You are almost right. Asbestos exposure can take 30 to 50 years for the possibility of becoming cancer, with no symptoms. My 20 years of exposure started in 1955 and started the clock of uncertainty, every year from 2000 on I thought I had dodged the bullet. The follow-up CT scans in my case are to monitor any growth of the nodules: some would often go from say 5ml to 6ml or vice, versa, no big deal, and still, now I get new ones. When they continue to grow yours as mine did will get a CT-assisted needle biopsy. A needle through to back, painless. The CT scan summary description of mine when it became cancer was unquestionable, but a biopsy was required. In a way, it was a relief, I knew I was under the care of the best. The clock is still running but it's not that high on my health concerns. Been there, done that.