Chemotherapy is used to treat several forms of cancer. Chemotherapy drugs are cytotoxic drugs that halt tumor cell growth and induce tumor cell death to help treat and shrink the tumor. There are a number of classes of chemotherapy drugs with distinct mechanisms of action, but all share the ability to kill rapidly proliferating cells. Use of chemotherapy leads to a number of effects, positive and negative, in cancer therapy.
Systemic Cancer Cell Death
A positive effect of chemotherapy treatment is that the drug is effective throughout the entire body. Other cancer treatment options like surgery can effectively remove a tumor, but may miss cancer cells that have invaded other tissue in a process called metastasis. Metastatic tumors can travel throughout the body and form tumors in distant organs, leading to a number of effects that are not treated by removing the original tumor. The American Cancer Society reports that most patients who die from cancer have distant metastases, and these distant tumors are usually the cause of death.
Chemotherapy drugs travel throughout the entire body and target any rapidly proliferating cell. This means that chemotherapy can target and kill cancer cells left behind after surgery or other cancer therapies. For this reason, chemotherapy can be effective in treating metastatic cancers.
Skin Rashes
Since chemotherapy targets any rapidly proliferating cell, chemotherapy can also have a number of negative effects on the body. A common effect of chemotherapy is the development of rashes and lesions over the course of treatment. The skin is made up of a number of cell types, and undergoes constant renewal that depends on the proliferation of skin precursor cells. The precursor cells, found deep within the skin and in the hair follicles, develop into mature skin cells as they approach the surface of the skin, and they are eventually sloughed off.
The proliferating precursor cells are targeted by chemotherapy drugs, and the decrease in precursor cells leads to delayed and inhibited wound healing--a process that requires cell proliferation. As a result, patients may develop rashes or skin lesions due to an inability of the skin to heal itself. The University of Virginia Health System lists methotrexate, sorafinib and docetaxel as examples of chemotherapy drugs that can cause rashes.
Vulnerability to Infection
Another negative effect of chemotherapy is the development of a condition called neutropenia, which leaves a patient vulnerable to infection. Neutropenia is caused by low levels of white blood cells. These cells develop from a population of blood stem cells within the bone marrow, a continually proliferating set of stem cells that can mature to form white and red blood cells, as well as other cells in the blood. Bone marrow stem cells are targeted by chemotherapy and do not produce enough white blood cells. Since the blood cells help make up the immune system, patients with low white blood cell counts are vulnerable to infection and disease. The Neutropenia Support Association notes that the use of certain therapeutics over the course of chemotherapy treatment can help alleviate neutropenia and protect the patient from infection.
