Usefulness of percutaneous microwave ablation for large non‑small cell lung cancer: A preliminary report

Abstract

The role of microwave ablation (MWA) in patients with non-small cell lung cancer (NSCLC) remains ill-defined. This retrospective study evaluated the oncological outcomes of CT-guided MWA in patients with large NSCLC. Kaplan-Meier analysis was used to evaluate overall survival (OS) and cancer-specific survival (CSS). The log-rank test was used to compare survival between patients with an NSCLC size greater or smaller than 4 cm. The likelihood of local tumor progression (LTP) was analyzed using a multivariable regression model. A total of 53 patients with 65 tumors were analyzed. The mean tumor size was 5.0±1.8 cm. At the 1-month CT scan, complete tumor ablation was observed in 44.6% of cases. In 18.5% of cases a redo-MWA session was carried out, while in 4.6%, a third MWA was necessary to obtain complete tumor necrosis. The mean follow-up was 28.1±20.6 months with a median duration of 21.5 months. The 1-year, 2-year, 3-year and 5-year OS rates were 78.2, 48.3, 34.8 and 18.3%, respectively. The median CSS was 25 months (95% CI 15.5–34.5). The 1-year, 2-year, 3-year and 5-year CSS rates were 84.3, 53.7, 42.1 and 30.0%, respectively. OS in patients with tumor size ≥4 cm was significantly lower when compared with those having smaller tumors (P=0.03). LTP was observed in 19 patients (35.8%). Incomplete tumor ablation [odds ratio (OR) 6.57; P<0.05] and tumor size ≥4 cm (OR 0.18; P<0.05) were significant independent predictors of LTP. In conclusion, CT-guided MWA may represent a useful tool in the multimodality treatment of patients with large advanced NSCLC.

Comparing cryoablation and microwave ablation for the treatment of patients with stage�IIIB/IV non‑small cell lung cancer

“…MWA and CA have received increasing attention in recent years for treating malignancies of the lung (6,28,32). However, whether MWA or CA should be used in specific patients remains unclear.…”

“…Larger tumors exhibit irregular tumor shapes, increasing the difficulty of the use of ablation applicators to optimize the entry route and completely kill the tumor cells resulting in tumor residues (25). Studies have reported that both MWA and CA have lower survival rates in patients with larger tumors compared with smaller tumor sizes (16,25,(28)(29)(30)39,40). However, the threshold tumor size used to differentiate small and large tumors varied across previous studies and depended on the maximum size of the tumor observed in each study.…”

“…However, the threshold tumor size used to differentiate small and large tumors varied across previous studies and depended on the maximum size of the tumor observed in each study. In a study by Pusceddu et al (28), 4 cm was used as the threshold, where the tumor size ranged between 3 and 14 cm in size, with a mean (± standard deviation) size of 5±1.8 cm. Wei et al (2) used 3.5 cm as the threshold, where the tumor sizes ranged between 1 and 7 cm.…”

“…Wei et al (2) used 3.5 cm as the threshold, where the tumor sizes ranged between 1 and 7 cm. Other studies enrolled patients with tumors ≤5 cm and thus used 3 cm as the threshold (28)(29)(30). Furthermore, previous studies did not compare the survival functions of both the ablation technique (MWA and CA) based on tumor size.…”

“…Survival analysis of sub-groups. Tumor size has been reported as a prognostic marker of disease progression in a number of previous studies (2,16,25,(28)(29)(30)(31)(32). Therefore, the survival function of patients treated with MWA and CA were analyzed according to tumor size.…”