The aim of this study was to determine the safety and efficacy of intrahepatic Mitomycin C (MMC) infusion in patients with advanced metastatic breast cancer (mBC) resistant to systemic chemotherapy with liver dominant metastatic disease. We determined factors influencing overall survival.
We retrospectively analysed patients with mBC, treated with MMC infusion between 2000 and 2017. Hepatic response was measured by comparing CT scans after MMC infusion with baseline CT scans according to response evaluation criteria in solid tumours (RECIST) 1.1. Toxicities were registered by the common toxicity criteria for adverse events (CTCae) version 5.0. Overall survival (OS) and hepatic progression free survival (hPFS) were evaluated using Kaplan Meier estimates. After univariable analysis, a stepwise forward multivariable (MV) prediction model was developed to select independent pre-treatment factors associated with OS.
We included 176 patients who received a median of 4 prior lines of systemic therapy for mBC. The median time from diagnosis of mBC to first MMC infusion was 36.9 months (SD 35.6). RECIST evaluation of liver lesions (n = 132) after 1-3 of MMC infusions showed a partial response rate of 20%, stable disease of 57% and progressive disease in 23%. CTCae toxicity grade 3 and 4 were reported in 17.5%. Median PFS was 5.5 months and median OS was 7.8 months. Significant independent baseline predictors of worse OS on MV analysis included amount of prior systemic chemotherapy (HR = 1.2 CI;1.1-1.3), prior liver ablation (HR = 5.9 CI;1.8-19.4), higher liver tumour burden (HR = 2.4 CI;1.5-3.7), elevated levels of bilirubin (HR = 2.18 CI;1.3-3.8) and ALT (HR = 1.5 CI;1.01-2.09).
MMC infusion was safe and effective in patients with advanced mBC. MV analysis showed a worse OS in patients with increased amount of prior systemic chemotherapy, prior liver ablation, higher liver tumour burden and elevated levels of bilirubin and ALT.
The authors.
Has not received any funding.
All authors have declared no conflicts of interest.