Explore the efficacy of microwave ablation combined with fruquintinib and tislelizumab in the treatment of metastatic colorectal cancer.

[BACKGROUND] Currently, the prognosis for metastatic colorectal cancer (mCRC) remains unfavorable. However, as advancements in local and systemic treatment modalities progress, therapeutic strategies for mCRC are becoming increasingly varied. For patients presenting with a limited number of metastases, the integration of radical local treatment with systemic therapy holds promise for achieving sustained tumor control. This study seeks to investigate the efficacy and safety of combining microwave ablation (MWA) with fruquintinib and tislelizumab in patients with mCRC.

[METHODS] Between March 2022 and September 2022, a screening process was conducted on patients with advanced colorectal cancer and liver metastases who had previously undergone radical colon cancer surgery at our institution. Eligible patients commenced a combined treatment regimen of fruquintinib (5 mg, administered daily from day 1 to day 14) and tislelizumab (200 mg, administered on day 1 every three weeks) within one week following the completion of MWA. Post-surgery, 21 patients received the combination of fruquintinib, a molecular-targeted therapy, and tislelizumab immunotherapy, whereas 34 patients were administered tislelizumab in conjunction with a placebo as the molecular-targeted treatment. The study evaluated all patients' progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and three-year overall survival (OS).

[RESULTS] In the study, the median PFS was 13.2 months for the experimental group compared to 7.35 months for the control group, with 1-year PFS rates of 66.7% and 23.5%, respectively. Tislelizumab monotherapy emerged as an independent risk factor for tumor recurrence, with the experimental group exhibiting a 0.184-fold reduction in recurrence risk relative to the control group (P = 0.036). Multivariate Cox regression analysis further identified elevated carcinoembryonic antigen levels and the number of liver metastases as significant risk factors for tumor recurrence. Specifically, patients with normal carcinoembryonic antigen levels demonstrated a 0.12-fold lower recurrence risk compared to those with elevated levels (P = 0.0002), while patients with a single liver metastasis had a 0.208-fold lower recurrence risk than those with multiple metastases (P = 0.0003). The ORR were 72.5% in the experimental group and 58.8% in the control group, indicating a significantly higher ORR in the experimental group. Additionally, the experimental group exhibited superior OS compared to the control group, with both groups achieving an OS exceeding 20 months.

[CONCLUSION] This study aims to provide novel clinical evidence supporting the integration of MWA with PD-1 inhibitors and anti-angiogenic agents in the systemic management of mCRC. It is anticipated that these findings will expand therapeutic options available to patients.

[CLINICAL TRIAL REGISTRATION] https://www.chictr.org.cn/showproj.html?proj=140822, identifier ChiCTR 2200058323 (China Clinical Trial Center).