Fluid buldup in lung cavity -2nd recurrence after masectomy

My wife had a mascetomyleft breast in December 2003 followed by chemotherapy. She had a recurrence in december 2007 in the mastectomy scar that required more surgery which was followed by radiation treatment, In Aug 2009 her pet scan showed fluid  around her lungs. She just had the fluid drained and the doctor said there was a reasonable chance there are cancer cells in the fluid. He suggested she go into the hopital to have all the fluid drained as he could not drain all the fluid at that time.We have not gotten the results back from the fluid analysis yet. What will the fluid analysis  tell me? Her oncologist suggested she would treat her with ziloda (sp). What prognosis is indicated from this fluid. The cancer has spread through the bloodstream? Is it now more likey to appear someplace else?

Thank you,

Tom