How bout not falling ill, or at least, finding out at an early stage, when the rate of full recovery is the highest, and in many cases close to 100%?
There are many available sources on the internet, depending on your country of origin, i can think of a few that are serious (i don't consider most of the said alternative treatments as fitting the criteria for seriousness).
It seems that up to 40% of cancers can be avoided by following rather simple guidelines, such as not smoking, doing some exercise, avoiding drinking too much, limiting some dangerous types of food etc.
That leaves 60% which are more difficult to avoid, either because of genetic factors, lack of luck, or because of excessive pollution in the region where you live. That doesn't look too favourable, so the next best thing is early diagnostic, that is finding a cancer while it's still at a very easily manageable stage, for instance stages I and II.
While you can have a comprehensive look at the links i posted, to see what's available in your country, i'll try to sum up my thoughts on the topic.
To simplify, i'll say there are two types of cancers, the ones you can seer feel, and the ones you can't.
You can see a skin melanoma as it starts growing, from a normal birth mark to something looking sinister, and larger.
You can't see a nascent colon cancer, or a bone cancer, or a brain tumour. You can also touch your breasts and find unusual lumps, at least if you're a female.
The other way to classify cancers easily is the ones that are symptomatic, and the ones that are not.
Unfortunately, in many cases, once you are feeling some symptoms, whichever they are (pain in the stomach, blood loss, bloody stool, fatigue, etc.), the cancer is full blown and at either stage III or IV, and treatment will be much heavier, and the perspectives are worse than if it is found while you don't feel anything (yet).
Which is why prevention and early screening are essential.
There are a number of blood indicators that are good (or perfect) warning signals for one or more types of cancers.
For instance, in men, the PSA test, taken from a blood sample, is a good indicator of prostate cancer (although there are some false positives, but at least you can then go for more specific tests).
A colonoscopy for men and women from 50 years on is useful every 10 years, as polyps take some time to go from benign to cancerous.
Testing for some viruses or bacteria, known to be linked to specific cancers can be useful, as there are ways to get rid of these undesirables, for instance with antibiotics. This is the case for HPV, which can cause cervical cancer in women. By the way, there is a vaccine that should be administered to young teenage girls to avoid this risk. Don't believe the antivax crowd, they're hysterical retrogrades.
X-rays for lungs every couple of years, mammograms for women from 40 onwards are also a good thing.
There are new upcoming ways to detect cancer, teams all over the world are competing as to who will come up with the first smartphone app and device that will be able to accurately find a number of early cancers. I know such a team working on medical imagery and IA for detecting skin cancer, as a first application.
Genetic testing may also help you find out that you specifically are more vulnerable to this or that type of illness, including some types of cancer, because of some mutations. Expect this area to develop a lot in the next 10 years.
From personal experience, i can tell you that for a few years, i was not a big fan of colonoscopy, and having gone through two, it is a bit unpleasant as a procedure. But all in all, it is still much preferable to surgery, and chemotherapy. And much preferable to having to finalise your will, urgently!
While i understand that all those test cost money, and not everybody can afford them, you should consider this cost as an investment in your future. In case you have good coverage, you would be a fool not to benefit from it and perform all the tests that are available to you, based on the medical insurance you have.
Live long and prosper!