Next Week's Schedule

Next Tuesday I go into the hospital and start high-dose chemo. It will run for seven days and I think will consist of three days of Etoposide, three days of Carmustine, and one day of cyclophosphamide.

Etoposide is a drug that inhibits the action of the enzyme topoisomerase, which itself is involved in the making and breaking of bonds in the "skeleton" of the DNA molecule. Whis this enzyme inhibited, the process of unzipping and duplicating DNA goes awry - it is thought that etoposide in particular inhibits the creation of new bonds in the DNA skeleton - and the target cell is either induced to commit cellular suicide or it just sits there, unable to complete the process of reproduction, until it eventually croaks.

Carmustine and cyclophosphamine, on the other hand, are alkylating agents, distantly derived from the mustard gas that was used to horrific effect in World War One. Here, the drugs bond alkyl groups to specific (but different) parts of the DNA molecule. Relatively specialized cells, such as muscle cells and liver cells, have some ability to correct this sort of DNA damage, but cancer cells are relatively undifferentiated and have poor DNA error correction capability - as the DNA unwinds to begin reproduction, the enzyme responsible hits the alkyl group, which effectively staples the DNA chain together at that point. The enzyme can't break the alkyl group, the cell can't back up and give up on the idea of reproducing, so there it sits, irretrievably broken, until it dies.

I've had Etoposide before - it was part of the ESHAP business - but my body had never seen Carmustine or cyclophosphamide before and presumably none of my cells have developed any immunity or resistance to them. The idea is that at high doses, these three drugs should go through my cancer like the prototypical white tornado - and honestly, there isn't much left of my cancer for a white tornado to go through.

They cause widespread damage to other parts of the body, especially those cells that tend to reproduce quickly or are undifferentiated. That means the hair follicles, the lining of the gastrointestinal tract, and sperm cells (really, the last of my worries right now). If I had any hair to lose, I'd lose it (but I'm as bald right now as Imhotep in The Mummy). I'm likely to develop sores in my mouth and throat. I'll become infertile, but who cares?

So it's seven days of high-dose chemo. On the eighth day I get my stem cells back, and then we simply wait to see how long it takes for my white blood cell count to recover before I can go back home. Two or three weeks total, though I'm hoping for two - last time, my stem cells implanted quickly and got back to work with vim; I'm hoping the same thing happens again.