Introduction
The treatment of cancer may include the use of chemotherapy, radiation therapy, biologic response modifiers, surgery, or some combination of all of these or other therapeutic options. All of these treatment options are directed at killing or eradicating the cancer that exists in the patient’s body. Unfortunately, the delivery of cancer therapy often affects the body’s normal organs not involved by cancer. The undesired consequence of affecting an organ not involved with cancer is referred to as a complication of treatment or a side effect.

Why do side effects occur?
Side effects, or complications, of treatment cause inconvenience, discomfort, and occasionally even fatality to patients. Additionally and perhaps more importantly, side effects may also prevent doctors from delivering the prescribed dose of therapy at the specific time and schedule of the treatment plan. This is extremely important to understand since the expected outcome from therapy is based on delivering treatment at the dose and schedule of the treatment plan. In other words, side effects not only cause discomfort and unpleasantness, but may also limit a patient’s ability to achieve the best outcome from treatment by preventing the delivery of therapy at its optimal dose and time.

While cancer treatment may be associated with a wide variety of side effects, some are more common than others. Additionally, certain treatments may lead to long-term side effects, also called “late complications”, which are conditions that do not resolve once treatment is completed.

What can be done about side effects?
Fortunately, in the last 15 years there has been a great deal of progress in the development of treatments to help prevent and control the side effects of cancer treatment. These compounds have led to vast improvements in the management of symptoms associated with cancer treatment, allowed for greater accuracy and consistency concerning the administration of cancer treatment, and have made many cancer treatments more widely available to patients.