Cancer an answer to prayer?

At a workshop a statement was made that to be a witness for Jesus, you must have a pure heart. Sitting there as a sponsor for the youth at my church, I knew I had a playground in my mind that made my heart not pure. No one would have ever guessed. I was a Sunday School teacher, and rarely missed church. But I let my mind wander. That day I prayed that God would give me a pure heart so that I may be a witness for Jesus. Five years later I got my prayer answered. I got a cancer diagnosis, went to my closet and kneeled. I told God that now I finally saw that He was all that mattered. It took five years because of the bondage of sin. I loved my playground.  I would give it up and take it back, give it up and take it back for five years. To date I have not taken back my sinful playground. Hearing you have a 30% chance to live and then the doctor added that with my type of case he had never seen survive tossed me into the reality and truth that following Jesus was all that mattered. Cancer then was the vehicle that brought me to a new place in my life. God answered my prayer. I emptied my heart of a sinful playground and replaced it with Jesus. I am now cancer free and have been for 5 years. Although having cancer was filled with much suffering, I can say that it was all worth it. I would have never put cancer on a vision board for myself but it did so much for me. Weird I know. I did ask God to give me a pure heart and He did. I am no way perfect. I am not saying that at all but my desire is to please Jesus. I fail often but my heart's desire is like King David---I desire to be a woman after God's own heart. I was now free of the sinful playground in my mind blocking my witness for Jesus.