Patterns of failure following bone marrow transplantation for metastatic breast cancer: the role of consolidative local therapy.

PURPOSE: The purpose of this analysis is to evaluate the patterns of failure and the role of local therapy in conjunction with bone marrow transplantation (BMT) for metastatic or recurrent breast cancer.

METHODS AND MATERIALS: Between June 1986 and November 1991, 46 patients with hormone unresponsive metastatic or recurrent breast cancer underwent high dose chemotherapy (HDC) with hematopoietic stem cell support. The most commonly used preparative regimen consisted of thiotepa (750 mg/m2), cisplatin (150 mg/m2), and cyclophosphamide (120 mg/kg) followed by autologous BMT. Consolidative surgery or irradiation was considered in patients whose cancer responded to BMT and had localized sites of disease.

RESULTS: Six patients (13%) died of BMT-related complications. Of the remaining 40 patients, 22 were candidates for consolidative therapy, and 18 of those patients received consolidative irradiation (17 patients) or surgery (1 patient) to one or more sites. At median follow-up of 27 months (range, 20-78), 12 of 18 (67%) patients have continuous local control at the 22 consolidated sites (1 of 4 controlled at chest wall sites, 7 of 8 at regional nodal sites, 7 of 7 at localized bone sites, and 1 of 3 at lung/mediastinal sites). Toxicity of consolidative irradiation was mainly limited to myelosuppression in 6 of 17 patients. Two patients did not complete the consolidative local therapy, one because of hematologic toxicity and one because of rapid systemic tumor progression during treatment.

CONCLUSION: In patients with localized areas of extravisceral metastases, consolidative irradiation is feasible with acceptable hematologic toxicity. Consolidative irradiation can result in continuous local control, especially in isolated bone metastases and in regional nodal sites; however, the advantage is less clear in patients undergoing consolidative irradiation for chest wall failures. Because distant visceral metastases still remain a major site of failure after this HDC regimen, a more effective systemic therapy is needed. Consolidative local treatment should be considered in future HDC/BMT protocols for metastatic breast cancer, especially in localized nodal and osseous sites.