Chemotherapy is the treatment of cancer with one or more cytotoxic agents. These agents kill cancer cells and prevent progression of this lethal disease. Chemotherapy may be given with a curative intent or it may aim to prolong life or to palliate symptoms. It is often used in conjunction with other cancer treatments, such as radiation therapy and surgery. Chemotherapy can be given before primary therapy (neoadjuvant chemotherapy), or after the primary therapy (adjuvant). In fact, in advanced cancer patients, chemotherapy becomes the most important modality of treatment, and in this case, the intent would be palliative.
Traditional chemotherapeutic agents act by killing cells that divide rapidly, one of the main properties of most cancer cells. This means that chemotherapy also harms cells that divide rapidly under normal circumstances - cells in the bone marrow, digestive tract, and hair follicles. This results in the most common side-effects of chemotherapy - myelosuppression (decreased production of blood cells, hence, also immunosuppression), mucositis (inflammation of the lining of the digestive tract), and alopecia (hair loss).
Some newer anticancer drugs (for example, various monoclonal antibodies) are not indiscriminately cytotoxic, but rather target proteins that are abnormally expressed in cancer cells and that are essential for their growth. Such treatments are often referred to as targeted therapy (as distinct from classic chemotherapy) and are often used alongside traditional chemotherapeutic agents in antineoplastic treatment regimens. Targeted therapy maybe expensive but strives to cure cancer at the molecular level. Recently, a group of drugs called Immunotherapy drugs are being extensively used for management of cancers (both solid and haematological malignancies). They block checkpoints in the body and allow the immune system to fight against Cancer antigens.
Chemotherapy may use one drug at a time (single-agent chemotherapy) or several drugs at once (combination chemotherapy or polychemotherapy). The agents are repeated weekly, biweekly or three weekly most of the times. It is not always necessary that a patient needs to be admitted for chemotherapy. He can take it from the daycare facility and get discharged on the same day.
Common side effects of chemotherapy though scary are nowadays better managed with advances in medical science. Anemia or fall in white blood cells can be stimulated by growth factors. Mucositis can be prevented using special gargle formulas. Nausea and vomiting, one of the most distressing symptoms of chemotherapy can be prevented with newer drug formulations.
Finally, chemotherapy can cure certain cancers like some lymphomas, choriocarcinoma, germ cell tumours, providing a ray of hope to mankind.
- Dr. Rakesh Roy
Department of Medical Oncology
Saroj Gupta Cancer Centre & Research Institute (SGCCRI), Thakurpukur.
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