Pleural Thickening

I had Stage I, grade 3, node neg. breast cancer last June. The CT scan showed pleural thickening or mets on the chest wall. (They wern't sure) This CT scan was before treatment. I went for another CT scan yestday (Wed July 25) and won't find out anything until Monday. Can anyone tell me if you had pleural thickening and what causes it. Is it the first sign of lung cancer?

Theresa