The on-going, first-hand tale of a journey through medical oncology... and what happens after.

Saturday, March 5, 2011

Whirrrrrrrr... bzzt

That is the sound that precedes the few drops of 5FU being pumped into my chest each minute for two days after an infusion of FOLFIRI and Erbitux. A semi-constant reminder of what is going on here - the purposeful interruption of cell division in my body. It is particularly unfriendly to my gut lining (food processing zone), bone marrow (blood component factory), and those nasty tumors in my liver (that is the hope, anyways).

Whirrrrrrrr... bzzt.

"5-FU is one of the oldest chemotherapy drugs, and has been around and in use for decades. The drug is believed to function as an antimetabolite (it interferes with metabolites, which aid in processing nutrients). After intracellular conversion to the active deoxynucleotide, it interferes with the synthesis of DNA by blocking the conversion of deoxyuridylic acid to thymidylic acid by the cellular enzyme thymidylate synthetase. Flourouracil may also interfere with RNA (ribonucleic acid) synthesis. It is preferentially taken up by actively dividing tissues and tumors after conversion to its nucleotide." That info is compiled from several websites, and is at the extreme edge of my recollection of biology and chemistry. But note that this function is "believed", not known. Hmmm...

Whirrrrrrrr... bzzt.

"Irinotecan (a semi-synthetic derivative of camptothecin) is much more complicated to describe, but it is an antineoplastic agent (it works to prevent the growth of new plasms), that acts as a specific inhibitor of DNA topoisomerase I." It is a replacement for the oxaliplatin that I received in round one of this adventure, since the neurotoxic effect of oxaliplatin is cumulative and is a gift that keeps on giving. As I understand it, more oxaliplatin would mean permanent neuropathy - and we don't want to go there.

Whirrrrrrrr... bzzt.

Erbitux (cetuximab) is my least-favorite treatment this time, though the 5FU is actually nastier. "Erbitux (cetuximab) is a recombinant, human/mouse chimeric monoclonal antibody that binds specifically to the extracellular domain of the human epidermal growth factor receptor (EGFR). Cetuximab binds specifically to the EGFR on both normal and tumor cells, and competitively inhibits the binding of epidermal growth factor (EGF) and other ligands, such as transforming growth factor–alpha. In vitro assays and in vivo animal studies have shown that binding of cetuximab to the EGFR blocks phosphorylation and activation of receptor-associated kinases, resulting in inhibition of cell growth, induction of apoptosis (intentional cell death), and decreased matrix metalloproteinase and vascular endothelial growth factor production." Another mouthful - but basically this one tells cells to stop growing and start dying.

Whirrrrrrrr... bzzt.

Each time I hear that sound, I am reminded of what is going on - even though it is only 5FU that is being pumped at that moment. The side effects of FOLFIRI plus cetuximab are too numerous to list, and there are drugs that counter those effects (creating a biochemical soup inside me that is too complicated to describe or even think about). Right now, the lovely side effects from Erbitux - acneform rash (looks like a rash with serious acne in it), pruritis (itching), and loss of appetite - are the worst. I have these all in spades, and the flaking off of skin is a general annoyance too. Luckily, the Erbitux will end when we have decided that it is time for the liver resection. Maybe I will still have some skin left on my face. :) And I know the fatigue only lasts five days...

Whirrrrrrrr... bzzt.

1 comment:

Anonymous said...

At first I thought you were making fun of the way my brain works (whirrrrrr...bzzt)...!

Great post Ed. I do hope the side effects calm down with time. Glad also to see you are exercising both mind and body!

Take care, joe