Chemotherapy drugs are designed to target cells that grow faster than normal cells—a characteristic trait of cancer cells. They work by targeting certain aspects of the cell growth cycle. The cell cycle is the series of steps a cell undergoes in an effort to copy its genetic substance and divide into two cells. It is divided into four phases: G-1, S, G-2, M phases. A chemotherapy agent may go in only one phase of the cycle (cell-cycle specific) or target all phases (cell-cycle nonspecific).
DNA replication is most active in the S phase, making it a prime target for many chemotherapy agents. That’s since most chemo agents eliminate cancer cells by having an effect on DNA synthesis or function. The major classes of chemo agents are alkylating agents, anthracyclines, antimetabolites, plant alkaloids, taxanes, antitumor antibiotics, and platinums. Each class of drug varies in the way it acts on a particular cell cycle phase.
The most common routes of administration for anti-neoplastic agents are by mouth (oral), through a vein (intravenous), or muscle (intramuscular). These are new techniques that are already designed to increase chemotherapy concentration at the tumor site. Chemotherapy can now be administered directly into a specific body cavity, the abdomen, the lung, the central nervous system, or applied directly to the skin.
While designed to target fast-growing cancer cells, radiation treatment also affects healthy cells and, consequently, cause side effects. Depending on the type and dose of chemotherapy, some patients may have a lot of side effects while others may have only a few or none at all. As such, it is important before you start chemotherapy to speak with a medical expert about what adverse reactions can be expected. Health professionals have many ways to stop or deal with radiation treatment side effects to help you recover and cope after each treatment. Other side effects may be delayed. Hence, a follow-up visit to your doctor is necessary.
There are many ways to manage chemotherapy side effects, which we shall discuss in our succeeding columns. Two chemotherapy side effects people worry about the most are nausea and vomiting. Nausea occurs when you’re feeling sick to the stomach, like you are going to throw up, while vomiting is when you actually throw up. You may also have dry heaves, which happens when the body attempts to be sick even though your stomach is empty.
One way to prevent vomiting is to prevent nausea. Bland, easy-to-digest foods and drinks that do not upset your tummy, for instance plain crackers, toast, and gelatin, are recommended to prevent nausea. Eating 5 to 6 little meals and snack foods every day instead of 3 large meals also helps. Stay away from food items and drinks with solid smells, such as coffee, fish, onions, garlic, and foods that are cooking. Try small bites of popsicle or ice chips.
New drugs, called antiemetic or antinausea prescription drugs, can assist protect against nausea or vomiting. Several antiemetics are available in the market, but there are antiemetics specifically formulated for chemotherapy-induced nausea and vomiting (CINV). Current drugs for CINV are available in tablet form and as intravenous fluid. A newer CINV drug in the form of a patch offers ease of administration and patient convenience. Ask your doctor about these new antiemetics and how they can help you deal with chemotherapy-induced nausea and vomiting.