Aims and background: Patients with metastatic breast carcinoma resistant to first line chemotherapy may require further treatment. Results o second line chemotherapy are still largely unsatisfactory. For this reason a phase II study on the combination of mitomycin C and vinorelbine was carried out.
Methods: Forty patients with anthracycline pretreated metastatic breast cancer were treated with a combination of mitomycin C 10 mg/m2 i.v. on day 1, and vinorelbine 25 mg/m2 i.v. on days 1 and 8. This cycle was repeated every 28 days. Responses were evaluated according to the WHO criteria.
Results: A major objective response was recorded in 16 cases (40%; 95% confidence limits 32%-48%), with 2 patients (5%) obtaining a complete response with a median duration of 8.0+ months, and 14 (35%) a partial response with a median duration of 7.3+ months. Nine patients (23%) showed no change, and 15 progressed. Patients who did not meet the minimal required criteria to be evaluable were considered as treatment failures. Responses were seen at all sites of disease, but skin, nodal, and soft tissue lesion were more chemosensitive than liver, lung, and bone ones. The mean survival of patients with complete and partial responses was 8.9+ months, whereas that of patients with no change or progressive disease was 7.8 and 6.0 months respectively. Treatment was very well tolerated by most patients. Gastrointestinal toxicity was mild. Grade 2 leukopenia was recorder in 45% of patients, and grade 3 leukopenia in only 10%. Grade 2 thrombocytopenia was seen in 5%. Reversible mild to moderate constipation occurred in 45%, but no case of severe neurotoxicity was observed.
Conclusions: Our data suggest that the combination of mitomycin C and vinorelbine is active in metastatic breast carcinoma refractory to first line chemotherapy containing anthracyclines, and may be safely administered on an outpatient basis.