Minimal residual disease in metastatic breast cancer: treatment with IFN-beta, retinoids, and tamoxifen.

The aim of this pilot study was to investigate if chemotherapy (CT) followed by the combination of interferon-beta (IFN-beta), retinoids, and tamoxifen could be effective in the treatment of metastatic breast cancer (MBC), Thirty-six patients with stage IV carcinoma of the breast mere treated with six courses of cyclophosphamide, 5-fluorouracil, 4-epidoxorubicin, vincristine, and prednisone every 3 weeks (FECPV), followed by two courses of non-cross-resistant drugs, methotrexate, mitomycin C, and mitoxantrone (MMM), Treatment was continued, in responders, with low dose IFN-beta, retinyl palmitate, and tamoxifen until relapse of the disease occurred, Among 36 evaluable patients, 23 achieved a clinical response (64%) (95% confidence interval [c.i.] 46%-79%), 7 had stable disease (19%), and 6 (17%) progressed, Leukopenia occurred in 15 patients, thrombocytopenia in 6, and anemia in 11, Sixteen patients had nausea/vomiting, stomatitis was observed in 9, and diarrhea occurred in 3, Toxicity from maintenance therapy was mild and mainly hepatic, Median response duration was 31 months (range 5-107), Median overall survival was 32 months (9-108), Our study shows that this combined approach for the treatment of MBC is feasible, with an acceptable toxicity.