A series of anti cancer drug treatments. Chemotherapy is normally given in cycles, where you have the chemotherapy drugs and then there is a break to allow the body to recover. That is one cycle. Then you have more drugs and another break. A course of treatment is made up of a number of cycles of treatment. So, a course of treatment may take anything from a few weeks to several months. Rarely, in some types of leukaemia, a course of treatment may take 2 to 3 years.