The National Cancer Institute estimated that esophageal cancer will cause 14,500 deaths and 16,640 new cancer diagnoses in the United States in 2010. Esophageal cancer is a form of adenocarcinoma, and the cancer develops within mucous-producing cells of the esophagus. A common treatment for this form of cancer is chemotherapy, a method involving the use of drugs to damage cancer cells. Chemo drugs have a range of mechanisms within cells and affect esophageal cancer in a variety of ways.
DNA Damage
Chemotherapy drugs damage esophageal cancer cells by damaging their deoxyribonucleic acid (DNA). Each cancer cell contains DNA made up of billions of chemicals that code for thousands of proteins the cell uses to grow and survive. Certain classes of chemotherapy drugs, such as alkylating agents, severely damage the structure of DNA, according to Weber State University. Alkylating agents add small chemical modifications onto the components of DNA, interfering with normal DNA processing and cellular metabolism. Ultimately, the esophageal cancer cell cannot use its DNA as a blueprint for the proteins it needs to survive, and the cell dies. Drugs such as cisplatin and mitomycin, both DNA-damaging agents, are effective treatments for esophageal cancer, according to the Swedish Medical Center.
Metabolic Inhibition
Other forms of chemotherapy have an effect on metabolism within esophageal cancer cells. Each cell within the body has a number of cellular pathways that transform chemicals into useable energy for the cell. In addition, cellular metabolism allows for the synthesis of chemicals required for cell division. For example, the cell must generate the components of DNA as a requirement for cell division. Some chemotherapy drugs work to inhibit these metabolic pathways in esophageal cancer cells, preventing the cells from replicating. Navaro College outlines that these drugs, called antimetabolites, may inactivate enzymes within the cells required for proper metabolism or interfere with specific stages of cellular proliferation. Following sustained exposure to these drugs, esophageal cancer cells lose the ability to divide and eventually die. The Swedish Medical Center lists the chemotherapy antimetabolite fluorouracil as an effective treatment for esophageal cancer.
Cancer Cell Death and Tumor Shrinkage
The overall effect of chemotherapy on esophageal cancer is massive cancer cell death. The continued exposure to damaging chemicals eventually renders a cancer cell unable to survive, and the resulting mass cell death leads to tumor shrinkage. Different classes of chemotherapy drugs may be used on their own or in combination with other drugs to attack multiple pathways within the cancer cells, increasing the rate of cancer cell death. Doctors may also use combinations of drugs to increase the chance of damaging drug-resistant cancer cells that might not be harmed by the use of a single drug. The Swedish Medical Center indicates that single-agent chemotherapy can produce a response in up to 30 percent of esophageal cancer patients, while combination chemotherapy can produce a response in up to 50 percent of patients. By developing combinations of chemotherapy tailored to the characteristics of a patient's esophageal cancer, doctors can effectively treat the cancer and help reduce the risk of cancer recurrence.
