We spent about an hour and a half with Dr. Ira Dunkel at MSKCC today. He agrees with Collin's oncologist, Dr. Melanie Comito, that Collin is still curable. He also agrees however that the best chance to cure disease that has proven to be resistant to chemo is to use non-chemo methods, namely radiation. The best chance of curing the disease using radiation would be to give the highest dose of radiation known to be curative. However, chances are high that this would not leave Collin with a good quality of life. So the dilemma is...which is more important-the highest chance of a cure despite the risk that Collin may be left unable to ever live independently? Or giving radiation at a reduced dose to improve his chances of still being left with a decent quality of life, but at the risk that the reduced dose of radiation alone may not cure him? If we choose the later, how can we "hedge our bets" to improve the chance of a cure as well as preserving quality of life?
Long before the FDA will approve drugs for widespread use, they go through years of testing and clinical trials by researchers and hospitals. Phase I clinical trials solely test the toxicity of a drug. During Phase II trials, while the toxicity is still monitored, the goal is to see benefit from the drug being tested. MSKCC is now conducting a Phase II clinical trial using an antibody that is known to react with the kind of disease Collin has. This clinical trial has been going on for about five years. However, the antibody has been used for twenty-some years in patients with Neuroblastoma, another childhood cancer of the central nervous system, and it is known to be effective.
Antibodies are proteins generally found in the blood that detect and destroy invaders, like bacteria and viruses. There is an antibody named 3F8 that attaches to tumor cells. When radioctive iodine (131I) is attached to the antibody, it is called 131I-3F8. When 131I-3F8 attaches to a tumor, it delivers radiation right to the tumor. To be able to do this, a permanent small plastic tube (called an Ommaya reservoir) would be placed in one of the ventricles of the brain, and through that the antibody would be injected directly into the cerebral spinal fluid (CSF). It would flow through the brain and spine via the CSF, attach to any tumor cells it finds, and deliver the radiation that will hopefully kill the tumor cells once and for all. Before the antibody injections are given, several other medications are given to protect the thyroid gland from radiation, and prevent allergic reaction, fever, and other side effects. The most likely side effects related to the antibody are headache, nausea, vomitting, and fever. Rare but serious side effects include injury to the spinal cord, brain, or muscles; walking problems; pain; tremors; seizures; coma; or death. The antibody injections will be given once a week over a maximum of five weeks. Certain tests will need to be done before, during, and after the study.
The antibody will only attach to tumor cells, not healthy cells, so the radiation that is attached to the antibody will only be released into tumor cells. However, it doesn't penetrate more than about a millimeter. Therefore, in order to give this method the highest chance of success, there are some things that would need to be done first. The new tumor that is present would have to be removed (resected) if possible. After recovery from that surgery, external craniospinal radiation would be administered to shrink any other tumors that may not be visible yet. Then after a four week recovery period following the completion of craniospinal radiation, the antibody therapy would be administered. It's also possible that at some point during or after all of this, Collin could go on more maintenance chemo using some drugs he hasn't had yet. This option is interesting because since the new tumor didn't become visible until after Collin's maintenance chemo was finished in August, it could be argued that some of the maintenance chemo was working to keep the tumor cells from growing. This is a concept I will go into at a later date.
Dr.Comito is very informed on the latest treatment options out there. She has been in contact with and referred us to some of the best pediatric oncologists in the country. These oncologists and Dr. Comito are in agreement over the best way to treat Collin next. These decisions are some of the most difficult decisions a parent could ever be forced to make, but we don't have a choice. The alternative, losing Collin to cancer, is not acceptable to us, and we are not ready to give up. So after weighing the options that have been presented to us by the best doctors, we have to make a decision, accept it, and not look back. We are meeting with Dr. Comito this afternoon to further discuss the options for resecting the tumor, the kind of external radiation to be used, the risks, the dose, and where we would have to go to get the radiation. Once the details are worked out, plans will be put into motion. After that we must push ahead, and hope for the best possible outcomes while keeping in mind how tough Collin is and how far he has already come. Your love, support, and prayers are appreciated more than you will know during the next steps of this journey.
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