My Sister Has Pleural Effusion Caused From Her Non Small

My sister has pleural effusion caused from her non small cell lung cancer. She has undergone many thoracentesis procedures as well as a pleural catheter for a period of time. Her pleural effusion buildup is slowing (primarily from the Gilotrif she is taking). Her doctors (oncologist, pulmonologist and primary care provider) have recommended she have the pleuraldesis. Our concerns are twofold: 1) if fluid continues to build, where does it go if the space is blocked, and 2) how long is the pleuraldesis effective.