Chemotherapy can be given as a pill, injection under the skin (subcutaneously), injection in the vein (intravenously), short infusion in the vein (intravenously), injection inside a body cavity (chest or abdomen), or directly inside the tumor.
The method of administration of chemotherapy treatments along with the dose is determined by rigorous testing called clinical trials, which are done prior to the specific chemotherapy drug being available for commercial use. During this testing process, scientists and doctors determine how chemotherapy drugs are absorbed in the body and how they work. Sometimes stomach juices can destroy the chemotherapy and such drugs must be administered as injections. Just because a chemotherapy drug comes in a pill form doesn’t mean it is a weaker drug.