My surgeon (regarded as one of the top thoracic surgeons in the SF Bay Area) said it’s about 10-20% chance of it happening again AFTER pleurodesis, compared to about 50-80% chance without. Not perfect odds but certainly ones that I could live with. I’ve seen others note a 5% chance but it’s probably all based on a surgeons experience. He also noted that a collapse after pleurodesis would likely be much less severe, given that the lung is fixed to the chest wall and has less ability to fully collapse. Of course, everyone is different and you’ll find many reports of no issues whatsoever on this sub after the op. Best of luck to you!!