Long-Term Effects of Chemotherapy on the Immune System

A strong immune system becomes a critical line of defense for those undergoing chemotherapy treatment. The likelihood of immediate side effects is high and often occur as a result of a weakened system. The condition of the body before, during and after treatment may determine the likelihood of long-term damage.

Identification

• Individuals who suffer from cancer may opt to receive chemotherapy as one form of treatment. Chemotherapy involves the use of chemical agents to kill cancer cells. Chemotherapy can be administered orally, through injections or intravenously. Some of the drugs used include Cisplatin, Cytoxan, Xeloda, 5-FU and Herceptin. Once the drug is in the system, it targets any suspected cancer cells in the body. Cancer cells grow faster than normal body cells, which is one way the agent is able to identify cancer formations. Fast-growing cells can also be found in the hair, bone marrow and digestive systems. As a result, chemotherapy effects can mistake normal cells as cancerous. When this happens, side effects may occur.

Immune System Function

• The body's immune system is made up of a network of tissues, cells and organs that work to fight off germs and infections. White blood cells, or leukocytes, play an essential role in this system. These cells travel throughout the body in lymphatic vessels, as well as in the bloodstream. White blood cells are fast-growing cells that are produced in the bone marrow, digestive system and the hair. When chemotherapy is administered, it often mistakes white blood cells for cancer cells because they grow so quickly. When the number of white blood cells dips below a certain number, the body becomes weak and vulnerable to possible infection.

Effects

• Side effects experienced from chemotherapy are mostly short-lived. Once the body replaces the healthy cells that were lost, symptoms like nausea, vomiting, fatigue and hair loss subside. Long-term effects can occur if chemotherapy damages a major organ like the reproductive organs, heart and lungs. When this happens, it may take anywhere from months to years before side effects stop. A person's overall health prior to receiving treatment may determine how quickly he recovers from chemotherapy.

Growth Factors

• Throughout the course of chemotherapy, scheduled blood testing is done to monitor white blood cell count. Frequent testing is meant to keep treatments from overwhelming the body's systems. If white blood cell counts drop below normal range, doctors may administer what's called growth factors, or Colony Stimulating Factors (CSF). CSF's are medications designed to stimulate the body's ability to produce white blood cells. Neupogen, Neulasta and Leukine are a few of the growth factor medications used.

Stem Cell Replacement

• In cases where a person receives intense chemotherapy treatment, there is a risk that the normal bone marrow production of white and red blood cells slows or shuts down completely. In effect, the treatment has mistakenly killed off bone marrow stem cells. Persons being treated for lymphoma or leukemia are most at risk of this happening. If this condition persists, the body will become anemic and highly susceptible to infections. A procedure called an allogenic stem cell transplant is designed to replace lost stem cells. Donor cells are typically taken from a relative to ensure compatibility.