Cancer is a class of diseases characterized by out-of-control cell growth. There are over 100 different types of cancer, and each is classified by the type of cell that is initially affected.

Cancer harms the body when damaged cells divide uncontrollably to form lumps or masses of tissue called tumors (except in the case of leukemia where cancer prohibits normal blood function by abnormal cell division in the blood stream). Tumors can grow and interfere with the digestive, nervous, and circulatory systems and they can release hormones that alter body function. Tumors that stay in one spot and demonstrate limited growth are generally considered to be benign.

Normally, your cells grow and die in a controlled way. Cancer cells keep forming without control. Chemotherapy is drug therapy that can kill these cells or stop them from multiplying. However, it can also harm healthy cells, which causes side effects.

During chemotherapy you may have no side effects or just a few. The kinds of side effects you have depend on the type and dose of chemotherapy you get. Side effects vary, but common ones are nausea, vomiting, tiredness, pain weak nails, dry skin and hair loss. Healthy cells usually recover after chemotherapy, so most side effects gradually go away.

Your course of therapy will depend on the cancer type, the chemotherapy drugs used, the treatment goal and how your body responds.