I would ask your sister in law to discuss her prognosis with her physician, but at stage 4 the prognosis is poor. Stage 4 means she has a tumor which has spread to her lymph nodes and she has distant mets. Surgery is not an option in stage 4. Radiation and chemo would be used. It is possible to have no symptoms, but thay will most likely come. Survival is hard to say but most likely a year or two. Make sure she asks about clinical trials. Sometimes they can offer advantages that regular treatment will not.