Salvage I brachytherapy for liver metastases of colorectal cancer in anatomically challenging locations after failure of systemic chemotherapy-A retrospective study.

Purpsoe: Colorectal cancer liver metastasis (CCLM) in anatomically challenging locations is difficult to treat. This retrospective study aimed to evaluate the effectiveness and safety of permanent I seeds implantation (ISI) for treatment of CCLM in anatomically challenging locations after failure of systemic chemotherapy.

Methods And Materials: A total of 31 liver metastases (in 25 patients) were treated by ISI under computerized tomography guidance from January 2011 to December 2017. Post-treatment follow-up was for 40 months. Adverse events were classified using the National Cancer Institute's Common Terminology Criteria for Adverse Events. Tumor response was evaluated by the mRECIST criteria. Objective response rate, overall survival rate, and complications were retrospectively analyzed.

Results: All ISI procedures were performed successfully. Most patients only complained of fatigue and mild pain after ISI. Only one patient had liver rupture during the procedure. Serum alanine aminotransferase and aspartate aminotransferase levels at 1 month after ISI were not significantly different from pre-procedure levels (p > 0.05). Computed tomography at 6 months after ISI treatment showed completed response in 11 (11/31, 35.5%) lesions, partial response in 14 (14/31, 45.2%) lesions, stable disease in 4 (4/31, 12.9%) lesions, and disease progression in 2 (2/31, 6.5%) lesions; thus, the objective response rate was 80.6%. Median survival was for 12 months. The 1 and 2 year overall survival rates were 52.0% and 20.0%, respectively.

Conclusions: I seeds implantation for CCLM in anatomically challenging locations is safe and effective. Survival benefit is limited in the salvage setting where patients have high intrahepatic tumor load after failed systemic chemotherapy.