What is up with cancer medicine?

 Good day fellow humans now first you may smile as I have brought answers to my previous query and discovered that it is an appropriate way to calculate acceleration however as you advance it gets complicated and starts to pull out derivatives and more which will require understanding for different fields I have yet to understand. The equation for non-uniform acceleration i have found in (a=dv/dt) and it is the world of ap physics for me right now.

Cancer Medicine is splitting my brain.

Today I come to you with just a spew of knowledge I have recently obtained and find interesting.

Cancer Medicine 

 Now I was doing a course on futurelearn called exploring cancer medicine and it was there that I solidified what I thought before; the problem with current treatment is it is unselective. It kills both healthy and cancer cells which sounds disheartening to me because it sounds like killing yourself to heal yourself; going to the brink of death to find life. 

Now this non-selective chemotherapy methods I have learned where stemend from nitrogen mustard and probably about 70 years ago which means everything is very recent in science terms to me. 

Thinking practically to get rid of cancer cells we need something that selectively kills them and only them and then find the cause of the cancer cells which the Mayo clinic says is "changes (mutations) to the DNA within cells." Sadly however life is not that simple as the DNA mutations are caused by so many things so I think the prevention is still a course away but treatment might be doable as there has been a selective treatment found.

With the selective treatment it seems they target a specific component within the cancer cell that can't be found in the healthy cell such as a specific protein. Example of these can be found at Penn Medicine ''Imatinib and nilotinib target a protein (BCR-ABL) that is critical to the growth of chronic myelogenous leukemia cells."

Now my brain is wondering if we have things that are specifically targeting cancer why is it still a problem. It could be because the fact that different people have different needs when it comes to treatment, or that the selective treatment is not fast enough or the way that we are stuck mostly reacting instead of acting.

Tell me fellow humans, for the answer to this question I have teachers to irritate, books to read and websites to search through.

Till we meet again, to my fellow humans I bid you a bye bye.