With the daily advancement of science and the use of different sciences in medicine, new achievements are made for the treatment of human beings. One of the pioneering sciences in this field is polymer engineering, these magical macromolecules can be designed to be used in a variety of fields. They can be used as a prosthesis, drug carrier, gene delivery, etc. In recent years, they have come to the service of medicine to diagnose and treat cancers. Polymers are a good candidate for the release of anti-cancer drugs. Timely release, non-toxicity, and biodegradability are important features of a carrier. These properties are found in many synthetic and natural polymers and can be used by designing their structure for a unique application. This study summarizes cancer statistics in the United States and Iran, and introduces several polymer-carriers such as dendrimer, chitosan, and micelle used in the diagnosis and treatment of cancer.