Chemotherapy

Chemotherapy is a general term for treatments that use chemical agents (drugs) to kill cancer cells. Many different kinds of drugs are used, either alone or in combination, to treat different cancers. The specific drug or combination used is chosen to best combat the type and extent of cancer present. Chemotherapy drugs are tested against various forms of cancer in an effort to find out which drugs work against that particular type of cancer. Multiple drugs, each individually effective against a certain cancer, are often combined to try and maximize the effect against the cancer. Drugs are combined so that there are few overlapping side effects, to make the treatment more tolerable. These combinations are then tested in clinical trials to see how effective they are. If a combination works better than the current “standard” treatment, it will become the new standard therapy.

Chemotherapy drugs are given for several reasons :-

  • To treat cancers that respond well to chemotherapy
  • To decrease the size of tumors for easier and safer removal by surgery
  • To enhance the cancer-killing effectiveness of other treatments, such as radiation therapy
  • In higher dosages, to overcome the resistance of cancer cells
  • To control the cancer and enhance the patient’s quality of life

Types of Chemotherapy Drugs

Drugs that generally kill cancer cells are referred to as cytotoxic agents.
Common types of cytotoxic chemotherapy drugs include :-
  • Alkylating agents modify/damage cancer cell DNA and block the replication of DNA, therefore interfering with the growth of cancer cells.
  • Antimetabolites block the enzyme pathways needed by cancer cells to live and grow.
  • Antitumor antibiotics block certain enzyme and cancer cell changes, thus affecting DNA.
  • Mitotic inhibitors slow cancer cell division or hinder certain enzymes necessary in the cell reproduction process.
  • Nitrosoureas impede enzymes that repair DNA

How Chemotherapy Works ?

Chemotherapy kills rapidly dividing cells. Cancer cells often multiply more rapidly than normal cells. Cancer cell are also less able to recover from the toxic effects of chemotherapy than can normal cells. Normal cells that divide rapidly, such as hair or blood cells, are also killed by chemotherapy. This results in common side effects such as hair falling out and blood counts dropping.
Chemotherapy drugs are tested against various forms of cancer in an effort to find out which drugs work against that particular type of cancer. Multiple drugs, each individually effective against a certain cancer, are often combined to try and maximize the effect against the cancer. Drugs are combined so that there are few overlapping side effects, to make the treatment more tolerable. These combinations are then tested in clinical trials to see how effective they are. If a combination works well than the current “standard” treatment, it will become the new standard therapy.

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