The ‘chaemo’ in chemotherapy refers to the chemicals that are used to kill the cancer cells.
The use of chemicals to kill cancer cells was first discovered in a different kind of war. During World War 2, doctors discovered that people who had been exposed to nitrogen mustard gas had much lower white blood cell counts. They began to wonder if the chemicals could be used to kill rapidly dividing cancer cells.
The initial study was performed in 1943 and the results were published in 1946, and mustard gas began to be used to treat all sorts of cancers. The research didn’t stop there. Doctors began to experiment with folic acid, plant alkaloids and various combinations of different chemicals.
In combination therapy, two or more drugs are given. This forms the basis of most of chemotherapy today. The different drugs enhance each other and are chosen so that they do not have the same side effects on tissue, in order for the side effects to be minimised.
The treatment is highly effective, but unfortunately, normal healthy cells are also affected and this causes the well-known side effects of chemotherapy. Fortunately, the normal healthy cells have repair mechanisms in place, so they are able to recover after the treatment.
Chemotherapy is also commonly used in combination with surgery, radiotherapy and biological treatment in order to:
- shrink a tumour before radiotherapy or surgery. This is called neo-adjuvant therapy;
- destroy any remaining cancer cells after surgery or radiotherapy. This is called adjuvant therapy;
- enhance the effect of radiotherapy and biological therapy; and
- destroy recurring cancer or destroy cancer that has spread to other parts of the body.