OBJECTIVES: A previous analysis showed the economic sustainability of adding liquid biopsy, whenever possible, to tissue biopsy for the assessment of epidermal growth factor receptor-positive (EGFR+) mutation in patients with advanced non-small cell lung cancer (mNSCLC). The following analysis evaluated the clinical outcome (progression free survival, PFS) when adopting two different diagnostic strategies in the first-line treatment of patients with EGFR+ mNSCLC.

METHODS: A previous decision-analytic model was adopted to compare the two diagnostic strategies: i) tissue strategy and ii) combined strategy (tissue biopsy and, were its outcome unknown, liquid biopsy). We only evaluated the PFS variation between the two diagnostic strategies considered. We assumed that mNSCLC EGFR+ patients were treated with 3^rd generation EGFR-TKI (PFS: 18.9 months), while mNSCLC EGFR Wilde Type (WT) patients were treated with chemotherapy (PFS: 5.7 months). Key variables were tested in the sensitivity analysis.

RESULTS: A total of 13,030 patients eligible for tissue biopsy in Italy were considered, of whom 2,463 were assumed to be EGFR+. The combined strategy showed an increase of the number of correctly identified EGFR+ patients (2,293 patients) compared to the tissue strategy (1,691 patients). When considering mNSCLC EGFR+ patients treated with 3^rd generation EGFR-TKI, the PFS would increase from 14.8 months per patient with the tissue strategy to 18.5 months per patient with the combined strategy. When considering mNSCLC EGFR+ patients treated with other 1^st/2^nd generation EGFR-TKI, the PFS would increase from 8.8 months per patient with the tissue strategy to 10.1 months per patient with the combined strategy.

CONCLUSIONS: The choice of a correct diagnostic strategy is crucial in order to optimize cancer therapies in the first-line treatment of mNSCLC EGFR+. The addition to the diagnostic pathway of the liquid biopsy would correctly identify a greater number of cases, supporting the prescription of a more effective oncological therapy.