High-intensity focused ultrasound ablation combined with systemic therapy for unresectable colorectal cancer liver metastasis: A propensity score-matched analysis.

Abstract

Unresectable colorectal cancer liver metastasis (CRLM) remains a challenging obstacle that often prevents curative treatment. In this study, we retrospectively analyzed the efficacy and safety of high-intensity focused ultrasound (HIFU) as a local adjuvant therapy for systemic chemotherapy for patients with unresectable CRLM. HIFU is a noninvasive method previously demonstrated as efficacious for various solid malignancies. Propensity score matching was used for the combination therapy group (HIFU group, n = 59) and the observation group receiving systemic therapy only (No-HIFU group, n = 59). In addition, the survival benefit, adverse effects, and factors affecting prognosis following HIFU were evaluated. The disease control rate was 77.9% and 62.7%, and the objective remission rate was 18.9% and 6.8% in the HIFU and non-HIFU groups, respectively. The survival analysis showed that median progression-free survival (mPFS) was 12.0 months and 11.0 months for the HIFU and non-HIFU groups, respectively (p = 0.002). The univariate and multivariate analysis showed that pre-treatment colorectal cancer liver metastasis lesion size was significantly associated with mPFS. In addition, patients that received a combination treatment for CRLM lesions <5.0 cm had a longer mPFS when compared to those receiving systemic therapy alone (13.0 months vs. 11.0 months, p = 0.001). In the HIFU group, patients with lesions <5.0 cm had a longer mPFS than patients with lesions ≥5.0 cm (13.0 months vs. 10.0 months, p = 0.04) (Figure3B,C). Most treatment-related adverse events observed in both groups were grade 1-2. Only four cases (6.8%) of grade 1-2 skin burns were observed in patients in the HIFU group; no other statistically significant adverse events were observed. Our study showed that HIFU ablation targeting unresectable CRLM alongside systemic therapy safely and significantly improved local control rates and prolonged mPFS, especially for lesions smaller than 5.0 cm.