5-FU Chemotherapy for Cholangiocarcinoma

My husband Tom just started on 5-FU for his reoccurance of an in-operable tumor. This was after a successful resection. Radiation killed the in-operable tumor…but his docs were watching another spot on the liver, close to the original new tumor. About 8 months ago the two spots were very distinct and a bit aways from one another. With his last scan however, the two spots have grown together, and now look like a snowman without a head!

He started on 5-FU this past Thursday.

First he gets an anti-nausea drug, then they hang a large bag of medication to protect his kidneys and that takes 2 hours. After one hour, or 1/2 way into that bag they administer a large syringe of 5-FU (Fluorouracil also known as Adrucil or 5-Flurouraicl) in what they call a IV push over a period of 10 minutes, then the remainder of the medication for the kidneys. He will have this every friday for 6 weeks, then 2 weeks off. After that 8 weeks we will discuss again.

The 5-FU is an anti-cancer (antineoplastic or cytotoxic) chemotherapy drug. This medication is classified as an “antimetabolite”.

How 5-FU works: Cancerous tumors are characteried by cell division, which is no longer controlled as it is in normal tissue. “Normal” cells stop deividing when they come into contact with like cells, a mechanism known as contact inhibition. Cancerous cells lose this ability. Cancer cells no longer have the normal checks and balances in lace that control and limit cell division. The process of cell divison, whether normal or cancerous cells, is through the cell cycle. The cell cycle goes from the resting phase, through active growing phases, and then to mitosid (division).

The ability of chemotherapy to kill cancer cells depends on its ability to halt cell division. Usually, the drugs work by damaging the RNA or DNA that tells the cell how to copy itself in division. If the cells are unable to divide, they die. The faster the cells are dividing, the more likely it is that chemotherapy will kill the cells, causing the tumor to shrink. They also induce cell suicide (self death or apoptosis).

Chemotherapy drugs that affect cells only when they are dividing are called cell-cycle specific. Chemotherapy drugs that affect cells when they are at rest are called cell-cycle non-specific. The scheduling of chemotherapy is set based on the type of cells, rate at which they divide, and the time at which a given drug is likely to be effective. This is why chemotherapy is typically given in cycles.

Chemotherapy is most effective at killing cells that are rapidly dividing. Unfortunately, chemotherapy does not know the difference between the cancerous cells and the normal cells. The ‘normal’ cells will grow back and be healthy but in the meantime, side effects occur. The ‘normal’ cells most commonly affected by chemotherapy are the blood cells, the cells in teh mouth, stomach and bowel, and the hair follicles; resulting in low blood counts, mouth sores, nausea, diarrhea and/or hair loss. Different drugs may affect different parts of the body.

5-FU belongs to the category of chemotherapy called antimetabolites. Antimetabolites are very similar to normal substances within the cell. When the cells incorporated these substances into the cellular metabolism, they are unable to divide. Antimetabolites are cell-cycle specific. They attack cells at very specific phases in the cycle. antmetabolites are classified according to the substances with which ther interfer.

Folic acid antagonist: Methotrexate
Pyrimidine antagonist: 5-Fluorouracil Foxuridine, Cyarabine, Capecitabine and Gemcitabine
Purine antagonist: 6-Mercaptopurine and 6-Thioguanine
Adenosine deaminase inhibitor: Cladribine, Fuldarabine and Pentostatin

I hope that somewhere down the line, this information on 5-FU is useful to someone else fighting Cholangiocarcinoma!

Love and Hugs,
Margaret