My Husband Has Stage IV Nsc Lung Cancer. There Is

My husband has stage IV nsc lung cancer. There is one primary tumor in his upper left lobe with mestasteses to the surface of the right parietal pleura. There is no pleural effusion. He started first line targeted therapy with Gilotrif at the end of August. I've noticed that his upper abdominal area, right below his chest, is hard and distended--what does that mean?