Sunday, July 19, 2009

Radiation 101

While survival rates for other types of cancers have improved greatly, the survival rates for pediatric brain tumors have not changed all that much over many years. The traditional treatment for pediatric brain tumors is radiation because the tumors did not usually respond well to chemotherapy or the doses of chemotherapy proved too toxic for the children. Radiation works by blasting a beam of energy (usually x-rays) at the cancer cells. The radiation energy then either kills the cancer cells or jumbles the DNA to stop them from replicating.

Unfortunately, traditional radiation has a host of short term and long term side effects. Radiation cannot distinguish between good cells and bad cells, and some good brain cells can be radiated. This can cause extreme fatigue, permanent hair loss, hearing loss, stunted growth, abnormal puberty, and decreased intelligence. There is also a small chance that radiation causes more cancer.

There is a relatively new type of radiation called Proton Radiation Therapy. With this type of radiation, we can fully control and target where the beam strikes so that we minimize damage to good brain cells. Currently, there are only 6 proton therapy centers in the country, with the closest being in Boston at Mass General Hospital.

Because of these radiation side-effects, the Head Start protocol (currently in Phase 3, which Isabella is part of) was created. The Head Start protocol looks to avoid or minimize radiation in children by using 5 high dose chemotherapy cycles. The last cycle is followed by a stem cell transplant to assist the child's blood counts to recover. Because of the size of Isabella's original tumor, we knew that we would have to do radiation at some point. Although we won't be able to eliminate radiation, we'll be able to minimize it since the remaining tumor has shrunk.

In addition, we will be taking advantage of the proton therapy radiation at Boston's Mass General Hospital. This past week, we were just in Boston meeting with the radiation oncologists to plan Isabella's treatments. Her radiation treatments will start on July 27 and run for 6 weeks. The treatments are done on a daily basis from Monday through Friday.

I do have plenty of pictures and videos from this summer as we all enjoy being home for the summer. I hope to post them soon. Isabella continues to be herself, which is an energetic and brilliant child.

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