Bone marrow involvement in breast cancer: effect on response and tolerance to combination chemotherapy.

Forty-three patients with metastatic breast cancer who had not received prior chemotherapy were divided into two groups on the basis of whether or not a bone marrow examination revealed tumor. Both groups were treated with combination chemotherapy regimens and were analyzed with regard to response and toxicity parameters. The positive marrow group had a response rate similar to that of the negative marrow group (67% vs 71%), and a slightly shorter median time to progressive disease (240 vs 258 days) and median duration of remission (213 vs 243 days). The positive marrow group had higher requirements for hematologic support and tended to have more infectious complications. The data suggest that metastatic breast cancer patients with a bone marrow examination revealing tumor, although requiring more supportive care, may be treated as effectively with combination chemotherapy as those patients in whom the marrow examination does not reveal tumor.