Chemotherapy circulates in the blood stream throughout the body so that it can treat cancer cells in almost any part of the body, known as systemic treatment.
Chemotherapy kills cells that are just dividing into 2 new cells.
Body tissue is made up of billions of individual cells. Once we are fully developed, most of the cells in the body do not divide or multiply very much.They only split when they need to repair the damaged tissue.
When cells divide, they divide into 2 new identical cells.So where there was 1 cell, there are now 2,then they divide into 4, then into 8 and so on.
In cancer, cells keep dividing until a mass of cells is formed that become a lump called a tumor.
Because cancer cells divide much more often than most normal cells, chemotherapy is more likely to kill them.
Some drugs kill dividing cells by damaging the part of the cell’s control centre that causes them to divide other drugs disrupt the chemical processes involved in cell division.Effects on dividing cells
Chemotherapy damages cells during cell division.
In the centre of every living cell there is a dark spot called the nucleus.The Cell nucleus is the control centre of the cell.It contains chromosomes, which are made up of genes.
These genes need to be copied exactly every time a cell divides into 2 in order to produce new cells.. Chemotherapy damages genes in the cell nucleus.
Some drugs damage cells where they divide. Some damage cells by making copies of all of their genes before they divide .Chemotherapy is much less likely to damage dormant cells as it does most normal cells.
You may be given a combination of different chemotherapy drugs .These include drugs that damage cells at different stages in the cell division process.This means there is a better chance of killing more cells.
Cancerous tumors are characterized by cell division that is no longer controlled as in normal tissue. “Normal” cells stop dividing when they come into contact with similar cells, a mechanism known as contact inhibition.Cancer cells lose this ability .Pictures of cancer cells show that cancer cells lose the ability to stop dividing when they come into contact with similar cells. Cancer cells no longer have the normal control mechanisms that control and limit cell division .The process of cell division, regardless of whether it is normal cells or cancer cells, takes place via the cell cycle .The cell cycle goes from the resting phase to active growth and phases and then to mitosis (division).
The ability of chemotherapy to kill cancer cells depends on its ability to stop cells from dividing .In general cancer drugs work by damaging the RNA or DNA that tells the cell how to copy itself when it divides.If cancer cells cannot divide, they die .The faster cancer cells divide, the more likely it is that chemotherapy will kill them and shrink the tumor. They also induce cell suicide (auto death or apoptosis).
Chemotherapy drugs that kill cancer cells only when they divide are called cell cycle specific. Chemotherapy drugs that kill cancer cells while at rest are known as non cyclic cells. specific. And when a particular drug is likely to be effective.For this reason, chemotherapy is usually given in cycles.
Chemotherapy is most effective at killing cells that are dividing rapidly.Unfortunately, chemotherapy doesn’t know the difference between cancer cells and normal cells .The “normal” cells grow back and are healthy, but side effects occur in the meantime .The normal cells most commonly affected by chemotherapy are blood cells, cells in the mouth, stomach and intestines, and hair follicles, causing low blood counts, mouth sores, nausea, diarrhea and / or hair loss. Different drugs can affect different parts of the body.
Chemotherapy (antineoplastic drugs) fall into five classes based on how they kill cancer. Although these drugs are divided into groups, there is some overlap between some of the specific drugs. Different types of chemotherapy are discussed in the following section in to explain these important procedures further.