Chemotherapy

As it’s always good to set out with something positive, here’s the good news.  My red blood cells have recovered.  With a hemoglobin count of 120 g/l and a hematocrit value of 40%, I’m still at the lower end of what’s normal and I won’t win races in the mountains, but I can exercise normally and won’t feel limited.

The blood for the test was taken from my finger this morning when I checked in at the outpatient oncology clinic of my favorite hospital.  It was like something out of a Theranos commercial when this hot air balloon was still floating.  A bit of blood from my finger, five minutes of analyses, and I was off with a sheet of paper with two dozen numbers and a few graphs.  I was happy with what I saw.  The doctor looked more closely and dampened my excitement.  I might yet get another iron transfusion.

The outpatient oncology clinic is a newish cube slightly off the main hospital building, connected by a tunnel-like walkway.  It is a quiet, friendly place with large windows towards the woods, four beds to a room and caring nurses.  Patients are offered tea and coffee, soup, a tablet to kill the boredom and toxins to do the same to the cancer.

I was made to swallow a bucket of drugs to suppress the nausea that inevitably accompanies chemotherapy.  Now I was ready to start.  To make recurring transfusions and the taking of blood samples easier on me, I’ve had a port implanted halfway between my right chest and shoulder.  It’s a circular button under the skin that protrudes about a centimeter.  After it was inserted during the surgery four weeks ago, it stretched the skin a bit, but now I don’t feel it anymore and appreciate the convenience.  No more puncturing of veins, and less damage to them by the drugs.  For efficient dilution of the drugs in the blood, the port extends almost into the heart.

Talking about drugs, today my cocktail comprises oxaliplatin, calcium folinate and 5-fluorouracil.  Initially, irinotecan was also prescribed, but the doctors thought its potential benefits would not outweigh the toxicity in my case.  This is quite frustrating.  Why are drugs kept from me?  How will I beat the cancer this way?  But I don’t know better and I have to trust the doctors.

• Oxaliplatin is a platinum-containing compound that forms both inter- and intrastrand crosslinks with DNA.  It prevents replication and transcription and thus causes cell death.
• Calcium folinate is a salt of folic acid, also known as vitamin B9.  If I understand it correctly, calcium folinate serves to increase the effect of oxaliplatin.  The two are given together.
  → I clearly didn’t understand this correctly.  Calcium folinate is the salt of folinic acid, which is very similar to but distinct from folic acid.  Calcium folinate, also known as Leucovorin, enhances the effect of 5-fluorouracil by inhibiting thymidylate synthase.
• 5-fluorouracil should be an easy one for a biochemist.  I would think that, as a nucleoside analog, it is incorporated into RNA instead of uracil and into DNA in place of thymine and thus screws with replication and transcription.  However, Wikipedia cautions that “how it works is not entirely clear”.

The chemicals wash into my blood while I lounge on a bed writing this post.  The administration itself is clearly harmless, but chemotherapy isn’t for chickens.  I was warned of severe and broad side effects, from numbness in my extremities to bleeding, from nausea to a higher risk of infections.  I might even lose some of my hair.  This is something for another post.

From the next session, Avastin will added to the mix.  This is an antibody that will turn chemotherapy into a biochemotherapy, which pleases the biochemist in me.  Avastin blocks the growth of blood vessels.  It is thus not an agent specific for colon cancer.  I wonder what happened to therapeutic antibodies.  Shouldn’t it be possible to genetically characterize the cancer and use therapeutics targeted to surface markers specific to my cancer.  Are we not there yet?