The threat posed by cancer centers on the capacity of the cancerous cells to uncontrollably replicate, taking over the space occupied the normal cells. Chemotherapy treatments are drugs that exploit vulnerabilities in cancer cell metabolism with the intention of killing the cells or limiting their capacity to replicate and spread. Several types of chemotherapy drugs are utilized in the treatment of cancer. Different types of chemotherapy utilize varying mechanisms to arrest cancer cell growth and spread.
Genotoxic Chemotherapy
Genotoxic chemotherapy treatment employs drugs that damage or interfere with the genetic material, or DNA, of cancer cells. The DNA damage inflicted by genotoxic drugs typically causes the death of the cell. Several classes of genotoxic drugs are used to treat different types of cancer. Alkylating agents are genotoxic drugs that chemically react with DNA, distorting its normal structure. The National Cancer Institute points out that alkylating agents were among the first chemotherapy drugs used to treat cancer. They remain the most frequently used type of chemotherapy medication. Commonly used alkylating agents include cyclophosphamide, thiotepa, lomustine, cisplatin, carboplatin, mechlorethamine, chlorambucil and oxaliplatin. Intercalating agents are another form of genotoxic chemotherapy, notes Emory University's Winship Cancer Institute. These drugs interject into the DNA structure, disrupting its normal processes. Drugs included in this class of gentoxic agents include doxorubicin, epirubicin and daunorubicin.Topoisomerase inhibitors are a newer class of genotoxic chemotherapy agents. These drugs interfere with an enzyme that enables DNA copying, an essential step in the formation of new cancer cells. Examples of topoisomerase inhibitors include etoposide, topotecan and irinotecan.
Antimetabolic Chemotherapy
Antimetabolic chemotherapy drugs interfere with the normal metabolic processes of cancer cells by mimicking required chemicals, tricking the cells into incorporating the drug. Once incorporated into the cancer cell, the drug induces fatal metabolic errors. Purine, pyrimidine and folate antagonists are the major classes of antimetabolic chemotherapy drugs, reports the National Cancer Institute. Purines and pyrimidines are the building blocks of the cellular genetic material. As a cancer cell prepares to duplicate itself, it makes a copy of the genetic material for the new cell. Purine and pyrimidine antagonist drugs "impersonate" their naturally occurring counterparts. Incorporation of the purine and pyrimidine look-alike drugs into the genetic material during genetic copying halts the process, thereby preventing cell replication. Commonly prescribed purine and pyrimidine antagonists include gemcitabine, 6-mercaptopurine, fludarabine, capecitabine and 5-fluorouracil. Folate antagonists interfere with the production of new purines and pyrimidines by inhibiting an essential enzyme in the process, explains Emory University's Winship Cancer Institute. The two commonly utilized folate antagonists are pemetrexed and methotrexate.
Antimitotic Chemotherapy
Mitosis is the process by which human cells produce new cells. The process involves making a duplicate copy of the contents within a cell, which then splits into two new cells. Antimitotic chemotherapy drugs, also known as spindle inhibitors, interfere with mitotic processes, thereby preventing the formation of new cancer cells. Vinorelbine, vincristine, docetaxel and paclitaxel are among the most commonly prescribed antimitotic chemotherapy drugs, according to the American Cancer Society.
