Local therapy treatment conditions for oligometastatic non-small cell lung cancer

Primary tumor consolidative therapy improves the outcomes of patients with advanced EGFR-mutant lung adenocarcinoma treated with first-line osimertinib

Background

Patients with advanced epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma (LAD) inevitably experience drug resistance following treatment with EGFR-tyrosine kinase inhibitors (TKIs).

Objectives

We aimed to analyze the effect of primary tumor consolidative therapy (PTCT) on patients treated with first-line osimertinib.

Design and methods

This retrospective cohort study was conducted in patients with advanced stage III or stage IV LAD with EGFR-sensitizing mutations (exon 19 deletion or L858R mutation) with disease control after first-line osimertinib. A curative dose of primary tumor radiotherapy or primary tumor resection was classified as PTCT. We compared the progression-free survival (PFS) and overall survival (OS) of patients with and without PTCT.

Results

This study included 106 patients with a median age of 61.0 years, and of those, 42% were male and 73.6% were never-smokers. Exon 19 deletion was observed in 67.9%, 30.2% had a programmed cell death ligand 1 (PD-L1) tumor proportion score <1%, 33.0% had brain metastasis, and 40.6% had oligometastasis. In all, 53 (50%) patients underwent PTCT. Patients who underwent PTCT demonstrated significantly better PFS [30.3 (95% confidence interval (CI), 24.1-36.4) versus 18.2 (95% CI, 16.1-20.2) months; p = 0.005] and OS [not reached versus 36.7 (95% CI, 32.5-40.9) months; p = 0.005] than patients who did not. A multivariate analysis showed that PTCT was an independent factor associated with better PFS [hazard ratio (HR), 0.22; 95% CI, 0.10-0.49; p < 0.001] and OS [HR, 0.10; 95% CI, 0.01-0.82; p = 0.032]. The PFS benefits of PTCT were consistent across subgroups, and the HR tended to be lower in patients aged <65 years, males, smokers, stage IVB disease, L858R, PD-L1 expression ⩾1%, non-oligometastasis, and brain metastasis.

Conclusion

Of the patients with advanced EGFR-mutant LAD, those who underwent PTCT had a significantly better survival outcome than those who did not. The survival benefits were consistent across different subgroups.

Impact of Waiting Response Evaluation to First-Line Systemic Therapy before Considering Local Ablative Therapy in Metastatic Non-Small-Cell Lung Cancer

Stereotactic radiotherapy (SRT) is gaining increasing importance in metastatic non-small-cell lung cancer (mNSCLC) management. The optimal sequence of tumor irradiation relative to systemic treatment remains unclear. If waiting response evaluation to first-line systemic therapy (FLST) before considering local treatment may allow for the exclusion of poorer prognosis progressive tumors that may not benefit from SRT, performing irradiation near immune check point inhibitor (ICI) first administration seems to improve their synergic effect. Herein, we aimed to determine whether delaying SRT after response evaluation to FLST would result in better prognosis. We compared overall survival (OS), progression-free survival (PFS), and time to first subsequent therapy (TFST) for 50 patients locally treated before or within 90 days of initiating FLST (early SRT), with 49 patients treated at least 90 days after initiating FLST (late SRT). Patients treated with conventional chemotherapy alone exhibited significantly poorer median OS, PFS, and TFST in the early SRT arm: (in months) 16.5 [8.33-NR] vs. 58.3 [35.05-NR] (p = 0.0015); 4.69 [3.57-8.98] vs. 8.20 [6.66-12.00] (p = 0.017); and 6.26 [4.82-11.8] vs. 10.0 [7.44-21.8] (p = 0.0074), respectively. Patient receiving ICI showed no difference in OS (NR [25.2-NR] vs. 36.6 [35.1-NR], p = 0.79), PFS (7.54 [6.23-NR] vs. 4.07 [2.52-NR], p = 0.19), and TFST (13.7 [9.48-NR] vs. 10.3 [3.54-NR], p = 0.49). These results suggest that delaying SRT treatment in order to filter a rapidly growing tumor may be less necessary when ICI is administered in mNSCLC.

Oligo-Metastatic Cancers: Putative Biomarkers, Emerging Challenges and New Perspectives

Some cancer patients display a less aggressive form of metastatic disease, characterized by a low tumor burden and involving a smaller number of sites, which is referred to as "oligometastatic disease" (OMD). This review discusses new biomarkers, as well as methodological challenges and perspectives characterizing OMD. Recent studies have revealed that specific microRNA profiles, chromosome patterns, driver gene mutations (ERBB2, PBRM1, SETD2, KRAS, PIK3CA, SMAD4), polymorphisms (TCF7L2), and levels of immune cell infiltration into metastases, depending on the tumor type, are associated with an oligometastatic behavior. This suggests that OMD could be a distinct disease with specific biological and molecular characteristics. Therefore, the heterogeneity of initial tumor burden and inclusion of OMD patients in clinical trials pose a crucial methodological question that requires responses in the near future. Additionally, a solid understanding of the molecular and biological features of OMD will be necessary to support and complete the clinical staging systems, enabling a better distinction of metastatic behavior and tailored treatments.