Mets all over and no pain

My mother was diagnosed stage IV in December and given 5-6 months. Initally she had the tumor on her pancreas, mets in her liver and in her adreanal gland. She tried Gymzar and it was great as far as no side effects however it did not reduce the tumors. CT scans in March showed that the mets had also developed in her lung, her intestinal wall as well as the abdominal fatty layer.....this was devestating. I rejoice in the fact that the dr's prognosis was not accurate and that todate my mother is in no pain directly from the cancer. There is secondary pain though. My mothers abdomin has become so distended that she suffers sever back pain (she looks quite pregnant and at 67 this is not a good thing). Does anyone know of a support belt (this those in maternity stores) that can be used to reduce back pain?