Table 2. Selected studies of local ablative therapy for primary and/or metastases in EGFR oligometastatic non-small cell lung cancer: characteristics and clinical outcomes.
| Study | Number of patient n (LAT)/n (control) | Study type | OM type | OM definition and organ involved | Mandated 18FDG PET/brain MRI | Type of LAT | Addiction and systemic therapy concomitant | PFS (median) | OS (median) |
|---|---|---|---|---|---|---|---|---|---|
| Peng et al. 2019 | 30/31 | Phase 2 Multicenter | Oligometastatic synchronous (no progression after 3 months TKI) |
<4 metastasis | Unknown | Primary and/or metastases | EGFR (common) | 17.4 vs. 8.9 months (P=0.042) (interim) | No mature |
| SBRT | TKI EGFR 1st Ge | ||||||||
| Ni et al. 2020 | 34/52 | Retrospective Single-center | Oligometastatic (no progression after 3 months TKI) | Extracranial <6 metastasis lung (39.5%), liver (23.3%), bone (14%), adrenal gland (16.2%), chest wall (7%) | No/No | Primary and/or metastases | EGFR (common and uncommon (n=1)) | 16.7 vs.12.9 months (P=0.02) | 34.8 vs. 22.7 months (P=0.04) |
| Microwave ablation | TKI EGFR 1st Ge | ||||||||
| Elamin et al. 2019 | 12/129 | Retrospective Single-center* | Oligometastatic (no progression after 3 months TKI) | ≤3 metastases (n=8), >3 (n=4) (positive thoracic nodes counted as 1 lesion) | No/No | Primary and/or metastases | EGFR (common and uncommon (n=1; L861Q)) | 36 vs. 14 months (P=0.0024) | Not reached vs. 36 months (P=0.06) |
| Hypofractionated radiotherapy or SRT (n=11)/Lung surgery (n=1) | TKI EGFR (no osimertinib) | ||||||||
| Xu et al. 2018 | 106/39 | Retrospective Single-center | Oligometastatic (no progression with TKI) | ≤5 metastases (90% with ≤2 metastases) | No/No | Primary and/or metastases** | EGFR (common) | 20.6 vs. 15.6 and 13.9 months (P<0.001) | 40.9 vs. 34.1 and 30.8 months (P<0.001) |
| Radiotherapy, surgery, radiofrequency | TKI EGFR 1st Ge |
*, post hoc Phase 2 - Multicenter (n=3) + Database single-center (n=9); **, treatment group: n=51 with LAT in all site and n=55 with partial LAT. EGFR, epidermal growth factor receptor; LAT, local ablative therapy; OM, oligometastatic; PFS, progression-free survival; OS, overall survival; TKI, tyrosine kinase inhibitor; EGFR common mutation: del 19 and L858R/uncommon: others; TKI EGFR 1st Generation: erlotinib icotinib or gefitinib; SRT, stereotaxic radiotherapy.