Intra-arterial Mitomycin C infusion in a large cohort of advanced liver metastatic breast cancer patients: safety, efficacy and factors influencing survival

PurposeThe aim of this study was to determine the safety and efficacy of Mitomycin C (MMC) infusion in a large cohort of advanced liver metastatic breast cancer patients (LMBC) and to determine factors influencing overall survival (OS).MethodsWe retrospectively analysed LMBC patients, treated with MMC infusion between 2000 and 2017. Hepatic response was measured with baseline CT scans and first available CT scan after MMC infusion by RECIST 1.1 criteria. Adverse events were registered by the CTCAE version 5.0. OS and hepatic progression free survival (hPFS) were evaluated using Kaplan-Meier estimates. After univariable analysis, a stepwise forward multivariable (MV) prediction analysis was developed to select independent pre-treatment factors associated with OS.ResultsWe included 176 patients with a total of 599 MMC infusions, mostly heavily pre-treated patients with a median time from diagnosis of MBC to MMC infusion of 36.9months. RECIST evaluation of liver lesions (n=132) showed a partial response rate of 15%, stable disease of 43% and progressive disease in 17%. Adverse events grade 3 and 4 were reported in 17.5%. Median PFS was 5.5months and median OS was 7.8months. Significant independent baseline predictors of worse OS included number of prior systemic chemotherapy lines, prior liver ablation, higher liver tumour burden and elevated levels of bilirubin and ALT.ConclusionMMC infusion is safe and effective in advanced LMBC patients. An increased number of prior therapies, a higher liver tumour burden and elevated levels of bilirubin and ALT were associated with a worse OS.