I'm just over 5 years as well. My cavity did shrink to 4 cm. My cavity is in my left upper lobe. My right lung has collapsed twice but after the 2nd time I had the talc pleurodesis procedure done (3 years ago) and it's held strong (fingers crossed, knock on wood etc - 🙂 )
I know how horrible I was in the beginning of this so I not dare complain much. I feel pretty lucky to have the quality of life I have while dealing with this monster.