<unk>  does not always work, and even when it is useful, it may not<unk> ompletely destroy the<unk> ancer. People frequently fail to understand its limitations. In one study of people who had been newly diagnosed with incurable, stage 4<unk> ancer, more than two-thirds of people with lung<unk> ancer and more than four-fifths of people with<unk> olorectal<unk> ancer still believed that<unk>  was likely to<unk> ure their<unk> ancer. The blood–brain barrier poses an obstacle to delivery of<unk>  to the brain. This is because the brain has an extensive system in place to protect it from harmful<unk> hemicals. Drug transporters<unk> an pump out drugs from the brain and brain's blood vessel<unk> ells into the<unk> erebrospinal fluid and blood<unk> irculation. These transporters pump out most<unk>  drugs, which reduces their efficacy for treatment of brain tumors. Only small lipophilic alkylating agents such as lomustine or temozolomide are able to<unk> ross this blood–brain barrier. Blood vessels in tumors are very different from those seen in normal tissues. As a tumor grows, tumor<unk> ells furthest away from the blood vessels become low in oxygen (hypoxic). To<unk> ounteract this they then signal for new blood vessels to grow. The newly formed tumor vasculature is poorly formed and does not deliver an adequate blood supply to all areas of the tumor. This leads to issues with drug delivery because many drugs will be delivered to the tumor by the<unk> irculatory system.
Chemotherapy
Irradiation
Radiation
Chemoradiotherapy
Hormone therapy
Radiation therapy
Adjuvant therapy
External beam radiotherapy