Saturday, April 25, 2009

Human granulocyte colony-stimulating factor

After my five days of chemotherapy, I get Neupogen (also called G-CSF) to help my bone marrow recover its ability to make neutrophils (bacteria- and fungus-eating white blood cells). White and red blood cells (among others) grow in several steps from stem cells; the chemotherapy does not kill the stem cells or the adult blood cells, but rather the steps in between. Adult blood cells normally die and are then replaced by younger ones; with chemotherapy disrupting the pipeline, though, blood counts drop lower and lower until the stem cells have had enough time to start over from scratch. The day with the lowest counts is called a nadir.

I get the Neupogen (subcutaneous in my abdomen area) every day until after my neutrophil nadir. My ANC (absolute neutrophil count) is always lowest on day 12 of my cycle, which works out to nine shots of Neupogen (cycle days six through fourteen). I suspect I'm actually good to go after eight shots. But confirming that would involve having bloodwork done on a Sunday, which I have not been motivated to pursue.

Last week, I came across this article on the EPOCH-R regimen, which says, "The ANC nadir was invariably observed around day 10–12 of treatment." Now I feel kinda behind the curve: having my nadir on day 12, when others are able to get that over with by day 10.

Neupogen has been on my mind more often lately, as just last cycle I did some of the injections myself. My oncologist's office normally has the nurses give all the shots, so I trekked into the office every day I needed the injections (including two weekends of each cycle). My last two shots of cycle five, though, I asked to take home and give to myself, and I'll do the same for these two weekends of cycle six. It's kinda neat to have a bag labeled "biohazard" in my refrigerator (the shots have to be kept chilled).

The manufacturer's directions for injecting Neupogen warn of hitting a capillary. If this happens, they say to discard that syringe and try again. My oncology nurses don't do this, they haven't had any adverse events from it, and at $350 per syringe I can understand the failure to follow this recommendation. The manufacturer's directions also specify either a 45º or 90º angle for the injection. All but one of my oncology nurses gives it at a 90º angle; after some experience with the 45º method, I found that it was more painful. So my own technique is the same as that of most of my oncology nurses: alcohol swab, straight in 90º, give the injection without checking for blood return.

It's fun to get the hang of this stuff, but I will be so glad when it's all behind me. I hope that time comes soon.

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