Impact of Tumor Size on Outcomes of Hepatic Arteriography and C-Arm CT-Guided Ablation (HepACAGA): > 3 cm Is No Absolute Contraindication.

[PURPOSE] A tumor diameter > 3 cm is considered a relative contraindication for thermal ablation due to a significant risk of post-ablation recurrence. However, current advanced ablation techniques might allow for successful ablation of larger tumors. This study aimed to evaluate the impact of tumor size on outcomes of Hepatic Arteriography and C-Arm CT-Guided Ablation (HepACAGA).

[METHODS] Patients treated with HepACAGA for hepatocellular carcinoma (HCC) or colorectal liver metastases (CRLM) between January 2021 and June 2025 were analyzed. All ablations were performed with microwave ablation. Patients were stratified by tumor size: ≤ 2 cm, 2-3 cm, and 3-5 cm. Outcomes assessed included local tumor progression-free survival (LTPFS), local tumor progression (LTP) rate, and complications.

[RESULTS] A total of 137 consecutive patients with 265 tumors (152 HCC and 113 CRLM) were included: 187 tumors ≤ 2 cm, 52 tumors 2-3 cm, and 26 tumors 3-5 cm. The 1-year LTPFS was most favorable for tumors ≤ 2 cm (96%; 95% CI: 93-99), followed by 2-3 cm (93%; 95% CI: 85-100), and 3-5 cm (90%; 95% CI: 78-100). No significant differences in LTPFS were found (p = 0.580). Overall, LTP occurred in 5% of tumors. Secondary LTP rates were 3% for tumors ≤ 2 cm and 4% for both tumors 2-3 cm and 3-5 cm (p = 0.966). Complication rates were 4% for tumors ≤ 2 cm, 6% for tumors 2-3 cm, and 13% for tumors 3-5 cm (p = 0.236).

[CONCLUSION] HepACAGA proved to be effective and safe for treating patients with HCC and CRLM across a broad range of tumor sizes. These findings suggest that intermediate-sized tumors (3-5 cm) could be eligible for thermal ablation without compromising post-ablation recurrence.