Selective intra-arterial mitomycin-C infusions for treatment-refractory colorectal liver metastases.

BACKGROUND

Mitomycin-C is an older drug which has a synergistic mechanism of action with irinotecan. This study evaluated the outcomes of selective intra-arterial mitomycin-C infusions in combination with bi-weekly systemic irinotecan for treatment of liver-dominant metastatic colorectal cancer (CRC) which progressed after hepatic arterial infusion (HAI) pump chemotherapy with floxuridine and at least two lines of systemic chemotherapy.

METHODS

An IRB-approved retrospective review of patients receiving at least two sessions of selective monthly mitomycin-C infusions in interventional radiology (IR) was performed. Anatomic and metabolic imaging was initially obtained at 4 weeks after the second infusion, and every 2-3 months thereafter. Response was evaluated according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 and European Organization for Research and Treatment of Cancer (EORTC) criteria. Patient, disease and procedural parameters were recorded. Progression-free survival (PFS), liver progression-free survival (LPFS) and overall survival (OS) were assessed with Kaplan Meier methodology.

RESULTS

From January 2019 to April 2023, 46 patients underwent a total of 190 selective infusions (range 2-10; median 4). Twenty-three/46 (50%) patients had KRAS mutations and 35/46 (76.1%) had extrahepatic disease at the time of the first infusion. On initial follow-up, liver disease control was observed in 38/46 using RECIST 1.1 (82.6%; partial response 13%, stable disease 69.6%) and 26/31 using EORTC criteria (83.9%; complete response 6.5%, partial response 48.4%, stable disease 29%). Median PFS, LPFS and OS were 4.1 [95% confidence interval (CI): 3.2-4.9], 5.5 (95% CI: 2.5-8.4) and 9.6 (95% CI: 8.2-11.1) months respectively. The infusions were discontinued in 26 (56.5%) patients due to disease progression. Eighteen patients (39.1%) discontinued the infusion protocol due to toxicities/complications, including hepatic/biliary toxicity (26.1%), hepatic arterial thrombosis (15.2%) and/or pulmonary toxicity (8.7%).

CONCLUSIONS

In this heavily pretreated population, addition of intra-arterial mitomycin-C was associated with initial liver disease control rates exceeding 80%. Toxicities were observed, particularly in patients with prolonged disease control who received ≥4 infusions.