Cancer is a broad term that covers a lot of different diseases that are basically abnormal cell growth that can invade other organs and nearby cell masses. There are somewhere between 200-250 different types of cancer, the number varies depending on exact definition, each with different causes, pathophysiologies, and treatments.

To state that there is "one cure that rules them all" would be like saying there is one cure for all viral infections or broken bones. There isn't.

Cancers are a curious example of evolution going on at a very micro-scale. Each cancer starts with one mutation in one cell. That mutation can be caused by some environmental issue (say smoking, or UV sunshine), viruses, or random genetic error (with billions of cells, it just happens).

Let's say the first mutation causes abnormal growth. Out of thousands of cells that grow from that first mutated cell (a mass too small to detect), a second mutation occurs in one cell that causes it to "hide" from the immune system. That cell is selected for, and it takes over. Eventually, another mutation occurs, that causes blood vessels to feed it. And etc. It takes 5-10 mutations before you have a full fledged cancer that can grow wildly, avoid the immune system, and proliferate into other organ systems.

Believe it or not, cancer is extraordinarily rare, given there are around 3.72X10^13 cells in the human, so random events that cause cell mutations are generally destroyed by the immune system. But the numbers of cells is so immense, even if it happens 0.0000001% of the time, there are tons of cells.

However, because it takes those 5 -10 mutations to actually lead to cancer, so it's rare.

There are ways to prevent cancer. I'm too lazy to look up the data, but if you quit smoking, the risk of lung cancer drops to near 0. If we eliminated smoking, even in a country like the USA where smoking is socially irresponsible and smoking is kind of rare, we'd "cure" 10-15% of cancers, because they wouldn't happen.

Staying out of the sun reduces risks of some cancer. Gardasil (HPV vaccines) can prevent human papilloma virus induced cancers of the cervix, penis, anus, mouth and other areas. Losing weight reduces the risks of many cancer.

But there's not single prevention. And certainly no single cure.

It is sad that somewhere in the 40's and 50's, a "war" was declared on cancer, that sort of implied that there was "one cure", but it's ridiculous.

One last thing. If Big Pharma had a cancer "cure," they wouldn't hide it, they'd make trillions of dollars in selling it. Without explaining how corporate finance works, there's more profit in selling one thing at a high price than it is to sell lots of things at a high price. No Big Pharma company is trying to protect its investments in individual cancer treatment products by suppressing research and development of a "one cure." Well, they wouldn't even look for a "one cure" because most of Big Pharma runs on science based medicine, and they know that an urban myth about "one cure" is laughable and ridiculous.