Q. I’m having TCH chemotherapy for breast cancer. What is it?
A. The chemotherapy drugs Paclitaxel (Taxol) or docetaxel (Taxotere) and carboplatin, paired with a biologic therapy, Herceptin, comprise the most common treatment for women with HER2-neu-positive (HER2+) breast cancer.
Q. Can we backtrack a minute? I know I’m HER2+, but what does that mean, anyway?
A. Cells do three things: they grow, they rest, and they repair themselves. Genes inside the chromosomes in your cells regulate their activity, telling them when to grow, and when to stop growing and rest. If the genes malfunction, the patterns of growth/rest/repair are disrupted.
In HER2+ breast cancer, there’s an excess of HER2 genes in the chromosomes of some of your cells. These genes tell the cells to grow extra protein receptors on their surface. With these extra receptors, the cells keep getting signals to grow, rather than to rest or repair. They grow much faster than the cells around them; this wild, uncontrolled growth turns them into cancer cells.
Q. So, what do all these drugs do?
Taxol/Taxotere slows or stops cell division, or keeps enzymes from making the proteins cells need in order to grow. Thus it slows down (and hopefully stops) cancer cells’ out of control growth.
Carboplatin, a so-called alkylating agent (and similar to the very common chemo drug Cytoxan, if you know anyone else who’s had chemo) stops cancer cells from replicating by sticking to their DNA. Basically, it gums up the works; which is a good thing, where cancer is concerned.
Herceptin (trastuzumab) is a bit different. Called a targeted therapy (or immune targeted therapy), it manufactures antibodies that “target” specific properties of cancer cells: their production of protein, their use of enzymes, or their ability to form new blood vessels to support growth. These antibodies leave healthy cells alone, which is a plus.
Herceptin attaches itself to a cancer cell’s protein receptors, effectively blocking the “grow” message. Herceptin can also signal your body’s immune system to destroy the cell to which it’s attached itself – so it packs a double punch.
Q. So, how do I take these drugs? They’re intravenous, right?
A. That’s right; they’re given by what’s called “infusion” (which is why you might see your hospital’s chemotherapy area called an “infusion suite” or “infusion room”).
Delivery methods and schedules vary, as the pharmacology is constantly changing. That said, you'll probably have a total of four to six treatments of Taxol/Taxotere and carboplatin, delivered at three-week intervals; though recently, some oncologists have changed the regimen to lower doses, delivered weekly.
The usual procedure is a slow infusion of Taxol/Taxotere by IV into your hand or arm, which takes about 3 hours; followed by about 30 minutes of carboplatin, delivered the same way.