Actually God didn't create cancer.
Cancer was a consequence of the fall of man, which was brought into the world by the sinful acts of mankind.
John 1:3
All things were made through him; and without him was not anything made that hath been made.
Cancer is simply cells not acting in the way they were designed.
God created and designed cells.
Without cells to mutate we wouldn't have cancer.
The fall of man allowed sin into the world, which has had negative consequences to the perfection of God's creation.
Some of the negative consequences of sin coming into the world are the cell mutations that cause cancer.
God allows sin to occur, because as a loving God he must give men the option of choosing their own selfish will over God's perfect will.
So the creation and the cells in it were made by God and without God there would be no cells to mutate.
It wasn't God's intention for there to be cancer, but the sin of mankind caused negative changes that resulted in negative effects like cancer to arise. God allowed man to sin.
God allows cancer to exist, because to force mankind to do HIS perfect will would not be loving, but to allow sin without consequence wouldn't be just.
I believe in a strict interpretation of the Bible, but even the Bible has context.
Quoting a single verse often leads to erroneous conclusions because the historical context and the additional revelation provided by surrounding verses is missing.
Above all, scripture must be read in a manner which is consistent with the nature of God, as expressed through the person of Jesus Christ.
If this was supposed to be a gotcha moment you're going to have to work a little harder.