Here is my opinion from a non-mdeical background but just my general idea of the topic.
There is no "cure" for cancer because it is a natural occuring mutation of cells in our body. The cells suffer a random mutation that kills us and in a vacuum it would happen normally in an extremely small % of all cells. We cannot successfully stop certain natural processes that occur in our bodies.
However, even though I believe in a natural clean world there were always be some normal cells that will sporadically mutate, we have created numerous things in society that forces a mutation to occur (smoking, improper diets, chemicals, etc..). We have created harmful substances that force many cells to mutate, either in defense to the external stimulous or that the outside chemcial or element simply causes a fundamental change in the cell structure which causes the cancer to occur.
Therefore, we cannot cure a natural occuring event but we can prevent or treat the things which accelrate the mutation or cause it to happen unintentionally.
For example, recent news is that a form of cervical cancer is linked to a virus. I have no doubt this virus affects the body by causing or forcing the mutation that leads to the cancer and the source of the virus is an environmental effect, but this virus is one external cause that has been isolated and an attempt has been made to kill the virus so that it will not have the chance to cause the cancer to begin. However, women will still get cervical cancer unfortunately caused by other negative stimulus as well as the random rare natural mutations that are possible.
Therefore, I feel that science will never cure cancer, but work to find what external factors force the mutation that would not ordinarily occur naturally and stop or "cure" that factor. For example, asbestos (cure - stop using it), smoking (cure stop smoking lol), virus leading to cervical (vaccine to kill virus), etc..
Further evidence of this is that we treat cancer once it is here byt simply trying to kill the mutated cells (chemo or radiation). In other words if a tree has an infestation of a beetle that kills trees we cut down the tree and all the trees around it to get it out of the forrest and take some surrounding trees to make sure we got them all. This is not a cure really, just a medieval approach. I think newer drugs treat the s side-effects of cancer to make it easier to live with or chemically attack the bad cells to kill them off with less damage than chemo.
This is also why studies say how eating broccoli or salmon help prevent some types of cancer because they have natural ingredients that (in a layman's guess) give cells the elements they need to stay healthy and stave off these harmful processes. The cure is not in nature, it is removing unnatural stimuluses but in our society that will not happen. I would not be surprised if rates of cancer in truly isolated tribes with no external pollutions, chemicals or unnatural foods are not only lower than in industrialized countries, but more in line with statistical studies (if it could be done) of truly natural random cell mutations that lead to cancer.
So all these talks of a cure for cancer are misdirected or limited useless unless they are truly focused on treating the factor that is proven with a higher than not degree of uncertainty (disproving the null hypothesis or some other statistical term I forgot) to casue the mutations.
Sorry for the long story but it seems that a cure could not really exist for what happens naturally in nature but we can work on figthing the unnatural causes we have created that lead to higher than normal occurences of these mutations which lead to cancer. For example, some cancers ar elinked genetically and you cannot cure your genes..... yet. I think atticus mentioned our environment and may have been saying something similar.