Depending on the types of cancer and its progression, different treatment options (alone or in combination) may be considered by the treating physicians (oncologist, surgeon, etc) and the patient.

Cancer treatment can be localized or systemic; localized treatment is performed to remove the primary tumour. Surgical resection is privileged if the tumour is contained and has not metastasized.

• Surgery: an operation to remove a tumour or to find out whether malignant tumours are present. It is often the first line of defence and sometimes the only efficient therapy.

For chemotherapy and radiotherapy, doses and frequency vary depending on many factors such as the type of cancer, the type of treatment, the response of the cancer to the treatment and the tolerance of the patient to the treatment doses.

• Radiation therapy (or irradiation or radiotherapy): a type of treatment using high-energy radiation (x-rays, gamma rays, neutrons, protons, etc.) to kill cancer cells and shrink tumours. Radiation may come from an external apparatus (localized external-beam radiation therapy), or it may come from a radioactive substance placed in the body (systemic internal radiation therapy).

• Chemotherapy: it is a systemic treatment and thus can attack any part of the body. It can be used alone or in combination. It is called adjuvant chemotherapy when used to shrink a tumour before surgery or radiotherapy. When a tumour has metastasized, chemotherapy is often called palliative because it is used to slow disease progression and decrease its effects without completely eliminating the disease.
  • Conventional chemotherapy: the conventional treatment, with drugs that kill cancer cells but also normal cells, thus having broad side effects. They are given either intravenously or orally. Combined chemotherapy refers to the use of more than one drug at the same time. Examples of currently used combined chemotherapy include CHOP (cyclophosphamide, adryamycine, vincristine and prednisone) for some types of non-hodgkin lymphoma and FEC (5-fluorouracil, epirubicine and cyclophosphamide) for breast cancer.
  • Targeted chemotherapy: refers to a new type of medication that targets a property of cancer cells and thus kills cancer cells more specifically. Such drugs are aimed at a particular target (usually a protein) made by cancer cells. Target identification can only be accomplished through research. This type of chemotherapy includes drugs such as biological therapies, angiogenesis inhibitors, signal-transduction inhibitors & cell cycle regulators, apoptosis promoters & senescence activators and monoclonal antibodies (antibodies like Herceptin for breast cancer). An example of broadly used targeted chemotherapy is imatinib (Gleevec), an inhibitor of a specific protein (called bcr-abl, a tyrosine kinase) that is expressed in certain form of leukemia (chronic myolegenous leukemia -CML).

• Other methods: and some still at the experimental level. They include gene therapy, laser and photodynamic therapy, hormone therapy and bone marrow and/or blood stem cell transplantation. Genes are the basic unit of heredity passed from parents to their children. Genes are pieces of DNA that code for the production of proteins in a cell. Gene therapy consists of the introduction of a new gene in a defective cell, in order to correct its defect. In cancer gene therapy, researchers are improving the body's natural ability to fight the disease and/or are making cancer cells more sensitive to other kinds of therapy.

Clinical trials are studies where people volunteer to test new drugs or procedures. Such studies are essential to improve treatments against serious disease like cancer. Physicians use clinical trials to determine if a new treatment (or a new combination of drugs) works and is safe for the patients.

References