Basic principles of chemotherapy and other systemic therapies

Systemic therapies are a crucial part of the armamentarium in the fight against cancer. Though the modern era of chemotherapy began in the 1940s with the use of estrogen to treat prostate cancer, today’s weapons include developments in cytotoxic drugs, targeted agents, and immunotherapies. Novel formulations, alternative dosing regimens, and varying schedules, sequences, combinations, and routes of administration have abounded. Fortunately, advances in supportive therapies have also evolved to help ameliorate gastrointestinal and hematologic toxicities of these treatments. A thorough understanding of the mechanisms of tumor growth, as well as therapeutic drug mechanism of action, efficacy, potential toxicity, and options for ameliorating those toxicities are essential to optimizing patient care.