It's not particularly complicated, but not knowing about it sends tens of thousands of people off on quests for non-traditional cancer cures and all of them are scams. I think it's about as low as a person can stoop to sell a $6,000 machine – and I am specifically referring to “RIFE” machines, which have absolutely no value whatsoever except to the people who make money from them – or a course of armadillo urine injections or some mineral supplement which promises to cure the cancer that some huge company has been hiding all these years simply to give some hope. A prime example of attempting to cure cancer 'naturally' is Steve Jobs. He didn't have to die. Neither did Warren Zevon and many others.
If any company had a cure for cancer, they wouldn't hide it. They would own the pharmaceutical world. So that concept is immediately illogical.
What happens is that, because of a mutation in a person's gene, and it can be any of thousands of variations caused by something (radiation) or by nothing that we know of. But the point is that everyone's cancer, since it is manufactured by their own body, is different than everyone else's for the most part. A 'cure' will work effectively on only a few percent of the people treated – usually three to five percent – and will not help anyone else.
That's why the only treatments commonly in use at the moment are chemo and radiation. Unfortunately, they kill the good with the bad. This is one case in which the cure is almost worse than the disease. But they work universally against almost all types of cancers and sometimes they are effective – but not always and they are not a 'cure'. They operate on the concept that, when cancer is diagnosed early, there are less cancer cells being produced than healthy cells. So if you start killing cells, you have a chance of killing the cancer cells before you kill ALL the cells.
Sometimes you can get lucky. Some types of cancer develop in place and can be diagnosed and surgically excised. Those are curable. But it's luck and everyone's luck is different.
You probably can't find a physician who will explain it that way but that's how it works.
At this point in human history there are no universal cures for cancer. There are some very interesting studies going on, but even the ones which work MOST of the time only work for about 5% of the cases – so the patients have to be screened to see if they are in that 5% – but, even if they are, medical insurance won't cover the treatment unless you are a congressman or a multi-millionaire who can afford to blow $100k a year for a course of treatment.