Cancer is not a single disease. It's actually an autoimunne process caused by uncontrolled division of your cells, which forms tumors that damage organs. There isn't a cure for cancer as much as there is a cure for "fever" or "headache". There are many kinds of cancer with all sorts of causes ( drinking heavily for a long time may cause liver cancer, smoking too much for too long may cause lung or mouth cancer, being exposed to radiation may cause thyroid cancer, etc,etc), as well as many cures (chemo, radio, surgical removal, and so on).

What I speculate is that many way less invasive and damaging drugs and treatments are being intentionally patented and locked away to secure Big Pharma's profits, and the arrest and execution of its heads and dissolution of their empires might allow these cures to reach the general public at an affordable price.