Chemotherapy is a broad class of medications primarily used in the treatment of cancer. There are more than 100 different chemotherapy agents, which can be administered orally, topically in creams, by injection into tumors or veins, or by infusion into the bladder, abdomen or central nervous system. Although many different chemotherapy drugs are used to treat all different kinds of cancer, the underlying purpose of all chemotherapy drugs is the same--to interfere with cell reproduction. This property of chemotherapy drugs is responsible for their effectiveness against cancer, but also for many side effects, including hair loss.
Chemotherapy and the Cell Cycle
Understanding why you lose your hair requires an understanding of how chemotherapy impacts cells in your body. Each cell in your body serves a specific function, as determined by its DNA. Some cells live a long time, while others reproduce and die quickly. Cells reproduce by copying themselves, including their DNA code, which determines their function. If enough of a specific type of cell dies without replicating themselves, then eventually there are not enough cells to serve that function in the body.
How Cell Reproduction Works
There are five phases of cell reproduction. Phase G0 is the resting phase, prior to cell reproduction beginning. Some cells stay in resting phases for longer than others. Cancer cells, and other cells that reproduce frequently like hair follicle cells, do not stay in this phase for long. Phase G1 is the first phase of cell reproduction, which lasts anywhere from 18 to 30 hours. Cells begin to grow and create more proteins during G1. The S phase comes next and is between 18 and 20 hours long. During the S phase, the cell makes a copy of its DNA so the new cell will know function. The G2 phase comes next, and lasts from two to 10 hours. The cell checks the new DNA strand, and begins splitting. It finishes splitting during the final M phase.
Chemotherapy and Hair Cells
Chemotherapy prevents cell reproduction from occurring by interfering with one of the phases of cell reproduction. Generally, chemotherapy drugs interrupt either the S or M phases of reproduction. The interruption to cell reproduction adversely affects any cells that reproduce frequently, because it prevents them from copying themselves. This is why chemotherapy is effective at killing cancer cells and shrinking tumors-cancer cells reproduce frequently. However, hair follicle cells reproduce frequently as well, and when their reproductive cycle is interrupted, eventually the body ends up with an insufficient number of hair follicle cells and hair loss occurs.
When Does Hair Loss Happen?
Generally, hair loss starts within two weeks of the first dose of chemotherapy treatment. By the time 14 days have passed, the number of hair follicle cells has dropped low enough that hair loss begins on the head, eyebrows and elsewhere on the body. Some chemotherapy medications cause total hair loss, which usually takes between three and seven days to occur from the time the hair loss begins. Hair loss is not permanent and once the chemotherapy medication is discontinued, the hair follicle cells will begin to reproduce again and eventually reach healthy levels.
Coping With Hair Loss
It is not possible to diminish or manage hair loss caused by chemotherapy. Any attempt to stop it, by applying ice to the scalp or otherwise, can interfere with the effectiveness of the cancer treatment by preventing cancer cells from being killed. The best management of hair loss is to cut all the hair off and/or shave the head to avoid discomfort or problems associated with uncontrolled hair loss.
Tags: cell reproduction, follicle cells, hair follicle, hair follicle cells, chemotherapy drugs, hair loss