Half-lives

What a wonderfully loaded title for a blog entry. There is so much that could be said about the way we live our lives in a half-awake manner until something happens that truly wakes us up. Or even about how, no matter how old we are, we feel like we are only half-way to somewhere or some-when. This blog entry, though, is about chemistry, the way our bodies deal with chemo, and the confusing "facts" that are available on the Web.

First, let me say that I have NOT checked any of the following with a pharmacist, and that I intend to do so the next time I visit my cancer clinic. And let me also say that I am not inclined to be concerned about the apparent disagreement about how long the Oxaliplatin resides in my body. I trust that my team of doctors and nurses all know what they are doing, especially since this is a clinical trial that they are trying very hard to control (dosage and production lot). OK, now that the silly disclaimers are out of the way, let's get into the math.

One website I went to indicated that the metabolized part of the oxaliplatin that is injected into my system has a half-life of 391 hours (16+ days). Being the math wiz that I am, I quickly calculated that 16+ days minus the 14 days that transpire between each treatment, leaves you with a difference of 2+ days. Ummm, and that was for half of the metabolized dose... So, over the course of twelve treatments, that residual stuff adds up to the equivalent of a dose and a third. In other words, that means that immediately after the 12th treatment I would have approximately 2.3 dose equivalents in my system. And that dose equivalent would take something like 68 days to get down to a 0.3 dose equivalent in my system. Hmmm. Maybe I'll be in a normal state by Christmas, if this website's information is correct. That would be very nice timing, but quite a bit longer than I thought would be the case!

But, then I went to another website (the Eloxatin site, which is the official drug website), and it says that the oxaliplatin has a very short span in system, and that after just 5 days 54% of the drug has been eliminated "through renal activity." Can I hear a "whoop whoop" for the kidneys! This, of course, is a much more encouraging mathematical problem, and might lead a patient to conclude that there is little or no accumulated concentration in their system. However, that doesn't seem to mesh well with the anecdotal stories you hear and read that say that the first half of the treatment regimen is relatively easy to tolerate, but the second half seems harder. What to conclude, what to think, what to do???

Well, in the first place, I ought to talk to my doctor and pharmacist about this. They will certainly be better sources than the Internet. Second, I should be careful extrapolating into my future based on averages. Third, well, I just need to relax. As the lovely wife has pointed out for two days running now, I am hyped up on a steroid and an anti-emetic to head off the nausea and heaving that usually accompanies the introduction of the FOLFOX combination into healthy gastro-intestinal systems. And finally, the reason for all this treatment-stuff is to lengthen my own half-life. At forty-five, I would be greatly surprised if I haven't already passed that temporal milepost, but I am working under the assumption that MY half-life is much closer to 45 years than it is to 25 years.

Have a great weekend!