I feel the bone marrow biopsy is necessary more often than not to determine the amount of myeloma in the bone marrow. Your Mother's numbers are not bad. My husband was diagnosed in September 2006 with 30 per cent. In Februay 2007 he had another biopsy before transplant after taking thal/dex from November 2006. Transplant was done March 2007. He had a 100 day biopsy after transplant and he was at 17 percent. In July 2007 he went on vel/dex and in August 2007 had another biopsy. He had to go off the vel/dex after one round because his other numbers were not good. This biopsy showed 75 per cent. He had another done in September and it showed 90 plus per cent. When he entered the hospital in October he was at 100 per cent. I think the biopsy is helpful to determine if the treatment is working. For my husband it was not. He was in the hospital for a radical chemo treatment in hopes of giving him more time. The chemo was working this time but in the process nothing else was. He passed away October 15, 2007 but not without a fight. Whatever tests they need to do allow them to do. My husband did not have the Bence Jones but he die have the missing 13 chromosone. Good luck with your Mom's treatment and keep up the good biopsy results.
Linda