Wednesday, July 19, 2006

Explanation of Chemo, warning this may bore you...

For all of you who haven't had chemo (and believe me, I pray that that is the majority of you), here is what it is like. It started with an appetizer of zofran (anti-emetic) and decedron (a steroid). After the zofran and decedron was in, she started with the mean and nasties. The first m&n (no, not m&m) was a test dose of adriamycin. This is the drug that makes you lose your hair. She injected a small amount first to ensure that I didn't have an allergic reaction to it. I didn't. Then she got out this syringe that looked like one of those in a comic book. She needed two hands to carry it. It contained adriamycin. It sort of looked like cherry koolaid. Next came two smaller pushes of velban and bleomycin. Finally, the main course was DTIC. Some initials that lay people aren't supposed to know. The main course lasted 45 minutes.

The tumor shrinkage due to chemo treatment follows the same logarithmic curve that they would if they were growing. Left alone tumors have a doubling time specific to the tumor. One interesting thing that I just found out about cancer is that, unlike normal cells that only proliferate during their embryionic stage and stay quiet for the rest of their lives, tumor cells enter into an unregulated reproduction stage and mitosis (cell division) occurs continuously. For tumors to grow, the cell has to be in a growth cycle and only a certain percent of the total number of tumor cells are actively growing (dividing). Let's say it the doubling time is 2 months and suppose that there were 100,000 cells on July 1. This means that there would be about 200,000 cells on September 1 and 400,000 cells on November 1. Another issue that separates cancer cells from normal cells is that cancer cells loss of the cell's ability to undergo "apoptosis." Apoptosis is basically cell suicide. So, not only has the cancer cells' gone reproductively crazy, it never dies.Likewise, for chemo to work, the cells have to be in their doubling mode and only a certain percentage of the cancer cells are actively doubling. So, the cells would be killed in the same cycle time and they will decrease exponentially, too. Let's say that there are 1,000,000 on the first week of treatment and the chemo kills 90% because that is how many of the cells are in play the tumor will shrink to 100,000 cells. Then, the next treatment 2 weeks later kills 90% and the tumor shrinks to 10,000 cells. Then on the next treatment 2 weeks later (or 4 weeks after the start) the tumor is down to 1,000 cells. If you put this on a chart paper the tumor cell count will go down following a specific type of curve called 'logarithmic decay'.Taking all this mathematical mumbo jumbo basically means that the largest tumor depletion should occur early in the treatment. Another interesting thing that I learned was that this tumor kill liberates lots of bad stuff that you have to get rid of. For example, people with gout have problems with metabolism of some body chemicals (proteins / DNA) and they build up uric acid. Imagine a flood gate opening of uric acid from these tumors. It clogs up the blood and you have to get rid of it. There are two ways to do so. One is to take allopurinal or a medicine to beat the uric acid. Another way (if you have good kidneys) is to drink lots and lots of water.
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