The purpose of this study was to compare efficacy and tolerance between radiofrequency ablation (RFA) and surgery for the treatment of oligometastatic lung disease.

This retrospective study reviewed patients treated in two institutions for up to 5 pulmonary metastases with a maximal diameter of 4cm and without associated pleural involvement or thoracic lymphadenopathy. Patient demographics, tumor characteristics, treatment outcome, and length of hospital stay were compared between the two groups. Efficacy endpoints were overall survival (OS), progression-free survival (PFS) and pulmonary or local tumor progression rates.

Among 204 patients identified, 78 patients (42 men, 36 women; mean age, 53.3±14.9 [SD]; age range: 15–81 years) were treated surgically, while 126 patients (59 men, 67 women; mean age, 62.2±10.8 [SD]; age range: 33–80 years) were treated by RFA. In the RFA cohort, patients were significantly older (P<0.0001), with more extra-thoracic localisation (P=0.015) and bilateral tumour burden (P=0.0014). In comparison between surgery and RFA cohorts, respectively, the 1- and 3-year OS were 94.8 and 67.2% vs. 94 and 72.1% (P=0.46), the 1- and 3-year PFS were 49.4% and 26.1% vs. 38.9% and 14.8% (P=0.12), the pulmonary progression rates were 39.1% and 56% vs. 41.2% and 65.3% (P>0.99), and the local tumour progression rates were 5.4% and 10.6% vs. 4.8% and 18.6% (P=0.07). Tumour size>2cm was associated with a significantly higher local tumor progression in the RFA group (P=0.010). Hospitalisation stay was significantly shorter in the RFA group (median of 3 days; IQR=2 days; range: 2–12 days) than in the surgery group (median of 9 days; IQR=2 days; range: 6–21 days) (P<0.01).

RFA should be considered a minimally-invasive alternative with similar OS and PFS to surgery in the treatment of solitary or multiple lung metastases measuring less than 4cm in diameter without associated pleural involvement or thoracic lymphadenopathy.