I believe cancer can usually be easily cured by good nutrition and lifestyle choices. What do you think?

Unfortunately not. If this were so, then every oncologist in america would gladly endorse the proper diets and supplements. These are terrible diseases that we would love to cure. Don't believe the conspiracy-mongers who suggest that someone is supressing some miracle cure. We'd all gladly shout it from the rooftops if it were so.
No Easy Cure. Cancer, regardless of the source, never has an "easy" cure. Medical science has provided us with a number of options for treating cancers, but there are never any guarantees. While lifestyle choices and good nutrition play a role with any disease process, if you are up against cancer you owe it to yourself to spend time learning about where medical science stands on the treatment for your cancer.
You are wrong. Once cancer has developed, it often requires surgery, chemotherapy, and/or radiation therapy to have the best chance for cure. Nutrition and lifestyle may play a big role in preventing cancer, it can certainly help cancer treatment, but expecting cure without standard therapy is quackery.
Unlikely. Cancer may be preventable by good nutrition, but once it manifests it usually will not respond to nutrition changes alone. Notwithstanding, a healthy weight, good diet, and exercise may prolong survival and prevent recurrence.
Nutrition? There is no doubt that nutrition can play a part in improving a patient's immune function, which may slow or delay cancer growth. For those that decide not to use surgery, chemotherapy, and or radiation for other reasons, healthy changes in nutrition may help. The cure rate for so many cancers is improving with our newer treatments, it is worth considering their use.
Here's what I think. You are gullible. You are too naive to survive in a world full of deception. There's nothing "spiritual" about believing "pretty" / "natural healing" lies. World leaders -- including spymasters and people like Hugo Chavez -- would know of any easy cure, but die of cancer like everybody else. Talk like this to someone you love who is dying of cancer, and they'll hate you for it -- and rightly so.