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Women's Health News Desk, August 10, 2016 ~ How does Chemotherapy Work?
by Eva Hvingelby, NP PhD
Chemotherapy uses drugs that have been designed to kill certain types of cells, often by interfering with their ability to reproduce. Chemotherapy is provided in a way that enables the entire body to absorb the medication. The goal is to kill cancerous cells at the site of the tumor, and cancerous cells that may have spread to other parts of the body.
Chemotherapy can be provided as a fluid directly into a vein. It can also be taken as a pill. Sometimes it is injected into the body, such as via a catheter into the abdominal cavity. When injected into a body cavity it works directly on cancer cells inside the cavity that would not have been reached via the blood stream. The chemo medication is also absorbed through the tissues and into the circulation with this approach.
One characteristic of cancer cells is that they divide much more quickly than other cells in the body. Many chemo drugs target cellular DNA in order to stop cells from reproducing. Even though chemo affects all cells in the body, the rapidly dividing nature of cancer cells means they are affected by the drug more quickly. The goal is to provide enough chemo to kill the cancer cells, but stop before there is permanent damage to other cells in the body.
How Much Chemo is Needed?
Every person’s chemotherapy regimen is tailored to the type of cancer cells present, how far it has spread, and any other unique characteristics of the cancer. It is most common to give two different types of drugs. This is called combination treatment. Combination treatment is effective because it targets the cancer in different ways, which makes it stronger. In other words, doctors try to kick the cancer when it’s already down.
There are usually three to six cycles of chemotherapy. During a cycle, chemotherapy is scheduled in regular doses, then there is a rest period. The rest period gives healthy cells time to recover before the next cycle begins. The goal is to repeatedly weaken the cancer cells, so that each cycle of medication kills the more effectively.
Many epithelial ovarian cancer tumors respond to treatment. It’s possible to see the tumors shrink on CT scan, and see tumor markers in the blood go down after treatment. Unfortunately, most of the time there are a few cancer cells left behind which start the process all over again. Chemo may be scheduled again six months to one year later, and repeated regularly, to stop the growth and spread of the original cancer.
Much of our writing is done by Eva Hvingelby NP, PhD is a Nurse Practitioner, writer, educator and researcher. She has been working in health care for over 25 years with a focus on traumatic injury and terminal illness.