Diagnostic Outcomes and Safety of CT-guided Synchronous Cryobiopsy and Microwave Ablation for High-risk Subsolid Nodules

Abstract

Rationale and objectives: To evaluate the feasibility, safety, and diagnostic yield of CT-guided synchronous cryobiopsy and microwave ablation (MWA) for high-risk pulmonary subsolid nodules (SSNs).

Materials and methods: A retrospective review was conducted of patients undergoing CT-guided synchronous cryobiopsy and MWA for high-risk SSNs at three institutions between January and December 2023. Patients were grouped by biopsy method (cryobiopsy alone, fine-needle aspiration [FNA] alone, or combined biopsy with both). The primary endpoint was diagnostic yield, defined as the rate of definitive pathological diagnosis. Secondary endpoints included technical success, technical efficacy, and 30-day adverse events.

Results: A total of 198 patients (21 cryobiopsy, 149 FNA, 28 combined) were analyzed. Technical success was 100% in all groups. Overall diagnostic yield was 80.3% (159/198). Diagnostic yield was 85.7% for cryobiopsy, 77.2% for FNA, and 92.9% for combined biopsy. Cryobiopsy (alone or combined) improved diagnostic yield compared to FNA alone, though the difference was not statistically significant (p = 0.129). Multivariable logistic regression identified no independent predictors of diagnostic yield. The complete ablation reached 100% in both groups. No patients experienced local tumor progression during the follow-up period. All adverse events were grade 1-2; no grade ≥3 events occurred. Self-limited pulmonary hemorrhage (grade 1) was the most common adverse event. Pulmonary hemorrhage rates were significantly higher in the cryobiopsy and combined groups than in the FNA group (38.1% and 39.3% vs. 14.1%, p = 0.001). Similarly, hemoptysis was more frequent in cryobiopsy and combined groups (14.3% and 21.4% vs. 4.0%, p = 0.003). Pneumothorax occurred in 16-19% of patients across groups (4.8-14.3% requiring chest tube); pneumothorax rates did not differ significantly among groups.

Conclusion: CT-guided synchronous cryobiopsy with MWA is a feasible and safe approach for diagnosing and treating high-risk SSNs. Cryobiopsy, alone or combined with FNA, demonstrated a higher diagnostic yield for SSNs than FNA alone, supporting its use to improve pathological confirmation during ablation procedures.

Keywords: Cryobiopsy; Diagnostic yield; Fine-needle aspiration; Microwave ablation; Sub-solid nodule.