryoma is a derivation of embryo, and have been described as recapitulation of fetal development. Some strategies in childhood cancer are targeting an attempt to differentiate the diseased tissues back to a normal state; so many of the forms of therapy are quite different.

The best difference between childhood and adult cancers is that childhood cancer is rare. But this makes research more difficult. Many adult cancers can have a research study at a single institution. You can’t with childhood cancer, there will never be enough cases to do that. So we have the Childhood Oncology Group, which covers the US, a few countries in Europe, New Zealand and Australia.

Treatment Facility
Most adults who are diagnosed with cancer are treated in their local community by their primary care physicians and cancer specialists. Children’s cancers are much more rare than those of adults, so specialists in many smaller communities do not have continuing experience with the management of these diseases. (The horror stories I could tell you of misdiagnoses and bad treatment.) For this reason, children usually are best treated by teams of doctors who specialize in the diagnosis, treatment, and management of childhood cancers. Such teams are much more likely to be found in eminent children’s hospitals, university medical centers, and cancer centers.

We were lucky in that we live near two of the best pediatric oncology departments. But I have many friends who have to travel for treatment.

Future Effects
This might be the most devastating difference between adult and childhood cancer.

While many of the same interventions such as chemotherapy, radiation and surgery are used to used to treat children's and adults’ cancers, children are more apt to suffer significant after-effects such as cognitive dysfunction, cataracts and organ failure as a result of the harsh impact of the treatment on their young and developing bodies. Additionally, as was reported a few months ago, there is a big chance of developing a secondary cancer at some point in their lives. It is only recently that we began having a significant amount of childhood cancer survivors – so we’re just now learning about those late affects.

Two more notes:
#1: In no way am I attempting to say that in adult/childhood cancers, one is easier/harder than the other. They both suck. Period.

#2: If anyone has an interest in working childhood cancer research into their Giving Budget, I recommend Cure Search. You can even specify that you want it to go to the Wilms' Initiative. Right now, there is no defined protocol for relapsed Wilms'.

And some factoids:
* Pediatric cancer is the #1 cause of death by disease in children under 15
* The ACS estimates that 10,400 cases of childhood cancer will be diagnosed in 2007
* Chemotherapy was first used on children with cancer