Need comments on chemotherapy or treatment -Thanks you!!!

lsmm19

My mom has recurrent breast cancer with metastasis to bone and liver. The type of breast cancer is ER+/PR+, HER2- (FISH). She is receiving Bisphosphonate treatment and the chemo treatment (Abraxane). The blood test showed decreased CEA level (from 480ug/ml to 133ug/ml) and decreased CA153 level (from 556U/ml to 284 U/ml) after first 3 cycles of the treatment. After another 3 cycles of treatment, the blood CEA level was 100.7 ug/ml and CA153 level was 300.3U/ml. But the CT results showed that the liver tumor did not shrink (but also didn't get bigger) after the 6 cycles of treatment. As the tumor didn't shrink during the course, does it still indicate that the chemo worked? The doctor now suggested her to take the combination chemo threapy (abraxane + xeloda) for the 7th and 8th chemo cycles. How do you think this treatment, I am so worried about the side effects of the treatment. I wonder how many cycles of chemo treatment do people usually take?